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Diverse proteomics-based strategies have been applied to saliva to quantitatively identify diagnostic and prognostic targets for oral cancer. Considering that these potential diagnostic and prognostic factors may be regulated by events that do not imply variation in protein abundance levels, we investigated the hypothesis that changes in protein conformation can be associated with diagnosis and prognosis, revealing biological processes and novel targets of clinical relevance. For this, we employed limited proteolysis-mass spectrometry in saliva samples to explore structural alterations, comparing the proteome of healthy control and oral squamous cell carcinoma (OSCC) patients, with and without lymph node metastasis. Fifty-one proteins with potential structural rearrangements were associated with clinical patient features. Post-translational modifications, such as glycosylation, disulfide bond, and phosphorylation, were also investigated in our data using different search engines and in silico analysis indicating that they might contribute to structural rearrangements of the potential diagnostic and prognostic markers here identified. Altogether, this powerful approach allows for a deep investigation of complex biofluids, such as saliva, advancing the search for targets for oral cancer diagnosis and prognosis. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=187 SRC="FIGDIR/small/552034v1_ufig1.gif" ALT="Figure 1"> View larger version (60K): [email protected]@17a8e2eorg.highwire.dtl.DTLVardef@10ca836org.highwire.dtl.DTLVardef@1f7843a_HPS_FORMAT_FIGEXP M_FIG Oral cancer progression is associated with potential structural rearrangements. C_FIG
Halting breast cancer metastatic relapses following primary tumor removal and the clinical dormant phase, remains challenging, due to a lack of specific vulnerabilities to target during dormancy. To address this, we conducted genome-wide CRISPR screens on two breast cancer cell lines with distinct dormancy properties: 4T1 (short-term dormancy) and 4T07 (prolonged dormancy). We discovered that loss of class-III PI3K, Pik3c3, revealed a unique vulnerability in 4T07 cells. Surprisingly, dormancy-prone 4T07 cells exhibited higher mTORC1 activity than 4T1 cells, due to lysosome-dependent signaling occurring at the cell periphery. Pharmacological inhibition of Pik3c3 counteracted this phenotype in 4T07 cells, and selectively reduced metastasis burden only in the 4T07 dormancy prone model. This mechanism was also detected in xenografts from human breast cancer patients, supporting that it may be relevant in humans. Our findings suggest dormant cancer cell-initiated metastasis may be prevented in patients carrying tumor cells that display PIK3C3-peripheral lysosomal signaling to mTORC1. TeaserPIK3C3-mTORC1 signaling is a novel druggable pathway in breast cancer metastasis.
Heterogeneity of colorectal carcinoma (CRC) represents a major hurdle towards personalized medicine. Efforts based on whole tumor profiling demonstrated that the CRC molecular subtypes were associated with specific tumor morphological patterns representing tumor subregions. We hypothesize that whole- tumor molecular descriptors depend on the morphological heterogeneity with significant impact on current molecular predictors. We investigated intra-tumor heterogeneity by morphology-guided transcriptomics to better understand the links between gene expression and tumor morphology represented by six morphological patterns (morphotypes): complex tubular, desmoplastic, mucinous, papillary, serrated, and solid/trabecular. Whole-transcriptome profiling by microarrays of 202 tumor regions (morphotypes, tumor-adjacent normal tissue, supportive stroma, and matched whole tumors) from 111 stage II-IV CRCs identified morphotype-specific gene expression profiles and molecular programs and differences in their cellular buildup. The proportion of cell types (fibroblasts, epithelial and immune cells) and differentiation of epithelial cells were the main drivers of the observed disparities with activation of EMT and TNF- signaling in contrast to MYC and E2F targets signaling, defining major gradients of changes at molecular level. Several gene expression-based (including single-cell) classifiers, prognostic and predictive signatures were examined to study their behavior across morphotypes. Most exhibited important morphotype-dependent variability within same tumor sections, with regional predictions often contradicting the whole-tumor classification. The results show that morphotype-based tumor sampling allows the detection of molecular features that would otherwise be distilled in whole tumor profile, while maintaining histopathology context for their interpretation. This represents a practical approach at improving the reproducibility of expression profiling and, by consequence, of gene-based classifiers.
Lipid metabolism plays a critical role in cancer metastasis. However, the mechanisms through which metastatic genes regulate lipid metabolism remain unclear. Here, we describe a new oncogenic-metabolic feedback loop between the epithelial-mesenchymal transition (EMT) transcription factor ZEB2 and the key lipid enzyme ACSL4 (long-chain acyl-CoA synthetase 4), resulting in enhanced cellular lipid storage and fatty acid oxidation to drive breast cancer metastasis. Functionally, Depletion of ZEB2 or ACSL4 significantly reduced lipid droplets (LD) abundance and cell migration. ACSL4 overexpression rescued the invasive capabilities of the ZEB2 knockdown cells, suggesting that ACSL4 is crucial for ZEB2-mediated metastasis. Mechanistically, ZEB2 activated ACSL4 expression by directly binding to the ACSL4 promoter. ACSL4 binds to and stabilizes ZEB2 by reducing ZEB2 ubiquitination. Notably, ACSL4 not only promotes the intracellular lipogenesis and lipid droplet accumulation but also enhances fatty acid oxidation (FAO) and ATP production by upregulating the FAO rate-limiting enzyme CPT1A (carnitine palmitoyltransferase 1 isoform A). Finally, we demonstrated that ACSL4 knockdown significantly reduced metastatic lung nodes in vivo. In conclusion, we reveal a novel positive regulatory loop between ZEB2 and ACSL4, which promotes LD storage to meet the energy needs of breast cancer metastasis, and identify the ZEB2-ACSL4 signaling axis as an attractive therapeutic target for overcoming breast cancer metastasis. HighlightsZEB2 activates FAO through transcription of ACSL4 ACSL4 regulates lipid metabolism through FAO, promoting breast cancer metastasis Targeting ZEB2-ACSL4 signaling axis inhibits breast cancer metastasis SignificanceWe describe a novel positive feedback loop between ZEB2 and ACSL4 that results in enhanced cellular lipid storage and FA oxidation to drive breast cancer metastasis.
Sarcomas are a family of rare malignancies composed of over 100 distinct histological subtypes. The rarity of sarcoma poses significant challenges in conducting clinical trials to identify effective therapies, to the point that many rarer subtypes of sarcoma do not have standard-of-care treatment. Even for established regimens, there can be substantial heterogeneity in responses. Overall, novel, personalized approaches for identifying effective treatments are needed to improve patient out-comes. Patient-derived tumor organoids (PDTOs) are clinically relevant models representative of the physiological behavior of tumors across an array of malignancies. Here, we use PDTOs as a tool to better understand the biology of individual tumors and characterize the landscape of drug resistance and sensitivity in sarcoma. We collected n=194 specimens from n=126 sarcoma patients, spanning 24 distinct subtypes. We characterized PDTOs established from over 120 biopsy, resection, and metastasectomy samples. We leveraged our organoid high-throughput drug screening pipeline to test the efficacy of chemotherapeutics, targeted agents, and combination therapies, with results available within a week from tissue collection. Sarcoma PDTOs showed patient-specific growth characteristics and subtype-specific histopathology. Organoid sensitivity correlated with diagnostic subtype, patient age at diagnosis, lesion type, prior treatment history, and disease trajectory for a subset of the compounds screened. We found 90 biological pathways that were implicated in response to treatment of bone and soft tissue sarcoma organoids. By comparing functional responses of organoids and genetic features of the tumors, we show how PDTO drug screening can provide an orthogonal set of information to facilitate optimal drug selection, avoid ineffective therapies, and mirror patient outcomes in sarcoma. In aggregate, we were able to identify at least one effective FDA-approved or NCCN-recommended regimen for 59% of the specimens tested, providing an estimate of the proportion of immediately actionable information identified through our pipeline. HighlightsO_LIStandardized organoid culture preserve unique sarcoma histopathological features C_LIO_LIDrug screening on patient-derived sarcoma organoids provides sensitivity information that correlates with clinical features and yields actionable information for treatment guidance C_LIO_LIHigh-throughput screenings provide orthogonal information to genetic sequencing C_LIO_LISarcoma organoid response to treatment correlates with patient response to therapy C_LIO_LILarge scale, functional precision medicine programs for rare cancers are feasible within a single institution C_LI
The molecular circadian clock, which controls rhythmic 24-hour oscillation of genes, proteins, and metabolites in healthy tissues, is disrupted across many human cancers. Deregulated expression of the MYC oncoprotein has been shown to alter expression of molecular clock genes, leading to a disruption of molecular clock oscillation across cancer types. It remains unclear what benefit cancer cells gain from suppressing clock oscillation, and how this loss of molecular clock oscillation impacts global gene expression and metabolism in cancer. We hypothesized that MYC or its paralog N-MYC (collectively termed MYC herein) suppress oscillation of gene expression and metabolism to upregulate pathways involved in biosynthesis in a static, non-oscillatory fashion. To test this, cells from distinct cancer types with inducible MYC were examined, using time-series RNA-sequencing and metabolomics, to determine the extent to which MYC activation disrupts global oscillation of genes, gene expression pathways, and metabolites. We focused our analyses on genes, pathways, and metabolites that changed in common across multiple cancer cell line models. We report here that MYC disrupted over 85% of oscillating genes, while instead promoting enhanced ribosomal and mitochondrial biogenesis and suppressed cell attachment pathways. Notably, when MYC is activated, biosynthetic programs that were formerly circadian flipped to being upregulated in an oscillation-free manner. Further, activation of MYC ablates the oscillation of nutrient transporter proteins while greatly upregulating transporter expression, cell surface localization, and intracellular amino acid pools. Finally, we report that MYC disrupts metabolite oscillations and the temporal segregation of amino acid metabolism from nucleotide metabolism. Our results demonstrate that MYC disruption of the molecular circadian clock releases metabolic and biosynthetic processes from circadian control, which may provide a distinct advantage to cancer cells.
Advanced prostate cancer (PCa) is overwhelmingly resistant to immune checkpoint blockade (ICB) therapy, representing a formidable clinical challenge. In this study, we developed a syngeneic murine PCa model with acquired ICB resistance. Using this model, synergistic efficacy was achieved by combining anti-PD1 and anti-CTLA4 antibodies with histone deacetylase inhibitor (HDACi) vorinostat, a cyclic ketogenic diet (CKD), or supplementation of ketone body {beta}-hydroxybutyrate (BHB, endogenous HDACi) via 1,3-butanediol-admixed food. CKD and BHB supplementation delayed PCa tumors as monotherapy, and both BHB and adaptive immunity are required for the anti-tumor activity of CKD. Single-cell transcriptomic and proteomic profiling revealed that the HDACi and ketogenesis-enhanced ICB therapy involves cancer-cell-intrinsic (upregulated MHC class I molecules) and extrinsic mechanisms (CD8+ T cell chemoattraction, M1/M2 macrophage rebalancing, monocyte differentiation toward antigen presenting cells, and diminished neutrophils). Overall, these findings underscore the potential of using HDACi and optimized KD to enhance ICB therapy for PCa.
Long non-coding RNAs (lncRNAs) represent vast and yet poorly characterized family of genes that can fine tune cellular plasticity, thereby allowing the emergence of aggressive therapy-resistant and metastatic cancers. Androgen deprivation therapies (ADT) are commonly used to treat prostate cancer by inactivating the Androgen Receptor (AR). However, castration-resistant prostate cancer (CRPC) with neuroendocrine subtypes (NEPC) often emerge. In this study, we explore the role of lncRNAs in response to androgen deprivation. Using a dynamic prostate cancer cell system mimicking the CRPC and NEPC onset, we identified 15 novel lncRNAs, with PROCA11 standing out as a first-choice candidate, being also highly abundant in high-risk prostate cancer tumors. This majorly nuclear lncRNA is expressed at low levels in androgen-dependent conditions of growth and strongly activated upon hormone withdrawal, preceding neuroendocrine genes and persisting at high levels in neuroendocrine cells. Extensive computational analysis of clinical data and functional studies in cells revealed PROCA11 association with basal-to-luminal transformation of the transcriptomic landscape and activation of metabolic and signaling pathways reminiscent of neurogenesis and of maintenance of AR signaling. We propose that PROCA11 is involved in the intricate circuits regulating cellular plasticity enabling cell survival and proliferation and emergence of the NE phenotype in response to ADT.
The cascade of events leading to tumor formation includes induction of a tumor supporting neovasculature as a primary hallmark of cancer. Developing vasculature is difficult to evaluate in vivo but can be captured using microfluidic chip technology and patient derived cells. Herein, we established an on chip approach to investigate the mechanisms promoting tumor vascularization and vascular targeted therapies via co-culture of metastatic renal cell carcinoma spheroids and endothelial cells in a 3D environment. Our model permitted real-time, high-resolution observation and assessment of tumor-induced angiogenesis, where endothelial cells sprout towards the tumor and mimic a vascular network. Bevacizumab, an angiogenic inhibitor, disrupted interactions between vessels and tumors, destroying the vascular network. The on chip approach enabled assessment of endothelial cell biology, vessels functionality, drug delivery, and molecular expression of PSMA. Finally, observations in the vascularized tumor on chip permitted direct and conclusive quantification of this therapy in weeks as opposed to months in a comparable animal model. TeaserVascularized tumor on microfluidic chip provides opportunity to study targeted therapies and improves preclinical drug discovery.
Endometrial cancer is one of the major cancers in women throughout the world. If diagnosed early, these cancers are treatable and the prognosis is usually good. However, one major problem in treating endometrial cancer is accurate diagnosis and staging. Till date, the choice method for diagnosis and staging is histopathology. Although there are few molecular markers identified, they are not always sufficient in making accurate diagnosis and deciding on therapeutic strategy. As a result, very often patients are under treated or over treated. In this study, our group has profiled microRNAs (miRNA) from Indian patients using NGS-based approach. We have identified differentially expressed microRNAs in endometrial cancer. These microRNAs have also been compared to data from TCGA (The Cancer Genome Atlas), which represent other populations and also correlated to relevance in overall survival. Using in-silico approaches, mRNA targets of the miRNAs have been predicted. After comparing with TCGA, we have identified 16 miRNA-mRNA pairs which could be potential prognostic biomarkers for endometrial cancer. This is the first miRNA profiling report from Indian cohort and one of the very few studies which have identified potential biomarkers of prognosis in endometrial cancer.
Field cancerization is a process in which a normal tissue is replaced with pre-cancerous but histologically normal tissue. This transformed field can give rise to malignancy and contribute to tumor relapse. In this paper, we create a mathematical model of field cancerization from the perspective of cancer behavioral ecology. In our model, field cancerization arises from a breakdown in signaling integrity and control, and investigate implications for acute wounding, chronic wounding, aging, and therapeutic interventions. We find that restoration of communication networks can lead to cancer regression in the context of acute injury. Conversely, long term loss of controls, such as through chronic wounding or aging, can promote oncogenesis. These results are paralleled in therapeutic interventions: those that simply target cells in cancerous states may be less effective than those that reestablish signaling integrity. Viewing cancer as a corruption of communication systems rather than as a corruption of individual cells may lead to novel approaches for understanding and treating this disease.
Barretts esophagus, a metaplastic condition that originates in the distal esophagus, is the only known precursor lesion for the development of esophageal adenocarcinoma, which has a devasting 5-year survival rate of <20%. The large number of subjects diagnosed with Barretts esophagus, and therefore at higher risk for esophageal adenocarcinoma, underscores the necessity for biomarkers that would benefit surveillance and potentially early treatment. To address this, we generated epithelial stem cell organoids from normal gastric cardia, non-dysplastic and dysplastic Barretts esophagus, and esophageal and gastric adenocarcinoma. Interestingly, non-dysplastic and dysplastic Barretts esophagus displayed higher expression of multiple archetypical cancer-associated genes compared with both esophageal and gastric adenocarcinoma in addition to expression of the novel biomarker CT83. ST6GAL1, a Golgi sialyltransferase upregulated in multiple epithelioid cancers, was strongly upregulated in dysplastic Barretts esophagus at both mRNA and protein levels. ST6GAL1 protein also was highly expressed in esophageal adenocarcinoma, suggesting that regulation of ST6GAL1 may play a role in Barretts esophagus progression to esophageal adenocarcinoma and serve as a potential biomarker of the development of esophageal cancer.
Poor response to Bacillus Calmette-Guerin (BCG) immunotherapy remains a major barrier in the management of patients with non-muscle-invasive bladder cancer (NMIBC). Among the multiple factors contributing to poor outcomes, a B cell infiltrated pre-treatment immune microenvironment of NMIBC tumors has emerged as a key determinant of response to BCG. The mechanisms underlying the paradoxical roles of B cells in NMIBC are poorly understood. Here, we show that B cell dominant tertiary lymphoid structures (TLSs), a hallmark feature of chronic mucosal immune response, are abundant and located close to the epithelial compartment in pre-treatment tumors from BCG non-responders. Digital spatial proteomic profiling of whole tumor sections revealed higher expression of immune exhaustion-associated proteins within the TLSs from both responders and non-responders. Chronic local inflammation, induced by the N-butyl- N-(4-hydroxybutyl) nitrosamine (BBN) carcinogen, led to TLS formation with recruitment and differentiation of the immunosuppressive atypical B cell (ABCs) subset within the bladder microenvironment, predominantly in aging female mice compared to their male counterparts. Depletion of ABCs simultaneous to BCG treatment delayed cancer progression in female mice. Our findings provide the first evidence indicating the role of ABCs in BCG response and will inform future development of therapies targeting the B cell exhaustion axis.
Myeloproliferative neoplasms are stem cell-driven cancers associated with a large burden of morbidity and mortality. The majority of patients present with early-stage disease, but a substantial proportion progress to myelofibrosis and/or secondary leukemia, advanced cancers with a poor prognosis and high symptom burden. Currently, it remains difficult to predict progression, and we lack therapies that reliably prevent or reverse fibrosis development. A major bottleneck to the discovery of disease-modifying therapies has been an incomplete understanding of the interplay between perturbed cellular and molecular states. Several cell types have individually been implicated, but a comprehensive analysis of myelofibrotic bone marrow is lacking. We therefore mapped the crosstalk between bone marrow cell types in myelofibrotic bone marrow. We found that inflammation and fibrosis are orchestrated by a quartet of immune and stromal cell lineages - with basophils and mast cells creating a TNF signaling hub, communicating with megakaryocytes, mesenchymal stromal cells and pro-inflammatory fibroblasts. We identified the y-galactoside binding protein galectin 1 as a striking biomarker of progression to myelofibrosis and poor survival in multiple patient cohorts, and as a promising therapeutic target, with reduced myeloproliferation and fibrosis in vitro and in vivo and improved survival following galectin 1 inhibition. In human bone marrow organoids, TNF increased galectin 1 expression, suggesting a feedback loop wherein the pro-inflammatory MPN clone creates a self-reinforcing niche, fueling progression to advanced disease. This study provides a valuable resource for studying hematopoietic cell-niche interactions, with broad relevance for cancer-associated inflammation and disorders of tissue fibrosis.
The comprehensive genomic analysis of the head and neck cancer (HNSCC) oncogenome revealed frequent loss of p16INK4A (CDKN2A) in most HPV negative HNSCC lesions, often concomitant with amplification of the cyclin D1 (CCND1) gene locus. However, cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors as single agents have shown modest effect in the clinic, even when combined with cetuximab. The aberrant activation of PI3K/mTOR pathway is highly prevalent in HNSCC, and recent clinical trials targeting mTOR showed promising results in terms of objective responses and progression free survival. However, the clinical efficacy of mTOR inhibitors (mTORi) for advanced HNSCC patients may be limited due to intrinsic or acquired resistance. By a kinome-wide CRISPR/Cas9 screen, we identified cell cycle inhibition as a synthetic lethal target for mTORi. Combination of mTORi and palbociclib, a CDK4/6 specific inhibitor, showed strong synergism in HNSCC-derived cells in vitro and in vivo. Remarkably, we found that adaptive increase in cyclin E1 (CCNE1) expression upon palbociclib treatment underlies the rapid acquired resistance to this CDK4/6 inhibitor in HNSCC. Mechanistically, mTORi inhibits the formation of eIF4G-CCNE1 mRNA complexes, with the consequent reduction in mRNA translation and CCNE1 protein expression. Our findings suggest that concomitant mTOR blockade reverts the adaptive resistance to palbociclib, thereby providing a novel multimodal therapeutic option for HNSCC patients by co-targeting mTOR and CDK4/6. Our findings may have broad implications to halt the emergence of palbociclib resistance.
Hypoxic cancer cells resist many anti-neoplastic therapies and can seed recurrence. We found previously that PTP1B deficiency promotes HER2+ breast cancer cell death in hypoxia by activating RNF213, an [~]600kDa protein containing AAA-ATPase domains and two ubiquitin ligase domains (RING and RZ), which is implicated in Moyamoya disease (MMD). Here we report that PTP1B and ABL1/2 reciprocally control RNF213 phosphorylation on tyrosine-1275. This phosphorylation promotes RNF213 oligomerization and RZ domain activation. The RZ domain ubiquitylates CYLD/SPATA2, and together with the LUBAC complex, induces their degradation. Decreased CYLD/SPATA2 levels cause NF-{kappa}B activation, which together with hypoxia-induced ER-stress triggers pyroptosis. Mutagenesis experiments show that the RING domain negatively regulates the RZ domain, and RING mutants, including MMD alleles, catalyze LUBAC-independent CYLD/SPATA2 degradation. Our results identify an inflammatory cell death pathway that kills hypoxic tumors, reveal new insights into RNF213 regulation, and have important implications for MMD, atherosclerosis, and inflammatory disorder pathogenesis.
Colorectal cancer (CRC) is highly heterogenous with variable survival outcomes and therapeutic vulnerabilities. A commonly used classification system in CRC is the Consensus Molecular Subtypes (CMS) based on gene expression patterns. However, how these CMS categories connect to axes of phenotypic plasticity and heterogeneity remains unclear. Here, we analyze 101 bulk transcriptomic datasets, along with patient tumor samples from TCGA and single-cell RNA sequencing data, to evaluate the extent of variation among CMS subtypes across metabolic plasticity and EMT axes. Our results show that CMS2 and CMS3 samples were relatively more epithelial as compared to CMS1 and CMS4. Single-cell RNA-seq analysis of CMS1 revealed two subpopulations: one close to CMS4 (more mesenchymal) and the other closer to CMS2 or CMS3 (more epithelial), indicating a partial EMT-like behavior. Further, in our meta-analysis and in TCGA data, epithelial phenotype score was positively correlated with scores of glycolysis, OXPHOS and FAO pathways, while mesenchymal scores showed CMS subtype-specific associations with metabolic axes. PD-L1 activity scores, however, consistently correlated positively with mesenchymal signature ones and negatively with epithelial signature ones, across the four CMS categories. Together, our results quantify the patterns of two interconnected axes of phenotypic heterogeneity - EMT and metabolic reprogramming - at a CMS subtype level in CRC.
Xp11 translocation renal cell carcinoma (tRCC) is a female-predominant kidney cancer driven by translocations between the TFE3 gene on chromosome Xp11.2 and partner genes located on either chrX or on autosomes. The rearrangement processes that underlie TFE3 fusions, and whether they are linked to the female sex bias of this cancer, are largely unexplored. Moreover, whether oncogenic TFE3 fusions arise from both the active and inactive X chromosomes in females remains unknown. Here we address these questions by haplotype-specific analyses of whole-genome sequences of 29 tRCC samples from 15 patients and by re-analysis of 145 published tRCC whole-exome sequences. We show that TFE3 fusions universally arise as reciprocal translocations with minimal DNA loss or insertion at paired break ends. Strikingly, we observe a near exact 2:1 female:male ratio in TFE3 fusions arising via X:autosomal translocation (but not via X inversion), which accounts for the female predominance of tRCC. This 2:1 ratio is at least partially attributable to oncogenic fusions involving the inactive X chromosome and is accompanied by partial re-activation of silenced chrX genes on the rearranged chromosome. Our results highlight how somatic alterations involving the X chromosome place unique constraints on tumor initiation and exemplify how genetic rearrangements of the sex chromosomes can underlie cancer sex differences.
Neuronal activity-driven mechanisms impact glioblastoma cell proliferation and invasion1-7, and glioblastoma remodels neuronal circuits8,9. Distinct intratumoral regions maintain functional connectivity via a subpopulation of malignant cells that mediate tumor-intrinsic neuronal connectivity and synaptogenesis through their transcriptional programs8. However, the effects of tumor-intrinsic neuronal activity on other cells, such as immune cells, remain unknown. Here we show that regions within glioblastomas with elevated connectivity are characterized by regional immunosuppression. This was accompanied by different cell compositions and inflammatory status of tumor-associated macrophages (TAMs) in the tumor microenvironment. In preclinical intracerebral syngeneic glioblastoma models, CRISPR/Cas9 gene knockout of Thrombospondin-1 (TSP-1/Thbs1), a synaptogenic factor critical for glioma-induced neuronal circuit remodeling, in glioblastoma cells suppressed synaptogenesis and glutamatergic neuronal hyperexcitability, while simultaneously restoring antigen-presentation and pro-inflammatory responses. Moreover, TSP-1 knockout prolonged survival of immunocompetent mice harboring intracerebral syngeneic glioblastoma, but not of immunocompromised mice, and promoted infiltrations of pro-inflammatory TAMs and CD8+ T-cells in the tumor microenvironment. Notably, pharmacological inhibition of glutamatergic excitatory signals redirected tumor-associated macrophages toward a less immunosuppressive phenotype, resulting in prolonged survival. Altogether, our results demonstrate previously unrecognized immunosuppression mechanisms resulting from glioma-neuronal circuit remodeling and suggest future strategies targeting glioma-neuron-immune crosstalk may open up new avenues for immunotherapy.
Several studies indicated anti-cancer effects of metformin in liver cancer. This was attributed to the activation of LKB-AMPK axis, which is associated with anti-hyperglycaemic effect and cytotoxicity. However, despite lack of evidence on cytotoxic effect of physiological metformin concentrations and ability of cancer cells to survive under glucose-deprivation, no study has examined the glucose-independent effect of non-cytotoxic metformin or metabolic reprogramming associated with it. In addition, no study has ever been conducted on reversibility of anti-cancer effects of metformin. Here, the dose-dependent effects of metformin on HepG2 cells were examined in presence and absence of glucose. The longitudinal evolution of metabolome was analyzed along with gene and protein expression as well as their correlations with and reversibility of cellular phenotype and metabolic signatures. Metformin concentrations up to 2.5mM were found to be non-cytotoxic but anti-proliferative irrespective of presence of glucose. Apart from mitochondrial impairment, derangement of fatty acid desaturation, one-carbon, glutathione and polyamine metabolism were associated with non-cytotoxic metformin treatment irrespective of glucose supplementation. Depletion of pantothenic acid, downregulation of essential amino acid uptake, metabolism and purine salvage were identified as novel glucose-independent effects of metformin. These were significantly correlated with cMyc expression and reduction in proliferation. Rescue experiments established reversibility upon metformin withdrawal and tight association between proliferation, metabotype and cMyc expression. Taken together, derangement of novel glucose-independent metabolic pathways and concomitant cMyc downregulation co-ordinately contribute to anti-proliferative effect of metformin even at non-cytotoxic concentrations, which is reversible and may influence its therapeutic utility.
Majority of the eukaryotic cell surface is decorated with a layer of membrane attached polysaccharides and glycoproteins collectively referred to as the glycocalyx. While formation of a bulky glycocalyx has been associated with cancer progression, the mechanisms by which the glycocalyx regulates cancer invasiveness is incompletely understood. We address this question by first documenting sub-type specific expression of the major glycocalyx glycoprotein Mucin-1 (MUC1) in breast cancer patient samples and breast cancer cell lines. Strikingly, glycocalyx disruption led to inhibition in inhibits 2D motility, 3D invasion and induce clonal scattering of breast cancer cells at the population level. Tracking of 2D cell motility and 3D invasiveness of MUC1-based sorted sub-populations revealed fastest motility and invasiveness in low/high MUC1-expressing cells, with glycocalyx disruption abolishing these effects. While differential sensitivity in 2D motility is attributed to a non-monotonic dependence of focal adhesion size on MUC1 levels, higher MUC1 levels enhance 3D invasiveness via increased traction generation. In contrast to inducing cell rounding on collagen-coated substrates, high MUC1 level promotes cell adhesion and confers resistance to shear flow on substrates coated with the endothelial surface protein E-selectin. Collectively, our findings illustrate how MUC1 drives cancer invasiveness by differentially regulating cell-substrate adhesion in a substrate-dependent manner.
Immune checkpoint blockade therapy targeting the PD-1/PD-L1 axis has shown remarkable clinical impact in multiple cancer types. Nontheless, despite the recent success of PD-1/PD-L1 blockade therapy, such response rates in cancer patients have been limited to tumors encompassing specific tumor microenvironment characteristics. The altered metabolic activity of cancer cells shapes the anti-tumor immune response by affecting the activity of immune cells. However, it remains mostly unknown how the altered metabolic activity of cancer cells impacts their resistance to PD-1/PD-L1 blockade therapy. Here we found that tumor cell-derived lactic acid renders the immunosuppressive tumor microenvironment in the PD-1/PD-L1 blockade-resistant tumors by inhibiting the interaction between the PD-L1 protein and anti-PD-L1 antibody. Furthermore, we showed that the combination therapy of targeting PD-L1 with our PD-L1 antibody-drug conjugate (PD-L1-ADC) and reducing lactic acid with the MCT-1 inhibitor, AZD3965, can effectively treat the PD-1/PD-L1 blockade resistant tumors. The findings in this study provide a new mechanism of how lactic acid induces an immunosuppressive environment and suggest a potential combination treatment to overcome the PD-1/PD-L1 blockade therapy resistance.
Loss-of-function mutations and deletions in core components of the epigenetic Polycomb Repressive Complex 2 (PRC2) are associated with poor prognosis and treatment resistance in T-acute lymphoblastic leukemia (T-ALL). We leveraged clinical mutational and transcriptional data to identify a functional link between PRC2 alterations and changes in WNT signaling pathway activity in leukemia cells. Computational integration of transcriptomic, proteomic and phosphoproteomic data from an isogenic T-ALL cellular model revealed reduced activity of the WNT-dependent stabilization of proteins (WNT/STOP) pathway in cells lacking core PRC2 factor EZH2. We discovered that PRC2 loss significantly reduced sensitivity to key T-ALL treatment asparaginase, and that this was mechanistically linked to increased cellular ubiquitination levels that bolstered leukemia cell asparagine reserves. We further found that asparaginase resistance in PRC2-depleted leukemic blasts could be mitigated by pharmaceutical proteasome inhibition, thereby providing a novel and clinically tractable means to tackle induction treatment failure in high-risk T-ALL.
While immunotherapy shows great promise in patients with triple negative breast cancer, many will not respond to treatment, and predicting response is made difficult by significant tumor heterogeneity. Non-invasive imaging of the tumor vasculature enables the monitoring of treatment and has potential to aid in predicting therapeutic response. Here, we use ultrafast power doppler ultrasound (US) to track longitudinal changes in the vascular response to radiotherapy in two breast cancer models to correlate vascular and immune changes in the tumor microenvironment. Tumor volume and vascular index were calculated to evaluate the effects of radiation using US imaging. US tumor measurements and the quantified vascular response to radiation were confirmed with caliper measurements and immunohistochemistry observations, respectively, demonstrating a proof-of-principle method for non-invasive vascular monitoring. Additionally, we found significant infiltration of CD8+ T cells into irradiated tumors 10 days after radiation, which followed a sustained decline in vascular index that was first observed 1 day post-radiation. Taken together, our findings reveal the potential for ultrafast power doppler US to evaluate changes in tumor vasculature that may be indicative of the tumor-immune microenvironment and ultimately improve patient outcomes by predicting response to immunotherapy.
Individuals with neurofibromatosis type 1 (NF-1), an autosomal dominant neurogenetic and tumor predisposition syndrome, are susceptible to developing low-grade glioma (LGG) and, less commonly, high-grade glioma (HGG). These gliomas exhibit loss of the neurofibromin gene (NF1), and 10-15% of sporadic HGG have somatic NF1 alterations. Loss of NF1 leads to hyperactive RAS signaling, creating opportunity given the established efficacy of MEK inhibitors (MEKi) in plexiform neurofibromas and some individuals with LGG. We observed that NF1-deficient glioblastoma neurospheres were sensitive to the combination of a MEKi (mirdametinib) with irradiation, as evidenced by synergistic inhibition of cell growth, colony formation, and increased cell death. In contrast, NF1-intact neurospheres were not sensitive to the combination, despite complete ERK pathway inhibition. No neurosphere lines exhibited enhanced sensitivity to temozolomide combined with mirdametinib. Mirdametinib decreased transcription of homologous recombination genes and RAD51 foci, associated with DNA damage repair, in sensitive models. Heterotopic xenograft models displayed synergistic growth inhibition to mirdametinib combined with irradiation in NF1-deficient glioma xenografts, but not those with intact NF1. In sensitive models, benefits were observed at least three weeks beyond the completion of treatment, including sustained phospho-ERK inhibition on immunoblot and decreased Ki-67 expression. These observations demonstrate synergistic activity between mirdametinib and irradiation in NF1-deficient glioma models and may have clinical implications for patients with gliomas that harbor germline or somatic NF1 alterations.
Cancer is the second leading cause of death globally, due primarily to metastatic dissemination and colonization of distal sites. Recurrent genetic drivers of metastasis are elusive, suggesting that, unlike the stereotyped mutations promoting primary tumor development, drivers of metastasis may be variable. Here, we interrogate pathways governing metastasis through CRISPR/Cas9-based forward genetic screening in a genetically defined colorectal adenocarcinoma tumor organoid (tumoroid) model using ex vivo invasion screens and orthotopic, in vivo screens for gain of metastatic potential. We identify Ctnna1 and Bcl2l13 as bona fide metastasis suppressors. CTNNA1 loss promotes carcinoma cell invasion and migration through an atypical EMT-like mechanism, whereas BCL2L13 loss promotes cell survival after extracellular matrix detachment and non-cell-autonomous macrophage polarization. Ultimately, this study provides a proof-of-principle that high-content forward genetic screening can be performed in tumor-organoid models in vivo and identifies novel regulators of colon cancer metastasis.
Breast cancer cells suppress the host immune system to efficiently invade the lymph nodes; however, the underlying mechanism remains incompletely understood. Here, we report that metastasized breast cancer cells selectively eliminate CD169+ lymph node sinus macrophages, an initiator of anti-cancer immunity, from the lymph nodes. The comparison between paired lymph nodes with and without metastasis from the same patients demonstrated that the number of CD169+ macrophages was reduced in metastatic lymph nodes, whereas the numbers of other major immune cell types were unaltered. We also detected the infiltration of CD169+ macrophages into metastasized cancer tissues depending on sections, suggesting that CD169+ macrophages were gradually eliminated after anti-cancer reactions. Furthermore, CD169+ macrophage elimination was prevalent in major breast cancer subtypes and correlated with breast cancer staging. Collectively, we propose that metastasized breast cancer cells dispel CD169+ macrophages from lymph nodes in a phased manner, disabling a critical step of anti-cancer immunity.
PLK1 (Polo-like kinase 1) plays a critical role in cancer progression of lung adenocarcinoma (LUAD). Recent studies have demonstrated that targeting PLK1 improves the efficacy of immunotherapy, indicating its important role in the regulation of tumor immunity. However, the correlation between PLK1 and tumor microenvironment (TME) is poorly understood. Here, using genetically engineered mouse model and single-cell RNA-seq analysis, we report that PLK1 promotes a general immunosuppressive TME in LUAD characterized with impaired tumor-infiltrating lymphocytes, enhanced M2 polarization and suppression of antigen presentation process. Mechanistically, elevated PLK1 coincides with increased secretion of CXCL2 cytokine, which promotes M2 polarization of macrophages and decreases expression of class II major histocompatibility complex (MHC-II) in professional antigen-presenting cells. Furthermore, PLK1 negatively regulates MHC-II expression in cancer cells, which has been shown to be associated with poor tumor immunity and patients outcomes. Taken together, our results reveal PLK1 as a novel modulator of TME in LUAD and provide possible therapeutic interventions. SignificanceThe characterization of PLK1 as a promoter of immunosuppressive tumor microenvironment enhances our understanding of PLK1s role in anti-tumor immunity and supports the idea of targeting PLK1 in cancer treatment.
Resistance to androgen deprivation therapies leads to metastatic castration-resistant prostate cancer (mCRPC) of adenocarcinoma (AdCa) origin that can transform to emergent aggressive variant prostate cancer (AVPC) which has neuroendocrine (NE)-like features. To this end, we used LuCaP patient-derived xenograft (PDX) tumors, clinically relevant models that reflects and retains key features of the tumor from advanced prostate cancer patients. Here we performed proteome and phosphoproteome characterization of 48 LuCaP PDX tumors and identified over 94,000 peptides and 9,700 phosphopeptides corresponding to 7,738 proteins. When we compared 15 NE versus 33 AdCa PDX samples, we identified 309 unique proteins and 476 unique phosphopeptides that were significantly altered and corresponded to proteins that are known to distinguish these two phenotypes. Assessment of protein and RNA concordance from these tumors revealed increased dissonance in transcriptionally regulated proteins in NE and metabolite interconversion enzymes in AdCa.
Identification of specific and therapeutically actionable vulnerabilities in acute myeloid leukaemia (AML) is needed to improve patients outcome. These features should be ideally present in many patients independently of mutational background. Here we identify de novo fatty acid (FA) desaturation, specifically stearoyl-CoA desaturase (SCD) inhibition, as a therapeutic vulnerability across multiple AML models in vitro and in vivo. SCD inhibition induces AML cell death via pleiotropic effects, and sensitivity is based on their dependency on FA desaturation regardless of mutational profile. Its efficacy is enhanced by driving FA biosynthesis in vitro and is less prominent in vivo due to stromal protection. SCD inhibition increases DNA damage and its combination with standard DNA damage-inducing chemotherapy prolongs survival in aggressive murine AML models. Our work supports developing FA desaturase inhibitors in AML while stressing the importance of identifying predictive biomarkers of response and biologically validated combination therapies to realize their therapeutic potential. KEY POINTSO_LISCD expression is highly prognostic in AML and SCD inhibition is toxic in AML cells displaying high rates of fatty acid desaturation. C_LIO_LISCD inhibition in combination with conventional chemotherapy prolongs survival in murine AML models. C_LI
Sialic acid-binding immunoglobulin-type lectins (Siglecs) are cell surface receptors that regulate innate and adaptive immunity, with inhibitory Siglecs promoting immune tolerance. In the tumor microenvironment, overexpression of sialic acid glycans exploits inhibitory Siglec signaling, leading to a cancer-permissive phenotype. AL009 is an engineered Siglec-9-Fc fusion molecule that functions as a sialic acid trap and reprograms suppressive macrophages to activate an anti-tumor immune response. AL009 treatment of human myeloid-derived suppressor cells (MDSCs), an in vitro model of tumor-associated macrophages (TAMs), resulted in an increase in proinflammatory cytokines and chemokines, changes in cell surface markers, and potent relief of T cell inhibition in a co-culture assay. In syngeneic mouse tumor models, AL009 engineered with a mouse Fc (AL009m) reduced tumor growth as a monotherapy and in combination with the checkpoint inhibitor anti-PD-L1. In addition, AL009m synergized with the tumor-targeting therapy anti-TRP1 to reduce lung nodules in the B16-F10 intravenous model. Pharmacodynamic marker analysis in syngeneic and humanized mouse tumor models supported an AL009 mechanism of action based on reprogramming TAMs and enhanced T cell activation. Future clinical studies are warranted to further elucidate the safety and efficacy of AL009. One Sentence SummaryPreclinical data for AL009 support investigation of this therapeutic for treatment of cancers rich in suppressive macrophages.
The susceptibility of cancer cells to DNA damages is influenced by their microenvironment. For example, unirradiated neighbors of irradiated cells can produce signals that reduce DNA damages. This phenomenon, known as Radiation-Induced Rescue Effect (RIRE), has profound implications on the efficacy of radiotherapy. Using bystander cells cocultured with mock-irradiated cells as a control, we demonstrated, for the first time, two types of RIRE. Conditioned medium from naive bystander cells, i.e., cells not exposed to irradiated cells, could mitigate UV-induced DNA damages in human breast carcinoma MCF7 cells, as judged by phospho-H2AX and 53BP1 immunostaining. This protective effect could be further enhanced by the prior treatment of bystander cells with factors from UV-irradiated cells. We named the former effect "basal RIRE" and the latter "active RIRE" which were cell type-dependent. As bystanders, MCF7 showed a significant active RIRE, whereas THP1-derived macrophages showed a strong basal RIRE but no active RIRE. Interestingly, RIRE of macrophages could further be modulated by polarisation. The basal RIRE of macrophages was abolished by M1 polarisation, while M2 and Tumour Associated Macrophages (TAM) demonstrated pronounced basal and active RIRE. When mixtures of MCF7 cells and polarised macrophages were used as bystanders, the overall RIRE was dictated by macrophage phenotypes: RIRE was suppressed by M1 macrophages but significantly enhanced by M2 and TAM. This study shows a previously unappreciated role of the innate immune system in RIRE. Depending on polarised phenotypes, macrophages in the tumour microenvironment can interfere with the effectiveness of radiotherapy by adjusting the RIRE magnitudes.
CK2 is considered a constitutively active protein kinase promoting/supporting several neoplastic properties and inducing a so-called non-oncogene addiction in tumor cells. Compared to the extensive body of pre-clinical research, the translational and clinical information on CK2 is still limited. The holoenzyme, composed by a tetrameric array of two catalytic (CSNK2A1 and/or CSNK2A1) and two regulatory (CSNK2B) subunits, remains to be clinically validated. Herein, we interrogated available cancer multiomics databases to unravel CK2 deregulated expression in NSCLC. We focused our analysis on individual CK2 subunits assuming subunit-specific tumor supportive roles across cancers and particularly, within two major NSCLC subtypes. Moreover, we performed meta-analysis to uncover associations between CK2 expression and patient survival, as well as further correlations analysis with components of the tumor-microenvironment. The genomic and transcriptomic data analysis was complemented by IHC evaluation of CSNK2A1, CSNK2A2 and CSNK2B subunit expression, and CK2 enzymatic activity thereof. Overall, our data suggests that epigenetic, transcriptional and post-transcriptional regulatory mechanisms rather than mutational/gene amplification events may account for differential CK2 subunits expression/activity in NSCLC. Of note, CSNK2A1 and CSNK2B mRNA up-regulation consistently determine a worse patient prognosis in LUAD and correlated with increased infiltration of MDSCs/CAFs. Importantly, we corroborated that CK2 protein subunits levels and enzymatic activity are significantly exacerbated in LUAD and LUSC, but only CSNK2A1 positively correlated with tumor size and disease stage in the analyzed patient cohort, thus supporting our transcriptomic-based correlation analysis. Finally, we concluded that CSNK2A1 alone and/or the homo-tetramer thereof may be more instrumental to support NSCLC than CSNK2A2; thus, tailored drugs against these molecular CK2 entities may achieve better therapeutic windows at least for advanced lung cancer treatment.
Colorectal cancer (CRC) is a major global health concern, resulting in numerous cancer-related deaths. CRC detection, treatment, and prevention can be improved by identifying genes and biomarkers. Despite extensive research, the underlying mechanisms of CRC remain elusive, and previously identified biomarkers have not yielded satisfactory insights. This shortfall may be attributed to the predominance of univariate analysis methods, which overlook potential combinations of variants and genes contributing to disease development. Here, we address this knowledge gap by presenting a novel multivariate machine-learning strategy to pinpoint genes associated with CRC. Additionally, we applied our analysis pipeline to Inflammatory Bowel Disease (IBD), as IBD patients face substantial CRC risk. The importance of the identified genes was substantiated by rigorous validation across numerous independent datasets. Several of the discovered genes have been previously linked to CRC, while others represent novel findings warranting further investigation.
The p53 protein is crucial for regulating cell survival and apoptosis in response to DNA damage. However, its influence on therapy effectiveness is controversial: when DNA damage is high p53 directs cells toward apoptosis, while under moderate genotoxic stress it saves the cells from death and promote DNA repair. Furthermore, these processes are influenced by the metabolism of transition metals, particularly copper since they serve as cofactors for critical enzymes. The metallochaperone Atox1 is under intensive study in this context because it serves as transcription factor allegedly mediating described effects of copper. Investigating the interaction between p53 and Atox1 could provide insights into tumor cell survival and potential therapeutic applications in oncology. This study explores the relationship between p53 and Atox1 in HCT116 and A549 cell lines with wild type and knockout TP53. The study found an inverse correlation between Atox1 and p53 at the transcriptional and translational levels in response to genotoxic stress. Atox1 expression decreased with increased p53 activity, while cells with inactive p53 had significantly higher levels of Atox1. Suppression of both genes increased apoptosis, while suppression of the ATOX1 gene prevented apoptosis even under the treatment with chemotherapeutic drugs. The findings suggest that Atox1 may act as one of key elements in promotion of cell cycle under DNA-damaging conditions, while p53 works as an antagonist by inhibiting Atox1. Understanding of this relationship could help identify potential targets in cell signaling pathways to enhance the effectiveness of antitumor therapy, especially in tumors with mutant or inactive p53.
The development of targeted therapy for patients with Multiple Myeloma (MM) is hampered by the low frequency of actionable genetic abnormalities. Gain or amplification of chr1q (Amp1q) is the most frequent arm-level copy number gain in patients with MM, and it is associated with higher risk of progression and death despite recent advances in therapeutics. Thus, developing targeted therapy for patients with MM and Amp1q stands to benefit a large portion of patients in need of more effective management. Here, we employed large-scale dependency screens and drug screens to systematically characterize the therapeutic vulnerabilities of MM with Amp1q and showed increased sensitivity to the combination of MCL1 and PI3K inhibitors. Using single-cell RNA sequencing, we compared subclones with and without Amp1q within the same patient tumors and showed that Amp1q is associated with higher levels of MCL1 and the PI3K pathway. Furthermore, by isolating isogenic clones with different copy number for part of the chr1q arm, we showed increased sensitivity to MCL1 and PI3K inhibitors with arm-level gain. Lastly, we demonstrated synergy between MCL1 and PI3K inhibitors and dissected their mechanism of action in MM with Amp1q.
Emerging data suggest that induction of viral mimicry responses through activation of double-stranded RNA (dsRNA) sensors in cancer cells is a promising therapeutic strategy. One approach to induce viral mimicry is to target molecular regulators of dsRNA sensing pathways. Here, we show that the exoribonuclease XRN1 is a negative regulator of the dsRNA sensor protein kinase R (PKR) in cancer cells with high interferon-stimulated gene (ISG) expression. XRN1 deletion causes PKR activation and consequent cancer cell lethality. Disruption of interferon signaling with the JAK1/2 inhibitor ruxolitinib can decrease cellular PKR levels and rescue sensitivity to XRN1 deletion. Conversely, interferon-{beta} stimulation can increase PKR levels and induce sensitivity to XRN1 inactivation. Lastly, XRN1 deletion causes accumulation of endogenous complementary sense/anti-sense RNAs, which may represent candidate PKR ligands. Our data demonstrate how XRN1 regulates PKR and nominate XRN1 as a potential therapeutic target in cancer cells with an activated interferon cell state.
Decoy-oligodeoxynucleotides (D-ODNs) can target undruggable transcription factors, such as STAT3. However, challenges in D-ODN delivery and potency hampered their translation. To overcome these limitations, we conjugated STAT3-specific D-ODN to thalidomide (Tha), a known ligand to cereblon (CRBN, a component of E3 ubiquitin ligase) to generate a proteolysis-targeting chimera (STAT3DPROTAC). STAT3DPROTAC downregulated STAT3, but not STAT1 or STAT5, in target cells. Computational modeling of the STAT3DPROTAC ternary complex predicted two surface lysines on STAT3, K601 and K626 as potential ubiquitination sites for the PROTAC bound E3 ligase. Accordingly, K601/K626 point mutations in STAT3, as well as proteasome inhibitors, and CRBN deletion alleviated STAT3DPROTAC effect. Next, we conjugated STAT3DPROTAC to a CpG ligand targeting Toll-like receptor 9 (TLR9) to generate myeloid/B-cell-selective C-STAT3DPROTAC conjugate. Naked C-STAT3DPROTAC was spontaneously internalized by TLR9+ myeloid cells, B cells as well as human Ly18 and mouse A20 lymphoma cells, but not by T cells. C-STAT3DPROTAC decreased STAT3 levels to 50% at 250 nM and over 85% at 2 {micro}M dosing in myeloid cells. We also observed significantly improved downregulation of STAT3 target genes involved in lymphoma cell proliferation and/or survival (BCL2L1, CCND2, MYC). Finally, we assessed the antitumor efficacy of C-STAT3DPROTAC compared to C-STAT3D or scrambled control (C-SCR) against human lymphoma xenotransplants. Local C-STAT3DPROTAC administration triggered lymphoma regression while control treatments had limited effects. Our results underscore feasibility of using PROTAC strategy for cell-selective, decoy oligonucleotide-based targeting of STAT3 and potentially other tumorigenic transcription factors for cancer therapy.
Cancer is an evolutionary process undergoing stringent immune selection. However, recent studies have revealed that certain tumors undergo neutral evolution following the malignant transformation. Here, we propose negative frequency-dependent selection (or NFDS), where the immune response against cancer cells depends on the clonality of neoantigens, can lead to an immunogenic landscape that is similar to neutral evolution. With a stochastic model of NFDS, we demonstrated that NFDS promotes early immune evasion in hypermutable tumors, leading to neutral-like evolutionary dynamics with high antigenic heterogeneity and worse response to immune checkpoint blockade (ICB) therapy. Our model also revealed that NFDS is characterized by a negative association between average clonality and total burden of neoantigens. Indeed, NFDS was validated with whole-exome sequencing datasets (357 tumor samples from 275 patients) from four melanoma cohorts with ICB therapy. Altogether, our study provides the first quantitative evidence supporting the theory of NFDS in immune-driven cancer evolution. These findings highlight the critical role of NFDS theory in devising more efficient and predictive immunotherapies.
The APOBEC3 family of enzymes convert cytosines in single-stranded DNA to uracils thereby causing mutations. These enzymes protect human cells against viruses and retrotransposons, but in many cancers they contribute to mutations that diversify the tumors and help them escape anticancer drug treatments. To understand the mechanism of mutagenesis by APOBEC3B, we expressed the complete enzyme or its catalytic carboxy-terminal domain (CTD) in repair-deficient Eschericia coli and mapped the resulting uracils using uracil pull-down and sequencing technology. The uracilomes of A3B-full and A3B-CTD showed peaks in many of the same regions where APOBEC3A also created uracilation peaks. Like A3A, the two A3B enzymes also preferred to deaminate cytosines near transcription start sites and in the lagging-strand template at replication forks. In contrast to an earlier report that A3B does not favor hairpin loops over linear DNA, we found that both A3B-full and A3B-CTD showed a strong preference for cytosines in hairpin loops. The major difference between A3A and A3B was that while the former enzyme prefers 3 nt loops the best, A3B prefers loops of 4 nt over those of other lengths. Furthermore, within 5 nt loops, A3A prefers cytosine to be in the penultimate position, while A3B prefers it to be at the 3 end of the loop. We confirmed these loop size and sequence preferences experimentally using purified A3A and A3B-CTD proteins. Reanalysis of hairpin loop mutations in human tumors using the size, sequence and position preferences of the two enzymes found that the tumors displayed mutations with intrinsic characteristics of both the enzymes with a stronger contribution from A3A.
Helicobacter pylori (H. pylori) infection is an established cause of many digestive diseases, including gastritis, peptic ulcers, and gastric cancer. However, the mechanism by which infection with H. pylori causes these disorders is still not clearly understood. This is due to insufficient knowledge of pathways that promote H. pylori-induced disease progression. We have established a Helicobacter-induced accelerated disease progression mouse model, which involves infecting mice deficient in the myeloid differentiation primary response 88 gene (Myd88-/-) with H. felis. Using this model, we report here that that progression of H. felis-induced inflammation to high-grade dysplasia was associated with activation of type I interferon (IFN-I) signaling pathway and upregulation of related downstream target genes, IFN-stimulated genes (ISGs). These observations were further corroborated by the enrichment of ISRE motifs in the promoters of upregulated genes. Further we showed that H. felis-induced inflammation in mice deficient in Toll/interleukin-1 receptor (TIR)-domain-containing adaptor inducing interferon-{beta} (TRIF, TrifLps2) did not progress to severe gastric pathology, indicating a role of the TRIF signaling pathway in disease pathogenesis and progression. Indeed, survival analysis in gastric biopsy samples from gastric cancer patients illustrated that high expression of Trif was significantly associated with poor survival in gastric cancer.
Mechanical phenotyping of tumors, either at an individual cell level or tumor cell population level is gaining traction as a diagnostic tool. However, the extent of diagnostic and prognostic information that can be gained through these measurements is still unclear. In this work, we focus on the heterogeneity in mechanical properties of cells obtained from a single source such as a tissue or tumor as a potential novel biomarker. We believe that this heterogeneity is a conventionally overlooked source of information in mechanical phenotyping data. We use mechanics-based in-silico models of cell-cell interactions and cell population dynamics within 3D environments to probe how heterogeneity in cell mechanics drives tissue and tumor dynamics. Our simulations show that the initial heterogeneity in the mechanical properties of individual cells and the arrangement of these heterogenous sub-populations within the environment can dictate overall cell population dynamics and cause a shift towards the growth of malignant cell phenotypes within healthy tissue environments. The overall heterogeneity in the cellular mechanotype and their spatial distributions is quantified by a "patchiness" index, which is the ratio of the global to local heterogeneity in cell populations. We observe that there exists a threshold value of the patchiness index beyond which an overall healthy cell population of cells will show a steady shift towards a more malignant phenotype. Based on these results, we propose that the "patchiness" of a tumor or tissue sample, can be an early indicator for malignant transformation and cancer occurrence in benign tumors or healthy tissues. Additionally, we suggest that tissue patchiness, measured either by biochemical or biophysical markers, can become an important metric in predicting tissue health and disease likelihood just as landscape patchiness is an important metric in ecology.
Could diet and mean plasma glucose concentration (MPGluC) explain the variation in cancer prevalence across species? We collected diet, MPGluC, and neoplasia data for 160 vertebrate species from existing databases. We found that MPGluC negatively correlates with cancer and neoplasia prevalence, mostly of gastrointestinal organs. Trophic level positively correlates with cancer and neoplasia prevalence even after controlling for species MPGluC. Most species with high MPGluC (50/78 species = 64.1%) were birds. Most species in high trophic levels (42/53 species = 79.2%) were reptiles and mammals. Our results may be explained by the evolution of insulin resistance in birds which selected for loss or downregulation of genes related to insulin-mediated glucose import in cells. This led to higher MPGluC, intracellular caloric restriction, production of fewer reactive oxygen species and inflammatory cytokines, and longer telomeres contributing to longer longevity and lower neoplasia prevalence in extant birds relative to other vertebrates.
Isocitrate Dehydrogenase-1 (IDH1) is commonly mutated in lower grade diffuse gliomas. The IDH1R132H mutation is an important diagnostic tool for tumor diagnosis and prognosis, however its role in glioma development, and its impact on response to therapy, is not fully understood. We developed a murine model of proneural IDH1R132H mutated glioma that shows elevated production of 2-Hydroxyglutarate (2-HG) and increased tri-methylation of lysine residue K27 on histone H3 (H3K27me3) compared to IDH1 wild-type tumors. We found that using Tazemetostat to inhibit the methyltransferase for H3K27, Enhancer of Zeste 2 (EZH2), reduced H3K27me3 levels and increased acetylation on H3K27. We also found that, although the histone deacetylase inhibitor (HDACi) Panobinostat was less cytotoxic in IDH1R132H mutated cells (either isolated from murine glioma or oligodendrocyte progenitor cells infected in vitro with a retrovirus expressing IDH1R132H) compared to IDH1-wildtype cells, combination treatment with Tazemetostat is synergistic in both mutant and wildtype models. These findings indicate a novel therapeutic strategy for IDH1-mutated gliomas that targets the specific epigenetic alteration in these tumors. Main PointsMurine gliomas initiated by the IDH1R132H mutation (in the presence of additional genetic alterations, such as p53 loss and PDGF overexpression) recapitulate the metabolic and transcriptional features of the proneural subtype, as they are characterized by increased 2HG levels, and are enriched for OPC lineage-restricted genes compared to IDH-wildtype murine gliomas. In murine IDH1-R132H glioma cells, EZH2 inhibition is not cytotoxic as a monotherapy but reduces levels of H3K27me3 and increases levels of H3K27ac. IDH1R132H cells are relatively resistant to Panobinostat cytotoxicity compared to IDH-wildtype cells, but combining treatment with EZH2 inhibition synergistically kills glioma cells and increases H3K27ac.
Poly(ADP-ribose)ylation or PARylation by PAR polymerase 1 (PARP1) and dePARylation by poly(ADP-ribose) glycohydrolase (PARG) are equally important for the dynamic regulation of DNA damage response. PARG, the most active dePARylation enzyme, is recruited to sites of DNA damage via pADPr-dependent and PCNA-dependent mechanisms. Targeting dePARylation is considered an alternative strategy to overcome PARP inhibitor resistance. However, precisely how dePARylation functions in normal unperturbed cells remains elusive. To address this challenge, we conducted multiple CRISPR screens and revealed that dePARylation of S phase pADPr by PARG is essential for cell viability. Loss of dePARylation activity initially induced S phase-specific pADPr signaling, which resulted from unligated Okazaki fragments and eventually led to uncontrolled pADPr accumulation and PARP1/2-dependent cytotoxicity. Moreover, we demonstrated that proteins involved in Okazaki fragment ligation and/or base excision repair regulate pADPr signaling and cell death induced by PARG inhibition. In addition, we determined that PARG expression is critical for cellular sensitivity to PARG inhibition. Additionally, we revealed that PARG is essential for cell survival by suppressing pADPr. Collectively, our data not only identify an essential role for PARG in normal proliferating cells but also provide a potential biomarker for the further development of PARG inhibitors in cancer therapy. Significance statementPoly(ADP-ribosyl)ation is a reversible post-translational modification. Although PARG may have a protective effect against excessive PARP1 engagement, detailed knowledge of PARGs mechanism of action remains elusive. Here, we showed that PARG participates in DNA replication, especially in Okazaki fragment maturation. Moreover, PARG level is critically important for cellular sensitivity to PARG inhibition, which is a valuable biomarker for PARGi-based therapy.
Metastasis of Lung adenocarcinoma (LUAD) is a major cause of death in patients. Aryl hydrocarbon receptor (AHR) is an important transcription factor involved in the initiation and progression of lung cancer. Polo-like kinase 1 (PLK1), a serine/threonine kinase, is an oncogene that promotes the malignancy of multiple cancer types. Nonetheless, the interaction between these two factors and significance in lung cancer remains to be determined. Here, we demonstrate that PLK1 phosphorylates AHR at S489 in LUAD, which leads to epithelial-mesenchymal transition (EMT) and metastatic events. RNA-seq analyses show that type 2 deiodinase (DIO2) is responsible for EMT and enhanced metastatic potential. DIO2 converts tetraiodothyronine (T4) to triiodothyronine (T3), which then activates thyroid hormone signaling. In vitro and in vivo experiments demonstrate that treatment with T3 or T4 promotes the metastasis of LUAD, whereas depletion of DIO2 or deiodinase inhibitor disrupts this property. Taken together, our results identify the phosphorylation of AHR by PLK1 as a mechanism leading to the progression of LUAD and provide possible therapeutic interventions for this event.
Transmissible cancer cell lines are rare biological entities giving rise to diseases at the crossroads of cancer and parasitic diseases. These malignant cells have acquired the amazing capacity to spread from host to host. They have been described only in dogs, Tasmanian devils and marine bivalves. The Mytilus trossulus Bivalve Transmissible Neoplasia 2 (MtrBTN2) lineage has even acquired the capacity to spread inter-specifically between marine mussels of the Mytilus edulis complex worldwide. To identify the oncogenic processes underpinning the biology of these atypical cancers we performed transcriptomics of MtrBTN2 cells. Differential expression, enrichment, protein-protein interaction network, and targeted analyses were used. Overall, our results suggest the accumulation of multiple cancerous traits that way be linked to the long-term evolution of MtrBTN2. We also highlight that vertebrate and lophotrochozoan cancers could share a large panel of common drivers, which supports the hypothesis of an ancient origin of oncogenic processes in bilaterians.
Melanoma is a heterogeneous tumor composed of many interacting cellular populations and highly plastic melanoma cells that pass through distinct cell states to adapt to the surrounding microenvironment. Slow cycling is a transient state that defines a minor population of cells with cancer-initiating features. These cells are enriched upon drug therapy and can trigger cancer relapse and metastasis dissemination when they acquire proliferative potential. This population is still not entirely characterized. Here we provide evidence of the existence of a slow cycling melanoma population isolated in vivo from melanoma PDXs using the H2B-GFP system. These cells display a highly invasive phenotype and are able to dynamically respond to cancer microenvironmental stimuli. Single cell transcriptomic analysis unveils a significant transcriptional heterogeneity of GFP-retaining slow cycling cells, defining a quiescent subpopulation of cells. These cells show a different phenotype in primary tumors and matched metastases, suggesting that tumor niche pressure drives a transcriptional reprogramming of quiescent cells during melanoma progression.
The cancer associated cachexia syndrome (CACS) is a systemic metabolic disorder resulting in loss of body weight due to skeletal muscle and adipose tissues atrophy. CACS is particularly prominent in lung cancer patients, where it contributes to poor quality of life and excess mortality. Using the Kras/Lkb1 (KL) mouse model, we found that CACS is associated with white adipose tissue (WAT) dysfunction that directly affects skeletal muscle homeostasis. WAT transcriptomes showed evidence of reduced adipogenesis, and, in agreement, we found low levels of circulating adiponectin. To preserve adipogenesis and restore adiponectin levels, we treated mice with the PPAR-{gamma} agonist, rosiglitazone. Rosiglitazone treatment increased serum adiponectin levels, delayed weight loss, and preserved skeletal muscle and adipose tissue mass, as compared to vehicle-treated mice. The preservation of muscle mass with rosiglitazone was associated with increases in AMPK and AKT activity. Similarly, activation of the adiponectin receptors in muscle cells increased AMPK activity, anabolic signaling, and protein synthesis. Our data suggest that PPAR-{gamma} agonists may be a useful adjuvant therapy to preserve tissue mass in lung cancer. Key points- The PPAR-{gamma} agonist, rosiglitazone, restores circulating adiponectin levels in mice with lung cancer. - Rosiglitazone preserves skeletal muscle and adipose tissue mass in mice with lung cancer. - The preservation of muscle mass with rosiglitazone is associated with increases in AMPK and AKT activity. - Stimulation of adiponectin signaling increases AMPK activity, anabolic signaling, and protein synthesis in muscle cell culture.
At over 200 years, the maximum lifespan of the bowhead whale exceeds that of all other mammals. The bowhead is also the second-largest animal on Earth, reaching over 80,000 kg1. In spite of its very large number of cells, the bowhead is not highly cancer-prone, an incongruity termed Petos Paradox2. This has been explained by the evolution of additional tumor suppressor genes in larger animals, which is supported by research on elephants demonstrating expansion of the p53 gene3-5. However, we show here that bowhead whale fibroblasts undergo oncogenic transformation after disruption of fewer tumor suppressors than required for human fibroblasts. Instead, analysis of DNA repair revealed that bowhead cells repair double-strand breaks with uniquely high efficiency and accuracy compared to other mammals. Further, we identified two proteins, CIRBP and RPA2, that are present at high levels in bowhead fibroblasts and increase the efficiency and fidelity of DNA repair in human cells. These results suggest that rather than possessing additional tumor suppressor genes as barriers to oncogenesis, the bowhead whale relies on more accurate and efficient DNA repair to preserve genome integrity. This strategy that does not eliminate cells but repairs them may be critical for the long and cancer-free lifespan of the bowhead whale. Our work demonstrates the value of studying long-lived organisms in identifying novel longevity mechanisms and their potential for translation to humans.
KRAS is the most commonly mutated oncogene. Targeted therapies have been developed against mediators of key downstream signaling pathways, predominantly components of the RAF/MEK/ERK kinase cascade. Unfortunately, single-agent efficacy of these agents is limited both by intrinsic and acquired resistance. Survival of drug-tolerant persister cells (DTPs) within the heterogeneous tumor population and/or acquired mutations that reactivate receptor tyrosine kinase (RTK)/RAS signaling can lead to outgrowth of tumor initiating cells (TICs) and drive therapeutic resistance. Here, we show that targeting the key RTK/RAS pathway signaling intermediates SOS1 or KSR1 both enhances the efficacy of, and prevents resistance to, the MEK inhibitor trametinib in KRAS-mutated lung (LUAD) and colorectal (COAD) adenocarcinoma cell lines depending on the specific mutational landscape. The SOS1 inhibitor BI-3406 enhanced the efficacy of trametinib and prevented trametinib resistance by targeting spheroid initiating cells (SICs) in KRASG12/G13-mutated LUAD and COAD cell lines that lacked PIK3CA co-mutations. Cell lines with KRASQ61 and/or PIK3CA mutations were insensitive to trametinib and BI-3406 combination therapy. In contrast, deletion of the RAF/MEK/ERK scaffold protein KSR1 prevented drug-induced SIC upregulation and restored trametinib sensitivity across all tested KRAS mutant cell lines in both PIK3CA- mutated and PIK3CA wildtype cancers. Our findings demonstrate that vertical inhibition of RTK/RAS signaling is an effective strategy to prevent therapeutic resistance in KRAS- mutated cancers, but therapeutic efficacy is dependent on both the specific KRAS mutant and underlying co-mutations. Thus, selection of optimal therapeutic combinations in KRAS-mutated cancers will require a detailed understanding of functional dependencies imposed by allele-specific KRAS mutations. Significance StatementWe provide an experimental framework for evaluating both adaptive and acquired resistance to RAS pathway-targeted therapies and demonstrate how targeting specific RAS pathway signaling intermediates SOS1 or KSR1 enhanced effectiveness of and prevented resistance to MEK inhibitors in KRAS-mutated cancer cells with genotypic precision. The contribution of either effector was dependent upon the mutational landscape: SOS1 inhibition synergized with trametinib in KRASG12/G13-mutated cells expressing WT PI3K but not in KRASQ61-mutated cells or if PIK3CA is mutated. KSR1 deletion inhibited MEK/ERK complex stability and was effective in cells that are unresponsive to SOS1 inhibition. These data demonstrate how a detailed understanding of functional dependencies imposed both by allele specific KRAS mutations and specific co-mutations facilitates the optimization of therapeutic combinations.
The clinical success of combined androgen deprivation therapy (ADT) and radiation therapy (RT) in prostate cancer (PCa) created interest in understanding the mechanistic links between androgen receptor (AR) signaling and the DNA damage response (DDR). Convergent data have led to a model where AR both regulates, and is regulated by, the DDR. Integral to this model is that the AR regulates the transcription of DDR genes both at steady state and in response to ionizing radiation (IR). In this study, we sought to determine which immediate transcriptional changes are induced by IR in an AR-dependent manner. Using PRO-seq to quantify changes in nascent RNA transcription in response to IR, the AR antagonist enzalutamide, or the combination of the two, we find that enzalutamide treatment significantly decreased expression of canonical AR target genes but had no effect on DDR gene sets in PCa cells. Surprisingly, we also found that the AR is not a primary regulator of DDR genes either in response to IR or at steady state in asynchronously growing PCa cells. Our data indicate that the clinical benefit of ADT and RT is not due to the direct regulation of DDR gene transcription by AR.
Loss of treatment-induced ovarian carcinoma (OC) growth suppression poses a major clinical challenge because it leads to disease recurrence. Therefore, there is a continuous need for approaches that can maintain OC suppression after treatment. We have profiled ascites as OC tumor microenvironments (TMs) to search for potential soluble components that would exert growth suppression on OC cell cultures. Our investigations revealed that low levels of taurine, a non-proteogenic sulfonic amino acid, were present within OC ascites. Taurine supplementation, beyond levels found in ascites, induced growth suppression without causing cytotoxicity in multiple OC cell cultures, including chemotherapy-resistant cell clones and multiple patient-derived organoids. Suppression of proliferation by taurine was associated with increased mutant or wild-type p53 proteins binding to DNA and induction of p21 and TIGAR expression. Taurine suppressed the cell-cycle progression, glycolysis, and mitochondria respiration. Expression of p21 or TIGAR in OC cells, in part, mimicked taurine-induced inhibition of cell proliferation. Our studies support the potential therapeutic value of taurine supplementation in OC.
REST is a widely expressed, dual role transcription factor that acts either as a transcriptional repressor or transcriptional activator depending on the genomic and cellular context. REST is an important oncogenic factor, a key player in brain cell differentiation and has a role in establishing DNA methylation status in proximity of its binding sites. Mutations in IDH cause significant changes to the epigenome contributing to blocking cell differentiation and are considered an oncogenic driver in glioma. We aimed at defining the REST role in the IDH mutation-related phenotype in gliomas accounting for its role in gene activation and repression. We studied the effects of REST knockdown, REST binding sites, and REST motifs methylation in context of IDH mutation, and found that both REST binding patterns and TF motif composition proximal to REST binding sites differed in IDH wild-type and mutant glioma. Among such REST targets were genes involved in glial cell differentiation and ECM organization. REST knockdown differently impacted glioma cell invasion depending on the IDH phenotype. DNA methylation of REST activated gene promoters showed positive correlation with gene expression. The canonical REST-repressed gene targets correlated with NPC-like cellular state properties in IDH-MUT grade 2/3 gliomas. The identified REST targets, gene regulatory networks and putative REST cooperativity with other TFs point to differential control of REST target gene expression in IDH-WT and IDH-MUT gliomas. We conclude that REST could be considered as a key factor in the design of targeted glioma therapies.
We re-analyzed the data from a recent large-scale study that reported strong correlations between microbial organisms and 33 different cancer types, and that created machine learning predictors with near-perfect accuracy at distinguishing among cancers. We found at least two fundamental flaws in the reported data and in the methods: (1) errors in the genome database and the associated computational methods led to millions of false positive findings of bacterial reads across all samples, largely because most of the sequences identified as bacteria were instead human; and (2) errors in transformation of the raw data created an artificial signature, even for microbes with no reads detected, tagging each tumor type with a distinct signal that the machine learning programs then used to create an apparently accurate classifier. Each of these problems invalidates the results, leading to the conclusion that the microbiome-based classifiers for identifying cancer presented in the study are entirely wrong. These flaws have subsequently affected more than a dozen additional published studies that used the same data and whose results are likely invalid as well.
Retroelements (RE) present in the human genome are silenced via multiple mechanisms, including DNA methylation, to prevent their potentially mutagenic effect. RE activity, demonstrated by their expression and somatic retrotransposition events, is deregulated in multiple tumor types but not in leukemia. We hypothesized that treatment with hypomethylating agents (HMA), commonly used in myelodysplastic syndromes and acute myeloid leukemia, could lead to increased RE activity and somatic retrotranspositions, and contribute to disease progression. We induced expression of ORF1p protein encoded by long interspersed nuclear element-1 (L1) after 72h treatment with HMA in DAMI and HL-60 cell lines. ORF1p was predominantly localized in the cytoplasm, as evidenced by fluorescent microscopy of the DAMI cell line. To study whether long-term HMA therapy may induce somatic retrotranspositions, we (i) treated both cell lines for four weeks, (ii) analyzed a cohort of 17 MDS patients before and on treatment with HMA. Using a previously established sensitive NGS-based method, no RE events were identified. To conclude, we show that although HMA induces the expression of L1-encoded proteins in tumor myeloid cell lines, de novo somatic retrotransposition events do not arise during the long-term treatment of MDS patients and myeloid cell lines with these agents.
The molecular basis of reduced autofluorescence in oral squamous cell carcinoma (OSCC) cells relative to normal cells has been speculated to be due to lower levels of free flavin adenine dinucleotide (FAD). This speculation, along with differences in the intrinsic optical properties of extracellular collagen, lie at the foundation of the design of currently-used clinical optical detection devices. Here, we report that free FAD levels may not account for differences in autofluorescence of OSCC cells, but that the differences relate to FAD as a co-factor for flavination. Autofluorescence from a 70 kDa flavoprotein, succinate dehydrogenase A (SDHA), was found to be responsible for changes in optical properties within the FAD spectral region with lower levels of flavinated SDHA in OSCC cells. Since flavinated SDHA is required for functional complexation with succinate dehydrogenase B (SDHB), decreased SDHB levels were observed in human OSCC tissue relative to normal tissues. Accordingly, the metabolism of OSCC cells was found to be significantly altered relative to normal cells, revealing vulnerabilities for both diagnosis and targeted therapy. Optimizing non-invasive tools based on optical and metabolic signatures of cancers will enable more precise and early diagnosis leading to improved outcomes in patients.
Immune-checkpoint therapy (ICT) has conferred significant and durable clinical benefit to some cancer patients. However, most patients do not respond to ICT, and reliable biomarkers of ICT response are needed to improve patient stratification. Here, we performed a transcriptome-wide meta-analysis across 1,486 tumors from ICT-treated patients and tumors with expected ICT outcomes based on microsatellite status. Using a transcriptome deconvolution approach, we inferred cancer and stroma-specific gene expression differences and identified cell-type specific features of ICT response across cancer types. Consistent with current knowledge, stromal expression of CXCL9, CXCL13, IFNG, and CD274 were among the top positive determinants of ICT response. Interestingly, we also identified a group of potential immune-suppressive genes, including FCER1A, associated with poor response to ICT. Surprisingly, the unbiased transcriptome-wide analysis failed to identify cancer-cell intrinsic features of ICT response conserved across tumor types. Overall, our results suggest that cancer cells lack tissue-agnostic molecular determinants of ICT response, which has implications for the development of improved ICT diagnostics and treatments.
Proteasome inhibitors such as Bortezomib, represent an established type of targeted treatment for several types of hematological malignancies, including multiple myeloma, Waldenstroms macroglobulinemia and mantle cell lymphoma, based on the cancer cells susceptibility upon impairment of the proteasome-ubiquitin system. However, a major problem limiting their efficacy is the emergence of resistance. Their application on solid tumors is currently being studied, while simultaneously, a wide spectrum of hematological cancers, such as Myelodysplastic Syndromes show minimal or no response to Bortezomib treatment. In this study, we utilize the prostate cancer cell line DU-145 to establish a model of Bortezomib resistance, studying the underlying mechanisms. Evaluating the resulting resistant cell line, we observed restoration of proteasome chymotrypsin-like activity, regardless of drug presence, an induction of pro-survival pathways, and the substitution of the Ubiquitin-Proteasome System role in proteostasis by induction of autophagy. Finally, an estimation of the oxidative condition of the cells, indicated that the resistant clones reduce the generation of reactive oxygen species induced by Bortezomib, to levels even lower than those induced in non-resistant cells. Our findings elucidate key proteins of survival and stress regulation pathways as potential pharmaceutical targets, which could increase the efficiency of the proteasome-targeting therapies, thus expanding the group of molecular targets for neoplastic disorders.
Cancer is a leading source of human lethality but current therapies have had limited efficacy in many cancers, which highlights an unmet need to assess the underlying mechanisms that govern cancer progression in vivo. Here we show that, upon malignant transformation, aggressive oncocells generate extracellular membranous compartments, cytocapsulas or cytocapsular tubes (CCTs), to enclose oncocells and engender cytocapsular oncocells in vivo. Cytocapsular oncocells are universally present in solid cancers and appear in hematologic cancers in the immune organs. Networks of cytocapsular tubes provide membrane-enclosed freeways for protected cancer metastasis. CCT networks interconnect cytocapsular tumors creating cytocapsular tumor network systems. Our findings suggest that cytocapsular oncocells drive membrane-encompassed cancer progression. Thus, interconnected cytocapsular oncocells, CCT networks and cytocapsular tumor network systems coordinate cancer progression in the integrated cytocapsular membrane systems.
A prominent source of mutation in cancer is single-stranded DNA cytosine deamination by cellular APOBEC3 enzymes, which results in signature C-to-T and C-to-G mutations in TCA and TCT motifs. Although multiple enzymes have been implicated, reports conflict and it is unclear which protein(s) are responsible. Here we report the development of a selectable system to quantify genome mutation and demonstrate its utility by comparing the mutagenic activities of three leading candidates - APOBEC3A, APOBEC3B, and APOBEC3H. The human cell line, HAP1, is engineered to express the thymidine kinase (TK) gene of HSV-1, which confers sensitivity to ganciclovir. Expression of APOBEC3A and APOBEC3B, but not catalytic mutant controls or APOBEC3H, triggers increased frequencies of TK mutation and nearly indistinguishable TC-biased cytosine mutation profiles in the selectable TK reporter gene. Whole genome sequences from TK mutant clones enabled an analysis of thousands of single base substitution mutations and extraction of local sequence preferences with APOBEC3A preferring YTCW motifs over 70% of the time and APOBEC3B just under 50% of the time (Y=C/T; W=A/T). Signature comparisons with breast tumor whole genome sequences indicate that most malignancies manifest intermediate percentages of APOBEC3 signature mutations in YTCW motifs, mostly between 50 and 70%, suggesting that both enzymes are contributing in a combinatorial manner to the overall mutation landscape. Although the vast majority of APOBEC3A- and APOBEC3B-induced single base substitution mutations occur outside of predicted chromosomal DNA hairpin structures, whole genome sequence analyses and supporting biochemical studies also indicate that both enzymes are capable of deaminating the single-stranded loop regions of DNA hairpins at elevated rates relative to control conditions. These studies combine to help resolve a long-standing etiologic debate on the source of APOBEC3 signature mutations in cancer and indicate that future diagnostic and therapeutic efforts should focus on both APOBEC3A and APOBEC3B.
YAP activation in cancer is linked to poor outcomes, making it an attractive therapeutic target. Previous research focused on blocking the interaction of YAP with TEAD transcription factors. Here, we took a different approach by disrupting YAPs binding to the transcription factor B-MYB using MY-COMP, a fragment of B-MYB containing the YAP binding domain fused to a nuclear localization signal. MY-COMP induced cell cycle defects, nuclear abnormalities, and polyploidization. In an AKT and YAP-driven liver cancer model, MY-COMP significantly reduced liver tumorigenesis, highlighting the importance of the YAP-B-MYB interaction in tumor development. MY-COMP also perturbed the cell cycle progression of YAP-dependent uveal melanoma cells but not of YAP-independent cutaneous melanoma cell lines. It counteracted YAP-dependent expression of MMB-regulated cell cycle genes, explaining the observed effects. We also identified NIMA-related kinase (NEK2) as a downstream target of YAP and B-MYB, promoting YAP-driven transformation by facilitating centrosome clustering and inhibiting multipolar mitosis.
Addiction to the WRN helicase is a unique vulnerability of human cancers with high levels of microsatellite instability (MSI-H). However, while prolonged loss of WRN ultimately leads to cell death, little is known about how MSI-H cancers initially respond to acute loss of WRN, knowledge that would be helpful for informing clinical development of WRN-targeting therapy, predicting possible resistance mechanisms, and identifying useful biomarkers of successful WRN inhibition. Here, we report the construction of an inducible ligand-mediated degradation system wherein the stability of endogenous WRN protein can be rapidly and specifically tuned, enabling us to track the complete sequence of cellular events elicited by acute loss of WRN function. We find that WRN degradation leads to immediate accrual of DNA damage in a replication-dependent manner that curiously did not robustly engage checkpoint mechanisms to halt DNA synthesis. As a result, WRN-degraded MSI-H cancer cells accumulate DNA damage across multiple replicative cycles and undergo successive rounds of increasingly aberrant mitoses, ultimately triggering cell death. Of potential therapeutic importance, we find no evidence of any generalized mechanism by which MSI-H cancers could adapt to near-complete loss of WRN. However, under conditions of partial WRN degradation, addition of low dose ATR inhibitor significantly increased their combined efficacy to levels approaching full inactivation of WRN. Overall, our results provided the first comprehensive view of molecular events linking upstream inhibition of WRN to subsequent cell death and suggested a potential therapeutical rationale for dual targeting of WRN and ATR.
Hypermutated neoantigens in cancers with DNA mismatch repair deficiency (dMMR) are prerequisite for favorable clinical responses to immune-checkpoint blockade (ICB) therapy. However, TMB is not significantly associated with favorable prognosis from Preclinical and clinical studies. It implys that except for TMB, other mechanisms should be needed to contribute to successful cancer immunotherapy. We found that the hyperactivation of PANoptotic effective molecules in dMMR tumor cells caused cell membrane damage, and induced ESCRT mediated membrane repair, and protectd tumor cells from the damage caused by Triton X100, while DNA mismatch repair proficient (pMMR) tumor cells were sensitive to Triton X100 mediating cell membrane damage due to the lack of ESCRT mediated membrane repair. There were hyperactivation of GSDMD, GSDME and p-MLKL in dMMR tumor cells. Co-treatment of IFN-{gamma} and TNF- induced rapid death of dMMR tumor cells by inducing PANoptosis including pyroptosis, apoptosis not necrosis. pMMR tumor cells had defects in PANoptosis pathway and were resistant to co-treatment of IFN-{gamma} and TNF-. In conclusion, we can activate immune cells to release IFN-{gamma} and TNF- to overcome resistance to ICB treatment.
Nut carcinoma (NC) is an aggressive cancer with no effective treatment. The majority (70%) of NUT carcinoma is associated with chromosome translocation events that lead to the formation of a BRD4-NUTM1 fusion gene. However, because the BRD4-NUTM1 gene is unequivocally cytotoxic when ectopically expressed in cell lines, there is no experimental evidence of the oncogenic potential of this fusion gene to initiate NC. We report here the first genetically engineered mouse model (GEMM) for NUT carcinoma. By inducing a chromosome translocation event mirroring the human event in mouse epithelial progenitors, we demonstrated that the Brd4-Nutm1 fusion gene could induce aggressive head and neck, and skin carcinomas in mice. The tumors present similar histopathological and molecular features to human NC. As the sole immunocompetent GEMM for NC, the model will have a far-reaching impact on understanding NC oncogenesis and developing NC treatment, including targeted therapies and immune therapies in a preclinical setting, which will benefit NC patients through translational research.
Combinations of oncogenic mutations drive inter-tumor heterogeneity in colorectal cancer (CRC), which promotes distinct phenotypes and affects therapeutic efficacy. We recently demonstrated that combinations of mutations in mouse small intestinal organoids lead to unique changes in microRNA (miRNA) expression profiles. However, it remains unknown how different mutational backgrounds shape miRNA profiles in the human colon. We leveraged human colonic organoid models, termed colonoids, with gene edits targeting genes commonly mutated in CRC to profile genotype-specific changes in miRNA expression. By small RNA-sequencing we characterized genotype-specific miRNA profiles. We identified one group of miRNAs, including mir-34a-5p and mir-10a-5p, that is strongly downregulated in APC/KRAS/TP53 mutant (AKP-mutant) colonoids. Using chromatin run-on sequencing, we showed that most miRNA alterations in AKP-mutant colonoids are concordant with transcriptional changes. Transcription factor (TF) motif enrichment analysis using transcriptional regulatory elements with increased activity in AKP-mutant colonoids revealed an enrichment of binding sites for multiple oncogenic TFs. Several of these harbor predicted binding sites for mir-10a-5p and/or mir-34a-5p, suggesting these miRNAs may play a role in regulating transcriptional programs in AKP-mutant contexts. Ultimately, our study offers a glimpse into regulatory mechanisms that drive inter-tumor heterogeneity, and we highlight candidate therapeutic targets for the advancement of precision medicine.
Immunotherapies for malignant melanoma seek to boost the anti-tumoral response of CD8+ T cells but have a limited patient response rate, in part due to limited tumoral immune cell infiltration. Genetic or pharmacological inhibition of Pannexin 1 (PANX1) channel-forming protein is known to decrease melanoma cell tumorigenic properties in vitro and ex vivo. Here, we crossed Panx1 knockout (Panx1-/-) mice with the inducible melanoma model: BrafCA, PtenloxP, Tyr::CreERT2 (BPC). We found that deleting the Panx1 gene in mice does not reduce BRAF(V600E)/Pten-driven primary tumor formation or improve survival. Notably, BPC-Panx1-/- mice tumors exhibited a significant infiltration of CD4+, CD8+ T lymphocytes, and increased Granzyme B+ cells with no changes in the expression of early T cell activation marker CD69, LAG-3 checkpoint receptor or PD-L1 in tumors when compared to BPC-Panx1+/+ genotype. Our results suggest that although Panx1 deletion does not overturn the aggressive BRAF/Pten-driven melanoma progression, in vivo, it does increase the infiltration of effector immune T cell populations in the tumor microenvironment. We propose that PANX1-targeted therapy could be explored as a strategy to increase tumor-infiltrating lymphocytes to boost anti-tumor immunity.
Unlike most cancer types, the incidence of esophageal adenocarcinoma (EAC) has rapidly escalated in the western world over recent decades. Using whole genome bisulfite sequencing (WGBS), we identify the transcription factor (TF) FOXM1 as an important epigenetic regulator of EAC. FOXM1 plays a critical role in cellular proliferation and tumor growth in EAC patient-derived organoids and cell line models. We identify ERBB2 as an upstream regulator of the expression and transcriptional activity of FOXM1. Unexpectedly, Gene Set Enrichment Analysis (GSEA) unbiased screen reveals a prominent anti-correlation between FOXM1 and immune response pathways. Indeed, syngeneic mouse models show that FOXM1 inhibits the infiltration of CD8+ T cells into the tumor microenvironment. Consistently, FOXM1 suppresses CD8+ T cell chemotaxis in vitro and antigen-dependent CD8+ T cell killing. This study characterizes FOXM1 as a significant EAC-promoting TF and elucidates its novel function in regulating anti-tumor immune response.
Pathologic Wnt/{beta}-catenin signaling drives various cancers, leading to multiple approaches to drug this pathway. Appropriate patient selection can maximize success of these interventions. Wnt ligand addiction is a druggable vulnerability in RNF43-mutant/RSPO-fusion cancers. However, pharmacologically targeting the biogenesis of Wnt ligands, e.g., with PORCN inhibitors, has shown mixed therapeutic responses, possibly due to tumor heterogeneity. Here we show that the tumor suppressor FBXW7 is frequently mutated in RNF43-mutant/RSPO-fusion tumors, and FBXW7 mutations cause intrinsic resistance to anti-Wnt therapies. Mechanistically, inactivation of FBXW7 stabilizes multiple oncoproteins including Cyclin E and MYC, and antagonizes the cytostatic effect of Wnt inhibitors. Moreover, although FBXW7 mutations do not mitigate {beta}-catenin degradation upon Wnt inhibition, FBXW7-mutant RNF43-mutant/RSPO-fusion cancers instead lose dependence on {beta}-catenin signaling, accompanied by dedifferentiation and loss of lineage specificity. These FBXW7-mutant Wnt/{beta}-catenin-independent tumors are susceptible to multi-CDK inhibition by dinaciclib. An in depth understanding of primary resistance to anti-Wnt/{beta}-catenin therapies allows for more appropriate patient selection and use of alternative mechanism-based therapies.
IntroductionOCCC has high incidence in Asia with frequent occurrence at early stage but without sufficient data on molecular stratification for high-risk patients. Recently, immune-hot features have been proposed as an indicator for poor prognosis for early-stage OCCC. Specific patterns of intra-tumoral heterogeneity (ITH) associated with immune-hot features need to be defined. MethodsFormalin-fixed paraffine embedded (FFPE) tumor sections from 10 early-stage OCCC patients were included. Digital Spatial Profiling (DSP) of 18 protein targets was conducted by using the nanoString GeoMx system to profile selected regions of interest (ROIs) based on the reference H&E staining morphology. Areas of illumination (AOIs) were defined according to ROI segmentation by the fluorescence signals of visualization markers pan-cytokeratin (PanCK), CD45, or DNA. ResultsUnsupervised hierarchical clustering of 252 AOIs from 229 ROIs showed that PanCK segments expressed different combinations of immune markers suggestive of immune mimicry features. Three immune-hot clusters were identified: granzyme B high (C1-a), immune signal high (C1-b) and immune-like cells (C1-c); two immune-cold clusters were identified: fibronectin-high (C2-a) and signal-cold (C2-b). Immune cells around C1-b and C1-c PanCK+ AOIs were tumor infiltrating immune cells (TIIs) with higher expression of CD68, while those around C1-a, C2-a and C2-b PanCK+ AOIs were non-TIIs with higher expression of SMA. C1-c and C2-a PanCK+ AOIs were associated with OCCC recurrence. TIIs had higher frequencies in C1-b and C1-c PanCK+ AOIs and were associated with OCCC recurrence. Correlating with morphology, tumor samples with recurrence showed higher frequency of papillary pattern. Plus, ROIs with papillary pattern had extremely high frequency of PanCK segments of C1-c feature, higher frequency of TIIs, and macrophage lineage immune mimicry with high intensity of CD68. ConclusionsSpatial profiling of early-stage OCCC tumors revealed that immune mimicry of tumor cells, the presence of TIIs, and papillary pattern in morphology were associated with recurrence.
Current cancer therapeutic strategies still face great challenges especially due to tumor relapse, drug resistance, and low treatment efficiency. The reason is that some tumor cells are able to outsmart the host immune mechanisms and evade the immune system. In this study, using the mouse cutaneous squamous cell carcinoma (mCSCC) as an example, a new cancer immunotherapeutic strategy with homologous neutralizing-antibodies was established. The experiment is divided into three stages. In the first stage, mCSCC cells were isolated and cultured from DMBA/TPA-induced mCSCC. In the second stage, the expanded tumor cells were then injected into healthy mice in order to produce anti-tumor homologous neutralizing-antibodies. In the final stage, therapeutic serum was extracted from healthy mice and injected back into tumor mice. ELISA assay was used to analyze the levels of p53, Bcl-xL, NF-{kappa}B, and Bax. The findings demonstrated that the serum treatment reduced tumor volume while also reversing changes in p53, Bcl-xL, NF-{kappa}B, and Bax. In conclusion, a novel immunotherapeutic strategy was developed to treat mCSCC, although more study is required to fully understand the mechanism of this serum treatment.
The chromatin-associated protein WDR5 is a promising target for cancer drug discovery, with most efforts blocking an arginine-binding cavity on the protein called the "WIN" site that tethers WDR5 to chromatin. WIN site inhibitors (WINi) are active against multiple cancer cell types in vitro, the most notable of which are those derived from MLL-rearranged (MLLr) leukemias. Peptidomimetic WINi were originally proposed to inhibit MLLr cells via dysregulation of genes connected to hematopoetic stem cell expansion. Our discovery and interrogation of small molecule WIN site inhibitors, however, revealed that they act in MLLr cell lines to suppress ribosome protein gene (RPG) transcription, induce nucleolar stress, and activate p53. Because there is no precedent for an anti-cancer strategy that specifically targets RPG expression, we took an integrated multi-omics approach to further interrogate the mechanism of action of WINi in MLLr cancer cells. We show that WINi induce depletion of the stock of ribosomes, accompanied by a broad translational choke, induction of a DNA damage response, and changes in alternative mRNA splicing that inactivate the p53 antagonist MDM4. We also show that WINi are synergistic with agents including venetoclax and BET-bromodomain inhibitors. Together, these studies reinforce the concept that WINi are a novel type of ribosome-directed anti-cancer therapy and provide a resource to support their clinical implementation in MLLr leukemias and other malignancies.
The cumulative number of stem cell divisions in a tissue, also known as mitotic age, is thought to be a major determinant of cancer-risk. Somatic mutational and DNA methylation (DNAm) clocks are promising tools to molecularly track mitotic age, yet their relationship is unexplored and their potential for cancer risk prediction in the tumor cell-of-origin remains to be demonstrated. Using advanced cell-type deconvolution methods in conjunction with a novel pan-tissue epigenetic mitotic clock called stemTOC, we here demonstrate that a samples mitotic age correlates with its putative tumor cell-of-origin fraction. We show that major cancer risk factors, including age, smoking and obesity-associated inflammation, increase the mitotic age of relevant normal tissues. StemTOC correlates with a somatic mutational clock-like signature, yet data indicates that the former is a more sensitive proxy for mitotic age. These results support the view that DNAm can track mitotic age in the tumor cell of origin of normal, preneoplastic and cancer tissues. StemTOC is freely available and could be adapted for future cancer-risk prediction strategies.
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The non-physiological nutrient levels found in traditional culture media have been shown to affect numerous aspects of cancer cell physiology, including how cells respond to certain therapeutic agents. Here, we comprehensively evaluated how physiological nutrient levels impact therapeutic response by performing drug screening in human plasma-like medium (HPLM). We observed dramatic nutrient-dependent changes in sensitivity to a variety of FDA-approved and clinically trialed compounds, including rigosertib, an experimental cancer therapeutic that has recently failed in phase 3 clinical trials. Mechanistically, we found that the ability of rigosertib to destabilize microtubules is strongly inhibited by the purine metabolism waste product uric acid, which is uniquely abundant in humans relative to traditional in vitro and in vivo cancer models. Structural modelling studies suggest that uric acid interacts with the tubulin-rigosertib complex and may act as an uncompetitive inhibitor of rigosertib. These results offer a possible explanation for the failure of rigosertib in clinical trials and demonstrate the utility of physiological media to achieve in vitro results that better represent human therapeutic responses.
Long-term tyrosine kinase inhibitor (TKI) treatment for patients with chronic myeloid leukemia (CML) causes various adverse events. Achieving a deep molecular response (DMR) is necessary for discontinuing TKIs and attaining treatment-free remission. Thus, early diagnosis is crucial as a lower DMR achievement rate has been reported in high-risk patients. Therefore, we attempted to identify CML cells using a novel technology that combines artificial intelligence (AI) with flow cytometry and investigated the basis for AI- mediated identification. Our findings indicate that BCR-ABL1-transduced cells and leukocytes from patients with CML showed significantly fragmented mitochondria and decreased mitochondrial membrane potential. Additionally, BCR-ABL1 enhanced the phosphorylation of Drp1 via the mitogen-activated protein kinase pathway, inducing mitochondrial fragmentation. Finally, the AI identified cell line models and patient leukocytes that showed mitochondrial morphological changes. Our study suggested that this AI- based technology enables the highly sensitive detection of BCR-ABL1-positive cells and early diagnosis of CML.
The ability of tumors to survive therapy reflects both cell-intrinsic and microenvironmental mechanisms. Across many cancers, including triple-negative breast cancer (TNBC), a high stroma/tumor ratio correlates with poor survival. In many contexts, this correlation can be explained by the direct reduction of therapy sensitivity by stroma-produced paracrine factors. We sought to explore whether this direct effect contributes to the link between stroma and poor responses to chemotherapies. Our in vitro studies with panels of TNBC cell line models and stromal isolates failed to detect a direct modulation of chemoresistance. At the same time, consistent with prior studies, we observed treatment-independent enhancement of tumor cell proliferation by fibroblast-produced secreted factors. Using spatial statistics analyses, we found that proximity to stroma is often associated with enhanced tumor cell proliferation in vivo. Based on these observations, we hypothesized an indirect link between stroma and chemoresistance, where stroma-augmented proliferation potentiates the recovery of residual tumors between chemotherapy cycles. To evaluate the feasibility of this hypothesis, we developed a spatial agent-based model of stroma impact on proliferation/death dynamics. The model was quantitatively parameterized using inferences from histological analyses and experimental studies. We found that the observed enhancement of tumor cell proliferation within stroma-proximal niches can enable tumors to avoid elimination over multiple chemotherapy cycles. Therefore, our study supports the existence of a novel, indirect mechanism of environment-mediated chemoresistance that might contribute to the negative correlation between stromal content and poor therapy outcomes.
BackgroundSurgery and/or platinum-based chemoradiation remain standard of care for patients with head and neck squamous cell carcinoma (HNSCC). While these therapies are effective in a subset of patients, a substantial proportion experience recurrence or treatment resistance. As cisplatin mediates cytotoxicity through oxidative stress while polyamines play a role in redox regulation, we posited that combining cisplatin with polyamine transport inhibitor, AMXT-1501, would increase oxidative stress and tumor cell death in HNSCC cells. MethodsCell proliferation was measured in syngeneic mouse HNSCC cell lines treated with cisplatin {+/-} AMXT-1501. Synergy was determined by administering cisplatin and AMXT-1501 at a ratio of 1:10 to cancer cells in vitro. Cancer cells were transferred onto mouse flanks to test the efficacy of treatments in vivo. Reactive oxygen species (ROS) were measured. Cellular apoptosis was measured with flow cytometry using Annexin V/PI staining. High-performance liquid chromatography (HPLC) was used to quantify polyamines in cell lines. Cell viability and ROS were measured in the presence of exogenous cationic amino acids. ResultsThe combination of cisplatin and AMXT-1501 synergize in vitro on HNSCC cell lines. In vivo combination treatment resulted in tumor growth inhibition greater than either treatment individually. The combination treatment increased ROS production and induced apoptotic cell death. HPLC revealed the synergistic mechanism was independent of intracellular polyamine levels. Supplementation of cationic amino acids partially rescued cancer cell viability and reduced ROS. ConclusionAMXT-1501 enhances the cytotoxic effects of cisplatin in vitro and in vivo in aggressive HNSCC cell lines through a polyamine-independent mechanism.
BRD4, a bromodomain and extraterminal (BET) protein, is deregulated in multiple cancers and has emerged as a promising drug target. However, the function of the two main BRD4 isoforms (BRD4-L and BRD4-S) has not been analyzed in parallel in most cancers. This complicates determining therapeutic efficacy of pan-BET inhibitors. In this study, using functional and transcriptomic analysis, we show that BRD-L and BRD4-S isoforms play distinct roles in embryonal rhabdomyosarcoma. BRD4-L has an oncogenic role and inhibits myogenic differentiation, at least in part, by activating myostatin expression. Depletion of BRD4-L in vivo impairs tumor progression but does not impact metastasis. On the other hand, depletion of BRD4-S has no significant impact on tumor growth, but strikingly promotes metastasis in vivo. Interestingly, BRD4-S loss results in the enrichment of BRD4-L and RNA Polymerase II at integrin gene promoters resulting in their activation. Our work unveils isoform-specific functions of BRD4 and demonstrates that BRD4-S functions as a gatekeeper to constrain the full oncogenic potential of BRD4-L.
AO_SCPLOWBSTRACTC_SCPLOWThe incidence and mortality of Endometrial Cancer (EC) is on the rise. 85% of ECs depend on Estrogen Receptor alpha (ER) for proliferation, but little is known about its transcriptional regulation in these tumors. We generated epigenomics and Hi-C data streams in healthy and tumor endometrial tissues, identifying robust ER reprogramming and profound alterations in 3D genome organization that lead to a gain of tumor-specific enhancer activity during EC development. Integration with WGS data from metastatic samples revealed a striking enrichment of non-coding somatic mutations at tumor-enriched ER sites. Through machine learning-based predictions and interaction proteomics analyses, we identified an enhancer mutation which alters 3D genome organization, impairing recruitment of the transcriptional repressor EHMT2/G9a/KMT1C, thereby alleviating transcriptional repression of ESR1 in EC. In summary, we identified a complex genomic-epigenomic interplay in EC development and progression, altering 3D genome organization to enhance expression of the critical driver ER.
While basal cell carcinomas (BCCs) arise from ectopic hedgehog pathway activation and can be treated with pathway inhibitors, sporadic BCCs display high resistance rates while tumors arising in Gorlin syndrome patients with germline Patched (PTCH1) mutations are uniformly suppressed by inhibitor therapy. In rare cases, Gorlin syndrome patients on long-term inhibitor therapy will develop individual resistant tumor clones that rapidly progress, but the basis of this resistance remains unstudied. Here we report a case of an SMOi-resistant tumor arising in a Gorlin patient on suppressive SMOi for nearly a decade. Using a combination of multi-omics and spatial transcriptomics, we define the tumor populations at the cellular and tissue level to conclude that Gorlin tumors can develop resistance to SMOi through the previously described basal to squamous cell carcinoma transition (BST). Intriguingly, through spatial whole exome genomic analysis, we nominate PCYT2, ETNK1, and the phosphatidylethanolamine biosynthetic pathway as novel genetic suppressors of BST resistance. These observations provide a general framework for studying tumor evolution and provide important clinical insight into mechanisms of resistance to SMOi for not only Gorlin syndrome but sporadic BCCs as well.
Neuroendocrine carcinoma of the cervix (NECC) is a rare subtype of cervical cancer with rapid metastasis. Lack of treatment regimens for metastatic NECC highlights the need for preclinical models and personalized treatment. Here, we established two patient-derived NECC organoid lines from lung metastases from the same patient, one of which was drug-free and the other exhibited tolerance to carboplatin plus etoposide (EP). The two organoids recapitulated the histopathology and genomic spectrum of the original tumors. Whole-genome sequencing revealed genomic structural variations (SVs), including HPV16 infection, NEUROD2, and ERBB2 amplification. The sensitivity phenotype of organoids to ERBB2 inhibitors coincides with the genomic features of ERBB2 amplification. In addition, the patient after relapse responded well to the paclitaxel plus carboplatin (TC) regimen as recommended by organoid drug screening, underscoring the utility of organoids as preclinical models. We first provide two NECC organoids of lung metastases with comprehensive molecular characteristics as valuable resources for this rare cancer and give a typical application for personalized treatment based on organoids.
Single cell transcriptomics studies have begun to identify breast epithelial cell and stromal cell specific transcriptome differences between BRCA1/2 mutation carriers and non-carriers. We generated a single cell transcriptome atlas of breast tissues from BRCA1, BRCA2 mutation carriers and compared this single cell atlas of mutation carriers with our previously described single cell breast atlas of healthy non-carriers. We observed that BRCA1 but not BRCA2 mutations altered the ratio between basal, luminal progenitor and mature luminal cells in breast tissues. A unique subcluster of cells within luminal progenitors is underrepresented in case of BRCA1 and BRCA2 mutation carriers compared to non-carriers. Both BRCA1 and BRCA2 mutations specifically altered transcriptomes in epithelial cells which are an integral part of NF-{kappa}B, LARP1, and MYC signaling. Reduction of MYC signaling and translational machinery in BRCA1/2 mutant epithelial cells is reminiscent of embryonic diapause-like adaptation that occurs in drug tolerant populations of cells. Signaling pathway alterations in epithelial cells unique to BRCA1 mutations included STAT3, BRD4, SMARCA4, HIF2A/EPAS1, and Inhibin-A signaling. BRCA2 mutations were associated with upregulation of IL-6, PDK1, FOXO3, and TNFSF11 signaling. These signaling pathway alterations are sufficient to alter sensitivity of BRCA1/BRCA2-mutant breast epithelial cells to transformation as epithelial cells from BRCA1 mutation carriers overexpressing hTERT + PIK3CAH1047R generated adenocarcinomas, whereas similarly modified mutant BRCA2 cells generated basal carcinomas in NSG mice. Thus, our studies provide a high-resolution transcriptome atlas of breast epithelial cells of BRCA1 and BRCA2 mutation carriers and reveal their susceptibility to PIK3CA mutation-driven transformation. Statement of SignificanceThis study provides a single cell atlas of breast tissues of BRCA1/2 mutation carriers and demonstrates that aberrant signaling due to BRCA1/2 mutations sufficient to initiate breast cancer by mutant PIK3CA.
Phosphatase and Tensin Homologue (PTEN) is one of the most frequently lost tumor suppressors in cancer and the predominant negative regulator of the PI3K/AKT signaling axis. A growing body of evidence has highlighted the loss of PTEN with immuno-modulatory functions including the upregulation of the programmed death ligand-1 (PD-L1) and the development of an immunosuppressive tumor immune microenvironment (TIME), which is most likely the result of an altered secretome. Given their roles in immunosuppression and tumor growth, this raises the question of how the loss of PTEN impacts the biogenesis and function of extracellular vesicles (EVs). Here we show that the loss of this tumor suppressor in glioma cells is accompanied by an enhanced ability to produce EVs enriched with PD-L1 that is largely dependent on PI3K activity. We further show that EVs derived from glioma cells lacking PTEN have a greater ability to suppress T cell receptor (TCR) signaling in response to IFN-{gamma}. Taken together, these findings provide important new insights into how the loss of PTEN can contribute to immune evasion and highlights a role for PI3K as a novel regulator of EV biogenesis and the cargo they contain.
SUMMARYCeO2 can consume intracellular reducing power, but its poor biocompatibility limits its application in tumor therapy. In this study, we designed and synthesized DSPE-PEG-CeO2, which is easy to enter cells, and showed that DSPE-PEG-CeO2 can induce the increase of ROS levels in tumor cells, thereby inducing tumor cell apoptosis and DNA damage. This suppresses the appearance and development of tumor cells. This provides a new idea for the application of inorganic nanomaterials.
Despite advancements in profiling multiple myeloma (MM) and its precursor conditions, there is limited information on mechanisms underlying disease progression. Clincal efforts designed to deconvolute such mechanisms are challenged by the long lead time between monoclonal gammopathy and its transformation to MM. MM mouse models represent an opportunity to overcome this temporal limitation. Here, we profile the genomic landscape of 118 genetically engineered Vk*MYC MM and reveal that it recapitulates the genomic heterogenenity and life history of human MM. We observed recurrent copy number alterations, structural variations, chromothripsis, driver mutations, APOBEC mutational activity, and a progressive decrease in immunoglobulin transcription that inversely correlates with proliferation. Moreover, we identified frequent insertional mutagenesis by endogenous retro-elements as a murine specific mechanism to activate NF-kB and IL6 signaling pathways shared with human MM. Despite the increased genomic complexity associated with progression, advanced tumors remain dependent on MYC expression, that drives the progression of monoclonal gammopathy to MM.
Mathematical modeling plays an important role in our understanding and targeting therapy resistance mechanisms in cancer. The polymorphic Gompertzian model, analyzed theoretically by Viossat and Noble, describes a heterogeneous cancer population consisting of therapy sensitive and resistant cells. This theoretically promising model has not previously been validated with real-world data. In this study, we provide this validation. We demonstrate that the polymorphic Gompertzian model successfully captures trends in both in vitro and in vivo data on non-small cell lung cancer (NSCLC) dynamics under treatment. Additionally, for the in vivo data of tumor dynamics in patients undergoing treatment, we compare the polymorphic Gompertzian model to the classical oncologic models, which were previously identified as the models that fit this data best. We show that the polymorphic Gompertzian model can successfully capture the U-shape trend in tumor size during cancer relapse, which can not be fitted with the classical oncologic models. In general, the polymorphic Gompertzian model corresponds well to both in vitro and in vivo real-world data, suggesting it as a candidate for improving the efficacy of cancer therapy, for example through evolutionary/adaptive therapies.
Glycosylation in human cholangiocarcinoma (CCA) actively contributes to pathophysiological steps of tumor progression. Of note is the dynamic modification of proteins by O-linked {beta}-N-acetyl-glucosamine (O-GlcNAcylation) that modulates various tumor-associated biological activities. By using a cutting-edge chemical proteomic methodology for intact glycopeptide analysis, we show herein that O-GlcNAcylation of Keratin 18 (K18) coordinates the tricarboxylic acid (TCA) cycle enzymes, namely isocitrate dehydrogenases (IDHs), to promote CCA progression. Mechanistically, site-specific O-GlcNAcylation of K18 on Ser 30 stabilizes K18, which benefits the expression of cell cycle checkpoints to enhance cell cycle progression and cell growth. Interaction with IDHs down-regulates the level of citrate and isocitrate, while up-regulates the level of -ketoglutarate (-KG). Our study thus expands the current understanding of protein O-GlcNAcylation, and adds another dimension of complexity to post-translational control over metabolism and tumorigenesis.
Steroid hormone receptors play a crucial role in the development and characterization of the majority of breast cancers. These receptors canonically function through homodimerization, but physical interactions between different hormone receptors play a key role in cell functions as well. The estrogen receptor (ER) and progesterone receptor (PR), for example, are involved in a complex set of interactions known as ER/PR crosstalk. Here, we developed a valuable panel of nuclear receptor expression plasmids specifically for use in NanoBRET assays to assess nuclear receptor homo- and heterodimerization. We demonstrate the utility of this assay system by assessing ER/PR physical interaction in the context of the endocrine therapy resistance- associated ER Y537S mutation. We identify a role of the ER Y537S mutation beyond that of constitutive activity of the receptor; it also increases ER/PR crosstalk. In total, the NanoBRET assay provides a novel avenue for investigating hormone receptor crosstalk. Future research may use this system to assess the effects of other clinically significant hormone receptor mutations on hormone receptor crosstalk.
Hepatocellular carcinomas (HCC) are driven by various etiologies and molecular diversity at presentation. Patient prognosis post-surgery is generally dismal, and the majority respond poorly to adjuvant targeted and/or immuno-therapies. Tumours are an ecosystem comprised of organization and interaction between different cell types that may contribute to clinically significant outcomes, such as disease recurrence. To better understand this phenomenon, we leveraged on a local cohort of patients with or without recurrence to generate spatial transcriptome profiles from multiple sectors from each tumour. We identified widespread gene expression intra- and inter tumour heterogeneity observed across the tumour sectors. Our analysis also revealed the cell type enrichment and localization, and ligand-receptor interactions identify a specific subset of endothelial cell enriched in primary tumours of patients with recurrence. Altogether, this study describes the spatial gene expression landscape in HCC patients associated with disease recurrence.
Tumor initiation represents the initial step in tumorigenesis during which normal progenitor cells undergo cell fate transition to cancer. Most studies investigating cancer-driving mechanisms in solid tumors rely on analyses of established malignant lesions, and thus cannot directly capture processes underlying the reprogramming of normal progenitor cells into cancer cells. Here, using spatiotemporally controlled oncogene expression in a genetically engineered system we demonstrate that concomitant YAP activation and HPVE6-E7-mediated inhibition of tumor suppressive pathways is sufficient to rapidly reprogram oral epithelial progenitor cells (OEPCs) into cancer stem cells (CSCs). Single cell analyses of these nascent CSCs revealed hallmark transcriptional programs driving tumor initiation. Importantly, these CSC-enriched expression signatures distinguish normal tissue from malignant head and neck tumors and are associated with poor patient survival. Elucidating mechanisms underlying OEPC to CSC reprogramming may offer new insights to halt the conversion of premalignant cells into invasive carcinoma. HIGHLIGHTSO_LIYAP and HPVE6-E7 reprogram oral epithelial progenitor cells into cancer stem cells. C_LIO_LISingle cell analyses reveal the transcriptional architecture of tumor initiation. C_LIO_LICSC transcriptional programs distinguish normal tissue from carcinoma. C_LIO_LICSC signatures are associated with poor head and neck cancer survival. C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=84 SRC="FIGDIR/small/550427v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): [email protected]@ca6df9org.highwire.dtl.DTLVardef@1fa21ecorg.highwire.dtl.DTLVardef@c928a3_HPS_FORMAT_FIGEXP M_FIG C_FIG
Myelodysplastic syndrome disease (MDS) has a variable risk for progression to AML. Mutations in CEBPA are associated with a high risk of disease progression, but whether this mutation is causative for AML development is unclear. To answer this question, we generated patient-derived, MDS-specific iPSCs recapitulating the patient disease phenotype upon differentiation to blood, with hematopoietic progenitor cells showing erythroid and myeloid-dysplasia. Introduction of a frameshift mutation affecting the C/EBP bZIP domain led to disease progression, with a reduction in clonogenic potential, block in granulocyte development and increased self-renewal capacity of erythroid progenitors. ATAC-seq revealed that the acquisition of this mutation reshaped the chromatin landscape at distal cis-regulatory regions, promoting changes in clonal composition as observed by single cell RNAseq. Our work identifies mutant CEBPA as causative for MDS disease progression, providing a new isogenic MDS experimental model for drug screening to improve diagnostic and therapeutic strategies. HighlightsO_LIDevelopment of isogenic iPSC model of clonal evolution of MDS C_LIO_LIMonoallelic disruption of CEBPA bZIP domain is causative for MDS disease progression C_LIO_LIMonoallelic disruption of CEBPA bZIP reshapes chromatin landscape C_LIO_LIPatient derived iPSCs recapitulate drug responsiveness C_LI
Immunotherapy is increasingly viewed as treatment of choice for lung cancer, however, clinical responses to immune checkpoint blockade remain highly unpredictable and are largely transient. A deeper mechanistic understanding of the dynamics of tumour:immune interactions is needed to drive rational development of improved treatment strategies. Progress is hampered by a paucity of autochthonous model systems in which to interrogate the 2-way interactions of immune responses to evolving tumours and vice-versa. Specifically, commonly used genetically engineered mouse models typically lack the genetic diversity needed to drive an adaptive immune response. APOBEC mutagenesis signatures are prominent in lung cancer and APOBEC activity is predicted to drive immune visibility through Cytidine deaminase activity, coupled with inaccurate DNA-repair responses. We therefore generated a CRE-inducible APOBEC3B allele, interbred with multiple oncogenic drivers of lung adenocarcinoma, and used the resulting mice to investigate the response to PD1 blockade at single cell resolution. SIGNIFICANCEUsing our novel immune-visible model of KRas-driven autochthonous lung adenocarcinoma, we uncovered a surprising increase in tumour-cell expression of EGFR/ERBB ligands following treatment with -PD1 and present evidence that transient ERBB blockade can restore immune surveillance in KRas mutant LuAd and combine effectively with immune checkpoint blockade.
Pancreatic ductal adenocarcinomas (PDACs) are resistant to systemic treatments including immunotherapy. Over 90% of PDACs have oncogenic KRAS mutations, and phosphoinositide 3-kinases (PI3Ks) are direct effectors of KRAS. Previously, we demonstrated that genetic ablation of PI3K isoform, Pik3ca in the KPC (KrasG12D; Trp53R172H; Pdx1-Cre) pancreatic cancer cell line induced complete tumor elimination by infiltrating T cells in a mouse model. However, clinical trials using PI3K inhibitors for PDAC patients exhibited limited efficacy due to drug resistance. To identify potential contributors to PI3K inhibitor resistance, we conducted an in vivo genome-wide gene-deletion screen using the Pik3ca-/- KPC (named KO) cells implanted in the mouse pancreas and discovered propionyl-CoA carboxylase subunit B (PCCB) modulates PIK3CA-mediated immune evasion. Deletion of Pccb gene in KO cells (named p-KO) allowed tumor progression causing death of host mice even though p-KO tumors are infiltrated with T cells. Single-cell RNA sequencing revealed that infiltrating clonally expanded T cells in p-KO tumors were more exhausted as compared to T cells founds in KO tumors. Blockade of PD-L1/PD1 interaction reversed T cell exhaustion, slowed tumor growth and improved the survival of mice implanted with p-KO cells. These results indicate that propionyl-CoA carboxylase activity modulates PIK3CA-regulated immune surveillance of PDAC.
Cytotoxic chemotherapies have been a crucial part of cancer treatment for over 40 years. While their primary target is cancer cells, they can also harm normal cells, resulting in dose-limiting toxicity. Most chemotherapies were approved before the advent of precision biomarkers, as such, many patients experience severe toxic side effects without any benefit. To address this challenge, we have developed three precision biomarkers to predict response to platins, taxanes, and anthracyclines. Based on chromosomal instability (CIN) signatures, these biomarkers can be computed from a single genomic test. For platins and taxanes, we used CIN signatures related to impaired homologous recombination, while for anthracyclines, we discovered a CIN signature representing micronuclei induction which predicts resistance. In a clinical study involving 41 high-grade serous ovarian cancers, patients predicted to be sensitive by these biomarkers showed significantly prolonged progression-free survival. To further validate the effectiveness of the taxane and anthracycline predictors, we conducted a retrospective randomised control study involving 182 ovarian and 219 breast cancer patients. Patients predicted as resistant showed increased risk of time to treatment failure compared to standard of care, hazard ratios of 1.73 (95%CI=0.98-3.07) for taxane in ovarian, 3.67 (95%CI=2.12-6.34) for taxane in breast, and 1.93 (95%CI=1.22-3.04) for doxorubicin in ovarian. We also found that liquid biopsies can be used to make these predictions in up to 30% of ovarian cancer patients. Our findings highlight the clinical value of CIN signatures in predicting treatment response to various chemotherapies across multiple different types of cancer. The ability to quantify multiple CIN signature biomarkers using a single genomic test offers a unified approach to guide treatment decisions for cytotoxic chemotherapies. Ultimately, this has the potential to transform the current one-size-fits-all chemotherapy approach into a more precise and tailored form of medicine.
Telomerase-negative tumors maintain telomere length by alternative lengthening of telomeres (ALT), but the underlying mechanism behind ALT remains poorly understood. A proportion of aggressive neuroblastoma (NB), particularly relapsed tumors, are positive for ALT (ALT+), suggesting that a better dissection of the ALT mechanism could lead to novel therapeutic opportunities. TERRA, a long non-coding RNA (lncRNA) derived from telomere ends, localizes to telomeres in a R-loop-dependent manner and plays a crucial role in telomere maintenance. Here we present evidence that RNA modification at the N6 position of internal adenosine (m6A) in TERRA by the methyltransferase METTL3 is essential for telomere maintenance in ALT+ cells, and the loss of TERRA m6A/METTL3 results in telomere damage. We observed that m6A modification is abundant in R-loop enriched TERRA, and the m6A-mediated recruitment of hnRNPA2B1 to TERRA is critical for R-loop formation. Our findings suggest that m6A drives telomere targeting of TERRA via R-loops, and this m6A-mediated R-loop formation could be a widespread mechanism employed by other chromatin-interacting lncRNAs. Furthermore, treatment of ALT+ NB cells with a METTL3 inhibitor resulted in compromised telomere targeting of TERRA and accumulation of DNA damage at telomeres, indicating that METTL3 inhibition may represent a therapeutic approach for ALT+ NB.
BackgroundImmune checkpoint inhibitors (ICIs) and their combination with other therapies such as chemotherapy, fail in most cancer patients. We previously identified the PDZ-LIM domain-containing protein 2 (PDLIM2) as a bona fide tumor suppressor that is repressed in lung cancer to drive cancer and its chemo- and immunotherapy resistance, suggesting a new target for lung cancer therapy improvement. MethodsHuman clinical samples and data were used to investigate PDLIM2 genetic and epigenetic changes in lung cancer. Using an endogenous mouse lung cancer model faithfully recapitulating refractory human lung cancer and a clinically feasible nano-delivery system, we investigated the therapeutic efficacy, action mechanism, and safety of systemically administrated Pdlim2 expression plasmids encapsulated in nanoparticles (nanoPDLIM2) and its combination with PD-1 antibody and chemotherapeutic drugs. ResultsPDLIM2 repression in human lung cancer involves both genetic deletion and promoter methylation. NanoPDLIM2 showed low toxicity, high tumor specificity, antitumor activity, and greatly improved the efficacy of anti-PD-1 and chemotherapeutic drugs, with complete tumor remission in 60% of mice and substantial tumor reduction in the remaining mice by the combination of three therapies. Mechanistically, nanoPDLIM2 increased major histocompatibility complex class I (MHC-I) expression, suppressed multi-drug resistance 1 (MDR1) induction, nuclear Rela and stat 3, and survival genes (Bcl-xl and cycline D1) in tumor cells; meanwhile it enhanced lymphocyte tumor infiltration and activation, thus turning the cold tumors hot and sensitive to ICIs and rendering them vulnerable to chemotherapeutic drugs. ConclusionsThese studies established a clinically applicable PDLIM2-based combination therapy with significantly improved efficacy for lung cancer and possibly other cold cancers.
Elevated Serine Peptidase Inhibitor, Kazal type 1 (SPINK1) levels in [~]10-25% of prostate cancer (PCa) patients associate with aggressive phenotype, for which there are limited treatment choices and dismal clinical outcomes. Using an integrative proteomics approach involving label-free phosphoproteome and proteome profiling, we delineated the downstream signaling pathways involved in SPINK1-mediated tumorigenesis in PCa, and identified tyrosine kinase KIT as a highly enriched kinase. Furthermore, high to moderate levels of KIT expression was detected in [~]85% of SPINK1-positive PCa specimens. KIT signaling regulates SPINK1-associated oncogenesis, and treatment with KIT inhibitor reduces tumor growth and distant metastases in preclinical mice models. Mechanistically, KIT signaling modulates WNT/{beta}-catenin pathway and confers stemness-related features in PCa. Notably, inhibiting KIT signaling restores AR/REST levels, forming a feedback loop enabling SPINK1 repression. Overall, we uncover the role of KIT signaling downstream of SPINK1 in maintaining lineage plasticity and provide new treatment modalities for advanced-stage SPINK1-positive subtype.
The presence of cell surface protein CD47 allows cancer cells to evade innate and adaptive immune surveillance resulting in metastatic spread. CD47 binds to and activates SIRP on the surface of myeloid cells, inhibiting their phagocytic activity. On the other hand, CD47 binds the matricellular protein Thrombospondin-1, limiting T-cell activation. Thus, blocking CD47 is a potential therapeutic strategy for preventing brain metastasis. To test this hypothesis, breast cancer patient biopsies were stained with antibodies against CD47 to determine differences in protein expression. An anti-CD47 antibody was used in a syngeneic orthotopic triple-negative breast cancer model, and CD47 null mice were used in a breast cancer brain metastasis model by intracardiac injection of the E0771-Br-Luc cell line. Immunohistochemical staining of patient biopsies revealed an 89% increase in CD47 expression in metastatic brain tumors compared to normal adjacent tissue (p [≤] 0.05). Anti-CD47 treatment in mice bearing brain metastatic 4T1br3 orthotopic tumors reduced tumor volume and tumor weight by over 50% compared to control mice (p [≤] 0.05) and increased IBA1 macrophage/microglia marker 5-fold in tumors compared to control (p [≤] 0.05). Additionally, CD47 blockade increased the M1/M2 macrophage ratio in tumors 2.5-fold (p [≤] 0.05). CD47 null mice had an 89% decrease in metastatic brain burden (p [≤] 0.05) compared to control mice in a brain metastasis model. Additionally, RNA sequencing revealed several uniquely expressed genes and significantly enriched genes related to tissue development, cell death, and cell migration tumors treated with anti-CD47 antibodies. Thus, demonstrating that CD47 blockade affects cancer cell and tumor microenvironment signaling to limit metastatic spread and may be an effective therapeutic for triple-negative breast cancer brain metastasis.
Nearly 30% of Pancreatic ductal adenocarcinoma (PDAC)s exhibit a marked overexpression of Monocarboxylate Transporter 1 (MCT1) offering a unique opportunity for therapy. However, biochemical inhibitors of MCT1 have proven unsuccessful in clinical trials. In this study we present an alternative approach using 3-Bromopyruvate (3BP) to target MCT1 overexpressing PDACs. 3BP is a cytotoxic agent that is known to be transported into cells via MCT1, but its clinical usefulness has been hampered by difficulties in delivering the drug systemically. We describe here a novel microencapsulated formulation of 3BP (ME3BP-7), that is effective against a variety of PDAC cells in vitro and remains stable in serum. Furthermore, systemically administered ME3BP-7 significantly reduces pancreatic cancer growth and metastatic spread in multiple orthotopic models of pancreatic cancer with manageable toxicity. ME3BP-7 is, therefore, a prototype of a promising new drug, in which the targeting moiety and the cytotoxic moiety are both contained within the same single small molecule. One Sentence SummaryME3BP-7 is a novel formulation of 3BP that resists serum degradation and rapidly kills pancreatic cancer cells expressing high levels of MCT1 with tolerable toxicity in mice.

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