Cancer-relevant Pathways Research Articles

Hub genes in a pan-cancer co-expression network show potential for predicting drug responses.

Background: The topological analysis of networks extracted from different types of "omics" data is a useful strategy for characterizing biologically meaningful properties of the complex systems underlying these networks. In particular, the biological significance of highly connected genes in diverse molecular networks has been previously determined using data from several model organisms and phenotypes. Despite such insights, the predictive potential of candidate hubs in gene co-expression networks in the specific context of cancer-related drug experiments remains to be deeply investigated. The examination of such associations may offer opportunities for the accurate prediction of anticancer drug responses. Methods: Here, we address this problem by: a) analyzing a co-expression network obtained from thousands of cancer cell lines, b) detecting significant network hubs, and c) assessing their capacity to predict drug sensitivity using data from thousands of drug experiments. We investigated the prediction capability of those genes using a multiple linear regression model, independent datasets, comparisons with other models and our own in vitro experiments. Results: These analyses led to the identification of 47 hub genes, which are implicated in a diverse range of cancer-relevant processes and pathways. Overall, encouraging agreements between predicted and observed drug sensitivities were observed in public datasets, as well as in our in vitro validations for four glioblastoma cell lines and four drugs. To facilitate further research, we share our hub-based drug sensitivity prediction model as an online tool. Conclusions: Our research shows that co-expression network hubs are biologically interesting and exhibit potential for predicting drug responses in vitro. These findings motivate further investigations about the relevance and application of our unbiased discovery approach in pre-clinical, translationally-oriented research.

Hub genes in a pan-cancer co-expression network show potential for predicting drug responses

Background: The topological analysis of networks extracted from different types of “omics” data is a useful strategy for characterizing biologically meaningful properties of the complex systems underlying these networks. In particular, the biological significance of highly connected genes in diverse molecular networks has been previously determined using data from several model organisms and phenotypes. Despite such insights, the predictive potential of candidate hubs in gene co-expression networks in the specific context of cancer-related drug experiments remains to be deeply investigated. The examination of such associations may offer opportunities for the accurate prediction of anticancer drug responses. Methods: Here, we address this problem by: a) analyzing a co-expression network obtained from thousands of cancer cell lines, b) detecting significant network hubs, and c) assessing their capacity to predict drug sensitivity using data from thousands of drug experiments. We investigated the prediction capability of those genes using a multiple linear regression model, independent datasets, comparisons with other models and our own in vitro experiments. Results: These analyses led to the identification of 47 hub genes, which are implicated in a diverse range of cancer-relevant processes and pathways. Overall, encouraging agreements between predicted and observed drug sensitivities were observed in public datasets, as well as in our in vitro validations for four glioblastoma cell lines and four drugs. To facilitate further research, we share our hub-based drug sensitivity prediction model as an online tool. Conclusions: Our research shows that co-expression network hubs are biologically interesting and exhibit potential for predicting drug responses in vitro. These findings motivate further investigations about the relevance and application of our unbiased discovery approach in pre-clinical, translationally-oriented research.

Therapeutic Targeting of BRD4 in Head Neck Squamous Cell Carcinoma.

The bromodomain and extraterminal family members are epigenetic readers and transcriptional coactivators which are critically involved in various biological processes including tumorigenesis. BRD4 has been increasingly appreciated as a key oncogene and promising anticancer target. Here, we sought to characterize the expression of BRD4 and its tumorigenic roles as well as therapeutic targeting in HNSCC.Methods: Expression of BRD4 mRNA and protein was determined by bioinformatics interrogation of publically available databases, primary HNSCC samples and 4NQO-induced HNSCC animal model. The tumorigenic roles of BRD4 in HNSCC were evaluated by genetic and pharmacological approach in vitro and in vivo. Therapeutic efficiency of BRD4 targeting by JQ1 was assessed in three preclinical models including xenograft model, 4NQO-induced model and patients-derived xenograft model. Gene candidates responsible for therapeutic effects of JQ1 were identified by transcriptional profiling in HNSCC cells after JQ1 exposure.Results: Significant upregulation of BRD4 was found in primary HNSCC samples and 4NQO-induced HNSCC model. Its overexpression associated with aggressive clinicopathological features and inferior overall and disease-free survival. BRD4 depletion by genetic silencing or pharmacological inhibition impaired cell proliferation, migration and invasion and reduced tumor growth and metastasis in vivo. Transcriptional profiling of HNSCC cells following JQ1 exposure identified hundreds of genes which might mediated its antitumor effects and enriched in cancer-relevant pathways. A novel prognostic risk score derived from JQ1-regulated genes was developed to stratify patients into subgroups with favorable or inferior prognosis.Conclusions: Our findings reveal that BRD4 serves as a novel and critical mediator underlying tumorigenesis and a robust prognostic biomarker in HNSCC. Therapeutic targeting of BRD4 represents a potent and promising strategy against HNSCC.

Hub genes in a pan-cancer co-expression network show potential for predicting drug responses

Background: The topological analysis of networks extracted from different types of “omics” data is a useful strategy for characterizing biologically meaningful properties of the complex systems underlying these networks. In particular, the biological significance of highly connected genes in diverse molecular networks has been previously determined using data from several model organisms and phenotypes. Despite such insights, the predictive potential of candidate hubs in gene co-expression networks in the specific context of cancer-related drug experiments remains to be deeply investigated. The examination of such associations may offer opportunities for the accurate prediction of anticancer drug responses. Methods: Here, we address this problem by: a) analyzing a co-expression network obtained from thousands of cancer cell lines, b) detecting significant network hubs, and c) assessing their capacity to predict drug sensitivity using data from thousands of drug experiments. We investigated the prediction capability of those genes using a multiple linear regression model, independent datasets, comparisons with other models and our own in vitro experiments. Results: These analyses led to the identification of 47 hub genes, which are implicated in a diverse range of cancer-relevant processes and pathways. Overall, encouraging agreements between predicted and observed drug sensitivities were observed in public datasets, as well as in our in vitro validations for four glioblastoma cell lines and four drugs. To facilitate further research, we share our hub-based drug sensitivity prediction model as an online tool. Conclusions: Our research shows that co-expression network hubs are biologically interesting and exhibit potential for predicting drug responses in vitro. These findings motivate further investigations about the relevance and application of our unbiased discovery approach in pre-clinical, translationally-oriented research.

Luteolin inhibits Musashi1 binding to RNA and disrupts cancer phenotypes in glioblastoma cells

ABSTRACTRNA binding proteins have emerged as critical oncogenic factors and potential targets in cancer therapy. In this study, we evaluated Musashi1 (Msi1) targeting as a strategy to treat glioblastoma (GBM); the most aggressive brain tumor type. Msi1 expression levels are often high in GBMs and other tumor types and correlate with poor clinical outcome. Moreover, Msi1 has been implicated in chemo- and radio-resistance. Msi1 modulates a range of cancer relevant processes and pathways and regulates the expression of stem cell markers and oncogenic factors via mRNA translation/stability. To identify Msi1 inhibitors capable of blocking its RNA binding function, we performed a ~ 25,000 compound fluorescence polarization screen. NMR and LSPR were used to confirm direct interaction between Msi1 and luteolin, the leading compound. Luteolin displayed strong interaction with Msi1 RNA binding domain 1 (RBD1). As a likely consequence of this interaction, we observed via western and luciferase assays that luteolin treatment diminished Msi1 positive impact on the expression of pro-oncogenic target genes. We tested the effect of luteolin treatment on GBM cells and showed that it reduced proliferation, cell viability, colony formation, migration and invasion of U251 and U343 GBM cells. Luteolin also decreased the proliferation of patient-derived glioma initiating cells (GICs) and tumor-organoids but did not affect normal astrocytes. Finally, we demonstrated the value of combined treatments with luteolin and olaparib (PARP inhibitor) or ionizing radiation (IR). Our results show that luteolin functions as an inhibitor of Msi1 and demonstrates its potential use in GBM therapy.

A genome-wide Drosophila epithelial tumorigenesis screen identifies Tetraspanin 29Fb as an evolutionarily conserved suppressor of Ras-driven cancer.

Oncogenic mutations in the small GTPase Ras contribute to ~30% of human cancers. However, Ras mutations alone are insufficient for tumorigenesis, therefore it is paramount to identify cooperating cancer-relevant signaling pathways. We devised an in vivo near genome-wide, functional screen in Drosophila and discovered multiple novel, evolutionarily-conserved pathways controlling Ras-driven epithelial tumorigenesis. Human gene orthologs of the fly hits were significantly downregulated in thousands of primary tumors, revealing novel prognostic markers for human epithelial tumors. Of the top 100 candidate tumor suppressor genes, 80 were validated in secondary Drosophila assays, identifying many known cancer genes and multiple novel candidate genes that cooperate with Ras-driven tumorigenesis. Low expression of the confirmed hits significantly correlated with the KRASG12 mutation status and poor prognosis in pancreatic cancer. Among the novel top 80 candidate cancer genes, we mechanistically characterized the function of the top hit, the Tetraspanin family member Tsp29Fb, revealing that Tsp29Fb regulates EGFR signaling, epithelial architecture and restrains tumor growth and invasion. Our functional Drosophila screen uncovers multiple novel and evolutionarily conserved epithelial cancer genes, and experimentally confirmed Tsp29Fb as a key regulator of EGFR/Ras induced epithelial tumor growth and invasion.

ADAR1-mediated RNA-editing of 3\u2032UTRs in breast cancer

BackgroundWhole transcriptome RNA variant analyses have shown that adenosine deaminases acting on RNA (ADAR) enzymes modify a large proportion of cellular RNAs, contributing to transcriptome diversity and cancer evolution. Despite the advances in the understanding of ADAR function in breast cancer, ADAR RNA editing functional consequences are not fully addressed.ResultsWe characterized A to G(I) mRNA editing in 81 breast cell lines, showing increased editing at 3′UTR and exonic regions in breast cancer cells compared to immortalized non-malignant cell lines. In addition, tumors from the BRCA TCGA cohort show a 24% increase in editing over normal breast samples when looking at 571 well-characterized UTRs targeted by ADAR1. Basal-like subtype breast cancer patients with high level of ADAR1 mRNA expression shows a worse clinical outcome and increased editing in their 3′UTRs. Interestingly, editing was particularly increased in the 3′UTRs of ATM, GINS4 and POLH transcripts in tumors, which correlated with their mRNA expression. We confirmed the role of ADAR1 in this regulation using a shRNA in a breast cancer cell line (ZR-75-1).ConclusionsAltogether, these results revealed a significant association between the mRNA editing in genes related to cancer-relevant pathways and clinical outcomes, suggesting an important role of ADAR1 expression and function in breast cancer.

Streamlined microfluidic analysis of phosphopeptides using stable isotope-labeled synthetic peptides and MRM-MS detection.

Modern high-throughput and high-content biological research is performed with advanced instrumentation and complex and time-consuming protocols, which, as a whole, pose a challenge for routine implementation in a research laboratory. In support of a "bioanalytical toolbox" with potential utility for exploring cellular functions mediated via protein phosphorylation-a post-translational modification (PTM) with essential regulatory roles in a variety of cellular processes-in this work, we describe the development of a simple, integrated microfluidic chip that can perform targeted, quantitative analysis of phosphopeptides involved in cancer-relevant signaling pathways. The microfluidic device comprises microreactors packed with C18 and TiO2 particles for on-chip solid phase extraction (SPE) and phosphopeptide enrichment, and an ESI interface for facilitating multiple reaction monitoring (MRM)-mass spectrometry (MS) detection. The chips are demonstrated for the detection of three phosphopeptides involved in ERBB2/MAPK signaling pathways, selected from the outcome of a proteomic study involving EGF stimulation of SKBR3/HER2+ breast cancer cells. The data demonstrate that the proposed microfluidic strategy can be used for the MS quantification of phosphopeptides in the low nM range from cell lysates without any prior sample pretreatment, fractionation or bioaffinity enrichment, and is generally applicable to the analysis of any phosphopeptide targets.

Reduced Arginyltransferase 1 is a driver and a potential prognostic indicator of prostate cancer metastasis.

Most prostate cancer cases remain indolent for long periods of time, but metastatic progression quickly worsens the prognosis and leads to mortality. However, little is known about what promotes the metastasis of prostate cancer and there is a lack of effective prognostic indicators, making it immensely difficult to manage options for treatment or surveillance. Arginyltransferase 1 (Ate1) is the enzyme mediating post-translational protein arginylation, which has recently been identified as a master regulator affecting many cancer-relevant pathways including stress response, cell cycle checkpoints, and cell migration/adhesion. However, the precise role of Ate1 in cancer remains unknown. In this study, we found the occurrence of metastasis of prostate cancer is inversely correlated with the levels of Ate1 protein and mRNA in the primary tumor. We also found that metastatic prostate cancer cell lines have a reduced level of Ate1 protein compared to non-metastatic cell lines, and that a depletion of Ate1 drives prostate cancer cells towards more aggressive pro-metastatic phenotypes without affecting proliferation rates. Furthermore, we demonstrated that a reduction of Ate1 can result from chronic stress, and that shRNA-reduced Ate1 increases cellular resistance to stress, and drives spontaneous and stress-induced genomic mutations. Finally, by using a prostate orthotropic xenograft mouse model, we found that a reduction of Ate1 was sufficient to enhance the metastatic phenotypes of prostate cancer cell line PC-3 in vivo. Our study revealed a novel role of Ate1 in suppressing prostate cancer metastasis, which has a profound significance for establishing metastatic indicators for prostate cancer, and for finding potential treatments to prevent its metastasis.

Abstract 2923: BET inhibitors synergize with HDAC inhibitors and downregulate expression of interferon response genes in glioblastoma

Abstract Glioblastoma (GBM) is the most aggressive brain tumor in adults with a median overall survival of only 15 months. Despite multiple attempts, single agent therapies have failed in clinical trials and new strategies for combination treatments are urgently needed. Here, our aim was to predict rational combination therapies with BET inhibitors (BETi) that target bromodomain and extra-terminal tail (BET) proteins and are currently evaluated as anti-cancer drugs. In order to identify BETi-induced vulnerabilities in cancer relevant pathways that may be targeted with a second drug, we obtained differential expression profiles of glioma sphere lines (GS-lines) treated with the BETi JQ1. Gene set enrichment analysis revealed several significantly disturbed pathways that included IFN-alpha response genes and signatures of response to histone deacetylase inhibitors (HDACi). In order to validate the observed down regulation of the interferon response gene signature, we primed the GS-lines with IFN-alpha and confirmed that interferon-stimulated genes (ISGs), such as MX1, OAS1, and CD274 are down regulated after a 4-hour exposure to JQ1. Importantly, the levels of pSTAT1 in the nucleus remained unchanged upon JQ1 treatment, suggesting that JQ1 was acting directly on the transcriptional level of ISGs and not on the canonical JAK-STAT pathway. Similar results were obtained in adherent GBM cell lines that constitutively express ISGs. Moreover, in U87MG orthotropic xenografts in mice, a single i.p. injection of JQ1 downregulated OAS1 and CD274 expression. Currently we are studying the mechanism of how BETi represses transcription of ISGs by chromatin immuno-precipitation. Finally, we show that HDACi and JQ1 synergize to reduce cell viability of GS-lines in vitro. Further experiments will test HDACi and BETi drug combinations in mouse orthotopic xenografts of GS-lines. Citation Format: Olga Gusyatiner, Minh Diêu Thanh Pham, Yvonne Lei, Jungyeon Park, Pierre Bady, Mauro Delorenzi, Monika Hegi. BET inhibitors synergize with HDAC inhibitors and downregulate expression of interferon response genes in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2923.

Abstract 966: Oncogenic signaling pathways differentially regulate clathrin-mediated endocytosis in cancer cells

Abstract Clathrin-mediated endocytosis (CME), the major endocytic pathway, regulates the rates of internalization of receptors as well as their downstream signaling activities. Recently, our lab has discovered that signaling can reciprocally regulate CME in cancer cells. The crosstalk between signaling and CME contributes to abnormal trafficking of signaling receptors and altered downstream signaling, leading to enhanced cancer metastasis. Accordingly, it is important to understand the nature and extent of interactions between CME and intracellular signaling in cancer cell biology. To address this issue, we targeted a set of prioritized kinases that are often implicated in cancer-relevant signaling pathways using validated pharmacologic inhibitors and compared their effects on CME function using different models for human noncancerous and cancer cells. We found that inhibition of several kinases selectively affected CME function in cancer cells. Notably, ERK inhibition had the most significant and consistent effects on CME activity across different types of cancer cells, while not affecting CME in several noncancerous cell lines tested. We established that a second ERK inhibitor, and importantly inhibition of the essential upstream kinase MEK, had the same cancer cell-specific effects on CME activity. Furthermore, we found that inhibition of ERK dramatically reduced the rate of clathrin-coated pit (CCP) initiation selectively in cancer cells. Characterization of one potential ERK substrate, FCHSD2, showed that knockdown of FCHSD2 had the similar cancer cell-specific effects on CME activity and on CCP initiation rate and that the cells depleted for FCHSD2 were insensitive to ERK inhibition. Surprisingly, the expression level of FCHSD2 is positively correlated with higher cancer patient survival rate, suggesting that FCHSD2 might be a tumor suppressor regulated by ERK. Our study provides new insight into the mechanisms and consequences of the reciprocal regulation of signaling and CME in cancer cells. Citation Format: Guan-Yu Xiao, Sandra Schmid. Oncogenic signaling pathways differentially regulate clathrin-mediated endocytosis in cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 966.

Abstract 4801: Potential of mebendazole as an anti-tumor agent for adenoid cystic carcinoma and other rare cancers

Abstract Adenoid Cystic Carcinoma (ACC) is a rare adenocarcinoma arising most commonly in the major and minor salivary glands of the head and neck. Despite a deepening understanding of the molecular events that lead to sustained tumor growth, there are currently no approved therapies for ACC or many other rare cancers. Repurposing of drugs for use in oncology is of increasing interest to promote the rapid development of new therapies and address the significant unmet medical need that remains for rare cancers. The FDA-approved anti-helminthic drug mebendazole (MBZ) has been identified as an agent that can affect several cancer relevant pathways involved in tumor growth and metastasis. Anti-tumor effects of MBZ include G2/M cell cycle arrest leading to apoptosis, inhibition of the IGF1R/AKT pathway, and induction of MYB degradation by the proteasome. Based on this biology, several rare cancer tumor cell lines including neuroblastoma, rhabdomyosarcoma and Ewing sarcoma, were analyzed for sensitivity to MBZ treatment in vitro. Cultured cells were exposed to increasing concentrations of MBZ and viability was measured after 72hours. Treatment with MBZ resulted in a significant decrease in cell viability with IC50s ranging from 0.05-1 μM suggesting that MBZ may represent a potent anti-cancer agent for several rare cancer indications. Identification of therapies for ACC has been hampered by the lack of ACC cell lines and transgenic mouse models. To circumvent these issues, in collaboration with the ACC Research Foundation, the activity of MBZ was tested in several ACC patient-derived xenograft (PDX) models. Mice were implanted subcutaneously with PDX tumors and treatment was initiated when tumors reached a size of 125-300 mm3. Mice were randomized into three treatment groups to receive daily treatment with vehicle or MBZ at either 50 or 200 mg/kg for the duration of the study. Daily oral dosing with MBZ was well tolerated with no overt toxicities. Significant anti-tumor activity was observed in 2 out of 3 ACC PDX models. In the most aggressive ACCX9 PDX model, MBZ showed statistically significant anti-tumor activity at the highest dose of 200 mg/kg resulting in a significant increase in median survival compared to vehicle-treated mice (38 vs 29.5 days respectively, p=0.0013). Inhibition of tumor growth was also observed in the less aggressive ACCX6 PDX model at both the 50 and 200 mg/kg dose levels compared to vehicle and was accompanied by an increase in median survival (95.5 and 64.5 days vs 42 days respectively; p=0.0085 and p=0.083). In the reportedly more refractory ACCX5M1 PDX model, treatment with MBZ did not inhibit tumor growth. Overall, the in vitro and in vivo results suggest that MBZ potentially represents a novel therapeutic option for the treatment of rare cancers including ACC. Citation Format: Jamie Dempsey Barber, Mahta Samizadeh, Nannan Jia, William Siders, Johanne Kaplan. Potential of mebendazole as an anti-tumor agent for adenoid cystic carcinoma and other rare cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4801.

A Pan-Cancer Compendium of Genes Deregulated by Somatic Genomic Rearrangement across More Than 1,400 Cases

A systematic cataloging of genes affected by genomic rearrangement, using multiple patient cohorts and cancer types, can provide insight into cancer-relevant alterations outside of exomes. By integrative analysis of whole-genome sequencing (predominantly low pass) and gene expression data from 1,448 cancers involving 18 histopathological types in The Cancer Genome Atlas, we identified hundreds of genes for which the nearby presence (within 100 kb) of a somatic structural variant (SV) breakpoint is associated with altered expression. While genomic rearrangements are associated with widespread copy-number alteration (CNA) patterns, approximately 1,100 genes-including overexpressed cancer driver genes (e.g., TERT, ERBB2, CDK12, CDK4) and underexpressed tumor suppressors (e.g., TP53, RB1, PTEN, STK11)-show SV-associated deregulation independent of CNA. SVs associated with the disruption of topologically associated domains, enhancer hijacking, or fusion transcripts are implicated in gene upregulation. For cancer-relevant pathways, SVs considerably expand our understanding of how genes are affected beyond point mutation or CNA.

Network-based analysis of oligodendrogliomas predicts novel cancer gene candidates within the region of the 1p/19q co-deletion

Oligodendrogliomas are primary human brain tumors with a characteristic 1p/19q co-deletion of important prognostic relevance, but little is known about the pathology of this chromosomal mutation. We developed a network-based approach to identify novel cancer gene candidates in the region of the 1p/19q co-deletion. Gene regulatory networks were learned from gene expression and copy number data of 178 oligodendrogliomas and further used to quantify putative impacts of differentially expressed genes of the 1p/19q region on cancer-relevant pathways. We predicted 8 genes with strong impact on signaling pathways and 14 genes with strong impact on metabolic pathways widespread across the region of the 1p/19 co-deletion. Many of these candidates (e.g. ELTD1, SDHB, SEPW1, SLC17A7, SZRD1, THAP3, ZBTB17) are likely to push, whereas others (e.g. CAP1, HBXIP, KLK6, PARK7, PTAFR) might counteract oligodendroglioma development. For example, ELTD1, a functionally validated glioblastoma oncogene located on 1p, was overexpressed. Further, the known glioblastoma tumor suppressor SLC17A7 located on 19q was underexpressed. Moreover, known epigenetic alterations triggered by mutated SDHB in paragangliomas suggest that underexpressed SDHB in oligodendrogliomas may support and possibly enhance the epigenetic reprogramming induced by the IDH-mutation. We further analyzed rarely observed deletions and duplications of chromosomal arms within oligodendroglioma subcohorts identifying putative oncogenes and tumor suppressors that possibly influence the development of oligodendroglioma subgroups. Our in-depth computational study contributes to a better understanding of the pathology of the 1p/19q co-deletion and other chromosomal arm mutations. This might open opportunities for functional validations and new therapeutic strategies.

Pathways Impacted by Genomic Alterations in Pulmonary Carcinoid Tumors.

Purpose: Pulmonary carcinoid tumors account for up to 5% of all lung malignancies in adults, comprise 30% of all carcinoid malignancies, and are defined histologically as typical carcinoid (TC) and atypical carcinoid (AC) tumors. The role of specific genomic alterations in the pathogenesis of pulmonary carcinoid tumors remains poorly understood. We sought to identify genomic alterations and pathways that are deregulated in these tumors to find novel therapeutic targets for pulmonary carcinoid tumors.Experimental Design: We performed integrated genomic analysis of carcinoid tumors comprising whole genome and exome sequencing, mRNA expression profiling and SNP genotyping of specimens from normal lung, TC and AC, and small cell lung carcinoma (SCLC) to fully represent the lung neuroendocrine tumor spectrum.Results: Analysis of sequencing data found recurrent mutations in cancer genes including ATP1A2, CNNM1, MACF1, RAB38, NF1, RAD51C, TAF1L, EPHB2, POLR3B, and AGFG1 The mutated genes are involved in biological processes including cellular metabolism, cell division cycle, cell death, apoptosis, and immune regulation. The top most significantly mutated genes were TMEM41B, DEFB127, WDYHV1, and TBPL1 Pathway analysis of significantly mutated and cancer driver genes implicated MAPK/ERK and amyloid beta precursor protein (APP) pathways whereas analysis of CNV and gene expression data suggested deregulation of the NF-κB and MAPK/ERK pathways. The mutation signature was predominantly C>T and T>C transitions with a minor contribution of T>G transversions.Conclusions: This study identified mutated genes affecting cancer relevant pathways and biological processes that could provide opportunities for developing targeted therapies for pulmonary carcinoid tumors. Clin Cancer Res; 24(7); 1691-704. ©2018 AACR.

Integrins and Exosomes, a Dangerous Liaison in Cancer Progression.

Integrin activity and function is classically related to the bi-directional regulation of cell-extracellular matrix (ECM) contacts that regulate a number of cell pathways linked to cell adhesion, cell detachment from ECM, cell migration, and anoikis. Interestingly, emerging data continue to uncover new roles for integrins in cancer-relevant pathways, particularly concerning the regulation of immune cell activity in the tumor niche, like myeloid cell differentiation and function and, very recently, the regulation of metastatic processes by exosomes. Exosomes are deeply involved in cell-cell communication processes and several studies have shown that integrins found in tumor-associated exosomes can promote cancer progression by two novel cooperative mechanisms: horizontal transfer of integrin transcripts as vescicle cargo, and selection of target tissues to form new tumor niches during metastatic spread by integrins carried on the exosome’s surface. In this review we will discuss mounting evidence that contribute to the development of a new picture for integrins in cancer, highlighting the role of integrins in the processes that leads to tumor niche formation. In particular, the role of the periostin pathway in the recruitment of tumor-associated macrophages, and the proposed contribution of exosome-derived integrins in the metastatic spread will be discussed. Finally, in light of the above considerations, an evaluation of integrins as possible therapeutic targets will be conducted.

Reciprocal regulation of signaling and endocytosis: Implications for the evolving cancer cell.

Cell surface receptor uptake via clathrin-mediated endocytosis (CME) and subsequent intracellular sorting for degradation or recycling regulates the strength and specificity of downstream signaling. Signaling, in turn, modulates early endocytic trafficking. This reciprocal regulation of signaling and endocytosis provides opportunities for the establishment of feedback loops to enhance or suppress surface-derived signals. Recent studies suggest that dynamin-1, a presumed neuron-specific isoform of the large, membrane fission GTPase, can be activated in nonneuronal cells downstream of cancer-relevant signaling pathways and thereby function as a nexus between signaling and early endocytic trafficking. I speculate that sustained up-regulation and/or acute activation of dynamin-1 in cancer cells contributes to a program of "adaptive" CME that alters signaling to enhance cancer cell survival, migration, and proliferation.

Abstract 5559: Using cancer dependency data to discover tumor suppressive and oncogenic functional modules

Abstract Efforts to define protein complexes and their functional networks are critical for systems-level understanding of the pathways involved in human cancer. Current methods to catalog human protein complexes via physical interaction are often unable to resolve functional differences between complex members or infer relationships governed by sub-stoichiometric interactions. While functional wiring maps in yeast have been generated by measuring epistatic interactions between pairs of genes, efforts to scale this concept in individual human cell lines have been met with challenges and have only been able to characterize limited numbers of genes at a time. We have developed a scalable approach that can measure functional similarity without the constraints of pairwise genetic interaction experiments. Using data from genome-wide RNAi and CRISPR dropout screens performed in hundreds of cancer cell lines, we leveraged the heterogeneity of gene dependencies across cancer types to measure functional similarity between thousands of genes at once, which in turn allowed us to recreate known inter- and intra-complex functional relationships and to uncover tumor suppressive and oncogenic functional modules in cancer-relevant pathways such as proteolysis, metabolism and transcription. Applying these approaches to the mammalian SWI/SNF (BAF) chromatin remodeling complex, which is mutated in over 20% of human cancer, revealed three functional modules that arose separately during metazoan evolution, one of which is entirely novel and uncharacterized. We then performed biochemical experiments that fully support three specialized complex configurations, each with distinct size, subunit composition, and function. These data reorganize the BAF complex into previously unrecognized modules that better explain mutational burden in human cancer. Notably, we observe that that all known BAF-driven, highly penetrant rare cancers and neurodevelopmental disorders involve disruption within a single functional module we defined, underscoring the value of evaluating disease genomics through the lens of functional modularity. Citation Format: Joshua Pan, Robin M. Meyers, Brittany C. Michel, Ann E. Sizemore, Francisca Vazquez, Barbara A. Weir, William C. Hahn, Aviad Tsherniak, Cigall Kadoch. Using cancer dependency data to discover tumor suppressive and oncogenic functional modules [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5559. doi:10.1158/1538-7445.AM2017-5559

Abstract 2378: A kinome analysis of the molecular pharmacodynamics of PT-112 in a human cancer cell line

Abstract Background: To better understand the mechanism of action of PT-112, we investigated the effects of PT-112 on kinase activity within HCT116 human colorectal cancer cells. PT-112 is a pyrophosphate-conjugated platinum (Pt) containing new chemical entity under clinical development in the US and Taiwan. Designed to reduce certain toxicities associated with Pt agents and drug resistance from DNA-repair pathway activity, PT-112 differs in significant ways from traditional Pt therapies. PT-112 results in potent anti-proliferation effects with lower Pt accumulation in whole cell and DNA extracts. Upregulation of p16 and p21 and, consistently, inhibition of the cell cycle at the G1/S phase transition is observed with PT-112 use, a finding not commonly associated with Pt agents. Further, sensitivity to PT-112 is not significantly affected by the functionality of DNA repair pathways. Finally, the induction of immunogenic cell death by PT-112 has been indicated via release of HMGB1, cell surface localization of calreticulin, and suppression of STAT3. Methods: A broad analysis of the phosphorylation pattern of kinase targets was achieved by utilizing the Tyrosine Kinase and Serine / Threonine Kinase PamChip® Arrays, each spotted with 144 peptides harboring kinase phosphorylation sites. Data were collected after 1, 6, and 24hr of exposure to 10 μM PT-112, a concentration achievable in human patient plasma at sub-toxic doses, and the degree of phosphorylation of these peptide targets was measured by the PamStation®. Results: A set of kinase targets was identified as differentially phosphorylated relative to untreated control samples. In total, 4/15/30 targets were more phosphorylated than controls at the 1/6/24hr time points, respectively, while 1/0/10 targets were less phosphorylated. Several of these targets connect to key cancer relevant pathways, including anti-angiogenesis (VGFR1), apoptosis (BAD), cell cycle regulation (CDC2, Rb, RBL2), cell growth (EGFR, MK07, RBL2), and cancer immunology (STAT4, CSF1R). Conclusions: A narrow set of initial effects on kinase activity from PT-112 exposure, which broaden over time, was observed. While we cannot discriminate direct from indirect effects, these data are consistent with PT-112 having mechanistic targets independent of nuclear DNA. Several observations were consistent with findings from previous experiments (e.g. evidence of impacts on apoptotic, cell cycle, and immunological pathways), while others were novel (e.g. impact on VGFR1, EGFR, MK07). In conclusion, PT-112 at pharmacologically achievable concentrations leads to a unique pattern of kinase disruption in vitro. Further work will be conducted to validate these findings, identify the driver kinases, and connect these observations into a coherent network of kinases and targets affected by PT-112 treatment, and to understand the clinical impact of the unique pharmacodynamic profile of PT-112. Citation Format: Diego Tosi, Esther Perez-Gracia, Philippe Pourquier, Tyler D. Ames, Richard A. Wing, José Jimeno, Céline Gongora. A kinome analysis of the molecular pharmacodynamics of PT-112 in a human cancer cell line [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2378. doi:10.1158/1538-7445.AM2017-2378

Abstract 208: Proteomic measurements of protein abundance and phosphorylation identify novel kinase-substrate relationships in ovarian cancer

Abstract As part of the Clinical Proteomic Tumor Analysis Consortium (CPTAC), we have recently published the first large-scale proteomic and phosphoproteomic analysis of high-grade serous ovarian tumors. We observed that phosphorylation status was an excellent indicator of pathway activity and could discriminate between patient survival times. This dataset covers tumor samples from 69 patients with deep phosphoproteomic depth (>20,000 phosphopeptides confidently identified). Our continuing analysis of this dataset, reported here, has revealed that the correlation between kinase protein abundance and abundance of phosphorylated target peptides is very low, indicating that kinase abundance is not a good proxy for phosphorylation status overall. However, highly correlated kinase-substrate pairs are significantly more likely to be true relationships (from existing knowledge), demonstrating that this method could be used to predict novel kinase targets in some cases. Using this approach we predicted novel kinase-target relationships and constructed a kinase activity network of ovarian cancer. To better analyze cancer-relevant pathway activity we developed a novel approach that characterizes correlation, differential abundance, and statistical interactions between components to analyze multiple omics types in the context of signaling and functional pathways. We used this approach, called the Layered Enrichment Analysis of Pathways (LEAP), to identify active pathways in molecular subtypes of ovarian cancer, contrasting observations in patients stratified for short versus long overall survival. This analysis resulted in a pre-treatment protein-based signature that is significantly predictive of overall survival. Our results show that integration of multiple omics types has the ability to inform our understanding of novel kinase-substrate interactions, and potentially identify novel interactions associated with patient survival. Note: This abstract was not presented at the meeting. Citation Format: Jason E. McDermott, Tao Liu, Samuel Payne, Vladislav Petyuk, Hui Zhang, Zhen Zhang, Daniel Chan, Richard Smith, Karin Rodland, Clinical Proteomic Tumor Analysis Consortium. Proteomic measurements of protein abundance and phosphorylation identify novel kinase-substrate relationships in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 208. doi:10.1158/1538-7445.AM2017-208