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Project description:Bromodomain inhibition comprises a promising therapeutic strategy in cancer, particularly for hematologic malignancies. To date, however, genomic biomarkers to direct clinical translation have been lacking. We conducted a cell-based screen of genetically-defined cancer cell lines using a prototypical inhibitor of BET bromodomains. Integration of genetic features with chemosensitivity data revealed a robust correlation between MYCN amplification and sensitivity to bromodomain inhibition. We characterized the mechanistic and translational significance of this finding in neuroblastoma, a childhood cancer with frequent amplification of MYCN. Genome-wide expression analysis demonstrated downregulation of the MYCN transcriptional program accompanied by suppression of MYCN transcription. Functionally, bromodomain-mediated inhibition of MYCN impaired growth and induced apoptosis in neuroblastoma. BRD4 knock-down phenocopied these effects, establishing BET bromodomains as transcriptional regulators of MYCN. BET inhibition conferred a significant survival advantage in three in vivo neuroblastoma models, providing a compelling rationale for developing BET bromodomain inhibitors in patients with neuroblastoma. Significance: Biomarkers of response to small-molecule inhibitors of BET bromodomains, a new compound class with promising anti-cancer activity, have been lacking. Here, we reveal MYCN amplification as a strong genetic predictor of sensitivity to BET bromodomain inhibitors, demonstrate a mechanistic rationale for this finding, and provide a translational framework for clinical trial development of BET bromodomain inhibitors for pediatric patients with MYCN-amplified neuroblastoma. JQ1 is a novel thieno-triazolo-1,4-diazepine, which displaces BET bromodomains from chromatin by competitively binding to the acetyl lysine recognition pocket. BE(2)-C and Kelly cells were treated in triplicate with 1 µM JQ1 or DMSO for 24 hours. RNA was extracted and a decrease in MYCN transcript was confirmed by real time RT-PCR as described above. The samples were profiled using the Affymetrix PrimeView Human Gene Expression Array (Affymetrix) at Beth Israel Deaconess Medical Center (Boston, MA, USA).
2013-02-25 | E-GEOD-43392 | biostudies-arrayexpress
Project description:Small molecule BET bromodomain inhibitors (BETi) are actively being pursued in clinical trials for the treatment of a variety of cancers, however, the mechanisms of resistance to targeted BET protein inhibitors remain poorly understood. Using a novel mass spectrometry approach that globally measures kinase signaling at the proteomic level, we evaluated the response of the kinome to targeted BET inhibitor treatment in a panel of BRD4-dependent ovarian carcinoma (OC) cell lines. Despite initial inhibitory effects of BETi, OC cells acquired resistance following sustained treatment with the BETi, JQ1. Through application of Multiplexed Inhibitor Beads (MIBs) and mass spectrometry, we demonstrate that BETi resistance is mediated by adaptive kinome reprogramming, where activation of compensatory pro-survival kinase networks overcomes BET protein inhibition. Furthermore, drug combinations blocking these kinases may prevent or delay the development of drug resistance and enhance the efficacy of BET inhibitor therapy. RNAseq was employed to identify changes in kinase RNA expression following short term (48h) or chronic (JQ1R) JQ1 treatment in three different ovarian cancer cell lines.
2016-07-21 | E-GEOD-82329 | biostudies-arrayexpress
Project description:The MYC transcription factor is a master regulator of diverse cancer pathways and somatic cell reprogramming. MYC is a compelling therapeutic target that exhibits cancer-specific cellular effects. Pharmacologic inhibition of MYC function has proven challenging due to its numerous modes of forced expression and the difficulty of disrupting protein-DNA interactions. Here we demonstrate the rapid and potent abrogation of MYC gene transcription by representative small molecule bromodomain inhibitors of the BET family of chromatin adaptors. This transcriptional suppression of MYC was observed in the context of the natural, chromosomally translocated, and amplified gene locus. Inhibition of BET bromodomain-promoter interactions and subsequent reduction of MYC transcript and protein levels resulted in G1 arrest and extensive apoptosis in a variety of leukemia and lymphoma cell lines. Exogenous expression of MYC from an artificial promoter that is resistant to BET regulation significantly protected cells from growth suppression by BET inhibitors and revealed that MYC exerts a direct and tight control of key pro-growth and anti-apoptotic target genes. Transcriptional profiling of two cells after 4 and 8 hours of treatment with BET inhibitor shows that both MYC and its targets are strongly down-regulated. We thus demonstrate that pharmacologic inhibition of MYC is achievable through targeting BET bromodomains, and suggest that such inhibitors may have broad clinical applicability given the widespread pathogenetic role of MYC in cancer. LP-1, a multiple myeloma cell line, and Raji, a Burkitt lymphoma cell line, were treated with BET inhibitor and an inactive enantiomer for 4 or 8 hours. Two biological replicates of each sample were profiled on exon arrays.
2011-09-18 | E-GEOD-29449 | biostudies-arrayexpress
Project description:The study was designed to determine the biological effects of novel marine alkaloid analog, FBA-TPQ on human ovarian cancer cells for its anti-tumor potential and the underlying mechanisms as a novel chemotherapeutic agent. Transcriptional profiling of human ovarian cancer cells comparing control vehicle-treated OVCAR-3(a human ovarian cancer cell line) cells with OVCAR-3 cells treated with 1000nM FBA-TPQ for 24 hours. Goal was to determine the effects of FBA-TPQ on global OVCAR-3 cells gene expression.
2011-11-12 | GSE25317 | GEO
Project description:Small molecule BET bromodomain inhibitors (BETi) are actively being pursued in clinical trials for the treatment of a variety of cancers, however, the mechanisms of resistance to targeted BET protein inhibitors remain poorly understood. Using a novel mass spectrometry approach that globally measures kinase signaling at the proteomic level, we evaluated the response of the kinome to targeted BET inhibitor treatment in a panel of BRD4-dependent ovarian carcinoma (OC) cell lines. Despite initial inhibitory effects of BETi, OC cells acquired resistance following sustained treatment with the BETi, JQ1. Through application of Multiplexed Inhibitor Beads (MIBs) and mass spectrometry, we demonstrate that BETi resistance is mediated by adaptive kinome reprogramming, where activation of compensatory pro-survival kinase networks overcomes BET protein inhibition. Furthermore, drug combinations blocking these kinases may prevent or delay the development of drug resistance and enhance the efficacy of BET inhibitor therapy.
2016-07-21 | GSE82329 | GEO
Project description:Epigenetic regulators have emerged as exciting targets for cancer therapy. Additionally, restoration of antitumor immunity by blocking the PD-L1 signaling using antibodies has proven to be beneficial in cancer therapy. Here we show that BET bromodomain inhibition suppresses PD-L1 expression and restores antitumor immunity in ovarian cancer. CD274 (encoding PD-L1) is a direct target of BRD4-mediated gene transcription. In mouse models, treatment with the BET inhibitor JQ1 significantly reduced PD-L1 expression on tumor cells and tumor-associated dendritic cells and macrophages, which correlated with an increase in the activity of antitumor cytotoxic T cells. Together, these data demonstrate an epigenetic approach to block PD-L1 signaling to restore antitumor immunity. Given the fact that BET inhibitors have been proven safe with manageable reversible toxicity in clinical trials, our findings indicate that pharmacological BET inhibitors represent a novel treatment strategy for targeting PD-L1 expression.
2016-10-17 | GSE81698 | GEO
Project description:The study was designed to determine the biological effects of novel marine alkaloid analog, FBA-TPQ on human ovarian cancer cells for its anti-tumor potential and the underlying mechanisms as a novel chemotherapeutic agent. Transcriptional profiling of human ovarian cancer cells comparing control vehicle-treated OVCAR-3(a human ovarian cancer cell line) cells with OVCAR-3 cells treated with 1000nM FBA-TPQ for 24 hours. Goal was to determine the effects of FBA-TPQ on global OVCAR-3 cells gene expression. One-condition experiment, control vehicle-treated OVCAR-3 vs. FBA-TPQ treated-OVCAR-3 cells. Biological replicates: 2 replicates.
2011-11-12 | E-GEOD-25317 | biostudies-arrayexpress
Project description:Three triple negative breast cancer cell lines (MDAMB231, SUM159, and HCC1806) were treated with small molecule inhibitors (JQ1, BET bromodomain inhibitor; GSK2801, BAZ2A/B bromodomain inhibitor) alone and in combination for 72 hours
2019-07-09 | GSE116907 | GEO
Project description:Three triple negative breast cancer cell lines (MDAMB231, SUM159, and HCC1806) were treated with small molecule inhibitors (JQ1, BET bromodomain inhibitor; GSK2801, BAZ2A/B bromodomain inhibitor) or BAZ siRNA alone and in combination with JQ1 for 48 hours
2019-07-09 | GSE116879 | GEO
Project description:The emergence of tumor cells with certain stem-like characteristics such as high aldehyde dehydrogenase (ALDH) activity contributes to chemotherapy resistance. Here we report that inhibition of the BET protein BRD4 potentiates the tumor suppressive effects of cisplatin by targeting ALDH activity. The clinically applicable small molecule BET inhibitor JQ1 synergized with cisplatin by suppressing the growth of epithelial ovarian cancer cells both in vitro and in vivo. This correlated with the suppression of ALDH activity and ALDH1A1 gene expression. BRD4 regulates ALDH1A1 gene transcription through a super-enhancer and expression of its associated enhancer RNA. Thus, targeting the BET protein BRD4 using clinical applicable small molecule inhibitors such as JQ1 is a promising strategy to enhance cisplatin response.
2017-02-05 | GSE77568 | GEO