Selective Inhibition of Tumor Oncogenes by Disruption of Super-Enhancers
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Richard Young
PROVIDER: E-GEOD-44931 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:Chromatin regulators have become highly attractive targets for cancer therapy, yet many of these regulators are expressed in a broad range of healthy cells and contribute generally to gene expression. An important conundrum has thus emerged: how can inhibition of a general regulator of gene expression produce selective effects at specific oncogenes? Here we investigate how inhibition of the transcriptional coactivator BRD4 (Bromodomain containing 4) leads to selective inhibition of disease-critical oncogenes in a highly malignant blood cancer, multiple myeloma (MM). We found that BRD4 generally occupies the promoter elements of active genes together with the Mediator coactivator, but remarkably high levels of these two coactivator proteins were associated with a small set of exceptionally large enhancers. These super-enhancers are associated with genes that feature prominently in MM biology, including the MYC oncogene. Treatment of MM tumor cells with the BET-bromodomain inhibitor JQ1 led to preferential loss of BRD4 at super-enhancers and consequent transcription elongation defects that preferentially impact genes with super-enhancers, including the c-MYC oncogene. Super-enhancers were found at key oncogenic drivers in many other tumor cells. Thus, super-enhancers can regulate oncogenic drivers in tumor cells, which in some cells can be preferentially disrupted by BRD4 inhibition, which in turn contributes to the selective transcriptional effects observed at these oncogenes. These observations have implications for the discovery of novel cancer therapeutics directed at components of super-enhancers in diverse tumor types. Gene expression profiling in multiple myeloma cells after BET-Bromodomain inhibition with JQ1
2013-03-07 | E-GEOD-44929 | biostudies-arrayexpress
Project description:ChIP-Seq of RNA Polymerase II, and transcriptional regulators in multiple myeloma (MM.1S), glioblastoma (U87-MG), and small cell lung carcinoma (H2171) treated with the BET bromodomain inhibitor JQ1. Cell lines (MM.1S, U87-MG, and H2171) representing multiple myeloma, glioblastoma, and small cell lung carcinoma, were treated with varying concentrations (5nM to 5µM) of the BET bromodomain inhibitor JQ1 followed by ChIP-Seq for RNA Polymerase II and transcriptional regulators. Other datasets from this series of experiments have been release as a part of GSE42355.
2013-07-26 | E-GEOD-49224 | biostudies-arrayexpress
Project description:Chromatin regulators have become highly attractive targets for cancer therapy, yet many of these regulators are expressed in a broad range of healthy cells and contribute generally to gene expression. An important conundrum has thus emerged: how can inhibition of a general regulator of gene expression produce selective effects at specific oncogenes? Here we investigate how inhibition of the transcriptional coactivator BRD4 (Bromodomain containing 4) leads to selective inhibition of disease-critical oncogenes in a highly malignant blood cancer, multiple myeloma (MM). We found that BRD4 generally occupies the promoter elements of active genes together with the Mediator coactivator, but remarkably high levels of these two coactivator proteins were associated with a small set of exceptionally large enhancers. These super-enhancers are associated with genes that feature prominently in MM biology, including the MYC oncogene. Treatment of MM tumor cells with the BET-bromodomain inhibitor JQ1 led to preferential loss of BRD4 at super-enhancers and consequent transcription elongation defects that preferentially impact genes with super-enhancers, including the c-MYC oncogene. Super-enhancers were found at key oncogenic drivers in many other tumor cells. Thus, super-enhancers can regulate oncogenic drivers in tumor cells, which in some cells can be preferentially disrupted by BRD4 inhibition, which in turn contributes to the selective transcriptional effects observed at these oncogenes. These observations have implications for the discovery of novel cancer therapeutics directed at components of super-enhancers in diverse tumor types. ChIP-Seq for chromatin regulators and RNA Polymerase II in multiple myeloma, glioblastoma multiforme, and small cell lung cancer
2013-01-02 | E-GEOD-42355 | biostudies-arrayexpress
Project description:The bromodomain and extraterminal (BET) protein Brd4 is a validated drug target in leukemia, yet its regulatory function in this disease is not well understood. Here, we show that Brd4 chromatin occupancy in acute myeloid leukemia closely correlates with the hematopoietic transcription factors (TFs) Pu.1, Fli1, Erg, C/EBPα, C/EBPβ, and Myb at nucleosome-depleted enhancer and promoter regions. We provide evidence that these TFs, in conjunction with the lysine acetyltransferase activity of p300/CBP, facilitate Brd4 recruitment to their occupied sites to promote transcriptional activation. Moreover, chemical inhibition of BET bromodomains is found to suppress the functional output each hematopoietic TF, thereby interfering with essential lineage-specific transcriptional circuits in this disease. These findings reveal a chromatin-based signaling cascade comprised of hematopoietic TFs, p300/CBP, and Brd4, which supports leukemia maintenance and is suppressed by BET bromodomain inhibition. PolyA selected RNA-Seq for drug treated or shRNA-expressing MLL-AF9 transformed acute myeloid leukemia cells (RN2)
2015-05-01 | E-GEOD-66068 | biostudies-arrayexpress
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2015-05-01 | E-GEOD-66123 | biostudies-arrayexpress
Project description:Triple-negative breast cancer (TNBC) is a highly aggressive form of breast cancer that exhibits extremely high levels of genetic complexity and yet a relatively uniform transcriptional program. We postulate that TNBC might be highly dependent on uninterrupted transcription of a key set of genes within this gene expression program and might therefore be exceptionally sensitive to inhibitors of transcription. Utilizing a novel kinase inhibitor and CRISPR/Cas9-mediated gene editing, we show here that triple-negative but not ER/PR+ breast cancer cells are exceptionally dependent on CDK7, a transcriptional cyclin-dependent kinase. TNBC cells are unique in their dependence on this transcriptional CDK and suffer apoptotic cell death upon CDK7 inhibition. An “Achilles cluster” of TNBC-specific genes are extremely sensitive to CDK7 inhibition and frequently associated with super-enhancers. We conclude that CDK7 mediates transcriptional addiction to a vital cluster of genes in TNBC and CDK7 inhibition may be useful therapy for this challenging cancer. Expression microarrays in H3K27ac in triple-negative breast cancer +/- treatment with covalent CDK7 inhibitor THZ1 treatment
2015-09-24 | E-GEOD-69106 | biostudies-arrayexpress
Project description:MM1.S cells are an aggressive dexamethasone sensitive multiple myeloma cell line whose transcritional program is driven by deregulated c-Myc activity. We present ChIP-seq analysis of key transcritional regulators that are implicated the c-Myc transcriptional network in MM1.S cells treated with vehicle or 500nM JQ1. Brd4, Cdk9, cMyc, Max, Med1, RNA Pol II, and the chromatin modifications H3K4me3 and H3K27Ac were profiled in MM1.S cells treated with 500nM JQ1 for 24hr
2012-11-30 | E-GEOD-42161 | biostudies-arrayexpress
Project description:Selective bromodomains inhibitors block the interaction between diverse bromodomains and extraterminal domains (BET) proteins and acetylated proteins. These inhibitors have shown beneficial effects in cancers malignancies and experimental inflammation in mouse models, but data on renal diseases are scarce. We have investigated the effect of the BET proteins inhibitor JQ1 in a mice model of unilateral ureteral obstruction. Treatment with JQ1 diminished renal damage, the presence of inflammatory cell infiltration and the upregulation of proinflammatory genes. The in vitro evaluation of JQ1 on TNF-α inducible genes in renal cells showed that BET inhibition modulated several biological processes, including inflammation or immune response. Moreover, gene-silencing experiments showed that BRD4 regulates several proinflammatory genes (IL-6, CCL-2 and CCL-5) and chromatin immunoprecipitation techniques demonstrated that BRD4 specifically binds to acetylated histone H3 in the promoter region of those genes. The nuclear factor-ï«B (NF-ï«B) pathway regulates renal inflammation. The RelA NF-ï«B subunit is activated by acetylation of lysine 310. In damaged kidneys and in TNF-α-treated renal cells, JQ1 blocked the nuclear translocation of RelA/NF-ï«B and NF-ï«B-mediated gene expression. Additionally, obstructed kidneys showed an activation of the Th17 immune response, which was diminished by JQ1 treatment. Our results demonstrate that the BET inhibition decreases renal inflammation by 3 independent mechanisms: 1) chromatin remodelling in the promoter regions of specific genes, 2) blocking NF-ï«B pathway activation, and 3) modulating the Th17 immune response. These results suggest that BET inhibitors could have important therapeutic applications in inflammatory renal diseases. HK2 cell line was treated with JQ1 or its enantiomer JQ1(-) (500nM) for 1 hour before stimulation or not with TNF-α (5ng/ml) for additional 3h. We analized the genes up- and down-regulated by TNF-α vs unstimulated cells, and further the genes downregulated or unaffected by JQ1 compared to the cells treated with the enantiomer (-) JQ1.
2016-07-01 | E-GEOD-71602 | biostudies-arrayexpress
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2014-09-29 | E-GEOD-54000 | biostudies-arrayexpress
Project description:Background. Heat shock protein 90 (Hsp90) is essential for the stability and the function of many client proteins, such as ERB2, C-RAF, CDK4, HIF-1 aplha and AKT. Recent reports demonstrated that inhibition of Hsp90 modulates multiple functions required for survival of human cancer, such as myeloma (Mitsiades et al, Blood:107, 1092, 2006), however, the precise mechanism of anti-cancer effect of Hsp90 inhibition is still uncertain. Aim. The aim of this study is evaluate the effect of Hsp90 inhibition, and to identify molecular pathways responsible for anti-proliferative effect on ATL cells. Method. For Hsp90 inhibition, Geldanamycin derivates, 17AAG (17-allylamino -17-demethoxygeldanamycin) and 17DMAG (17-(dimethylaminoethylamino) 17-demethoxygeldanamycin) were used in this study. Interleukin 2-independent ATL cell lines (MT-2 and MT-4) and an interleukin 2-dependent ATL cell line (TaY) were incubated, with or without Hsp90 inhibitors. Fresh ATL cells obtained from patients were also used after obtaining informed consent. Cell numbers at 48 h after incubation with or without Hsp90 inhibitors were assessed with the Cell Counting Kit-8 assay (Dojindo Molecular Technologies, Gaithersburg, MD, USA). For detection of apoptosis, we used Annexin V-biotin apoptosis detection kit (Calbiochem, La Jolla, CA, USA). Gene expression analysis was done using a DNA microarray (NCBI Gene expression omnibus; GPL 2531) and statistical analysis was done by a GeneSifter (VizXlabs, Seattle, WA, USA). Results. We found cell death induced by Hsp90 inhibitors in all the 3 ATL cell lines as well as patient specimens. Inhibitory concentration (IC50) of 17AAG in 3 ATL cell lines was 300 to 700 nM, and that of 17DMAG was 150 to 200 nM. Fresh ATL cells obtained from patients were more sensitive for either 17AAG or 17DMAG. Gene expression analysis of ATL cells revealed that up-regulation of HSPA1A encoding Hsp70, and genes related to cell cycle arrest (i.e. CDKN1A). Genes regulating cell proliferation or anti-apoptosis (i.e. MYC, BCL2 and Cyclin C), genes related to cytokine or chemokine (i.e. IL9, CCL 17, and CCL27), and notably, genes involved in Wnt/-catenin signaling pathway (i.e.TCF7L2 and TCF4), were remarkably repressed. Inhibition of AKT at the protein level was also evident, suggesting the possibility that AKT may down-regulates -catenin/ TCF7L2 pathways in response to Hsp90 inhibitors in ATL cells. Conclusion. Our results have provided new insights into the complex molecular pharmacology of Hsp90 inhibitors, and suggest that Hsp90 inhibitors might be beneficial as anti-proliferative agent in treating ATL patients. Six samples treated with Hsp90 inhibitors (17-AAG or 17-DMAG) were analyzed in biological duplicate.
2009-05-27 | E-GEOD-12257 | biostudies-arrayexpress