Resistance of estrogen receptor function to BET bromodomain inhibition is mediated by transcriptional coactivator cooperativity
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE241695 | GEO | 2024/06/25
REPOSITORIES: GEO
Similar Datasets
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 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. ChIP-Seq for regulatory factors of Brd4 in MLL-AF9 transformed acute myeloid leukemia cells (RN2)
2015-05-01 | E-GEOD-66122 | biostudies-arrayexpress
Project description:BET bromodomain inhibition (BETi) abrogates cancer cell growth by disrupting oncogenic gene expression. BRD4 loading at enhancers has been suggested to mediate pause-release and underlie the selective transcriptional response to BETi. Here, we utilized GRO-seq coupled with ChIP-seq to assess the association between gene control elements and the transcriptional response to BETi. Genes immediately down-regulated by BETi display a marked pause-release defect with a minimal impact on transcript elongation within the gene body. Surprisingly, we find that BRD4 at super-enhancers does not render its associated genes or enhancer RNAs preferentially sensitive to BETi. In contrast, disproportionate loading of BRD4 at transcription start sites (TSS) correlates with the transcriptional response to BETi. Moreover, BRD4 loading at TSSs, but not enhancers, is associated with enhanced promoter-proximal pausing following BETi. Our findings stress a mechanistic role of promoter-associated BRD4 in pause-release and suggest that BRD4 loading at the TSS drives the selective transcriptional response to BETi.
2023-01-06 | GSE70449 | GEO
Project description:BET bromodomain inhibition (BETi) abrogates cancer cell growth by disrupting oncogenic gene expression. BRD4 loading at enhancers has been suggested to mediate pause-release and underlie the selective transcriptional response to BETi. Here, we utilized GRO-seq coupled with ChIP-seq to assess the association between gene control elements and the transcriptional response to BETi. Genes immediately down-regulated by BETi display a marked pause-release defect with a minimal impact on transcript elongation within the gene body. Surprisingly, we find that BRD4 at super-enhancers does not render its associated genes or enhancer RNAs preferentially sensitive to BETi. In contrast, disproportionate loading of BRD4 at transcription start sites (TSS) correlates with the transcriptional response to BETi. Moreover, BRD4 loading at TSSs, but not enhancers, is associated with enhanced promoter-proximal pausing following BETi. Our findings stress a mechanistic role of promoter-associated BRD4 in pause-release and suggest that BRD4 loading at the TSS drives the selective transcriptional response to BETi.
2023-01-06 | GSE70448 | GEO
Project description:BET bromodomain inhibition (BETi) abrogates cancer cell growth by disrupting oncogenic gene expression. BRD4 loading at enhancers has been suggested to mediate pause-release and underlie the selective transcriptional response to BETi. Here, we utilized GRO-seq coupled with ChIP-seq to assess the association between gene control elements and the transcriptional response to BETi. Genes immediately down-regulated by BETi display a marked pause-release defect with a minimal impact on transcript elongation within the gene body. Surprisingly, we find that BRD4 at super-enhancers does not render its associated genes or enhancer RNAs preferentially sensitive to BETi. In contrast, disproportionate loading of BRD4 at transcription start sites (TSS) correlates with the transcriptional response to BETi. Moreover, BRD4 loading at TSSs, but not enhancers, is associated with enhanced promoter-proximal pausing following BETi. Our findings stress a mechanistic role of promoter-associated BRD4 in pause-release and suggest that BRD4 loading at the TSS drives the selective transcriptional response to BETi.
2023-01-06 | GSE70447 | GEO
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
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.
2013-02-25 | GSE43392 | GEO
Project description:IL-17-producing T helper (TH17) cells have been selected through evolution for their ability to control fungal and bacterial infections. It is also firmly established that their aberrant generation and activation results in autoimmune conditions. Using a characterized potent and selective small molecule inhibitor, we show that the bromodomain and extra-terminal domain (BET) family of chromatin adaptors plays fundamental and selective roles in human and murine TH17 differentiation from naM-CM-/ve CD4+ T cells, as well as in the activation of previously differentiated TH17 cells. We provide evidence that BET controls TH17 differentiation in a bromodomain-dependent manner through a mechanism that includes the direct regulation of multiple effector TH17-associated cytokines, including IL17, IL21 and GMCSF. We also demonstrate that BET family members Brd2 and Brd4 associate with the Il17 locus in TH17 cells, and that this association requires bromodomains. We recapitulate the critical role of BET bromodomains in TH17 differentiation in vivo and show that therapeutic dosing of the BET inhibitor is efficacious in mouse models of autoimmunity. Our results identify the BET family of proteins as a fundamental link between chromatin signaling and TH17 biology, and support the notion of BET inhibition as a point of therapeutic intervention in autoimmune conditions. 4 samples were analyzed: two conditions in duplicate. Naive T cells were placed in conditions leading to TH17 differentiation, with and without BET inhibitor. RNA was collected at 48 hours.
2013-09-20 | E-GEOD-37270 | biostudies-arrayexpress
Project description:The BET family protein BRD4, which forms the CDK9-containing BRD4-PTEFb complex, is considered to be a master regulator of RNA polymerase II (Pol II) pause release. Because its tandem bromodomains interact with acetylated histone lysine residues, it has long been thought that BRD4 requires these bromodomains for its recruitment to chromatin and transcriptional regulatory function. Here, using rapid depletion and genetic complementation with domain deletion mutants, we demonstrate that BRD4 bromodomains are dispensable for Pol II pause release. A minimal, bromodomain-less C-terminal BRD4 fragment containing the PTEFb-interacting C-terminal motif (CTM) is instead both necessary and sufficient to mediate Pol II pause release in the absence of full-length BRD4. Although BRD4-PTEFb can associate with chromatin through acetyl recognition, our results indicate that a distinct, active BRD4-PTEFb population functions to regulate transcription independently of bromodomain-mediated chromatin association. These findings may enable more effective pharmaceutical modulation of BRD4-PTEFb activity.
2023-07-14 | GSE232869 | GEO