Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1060487 | ENA |
REPOSITORIES: ENA
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Project description:Bromodomain and Extra Terminal protein (BET) inhibitors are first-in-class targeted therapies that deliver a new therapeutic paradigm by directly targeting epigenetic readers1,2. Early clinical trials have shown significant promise especially in acute myeloid leukaemia (AML)3; therefore the evaluation of resistance mechanisms, an inevitable consequence of cancer therapies, is of utmost importance to optimise the clinical efficacy of these drugs. Using primary murine stem and progenitor cells immortalised with MLL-AF9, we have used an innovative approach to generate 20 cell lines derived from single cell clones demonstrating stable resistance, in vitro and in vivo, to the prototypical BET inhibitor, I-BET. Resistance to I-BET confers cross-resistance to chemically distinct BET inhibitors such as JQ1, as well as resistance to genetic knockdown of BET proteins. Resistance is not mediated through increased drug efflux or metabolism but is demonstrated to emerge from leukaemia stem cells (LSC). Resistant clones display a leukaemic granulocyte-macrophage progenitor (L-GMP) phenotype (Lin-, Sca-, cKit+, CD34+, Fc³RII/RIII+) and functionally exhibit increased clonogenic capacity in vitro and markedly shorter leukaemia latency in vivo. Chromatin bound BRD4 is globally reduced in resistant cells, however expression of key target genes such as MYC remains unaltered, highlighting the existence of alternative mechanisms to regulate transcription. We demonstrate that resistance to BET inhibitors is in part a consequence of increased Wnt/²-catenin signaling. Negative regulation of this pathway results in differentiation of resistant cells into mature leukaemic blasts, inhibition of MYC expression and restoration of sensitivity to I-BET in vitro and in vivo. Finally, we show that the sensitivity of primary human AML cells to I-BET correlates with the baseline expression of Wnt/²-catenin target genes. Together these findings provide novel insights into the biology of AML, highlight the potential therapeutic limitations of BET inhibitors and identify strategies that may overcome resistance and enhance the clinical utility of these unique targeted therapies. Comparison of iBET resistant and sensitive cell lines
2015-09-15 | E-GEOD-63682 | biostudies-arrayexpress
Project description:Patients with cholangiocarcinoma have poor clinical outcomes due to late diagnoses, poor prognoses, and limited treatment strategies. To identify novel drug combinations for this disease, we have conducted a genome-wide CRISPR screen anchored on the bromodomain and extraterminal domain (BET) PROTAC degrader ARV-825, from which we identified anti-cancer synergy when combined with genetic ablation of members of the mTOR pathway. This combination effect was validated using multiple pharmacological BET and mTOR inhibitors, accompanied by increased levels of apoptosis and cell cycle arrest. In a xenograft model, combined BET degradation and mTOR inhibition induced tumor regression. Mechanistically, the two inhibitor classes converged on H3K27ac-marked epigenetic suppression of the serine glycine one carbon (SGOC) metabolism pathway, including the key regulators PHGDH and PSAT1. Knockdown of PSAT1 was sufficient to replicate synergy with single agent inhibition of either BET or mTOR. Our results tied together epigenetic regulation, metabolism, and apoptosis induction as key therapeutic targets for further exploration in this underserved disease.
2024-02-01 | GSE248633 | GEO
Project description:Diffuse Large B-Cell Lymphoma (DLBCL) is a biologically heterogeneous and clinically aggressive disease. Here, we explore the role of BET bromodomain proteins in DLBCL, using integrative chemical genetics and functional epigenomics. We observe highly asymmetric loading of BRD4 at enhancers, with approximately 33% of all BRD4 localizing to enhancers at 1.6% of occupied genes. These super-enhancers prove particularly sensitive to bromodomain inhibition, explaining the selective effect of BET inhibitors on oncogenic and lineage-specific transcriptional circuits. Functional study of genes marked by super-enhancers identifies DLBCLs dependent on OCA-B and suggests a strategy for discovering unrecognized cancer dependencies. Translational studies performed on a comprehensive panel of DLBCLs establish a therapeutic rationale for evaluating BET inhibitors in this disease. ChIP-Seq for various transcription factors and histone modifications in diffuse large B-cell lymphoma cells
2013-12-10 | E-GEOD-46663 | biostudies-arrayexpress
Project description:NUT midline carcinoma (NMC) is a rare, aggressive subtype of squamous carcinoma that is driven by the BRD4-NUT fusion oncoprotein. BRD4, a BET protein, binds to chromatin through its two bromodomains, and NUT recruits the p300 histone acetyltransferse (HAT) to activate transcription of oncogenic target genes. BET selective bromodomain inhibitors have demonstrated on-target activity in NMC patients, but with limited efficacy. P300, like BRD4, contains a bromodomain. We show that combining selective p300/CBP and BET bromodomain inhibitors, GNE-781 and OTX015, respectively, induces synergistic inhibition of NMC growth. Treatment of NMC cells with the novel dual p300/CBP and BET bromodomain selective inhibitor, NEO2734, potently inhibits growth and induces differentiation of NMC cells in vitro; findings that correspond with potentiated transcriptional effects from combined BET and p300 bromodomain inhibition. In three disseminated NMC xenograft models, NEO2734 provided greater growth inhibition, with tumor regression and significant survival benefit seen in two of three models, compared with a lead clinical BET inhibitor or 'standard' chemotherapy.
2020-06-19 | GSE142481 | GEO
Project description:Bromodomain and extra-terminal domain (BET) proteins are therapeutic targets in several cancers including the most common malignant adult brain tumor glioblastoma (GBM). Multiple small molecule inhibitors of BET proteins have been utilized in preclinical and clinical studies. Unfortunately, BET inhibitors have not shown efficacy in clinical trials enrolling GBM patients. One possible reason for this may stem from resistance mechanisms that arise after prolonged treatment within a clinical setting. However, the mechanisms and timeframe of resistance to BET inhibitors in GBM is not known. To identify the temporal order of resistance mechanisms in GBM we performed quantitative proteomics using multiplex-inhibitor bead mass spectrometry and demonstrated that resistance to BET inhibitors in GBM treatment occurs rapidly within hours and involves the fibroblast growth factor receptor 1 (FGFR1) protein. Small molecule inhibition of BET proteins and FGFR1 simultaneously induces synergy in reducing GBM tumor growth in vitro and in vivo. Further, FGFR1 knockdown synergizes with BET inhibitor mediated reduction of GBM cell proliferation. Collectively, our studies suggest that co-targeting BET and FGFR1 may dampen resistance mechanisms to yield a clinical response in GBM.
2024-06-16 | PXD043214 | Pride
Project description:Following the discovery of BRD4 as a non-oncogene addiction target in acute myeloid leukemia (AML), BET inhibitors are being explored as promising therapeutic avenue in numerous cancers. While clinical trials have reported single-agent activity in advanced hematologic malignancies, mechanisms determining the response to BET inhibition remain poorly understood. To identify factors involved in primary and acquired BET resistance in leukemia, we performed a chromatin-focused shRNAmir screen in a sensitive MLL/AF9; NrasG12D‑driven AML model, and investigated dynamic transcriptional profiles in sensitive and resistant murine and human leukemias. Our screen reveals that suppression of the PRC2 complex, contrary to effects in other contexts, promotes BET resistance in AML. PRC2 suppression does not directly affect the regulation of Brd4-dependent transcripts, but facilitates the remodeling of regulatory pathways that restore the transcription of key targets such as Myc. Similarly, while BET inhibition triggers acute MYC repression in human leukemias regardless of their sensitivity, resistant leukemias are uniformly characterized by their ability to rapidly restore MYC transcription. This process involves the activation and recruitment of WNT signaling components, which compensate for the loss of BRD4 and drive resistance in various cancer models. Dynamic ChIP- and STARR-seq enhancer profiles reveal that BET-resistant states are characterized by remodeled regulatory landscapes, involving the activation of a focal MYC enhancer that recruits WNT machinery in response to BET inhibition. Together, our results identify and validate WNT signaling as a driver and candidate biomarker of primary and acquired BET resistance in leukemia, and implicate the rewiring of transcriptional programs as an important mechanism promoting resistance to BET inhibitors and, potentially, other chromatin-targeted therapies. RNA-Seq of DMSO- or JQ1-treated cancer cell lines; ChIP-seq for H3K36me3 and H3K27me3 in a leukemia cell line treated either with DMSO or JQ1, ChIP-seq for H3K27ac in resistant and sensitive mouse and human leukemia. Functional enhancer mapping (STARR-seq) in K-562 treated either with DMSO or JQ1.
2015-09-08 | E-GEOD-63782 | biostudies-arrayexpress
Project description:Background: Bromodomain and extra-terminal domain (BET) proteins and the spleen tyrosine kinase (SYK) represent promising targets in Diffuse large B-cell (DLBCL) and Burkitt’s lymphoma (BL). We evaluated the anti-lymphoma activity of the isoform specific bivalent BET inhibitor AZD5153 (AZD) and the pan-BET inhibitor I-BET151 (I-BET) as single agents and in combination with SYK inhibitor Entospletinib in vitro. Methods: Single agent exposures were evaluated on two DLBCL and two BL cell lines analyzing cell proliferation and metabolic activity. Proliferation, metabolic activity, apoptosis, cell cycle and morphology were investigated after combined AZD or I-BET and Ento exposure. RNAseq of combined AZD+Ento exposure was characterized in SU-DHL-4. Background: Bromodomain and extra-terminal domain (BET) proteins and the spleen tyrosine kinase (SYK) represent promising targets in Diffuse large B-cell (DLBCL) and Burkitt’s lymphoma (BL). We evaluated the anti-lymphoma activity of the isoform specific bivalent BET inhibitor AZD5153 (AZD) and the pan-BET inhibitor I-BET151 (I-BET) as single agents and in combination with SYK inhibitor Entospletinib in vitro. Methods: Single agent exposures were evaluated on two DLBCL and two BL cell lines analyzing cell proliferation and metabolic activity. Proliferation, metabolic activity, apoptosis, cell cycle and morphology were investigated after combined AZD or I-BET and Ento exposure. RNAseq of combined AZD+Ento exposure was characterized in SU-DHL-4. Results: Both BET inhibitors reduced cell proliferation/metabolic activity dose and time de-pendently. Combined BET and SYK inhibition enhanced the anti-proliferative effect and induc-ing a G0/G1 cell cycle arrest. SU-DHL-4 demonstrated a pronounced modulation of gene expres-sion by AZD, which was markedly increased by additional SYK inhibition. Functional enrich-ment analyses identified combination-specific GO terms related to cell division, transport and DNA replication. Genes such as PLEKHH3, MYB, SLC8A1, PARP9, HSPB1 and S100A4 were iden-tified as the presumable key regulators. Conclusion: Simultaneous inhibition of BET and SYK enhanced the anti-proliferative effects, and especially the combination-specific gene expression signature.
2022-07-08 | GSE207381 | GEO
Project description:In the activated B cell-like (ABC) subtype of diffuse large B cell lymphoma (DLBCL), NF-kappaB activity is essential for viability of the malignant cells and is sustained by constitutive activity of IkappaB kinase (IKK) in the cytoplasm. Here, we report an unexpected role for the bromodomain and extraterminal domain (BET) proteins BRD2 and BRD4 in maintaining oncogenic IKK activity in ABC DLBCL. IKK activity was reduced by small molecules targeting BET proteins as well as by genetic knockdown of BRD2 and BRD4 expression, thereby inhibiting downstream NF-kappaB-driven transcriptional programs and killing ABC DLBCL cells. Using a high-throughput platform to screen for drug-drug synergy, we observed that the BET inhibitor JQ1 combined favorably with multiple drugs targeting B cell receptor signaling, one pathway that activates IKK in ABC DLBCL. The BTK kinase inhibitor ibrutinib, which is in clinical development for the treatment of ABC DLBCL, synergized strongly with BET inhibitors in killing ABC DLBCL cells in vitro and in a xenograft mouse model. These findings provide a mechanistic basis for the clinical development of BET protein inhibitors in ABC DLBCL, particularly in combination with other modulators of oncogenic IKK signaling. For JQ1 time course gene expression profiling, HBL1 and LP1 cells were treated with either DMSO or 100nM JQ1 for 1h, 3h, 8h, and 24h. For shRNA gene expression profiling, HBL1 cells were infected with either a Ctrl shRNA or with shRNA targeting BRD2 or BRD4. Following puromycin selection, shRNA expression was induced for 1 day and 2 days.
2014-08-01 | E-GEOD-58791 | biostudies-arrayexpress
Project description:Background: Bromodomain and extra-terminal domain (BET) proteins and the spleen tyrosine kinase (SYK) represent promising targets in Diffuse large B-cell (DLBCL) and Burkitt’s lympho-ma (BL). We evaluated the anti-lymphoma activity of the isoform specific bivalent BET inhibitor AZD5153 (AZD) and the pan-BET inhibitor I-BET151 (I-BET) as single agents and in combination with SYK inhibitor Entospletinib in vitro. Methods: Single agent exposures were evaluated on two DLBCL and two BL cell lines analyzing cell proliferation and metabolic activity. Proliferation, metabolic activity, apoptosis, cell cycle and morphology were investigated after combined AZD or I-BET and Ento exposure. RNAseq of combined AZD+Ento exposure was characterized in SU-DHL-4. Results: Both BET inhibitors reduced cell proliferation/metabolic activity dose and time de-pendently. Combined BET and SYK inhibition enhanced the anti-proliferative effect and induc-ing a G0/G1 cell cycle arrest. SU-DHL-4 demonstrated a pronounced modulation of gene expres-sion by AZD, which was markedly increased by additional SYK inhibition. Functional enrich-ment analyses identified combination-specific GO terms related to cell division, transport and DNA replication. Genes such as PLEKHH3, MYB, SLC8A1, PARP9, HSPB1 and S100A4 were iden-tified as the presumable key regulators. Conclusion: Simultaneous inhibition of BET and SYK enhanced the anti-proliferative effects, and especially the combination-specific gene expression signature.
2022-07-08 | GSE207382 | GEO
Project description:We have identified a cluster of ELOA3 gene homologs that are activated upon treatment with BET bromodomain inhibitors and mediate sensitivity to BET inhibition.
2023-11-29 | GSE210196 | GEO