RNAi screen identifies Brd4 as a therapeutic target in acute myeloid leukemia
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ABSTRACT:
PROVIDER: PRJNA141017 | ENA |
REPOSITORIES: ENA
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Project description:Epigenetic pathways regulate gene expression by controlling and interpreting chromatin modifications. Cancer cells are characterized by altered epigenetic landscapes and commonly exploit the chromatin regulatory machinery to enforce oncogenic gene expression programs. While chromatin alterations are, in principle, reversible and often amendable to drug intervention, the promise of targeting such pathways therapeutically has been hampered by our limited understanding of cancer-specific epigenetic dependencies. Here we describe a non-biased approach to probe epigenetic vulnerabilities in acute myeloid leukemia (AML) – an aggressive hematopoietic malignancy often associated with aberrant chromatin states. By screening a custom shRNA library targeting known chromatin regulators in a genetically defined AML mouse model, we identify the bromodomain-containing protein Brd4 as a critical requirement for disease maintenance. Suppression of Brd4 using shRNAs or the small-molecule inhibitor JQ1 led to robust anti-leukemic effects in vitro and in vivo, accompanied by terminal myeloid differentiation. Extensive evaluation of JQ1-sensitivity in primary human leukemia samples and in established cell lines revealed a broad activity of this compound against diverse AML subtypes. These effects are, at least in part, due to a requirement for Brd4 in maintaining Myc expression and promoting aberrant self-renewal. Together, our results indicate that Brd4 is a promising therapeutic target in AML and identify a small molecule that efficiently targets Myc. These findings also highlight the utility of RNAi screening as a discovery platform for revealing epigenetic vulnerabilities for direct pharmacologic intervention in cancer. In order to understand downstream targets of Brd4, we performed array in murine or human MLL-AF9/NrasG12D cell line under the condition that Brd4 was suppressed by using shRNAs or the small molecule inhibitor JQ1. To test the hypothesis that Myc might be an important target of Brd4, we performed arrary on murine ectopic Myc overexpression MLL-AF9/NrasG12D cell under JQ1 treatment.
2011-08-03 | E-GEOD-29799 | biostudies-arrayexpress
Project description:Epigenetic pathways regulate gene expression by controlling and interpreting chromatin modifications. Cancer cells are characterized by altered epigenetic landscapes and commonly exploit the chromatin regulatory machinery to enforce oncogenic gene expression programs. While chromatin alterations are, in principle, reversible and often amendable to drug intervention, the promise of targeting such pathways therapeutically has been hampered by our limited understanding of cancer-specific epigenetic dependencies. Here we describe a non-biased approach to probe epigenetic vulnerabilities in acute myeloid leukemia (AML) – an aggressive hematopoietic malignancy often associated with aberrant chromatin states. By screening a custom shRNA library targeting known chromatin regulators in a genetically defined AML mouse model, we identify the bromodomain-containing protein Brd4 as a critical requirement for disease maintenance. Suppression of Brd4 using shRNAs or the small-molecule inhibitor JQ1 led to robust anti-leukemic effects in vitro and in vivo, accompanied by terminal myeloid differentiation. Extensive evaluation of JQ1-sensitivity in primary human leukemia samples and in established cell lines revealed a broad activity of this compound against diverse AML subtypes. These effects are, at least in part, due to a requirement for Brd4 in maintaining Myc expression and promoting aberrant self-renewal. Together, our results indicate that Brd4 is a promising therapeutic target in AML and identify a small molecule that efficiently targets Myc. These findings also highlight the utility of RNAi screening as a discovery platform for revealing epigenetic vulnerabilities for direct pharmacologic intervention in cancer.
2011-08-04 | GSE29799 | GEO
Project description:Epigenetic pathways can regulate gene expression by controlling and interpreting chromatin modifications. Cancer cells are characterized by altered epigenetic landscapes, and commonly exploit the chromatin regulatory machinery to enforce oncogenic gene expression programs. Although chromatin alterations are, in principle, reversible and often amenable to drug intervention, the promise of targeting such pathways therapeutically has been limited by an incomplete understanding of cancer-specific dependencies on epigenetic regulators. Here we describe a non-biased approach to probe epigenetic vulnerabilities in acute myeloid leukaemia (AML), an aggressive haematopoietic malignancy that is often associated with aberrant chromatin states. By screening a custom library of small hairpin RNAs (shRNAs) targeting known chromatin regulators in a genetically defined AML mouse model, we identify the protein bromodomain-containing 4 (Brd4) as being critically required for disease maintenance. Suppression of Brd4 using shRNAs or the small-molecule inhibitor JQ1 led to robust antileukaemic effects in vitro and in vivo, accompanied by terminal myeloid differentiation and elimination of leukaemia stem cells. Similar sensitivities were observed in a variety of human AML cell lines and primary patient samples, revealing that JQ1 has broad activity in diverse AML subtypes. The effects of Brd4 suppression are, at least in part, due to its role in sustaining Myc expression to promote aberrant self-renewal, which implicates JQ1 as a pharmacological means to suppress MYC in cancer. Our results establish small-molecule inhibition of Brd4 as a promising therapeutic strategy in AML and, potentially, other cancers, and highlight the utility of RNA interference (RNAi) screening for revealing epigenetic vulnerabilities that can be exploited for direct pharmacological intervention.
| S-EPMC3328300 | biostudies-literature
Project description:Targeted therapy has vastly improved outcomes in certain types of cancer. Extension of this paradigm across a broad spectrum of malignancies will require an efficient method to determine the molecular vulnerabilities of cancerous cells. Improvements in sequencing technology will soon enable high-throughput sequencing of entire genomes of cancer patients; however, determining the relevance of identified sequence variants will require complementary functional analyses. Here, we report an RNAi-assisted protein target identification (RAPID) technology that individually assesses targeting of each member of the tyrosine kinase gene family. We demonstrate that RAPID screening of primary leukemia cells from 30 patients identifies targets that are critical to survival of the malignant cells from 10 of these individuals. We identify known, activating mutations in JAK2 and K-RAS, as well as patient-specific sensitivity to down-regulation of FLT1, CSF1R, PDGFR, ROR1, EPHA4/5, JAK1/3, LMTK3, LYN, FYN, PTK2B, and N-RAS. We also describe a previously undescribed, somatic, activating mutation in the thrombopoietin receptor that is sensitive to down-stream pharmacologic inhibition. Hence, the RAPID technique can quickly identify molecular vulnerabilities in malignant cells. Combination of this technique with whole-genome sequencing will represent an ideal tool for oncogenic target identification such that specific therapies can be matched with individual patients.
| S-EPMC2680429 | biostudies-literature
Project description:Genomewide T. brucei RNAi screen using proteasome inhibitor
| PRJEB31738 | ENA
Project description:Developing & Optimizing Acute Myeloid Leukemia Specific Therapeutic Antibodies [CRISPR Screen]
| PRJNA843099 | ENA
Project description:Recent research has revealed that BRD4, a bromodomain and extra terminal domain (BET) epigenetic ‘reader’ protein, plays an essential role in regulating behavioral and molecular responses to cocaine. To date, the roles of BRD4 and other BET proteins in substance use disorder (SUD) models have been mainly studied using small molecule inhibitors that block the bromodomain interactions with acetylated histones. In other disease models, non-bromodomain BRD4-protein interactions have also been shown to play an important role in BRD4’s molecular functions, but these interactions have yet to be studied in SUD models. Here, using BRD4 co-immunoprecipitation coupled to tandem mass spectrometry, we identified several putative BRD4-interacting proteins in the nucleus accumbens (NAc) that are altered by acute or repeated cocaine exposure in male and female Sprague Dawley rats. In BRD4-immunoprecipitated samples, gene ontology molecular function analysis revealed an enrichment of pathways associated with polymerase activity, SH3 domain binding, and chromatin-protein-adaptor activity in the cocaine treated groups. Notably, casein kinase 1 epsilon (CK1ε), a protein previously implicated in SUDs, was identified as a putative BRD4-interacting protein, and this association was increased following repeated cocaine injections. However, no significant change in total CK1ε protein expression was observed in the NAc via western blot following acute or repeated cocaine treatment. In additional experiments, we sought to determine the effects of CK1ε inhibition on the expression of a cocaine-related memory. Pharmacological inhibition of CK1ε with PF-4800567 diminished the expression of cocaine conditioned place preference. In a separate cohort of rats, an acute injection of PF-4800567 did not alter locomotor activity and anxiety-like behavior in the open field test. Collectively, these findings suggest that several novel proteins, including CK1ε, may play a role in BRD4-mediated molecular adaptations to cocaine exposure, and that CK1ε represents a potential target for future investigation in animal models of cocaine-seeking behavior.
2026-01-22 | PXD065009 | Pride
Project description:We performed microarray analysis of cells expressing LACZ or HOXC10 treated with MEK and BRD4 inhibition in combination for 24 hours, prior to the induction of cell death, to analyze transcriptional changes that might be mechanistic drivers of the therapeutic effect. 12 samples in triplicate, 3X LACZ + vehicle treatment, 3X HOXC10 + vehicle treatment, 3X LACZ + combo treatment, 3X HOXC10 + combo treatment
2021-09-02 | E-MTAB-7181 | biostudies-arrayexpress
Project description: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. Expression of BRD4 mRNA and protein was determined by bioinformatics interrogation of public 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. 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-regualted genes was developed to stratify patients into subgroups with favorable or inferior prognosis. Our findings reveal that BRD4 serves as a novel oncogene driving cancer progression and a robust prognostic biomarker in HNSCC. Therapeutic targeting of BRD4 represents a potent and promising strategy against HNSCC.
2019-05-09 | GSE122522 | GEO
Project description:Genome-wide T. brucei RNAi screen with compound 25
| PRJEB38509 | ENA