Project description:Assess the efficacy of OTX015 (MK-8628) BET inhibitor, with respect to various lung carcinomas tumors, and to characterize its mechanism of action
Project description:assess the efficacy of OTX015, a BET Bromodomain inhibitor,with respect to various lymphoma models, and to characterize its mechanism of action
Project description:The BET Bromodomain inhibitor OTX015 (MK-8628) in mantle cell lymphoma: in vivo activity and identification of novel combinations to overcome adaptive resistance
Project description:Aberrant changes in microRNAs (miRNAs) contribute to lymphomagenesis and represent potential therapeutic targets. OTX015 (MK-8628), a bromodomain and extra-terminal domain (BET) inhibitor (BETi), has demonstrated preclinical and clinical activity in haematological tumours. To better understand the mechanism of action of OTX015 we studied its effects on miRNAs in lymphomas. We performed miRNA profiling of DLBCL cells treated with OTX015 and observed changes in the expression levels of a subset of miRNAs, including miR-92a-1-5p, miR-21-3p, miR-155-5p and miR-96-5p, which are known to play a role in lymphomagenesis and/or resistance to chemotherapy. Analysis of publicly available BRD4 ChIP-Seq data of DLBCL cells treated with the BETi JQ1 showed that BRD4 was bound to the upstream regulatory regions of multiple miRNA genes and that this binding decreased following BETi. Alignment of our miRNA profiling data with the BRD4 ChIP-Seq data revealed that many miRNAs downregulated by OTX015 also exhibited reduced BRD4 binding in their promoter regions following BETi treatment, indicating that BRD4 directly modulated miRNA expression in lymphoma. Among the miRNAs upregulated in response to OTX015 was miR-96-5p, a miRNA known to play a role in B-cell transformation. In lymphomas, miR-96-5p transcription is repressed by the arginine methyltransferase PRMT5. In turn, PRMT5 translation is inhibited by miR-96-5p. We demonstrated that BRD4 bound to the 5’ regulatory region of PRMT5 and that following BET inhibition PRMT5 expression decreased, BRD4 binding to the 5’ region of PRMT5 was reduced and enrichment of PRMT5 at the miR-96-5p promoter lessened. Our results demonstrate that BRD4 binds to the promoters of miRNA genes to directly modulate their expression in lymphoma cells and that BETi administration results in decreased binding of BRD4 to the promoters of specific miRNAs to reduce their expression. Additionally, we show that BETi treatment can affect the expression of genes that control miRNA transcription to indirectly modulate miRNA expression. The data presented here indicate that the ability of BETi to inhibit or activate specific signalling pathways and processes critical to lymphoma cell proliferation and survival is in part due to changes in miRNA expression.
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
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.
Project description:The epigenome is often deregulated in cancer and treatment with inhibitors of bromodomain and extra-terminal proteins, the readers of epigenetic acetylation marks, represents a novel therapeutic approach. Here, we have characterized the anti-tumour activity of the novel bromodomain and extra-terminal (BET) inhibitor BAY 1238097 in preclinical lymphoma mod- els. BAY 1238097 showed anti-proliferative activity in a large panel of lym- phoma-derived cell lines, with a median 50% inhibitory concentration between 70 and 208 nmol/l. The compound showed strong anti-tumour efficacy in vivo as a single agent in two diffuse large B cell lymphoma mod- els. Gene expression profiling showed BAY 1238097 targeted the NFKB/ TLR/JAK/STAT signalling pathways, MYC and E2F1-regulated genes, cell cycle regulation and chromatin structure. The gene expression profiling sig- natures also highly overlapped with the signatures obtained with other BET Bromodomain inhibitors and partially overlapped with HDAC-inhibitors, mTOR inhibitors and demethylating agents. Notably, BAY 1238097 presented in vitro synergism with EZH2, mTOR and BTK inhibitors. In conclusion, the BET inhibitor BAY 1238097 presented promising anti-lym- phoma preclinical activity in vitro and in vivo, mediated by the interference with biological processes driving the lymphoma cells. Our data also indicate the use of combination schemes targeting EZH2, mTOR and BTK along- side BET bromodomains.
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.
