Dataset Information

Multiple myeloma cell lines expression profile of OTX015-treated cells compared to DMSO controls

ABSTRACT: Several studies demonstrate that the bromodomain inhibitor OTX015 has preclinical antitumor activity in a variety of solid tumors and hematologic cancers. However, translation of these data to molecules suitable for clinical development has not yet to be accomplished in multiple myeloma (MM). Here, we identified genes and biologic processes that underpin the antimyeloma activity of OTX015 with global transcriptomics. OTX015 exerted strong antiproliferative effect and induced cell cycle arrest in vitro. Gene expression profiling showed that OTX015 targeted NF-κB, EGFR, cell cycle regulation, cancer proliferation signaling pathway. Gene expression signatures associated with different sensitivity to OTX015 were also identified. The data also showed that oral administration of OTX015 displayed significant antitumor activity in mice model of disseminated human myeloma. In addition, our study provided the first evidence and rationale that OTX015 could promoted osteoblast differentiation of mesenchymal stem cells (MSCs) and inhibited osteoclast formation and resorption in vivo experiments. Herein we expanded the mechanistic understanding of BET inhibitors OTX015 in MM. Our preclinical studies provided a strong rationale for extending the clinical testing of the novel antimyeloma agent OTX015 and revealed insights into biologic pathways required for myeloma cell proliferation.

ORGANISM(S): Homo sapiens

PROVIDER: GSE111422 | GEO | 2019/03/08

REPOSITORIES: GEO

ACCESS DATA

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

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:Multiple myeloma (MM) is a malignant disorder characterized by the clonal proliferation of plasma cells (PCs) in the bone marrow (BM). The genetic background and clinical course of the disease are largely heterogeneous, and MM pathophysiology ranges from the premalignant condition of monoclonal gammopathy of undetermined significance (MGUS) to smoldering MM, symptomatic MM, and extramedullary MM/plasma cell leukemia (PCL). Recent genome-wide sequencing efforts have provided the rationale for molecularly aimed treatment approaches, identifying mutations that can be specifically targeted, such as those in the mitogen-activated protein kinase (MAPK) pathway, which represent the most prevalent mutations in MM. Among these, mutations affecting BRAF gene, detected in 4-15% of patients, are of potential immediate clinical relevance due to the availability of effective inhibitors of this serine-threonine kinase which are in fact being explored also in myeloma. In this study, we screened by next generation sequencing (NGS) a large and representative series of intramedullary and extramedullary MM patients, including primary and secondary plasma cell leukemia (pPCL and sPCL, respectively), for mutations in BRAF, NRAS and KRAS genes. We evaluated the relationship of identified variants with other clinical and biological features and determined the transcriptional signature associated with MAPK pathway activation in MM. To further elucidate the transcriptional programs modulated by BRAF activation in MM, we used the PLX4032 drug to inhibit BRAF activity in U266 human myeloma cell line (HMCL), carrying K601N mutation and showing constitutive activation of MEK/ERK signaling. After confirming its ability to suppress MAPK pathway and myeloma cell proliferation in culture in the U266 cell line, we investigated the specific modulation of gene expression induced by the drug. U266 cells were treated with PLX4032 (30 µM) or DMSO for 12 hours and subjected to gene expression profiling (GEP) analysis by using Affymetrix GeneChip Human Gene 1.0ST arrays.

Dataset Information

Multiple myeloma cell lines expression profile of OTX015-treated cells compared to DMSO controls

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets