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Integrated analysis of the molecular action of Vorinostat identifies epi-sensitised targets for combination therapy

ABSTRACT: Acute myeloid leukaemia (AML) is a highly heterogeneous entity of disorders in haematopoietic progenitors, characterised by an arrest in differentiation and an outgrowth of myeloid blasts in the bone marrow. AML is a disease of the aging, many patients are unable to withstand standard chemotherapy therefore novel approaches for anti-cancer agents has arisen in the understanding of epigenetic regulation in cancer cells, such as chromatin remodelling. Acetylation of histones is a reversible process, whereby acetyl groups are transferred on the ε-amino groups of specific lysine residues by a specific group of enzymes, histone acetyltransferases (HATs) and removed by histone deacetylase complexes (HDACs). HDACs are involved in regulating a number of processes in the cell, such as cell proliferation, differentiation as well as apoptosis. Deregulation of the activity of these enzymes is associated with cancer; therefore it is important that the HAT and HDAC equilibrium is regained. This equilibrium can be improved through the inhibition of HDAC enzymes using HDAC inhibitors. Vorinostat is a HDAC inhibitor, clinically approved for the treatment of CTCL, and is in phase II clinical trials for AML and a number of haematological malignancies. Studies have shown that some patients are non-responsive/resistant to Vorinostat; therefore a fuller characterisation of Vorinostat needs to be made so an adequate combination drug can be identified, as understanding of resistance is crucial to overcoming it. The purpose of this study was to provide a comprehensive analysis of Vorinostat in AML cell lines and to identify potential synergistic therapies that could be used in combination with Vorinostat to provide a better outlook in AML. The global identification of genes associated with Vorinostat induced histone H3 lysine 9 (H3K9) acetylation, investigated using chromatin immunoprecipitation coupled with next generation sequencing (ChIP-SEQ), was integrated with data from gene expression studies to provide a comprehensive approach to understanding Vorinostat. This study has identified the sonic hedgehog homolog (SHH) as a rational and potential therapeutic target for combination therapy with Vorinostat

ORGANISM(S): Homo sapiens

PROVIDER: GSE86445 | GEO | 2017/03/01

SECONDARY ACCESSION(S): PRJNA341945

REPOSITORIES: GEO

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Project description:The identification of recurrent somatic mutations in genes encoding epigenetic enzymes, coupled with biochemical studies demonstrating aberrant recruitment of epigenetic enzymes such as histone deacetylases (HDACs) and histone methyltransferases (HMTs) to promoter regions through association with oncogenic fusion proteins such as PML-RARM-NM-1 and AML1-ETO has provided a strong rationale for the development compounds that target the epigenome for the treatment of cancer. HDAC inhibitors (HDACi) are potent inducers of tumor cell apoptosis but it remains unclear why tumor cells are selectively sensitive to HDACi-induced cell death. Herein we assessed the biological and molecular responses of normal and transformed cells to the FDA-approved HDACi vorinostat. Both HDACi selectively killed cells of diverse tissue origin that had been transformed through the serial introduction of different oncogenes. Time course microarray expression profiling revealed that normal and transformed cells transcriptionally responded to vorinostat treatment. Over 4200 genes responded differently to vorinostat in normal and transformed cells and gene ontology and pathway analyses identified a tumor-cell-selective pro-apoptotic gene-expression signature that consisted of BCL2 family genes. In particular, HDACi induced tumor cell-selective upregulation of the pro-apoptotic gene BMF and downregulation of the pro-survival gene BCL2A1 encoding BFL-1. Maintenance of BFL-1 levels in transformed cells through forced expression conferred vorinostat resistance indicating that specific and selective engagement of the intrinsic apoptosis pathways underlies the tumor cell-selective apoptotic activities of these agents. The ability of HDACi to affect the growth and survival of tumor cells whilst leaving normal cells relatively unharmed is fundamental to their successful clinical application. This study provides new insight into the transcriptional effects of HDACi in human donor-matched normal and transformed cells, and identifies molecules and pathways that could underpin the tumor-selective cytotoxic activity of these compounds. Whole genome expression profiling was performed for vorinostat-treated samples and control samples (DMSO vehicle control). Fourteen samples were included in this study. Each sample has three biological replicates, making forty-two arrays in total.

Project description:The identification of recurrent somatic mutations in genes encoding epigenetic enzymes, coupled with biochemical studies demonstrating aberrant recruitment of epigenetic enzymes such as histone deacetylases (HDACs) and histone methyltransferases (HMTs) to promoter regions through association with oncogenic fusion proteins such as PML-RARα and AML1-ETO has provided a strong rationale for the development compounds that target the epigenome for the treatment of cancer. HDAC inhibitors (HDACi) are potent inducers of tumor cell apoptosis but it remains unclear why tumor cells are selectively sensitive to HDACi-induced cell death. Herein we assessed the biological and molecular responses of normal and transformed cells to the FDA-approved HDACi vorinostat. Both HDACi selectively killed cells of diverse tissue origin that had been transformed through the serial introduction of different oncogenes. Time course microarray expression profiling revealed that normal and transformed cells transcriptionally responded to vorinostat treatment. Over 4200 genes responded differently to vorinostat in normal and transformed cells and gene ontology and pathway analyses identified a tumor-cell-selective pro-apoptotic gene-expression signature that consisted of BCL2 family genes. In particular, HDACi induced tumor cell-selective upregulation of the pro-apoptotic gene BMF and downregulation of the pro-survival gene BCL2A1 encoding BFL-1. Maintenance of BFL-1 levels in transformed cells through forced expression conferred vorinostat resistance indicating that specific and selective engagement of the intrinsic apoptosis pathways underlies the tumor cell-selective apoptotic activities of these agents. The ability of HDACi to affect the growth and survival of tumor cells whilst leaving normal cells relatively unharmed is fundamental to their successful clinical application. This study provides new insight into the transcriptional effects of HDACi in human donor-matched normal and transformed cells, and identifies molecules and pathways that could underpin the tumor-selective cytotoxic activity of these compounds.

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Integrated analysis of the molecular action of Vorinostat identifies epi-sensitised targets for combination therapy

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