Histone deacetylases up-regulate C/EBPα expression through reduction of miR-124-3p and miR-25 in hepatocellular carcinoma

Abstract Background CCAAT enhancer binding protein α (C/EBP α ), as an important transcription factor involved in cell proliferation, differentiation and metabolism, was up-regulated in primary hepatocellular carcinoma (HCC) and predicted poorer prognosis. In this study, we explored how histone deacetylases (HDACs) up-regulated C/EBP α in HCC. Methods The protein expressions of HDAC1, HDAC2 were associated with C/EBP α by immunohistochemistry staining in a HCC tissue microarray. HCC cells were then treated with HDAC inhibitors or siRNAs to determine the roles of miR-124-3p and miR-25 in the regulation of C/EBP α mRNA expression. Results Both HDAC1 and HDAC2 proteins were significantly associated with C/EBP α. Inhibition of HDAC by either pharmacological inhibitors or siRNAs decreased C/EBP α mRNA expression in dose-dependent manners in HCC cells. HDAC inhibitors reduced C/EBP α mRNA stability as shown by pmiRGLO luciferase reporter assays. HDAC inhibition consistently induced miR-124-3p and miR-25 expression. Conversely, blockage of miR-124-3p and/or miR-25 by treatment with specific synthetic inhibitors abolished C/EBP α reduction. More importantly, C/EBP α mRNA stability could be rescued by site-directed mutations of miR-124-3p or miR-25 recognition sites in the C/EBP α 3′UTR sequence. In summary, HDAC may up-regulate C/EBP α expression through miR-124-3p and miR-25 in HCC.