lncRNA MIAT promotes proliferation and invasion of HCC cells via sponging miR-214.

The aberrant expression of long noncoding RNAs (lncRNAs) has been involved in various human tumors including hepatocellular carcinoma (HCC). Our study aimed to investigate the potential molecular mechanism of lncRNA myocardial infarction-associated transcript (MIAT) in HCC. The expression of MIAT and micro-RNA (miR)-214 in HCC tissues and cells was examined by quantitative real-time PCR, and the levels of enhancer of zeste homolog 2 (EZH2) and β-catenin were detected by Western blot assay. Immunoprecipitation analysis was used to detect the level of H3/H4 histone acetylation. RNA pull-down assay was performed to confirm the targeting regulatory relationship between miR-214 and MIAT. Cell viability, proliferation, and invasion were analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), [3H]thymidine incorporation, and Transwell assays, respectively. BALB/c nude mice were used to establish a hepatocellular carcinoma animal model with subcutaneous injection of SK-HEP-1 cells. Upregulation of MIAT is related to the proliferation and invasion of HCC, and downregulating MIAT expression inhibited HCC cell proliferation and invasion. The H3/H4 histone acetylation level of MIAT promoter in HCC tissues was higher than that in normal tissues. MIAT negatively regulated miR-214 in HCC cells. Inhibition of miR-214 reversed the influence of MIAT downregulation on HCC cell proliferation and invasion. In nude mouse xenograft models, downregulation of MIAT markedly suppressed the tumor growth of HCC via releasing miR-214. In conclusion, lncRNA MIAT promotes the proliferation and invasion of HCC cells through sponging miR-214, which brings a novel target for the therapy and prognosis of hepatocellular carcinoma. NEW & NOTEWORTHY This is the first research showing long noncoding RNA (lncRNA) myocardial infarction-associated transcript (MIAT) to have a regulatory effect on hepatocellular carcinoma. Micro-RNA (miR)-214 could be sponged by MIAT to promote the proliferation and invasion of hepatocellular carcinoma cells. The lncRNA MIAT/miR-214 axis brings a novel insight for the therapy and prognosis of hepatocellular carcinoma.