The Key Laboratory of Living Donor Liver Transplantation, Center of Liver Transplantation, Ministry of Health, The First Affiliated Hospital of Nanjing Medical University , Nanjing , People's Republic of China.
Am J Physiol Gastrointest Liver Physiol. 2018 May 1;314(5):G559-G565. doi: 10.1152/ajpgi.00242.2017. Epub 2017 Nov 2.
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), [H]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.
长链非编码 RNA（lncRNA）的异常表达与包括肝细胞癌（HCC）在内的各种人类肿瘤有关。本研究旨在探讨 lncRNA 心肌梗塞相关转录物（MIAT）在 HCC 中的潜在分子机制。通过实时定量 PCR 检测 HCC 组织和细胞中 MIAT 和 microRNA（miR）-214 的表达，Western blot 检测增强子结合蛋白 2（EZH2）和 β-连环蛋白的水平。免疫沉淀分析用于检测 H3/H4 组蛋白乙酰化水平。RNA 下拉实验证实了 miR-214 和 MIAT 之间的靶向调节关系。3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四唑溴盐（MTT）、[H]胸苷掺入和 Transwell 测定分别用于分析细胞活力、增殖和侵袭。BALB/c 裸鼠用于皮下注射 SK-HEP-1 细胞建立肝细胞癌动物模型。MIAT 的上调与 HCC 的增殖和侵袭有关，下调 MIAT 表达抑制 HCC 细胞增殖和侵袭。HCC 组织中 MIAT 启动子的 H3/H4 组蛋白乙酰化水平高于正常组织。MIAT 在 HCC 细胞中负调控 miR-214。抑制 miR-214 逆转了 MIAT 下调对 HCC 细胞增殖和侵袭的影响。在裸鼠异种移植模型中，下调 MIAT 通过释放 miR-214 显著抑制 HCC 肿瘤的生长。总之，lncRNA MIAT 通过海绵 miR-214 促进 HCC 细胞的增殖和侵袭，为肝细胞癌的治疗和预后提供了新的靶点。
