Li Shuo, Li Jing, Fei Bing-Yuan, Shao Dan, Pan Yue, Mo Zhan-Hao, Sun Bao-Zhen, Zhang Dan, Zheng Xiao, Zhang Ming, Zhang Xue-Wen, Chen Li
Department of Hepatobiliary and Pancreatic Surgery, China-Japan Union Hospital, Jilin University, Changchun, Jilin 130021, China.
Chin Med J (Engl). 2015 Apr 5;128(7):941-7. doi: 10.4103/0366-6999.154302.
MicroRNAs (miRNAs) function as essential posttranscriptional modulators of gene expression, and are involved in a wide range of physiologic and pathologic states, including cancer. Numerous miRNAs are deregulated in hepatocellular carcinoma (HCC). This study aimed to investigate the role of miR-27a in the development of HCC.
The expression of MiR-27a was measured by quantitative real-time polymerase chain reaction (qRT-PCR). 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide was used to examine changes in the viability of HepG2, Bel-7402, Bel-7404 hepatoma cell lines associated with up-regulation or down-regulation of miR-27a. A dual-luciferase activity assay was used to verify a target gene of miR-27a. Immunohistochemistry, qRT-PCR, Western blotting analysis, and cell cycle and apoptosis flow cytometric assays were used to elucidate the mechanism by which miR-27a modulates liver cancer cell proliferation.
The expression of miR-27a was significantly increased in HCC tissues and HepG2, Bel-7402, Bel-7404 hepatoma cell lines (P < 0.05). We also found that the down-regulation of miR-27a in HepG2 cells dramatically inhibited proliferation, blocked the G1 to S cell cycle transition and induced apoptosis (P < 0.05). In addition, miR-27a directly targeted the 3'- untranslated region of peroxisome proliferator-activated receptor γ (PPAR-γ), and ectopic miR-27a expression suppressed PPAR-γ expression on the mRNA and protein levels. The rosiglitazone-induced overexpression of PPAR-γ attenuated the effect of miR-27a in HCC cells.
Our findings suggested that miRNA-27a promoted HCC cell proliferation by regulating PPAR-γ expression. MiR-27a may provide a potential therapeutic strategy for HCC treatment.
微小RNA（miRNA）作为基因表达至关重要的转录后调节因子，参与包括癌症在内的多种生理和病理状态。在肝细胞癌（HCC）中，众多miRNA的表达失调。本研究旨在探究miR-27a在HCC发生发展中的作用。
采用定量实时聚合酶链反应（qRT-PCR）检测MiR-27a的表达。使用3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐检测与miR-27a上调或下调相关的HepG2、Bel-7402、Bel-7404肝癌细胞系活力变化。采用双荧光素酶活性测定法验证miR-27a的靶基因。运用免疫组织化学、qRT-PCR、蛋白质印迹分析以及细胞周期和凋亡流式细胞术检测，以阐明miR-27a调节肝癌细胞增殖的机制。
miR-27a在HCC组织以及HepG2、Bel-7402、Bel-7404肝癌细胞系中的表达显著增加（P < 0.05）。我们还发现，HepG2细胞中miR-27a的下调显著抑制增殖，阻断G1期到S期的细胞周期转换并诱导凋亡（P < 0.05）。此外，miR-27a直接靶向过氧化物酶体增殖物激活受体γ（PPAR-γ）的3'-非翻译区，异位表达miR-27a可在mRNA和蛋白质水平上抑制PPAR-γ的表达。罗格列酮诱导的PPAR-γ过表达减弱了miR-27a对HCC细胞的作用。
我们的研究结果表明，miRNA-27a通过调节PPAR-γ表达促进HCC细胞增殖。MiR-27a可能为HCC治疗提供一种潜在的治疗策略。
