miR-181b对肝癌HepG2细胞增殖以及Bcl-2和SP1蛋白表达的影响

目的: 研究miR-181b对人肝癌G2细胞(HepG2)中B细胞淋巴瘤/白血病-2(Bcl-2)和转录因子SP1蛋白及mRNA表达的调节作用,探讨miR-181b对HepG2细胞增殖的影响。方法: 用人工合成的miR-181b相应的双链互补DNA片段,插入miRNASelect^TM pEGP-miR载体中,经测序鉴定后克隆microRNA的高表达质粒;用脂质体将miR-181b高表达质粒转染进HepG2细胞,经嘌呤霉素筛选获得阳性克隆。用RT-PCR技术和Western blotting方法分别检测该细胞系中Bcl-2和SP1的mRNA和蛋白表达情况。用MTT法检测HepG2细胞增殖的变化情况。结果: Western blotting结果显示miR-181b能够减少Bcl-2和SP1蛋白质的表达,RT-PCR分析显示Bcl-2和SP1 mRNA表达减少。MTT显示转染后细胞的生长速率比未转染的细胞明显减慢。 结论: miR-181b抑制HepG2肝癌细胞增殖, 提示可能与其下调Bcl-2和SP1 的表达有关。

Effect of miR-181b on cell proliferation and expression of Bcl-2 and SP1 in HepG2 cells

AIM: To investigate the role of miR-181b in the expression of Bcl-2 and SP1 at mRNA and protein levels in the human hepatoma G2 cells (HepG2), and to explore the effect of miR-181b on the regulation of HepG2 cell proliferation. METHODS: The synthetic double-strand complementary DNA based on the sequence of miR-181b was inserted into the vector of miRNASelect^TM pEGP-miR. The microRNA high-expression plasmid was cloned, and the sequences were identified. The miR-181b plasmid was transfected into HepG2 cells with liposomes. The stable cell line was screened by puromycin. The mRNA and protein levels of Bcl-2 and SP1 were measured by RT-PCR and Western blotting, respectively. Methyl thiazolyl tetrazolium (MTT) method was used to analyze the proliferation of HepG2 cells. RESULTS: The Western blotting results showed that miR-181b inhibited the protein expression of Bcl-2 and SP1. The result of RT-PCR also indicated that the mRNA expression of Bcl-2 and SP1 was suppressed. Compared with the control, the growth rate of HepG2 with high expression of miR-181b was significantly decreased.CONCLUSION: miR-181b inhibits the proliferation of HepG2, which may be related to the down-regulation of Bcl-2 and SP1.