INI1基因对胃癌细胞增殖活性的影响及其机制

Effect of INII on gastric cancer cell proliferation

目的通过改变INI1基因表达水平探讨INI1对胃癌细胞增殖活性影响的分子机制。方法荧光定量逆转录一聚合酶链反应（RT—PCR）及Westernblot方法检测15例胃癌及癌旁组织INI1基因mRNA和蛋白质的表达水平；将INI1-GFP真核表达质粒及INI1特异性小干扰RNA（INI1-siRNA）分别转染人胃癌SGC7901细胞株，Westernblot方法检测过表达及下调表达INI1的效率；噻唑蓝（MTY）比色法检测过表达及下调表达INI1后SGC7901细胞的增殖活性的改变，荧光定量RT—PCR及Westernblot方法检测增殖细胞核抗原（PCNA）表达改变。结果临床胃癌组织中INI1蛋白及mRNA表达水平明显低于癌旁组织（P〈0．01）；INI1GFP转染SGC7901细胞可明显增加INI1表达水平，同时降低细胞增殖活性（P值均〈0．01）；而INI1-siRNA转染可明显降低INI1表达水平，同时增加SGC7901细胞增殖活性（P值均〈0．01）；上调INI1表达可抑制PCNA表达水平，而下调INI1表达则增加PCNA的表达（P值均〈0．01）。结论INI1具有抑制胃癌细胞增殖的作用，此作用与其负向调节PCNA表达有关。

Objective To explore the effects of INI1 on gastric cancer cell line SGC7901 proliferation and its molecular mechanisms. Methods The expression levels of INI1 in the samples of gastric carcinoma and surrounding tissue were detected by using quantitative reverse transeription-polymerase chain reaction （RT-PCR） and Western blotting. The INI1-GFP plasmid and INII-siRNA were transfected into gastric cancer cell line SGC7901 by LipofectamineTM 2000 transfection reagent, then the expression levels of INI1 and proliferating cell nuclear antigen （PCNA） were detected by quantitative RT-PCR and Western blotting, and the SGC7901 cell proliferation activities were assayed by methyl thiazol tetrazolium （MTT） and cell number counting. Results The INI1 expression level in samples of gastric carcinoma was lower than that of surround- ing tissue （P 〈0. 01 ）. The INII-GFP transfection increased the INIi expression dramatically, and the cell proliferation was suppressed significantly; At the same time, the expression of PCNA was down-regulated as compared with control group （all P 〈 0. 01 ）. On the contrary, the INII-siRNA transfection down-regulated the INI1 expression markedly, while the cell proliferation was increased significantly, and the expression of PCNA was up-regnlated as compared with control group （ all P 〈 0. 01 ）. Conclusion INI1 is an inhibitor to gastric cancer cell proliferation probably by suppressing the PCNA expression.