靶向COX-2的siRNA抑制三种不同分化程度胃癌细胞生长及作用机制

目的:利用RNA干扰(RNA interference,RNAi)技术在体外抑制COX-2表达,研究其抑制三种不同分化程度的胃癌细胞(MKN-28,SGC-7901,BGC-823)的可能性,探讨RNAi抑制胃癌生长与胃癌细胞分化程度的相关性. 方法:设计靶向COX-2基因的siRNA,构建重组表达质粒pTZU6 1-siRNA-COX-2并导入胃癌细胞株,体外诱导RNAi,采用逆转录PCR(RT-PCR)和Western blotting检测COX-2基因表达变化,MTT法检测细胞活力,原位末端标记(TUNEL)及透射电镜检测细胞凋亡,Western blotting检测凋亡相关蛋白Bax和Bcl-2的改变. 结果:pTZU6 1-siRNA-COX-2质粒导入细胞后,SGC-7901和BGC-823中COX-2表达明显下调,细胞生长被抑制,并出现特征性的细胞凋亡,同时有Bax蛋白上调和Bcl-2蛋白下调. 对照组则无明显变化. 结论:RNAi显著抑制胃癌细胞生长,可能与下调COX-2基因表达和诱导细胞凋亡有关,其对中分化胃癌细胞的抑制作用最为显著,提示RNAi的作用可能依赖于胃癌细胞的分化程度.

Inhibitory effect of siRNA targeting COX-2 on the growth of gastric carcinoma cells of well, moderate or poor differentiation and its mechanism

AIM: To investigate the inhibitory effect of siRNA targeting COX-2 on the growth of gastric carcinoma cells of well, moderate or poor differentiation (MKN-28, SGC-7901, BGC-823) and related mechanism. METHODS: siRNA targeting COX-2 gene was designed, siRNA-COX-2 vector was constructed and transfected into gastric carcinoma cells to induce RNA interference. The changes of COX-2 were detected with RT-PCR and Western blotting.Cell viability was detected by MTT. Cell apoptosis was judged by TUNEL and electromicroscopy, and expressions of Bax and Bcl-2 were tested by Western blot. RESULTS: Both COX-2 expression and cell growth were inhibited in SGC-7901 and BGC-823 after transfection of siRNA-COX-2 vector into the cells. But, in MKN-28 ,only COX-2 expression decreased. The obvious cell apoptosis both in SGC-7901 and BGC-823 was observed. Bax was up-regulated and Bcl-2 was down-regulated in SGC-7901 and BGC-823. In contrast, there were almost no changes in control group in vitro. CONCLUSION: RNA interference inhibits the growth of gastric carcinoma cells, which may be related to down-regulation of COX-2 and induction of cell apoptosis. The inhibitory effect of RNAi was relatively strong in SGC-7901, which indicated that the effect of siRNA was dependent on the differentiation degree of gastric carcinoma cells.