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.