目的: 构建pEGFPC1Smad4表达载体，观察Smad4过表达对人胃癌SGC7901细胞增殖的影响，探讨其与NFκB的相关性。方法：构建增强绿色荧光蛋白（EGFP）与Smad4的融合表达载体， 转染人胃癌SGC7901细胞，荧光显微镜观察转染后细胞EGFP的表达，Western blotting检测SGC7901Smad4细胞中Smad4和NFκB的表达，电泳迁移率变异分析（electrophoretic mobility shif assay,EMSA）检测过表达Smad4对胃癌SGC7901细胞NFκB 活化的影响,MTT法检测过表达Smad4对SGC7901细胞增殖的影响。结果：在转染pEGFPC1Smad4的人胃癌SGC7901细胞（SGC7901Smad4）中观察到EGFP的表达；Western blotting检测显示，SGC7901 Smad4细胞中Smad4过表达,并伴随核转录因子NFκB p65的表达水平下调；EMSA检测显示Smad4过表达可下调NFκB活化；MTT法显示过表达Smad4显著抑制SGC7901细胞增殖（P<0.05或P<0.01）。结论：Smad4过表达显著抑制人胃癌细胞增殖，其机制可能与下调NFκB信号通路有关。

Objective:To construct pEGFPC1Smad4 expression vector and to observe the influence of Smad4 overexpression on the proliferation of human gastric cancer SGC7901 cells and its relationship with nuclear factor kappa B (NFκB). Methods:Recombinant expression vector pEGFPC1Smad4 was constructed and was used to transfect human gastric cancer SGC7901 cells. EGFP expression in transfected cells was detected by fluoroscopy. Smad4 and NFκB expression in transfectant was examined by Western blotting. Effect of Smad4 overexpression on activation of NFκB and proliferation of transfected SGC7901 cells were examined by electrophoretic mobility shift assay (EMSA) and MTT assay, respectively. Results: Expression of EGFP in transfected SGC7901 cells was observed under fluorescence microscope. Smad4 was overexpressed in transfected SGC7901 cells, accompanied by downregulation of NFκB p65 expression in the tranfectants. EMSA and MTT demonstrated that Smad4 overexpression significantly inhibited the activation of NFκB and the proliferation of SGC7901 cells (P<0.05, P<0.01).Conclusion: Smad4 overexpression can greatly inhibit the proliferation of human gastric cancer cells, probably through downregulation of NFκB pathway.

浙江省医药卫生科学研究基金立项资助项目（No. 2008B204）