EGCG通过抑制COX-2表达及PGE_2合成诱导胃癌细胞系HGC27凋亡

EGCG Induces Cell Apoptosis Through Inhibiting the Expression of COX-2 and PGE_2 Synthesis in HGC27 Gastric Cancer Cells

目的：探讨EGCG对胃癌细胞系HGC27细胞凋亡的影响及其机制。方法：体外培养的HGC27细胞,分为对照组和实验组,实验组用不同浓度EGCG处理24、48、72 h,对照组加入同等体积的培养基,MTT法测定其对HGC2细胞增殖的影响;EGCG（浓度分别为0、10、20、40μg/mL）处理HGC27细胞48 h后,分别采用流式细胞仪检测细胞凋亡,分光光度计检测Casepase-3、Casepase-9相对活性,Rh123探针染色流式细胞仪检测线粒体膜电位变化,western blot法检测环氧合酶2（COX-2）基因表达,ELISA法检测PGE2含量。结果：EGCG（浓度10-80μg/mL）能显著抑制HGC27细胞增殖,呈剂量和时间依赖性;EGCG（浓度分别为10、40、80μg/mL）作用HGC27细胞48 h后,细胞凋亡率分别为14.8%、25.8%、37.7%,对照组凋亡率为0.6%;Casepase-3、Casepase-9相对活性显著增加,线粒体膜电位降低,COX-2的表达降低,PGE2合成减少。结论：EGCG可通过抑制HGC27细胞COX-2表达及PGE2合成,激活线粒体凋亡途径,抑制细胞增殖并促进其凋亡。EGCG可能是一种前景广阔的抗肿瘤药物。

Objective：To investigate the effect of EGCG on the cell apoptosis of gastric cancer line HGC27 cells and discuss its possible mechanisms. Methods：HGC27cells were cultured in vitro. The experiments were divided into two groups,including control group and drug treated group. The control group received only the culture medium. After treatment by EGCG at different concentrations respectively at different time,the cell survival was determined by the MTT method. Apoptosis was detected by flow cytometry. The relative activity of caspase-3 and caspase-9 were monitored by spectrophotometer. The mitochondrial membrane potential was evaluated by flow cytometry analysis after Rh123 probe staining. Western blot were used for COX-2 protein analysis. The expression of PGE2 in the culture medium was detected by ELISA. Results：From the data of MTT,the cell proliferation of HGC27 cells was inhibited by EGCG in a dose-dependent and time-dependent manner. Flow cytometry assays showed that EGCG significantly induced cell apoptosis. After treated with EGCG,the apoptosis rate of HGC27 cells was 14.8%,25.8%,and 37.7% respectively,which showed an obvious concentration-effect relationship. The relative activities of caspase-3 and caspase-9 of EGCG group were increased. The mitochondrial membrane potential was reduced. The data of western blot showed that EGCG down-regulated COX-2 in a dose-dependent manner. And EGCG inhibited the PGE2 synthesis. Conclusion：EGCG inhibits the cell proliferation and induces cell apoptosis through inhibiting the expression of COX-2 and PGE2 synthesis in HGC27 gastric cancer cells. EGCG may be a promising antitumor agent for gastric cancer treatment.