Objective To observe the effects of total Saponins of Panax notoginseng (TSPN) on proliferation and apoptosis of human gastric cancer MKN-28 cell, and to explore whether the mechanism of apoptosis involves the up-regulation of expres-sion of death receptors-5 (DR5). Method Human gastric cancer MKN-28 cells were cultured in vitro, and their fixed-dependent growth ability were assayed by agar colony formation. The cell cycle and apoptosis rate were detected by PI staining and flow cy-tometry (FCM). The morphology of apoptotic cells was observed by Hoechst 33258 fluorescence staining under fluorescence mi-croscopy. The effect of drugs on the DR5 protein expression was analyzed by Western Bloting. Result Agar colony formation as-say showed that MKN-28 cell growth was inhibited by TSPN in a dose-dependent manner. PI staining FCM results showed that the TSPN induced apoptosis of MKN-28 cells in a time and concentration-dependent manner and the cell cycle was retarded at G1 phase. Nuclear chromatin condensation can be observed by fluorescence microscopy after Hoechst 33258 staining, and apop-totic cells were dense stained. Compared with control group, the proportion of apoptotic cells increased after TSPN treatment in a time and concentration-dependent manner. Western Bloting analysis showed that apoptosis induced by TSPN involved the up-regulation of death receptor-5 expression activity. Conclusion TSPN have a role in inhibiting proliferation and inducing apoptosis on human gastric cancer MKN-28 cells in vitro. It is inferred that this induce of apoptosis may be concerned with its role in up-regulating the expression of the death receptor-5.% 目的观察三七总皂苷(Total Saponins of Panax notoginseng, TSPN)对人胃癌细胞株MKN-28增殖和凋亡的影响,探讨其诱导细胞凋亡是否涉及上调死亡受体5(DR5)的表达.方法体外培养人胃癌细胞株MKN-28,平皿克隆形成法测定细胞锚定依赖性生长能力,PI染色流式细胞术(Flow cytometry, FCM)分析细胞周期和凋亡率,Hoechst 33258染色荧光显微镜观察凋亡细胞的形态,Western Bloting检测分析药物对DR5蛋白表达的影响.结果平皿集落形成法检测显示TSPN对MKN-28细胞生长有抑制作用,且呈浓度依赖性.PI染色FCM结果表明TSPN以时间和浓度依赖性方式诱导MKN-28细胞凋亡,且使细胞周期阻滞于G1期.Hoechst 33258染色荧光显微镜观察可见核染色质凝集,凋亡细胞呈致密浓染,与对照组相比,TSPN处理后,凋亡细胞比例增加,且呈时间和浓度依赖性.Western Bloting检测显示TSPN诱导细胞凋亡的机制涉及上调死亡受体5的表达活性.结论 TSPN在体外对人胃癌MKN-28细胞具有抑制增殖和诱导凋亡的作用,初步推断TSPN诱发胃癌细胞凋亡与其上调死亡受体5的表达活性有关.
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