二十碳五烯酸（EPA）对胃癌细胞增殖与凋亡的影响

The effect of eicosapentaenoic acid on the proliferation and apoptosis of gastric cancer cells

目的观察二十碳五烯酸（EPA）对人胃癌细胞系增殖与凋亡的影响，并探讨其作用机制。方法以终浓度为10、20、40μg／ml的EPA作用于SGC-7901和MGC-803人胃癌细胞系24-72h。采用四甲基偶氮唑蓝法检测细胞增殖抑制率，采用流式细胞技术分析细胞周期分布与细胞凋亡，利用荧光探针rhodamine 123测定线粒体膜电位，酶联免疫吸附法测定线粒体和胞浆中细胞色素C水平，荧光光谱法测定凋亡效应酶半胱天冬蛋白酶-3（caspase-3）活性。结果经10-40μg／ml EPA处理的胃癌细胞增殖率显著降低，且呈现时间依赖性。与对照组比较，经40g／ml EPA作用72h后，SGC-7901和MGC-803细胞G0／G1期细胞的比例均增加（P=0.006、P=0.009）。经40g／ml EPA作用24h后，胃癌细胞线粒体膜电位显著低于对照组（P=0.001、P=0.047）；线粒体内细胞色素C的含量明显少于对照组（P=0.001、P=0.000），而细胞浆中细胞色素C含量显著高于对照组（P=0．001、P=0．000）。在SGC-7901细胞中，caspase-3活性随着EPA（40g／mL）作用时间延长而升高。结论EPA通过诱导细胞周期阻滞和激活线粒体通路，抑制人胃癌细胞增殖，诱导细胞凋亡。

Objective To observe the effect of eicosapentaenoic acid （EPA） on the proliferation and apoptosis of human gastric cancer cells and to explore the potential mechanism involved. Methods Human gastric cancer cell lines SGC-7901 and MGC-803 were treated with EPA at 10, 20, 40 Izg/ml for 24-72 hours. The inhibition of cell proliferation was evaluated by methyl thiazolyl tetrazolium assay, The apoptosis and the distribution of cell cycle were analyzed by flow cytometry. Mitochondria membrane potential was determined with a fluorescence probe rhodamine 123. Cellular distribution of cytochrome C was quantitatively detected with enzyme-linked immunosorbent assay. Caspase-3 activity was measured with spectrofluoremetry. Results After incubation with 10-40 μg/ml EPA for 24-72 hours, the proliferation of human gastric cancer cells was markedly inhibited in a time-dependent manner. The treatment of 40 g/ml EPA for 72 hours increased the proportion of G0/G1 phase cells in both SGC-7901 and MGC-803 （P =0. 006, P =0. 009）. In SGC-7901 and MGC-803 cells incubated with 40 ~g/ml EPA for 24 hours, mitochondria membrane potential decreased significantly （P = 0. 001, P = O. 047 ） ; cytochrome C level significantly declined in mitochondria （P =0. 001, P =0. 000） but increased in cytosol （P =0. 001, P =0. 000）. In SGC-7901 cells, the apoptotic effector caspase-3 activity increased time-dependently along with incubation with 40 g/ml EPA. Conclusion EPA could inhibit the proliferation and promote the apoptosis of human gastric cancer cells through inducing cell cycle arrest and activating intrinsic death pathway mediated by mitochondria.