ω-3多不饱和脂肪酸诱导人胃癌细胞凋亡的实验研究

目的观察ω-3多不饱和脂肪酸(ω-3PUFAs)对SGC-7901人胃癌细胞系凋亡的影响并探究其机制。方法采用四甲基偶氮唑蓝(MTT)法、细胞形态学、DNA电泳和流式细胞技术对细胞生长与凋亡进行观察和分析,利用荧光探针rhodamine123检测线粒体跨膜电位,酶联免疫吸附法分析线粒体和胞质中细胞色素C的分布,气相色谱分析线粒体膜磷脂构成。结果二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)能显著抑制胃癌细胞的生长,诱发细胞凋亡,并呈现时间和剂量依赖性关系。40μg/mlEPA和DHA作用细胞24h后,线粒体跨膜电位显著降低(P<0.001),线粒体膜间细胞色素C大量释入胞质,EPA和DHA在线粒体膜磷脂构成中的比例迅速升高(P<0.001),而花生四烯酸(20:4ω-6,AA)占总磷脂的比例明显降低,由对照组的30.8%分别下降为20.9%和18.6%。结论ω-3PUFAs通过诱导细胞凋亡抑制胃癌细胞的生长,线粒体膜构成和功能的改变可能是ω-3PUFAs诱导凋亡的重要机制。

Apoptosis of human gastric cancer cells induced by ω-3 polyunsaturated fatty acids

OBJECTIVE: To investigate the effect of omega-3 polyunsaturated fatty acids(omega-3PUFAs) on the apoptosis of human gastric cancer cell line SGC-7901 and to explore the potential mechanisms. METHODS: Cells were treated with eicosapentaenoic acid (20:5 omega-3,EPA) or docosahexaenoic acid (22:6 omega-3, DHA) at concentrations of 10, 20 and 40 microg/ml. Cell growth and apoptosis were analyzed with MTT assay, cell morphology, DNA electrophoresis and flow cytometry. Mitochondrial membrane potential ( triangle right psi mt) was measured by fluorescent probe rhodamine 123. The distribution of cytochrome C in mitochondria and cytosol was determined by enzyme-linked immunoadsorbent assay. The composition of mitochondrial membrane phosphlipid(MMP)was examined by gas chromatography. RESULTS: Both EPA and DHA markedly inhibited the SGC-7901 cell growth and induced apoptosis in a time- and dose-dependent manner. After incubation of the cells with 40 microg/ml EPA or DHA for 24 hours, the level of Deltapsimt siginificantly decreased (P<0.001), and cytochrome C largely released into cytosol from mitochondria. The proportions of EPA and DHA in MMP rapidly elevated while that of arachidonic acid sharply decreased. CONCLUSIONS: omega-3PUFAs inhibit the growth of gastric cancer cells through promoting apoptosis. Compositional and functional alterations in mitochondrial membrane may be an important initiator of apoptosis induced by omega-3PUFAs.