Mcl-1、PI3K通路活化对胃癌细胞生长及化疗敏感性的影响

Effect of Activation of Mcl-1 and PI3K Signal Transduction Pathway of Human Gastric Cancer Cells on the Sensitivity to Chemotherapy

目的:探讨Mcl-1以及PI3K通路活化对胃癌细胞生长及化疗敏感性的影响。方法:分别用阿霉素、足叶乙甙和PI3K通路抑制剂(wortmannin)在不同时间段处理胃癌细胞BGC-823后,采用四甲基偶氮唑蓝法检测细胞对药物的敏感性,流式细胞仪检测细胞凋亡情况并分析细胞周期,Western blot法测定细胞Mcl-1蛋白活性,RT-PCR法测定细胞Mcl-1 mRNA活性。结果:阿霉素、足叶乙甙作用BGC-823 24 h后,Mcl-1蛋白活性降低,Mcl-1 mRNA表达下降。加用Wortmannin后,阿霉素、足叶乙甙对BGC-823凋亡诱导和周期阻滞作用持续增强,Mcl-1蛋白及mRNA表达进一步降低,肿瘤细胞对药物保持较高敏感性。结论:阿霉素、足叶乙甙至少部分是通过下调Mcl-1的表达诱导胃癌细胞凋亡。Mcl-1、PI3K通路活化可促进胃癌细胞的生存,降低化疗敏感性。

Objective： To investigate the effect of activation of Mcl-1 and PI3K signal transduction pathway of human gastric cancer cells on the chemosensitivity. Methods： The gastric cancer cells BGC-823 were treated with Adriamycin, Etoposide or PI3K inhibitor Wortmannin at different time. The growth rates of gastric cancer cells BGC-823 and their sensitivities were examined by 3-（4,5-dimethylthiazol-2,1）-2,5 diphanytetrazolium bromide assay. Apoptosis and generation cycle of gastric cancer cells were detected by flow cytometry. The activity of protein of Mcl-1 was measured by Western blot analysis. Mcl-1 mRNA expression were determined by RT-PCR. Results： Adriamycin and Etoposide induced apoptosis of BGC- 823 cells and inhibited their generation cycle effectively, especially after 24 hours. The activity of Mcl-1 protein and the expression of Mcl-1 mRNA were decreased after treatment by Adriamycin and Etoposide for 24 hours. After treated with Wortmannin, the activity of protein of Mcl-1 and Mcl-1 mRNA expres- sion were markedly reduced. Wortmannin suppressed the growth and potentiated the apoptosis of BGC- 823 cells. Potentiation of apoptosis by Wortmannin correlated with Mcl-1 and PI3K signal transduction pathway. Conclusion： Etoposide and Adriamycin induced apoptosis of BGC-823 cells by reducing the ac- tivity of Mcl-1 at least partly. Activation of Mcl-1 and PI3K signal transduction pathway promotes hu-man gastric cancer cells survival and resistance to chemotherapy.