蛋白激酶B、Caspase-9通路活化对胃癌细胞生长及化疗敏感性的影响  

Effect of activation of protein kinase B and Caspase-9 signal transduction pathway of human gastric cancer cells on the cell chemosensitivity to etoposide

作　　者：李军华[1] 于皆平[1] 于红刚[1] 刘晋[1] 罗和生[1] 

机构地区：[1]武汉大学人民医院消化内科,430060

出　　处：《中华消化杂志》2006年第1期2-5,共4页Chinese Journal of Digestion

基　　金：国家自然科学基金资助项目(30300154)

摘　　要：目的探讨蛋白激酶B(PKB)、Caspase-9信号通路活化对胃癌细胞生长的影响及其与胃癌细胞对足叶乙甙化疗敏感性的关系。方法分别用足叶乙甙、足叶乙甙和PKB通路特异性抑制剂Wortmannin在不同时间段处理胃癌肿瘤细胞SGC7901后,采用四甲基偶氮唑蓝法检测细胞对药物的敏感性,流式细胞仪检测肿瘤细胞的凋亡情况,非放射性免疫沉淀法检测PKB活性,Western-blot法检测Caspase-9磷酸化程度和Caspase-3蛋白的表达。结果足叶乙甙对SGC7901有明显的增殖抑制作用,能明显诱导肿瘤细胞凋亡,但在12 h时,其增殖抑制作用和凋亡诱导作用较6 h时均明显降低,细胞对足叶乙甙敏感性降低,24 h时有所上升。足叶乙甙作用SGC7901后PKB活性逐渐增强,Caspase-9活性和Caspase-3表达12 h时明显降低。加用Wortmannin预处理后,PKB活性明显降低,Caspase-9活性和Caspase-3表达呈上升趋势,12 h时上升最明显;足叶乙甙对SGC7901的增殖抑制作用和凋亡诱导作用持续增强,肿瘤细胞对足叶乙甙持续较高敏感性。结论蛋白激酶B、Caspase-9信号通路活化可促进胃癌细胞生存,降低其化疗敏感性,特异性的PKB通路抑制剂可增强胃癌细胞的化疗效果。Objective To investigate the effect of activation of protein kinase B （PKB） and Caspase-9 signal transduction pathway of human gastric cancer cells on the cell growth and chemosensitivity to etoposide. Methods The gastric cancer cells SGC7901 were treated with etoposide or etoposide plus PKB inhibitor Wortmannin at different time. The growth rates of gastric cancer cells SGC7901 and their sensitivity to etoposide were examined by 3-（4, 5-dimethylthiazol-2, 1 ）-2, 5 diphanytetrazolium bromide assay. Apoptosis of gastric cancer cells was detected by flow cytometry. PKB activity was measured by immunoprecipitation. Caspase-3 expression and Caspase-9 activity were determined by Western bolt analysis. Results Etoposide induced apoptosis of SGC7901 cells and inhibited its survival effectively, which was much weaker 12 h after treatment. PKB activity became higher gradually, and Caspase-3 expression, Caspase-9 activity significantly reduced at 12 h treated with etoposide. Conversely, after pretreated with Wortmannin, PKB activity remarkably reduced, and Caspase-3 expression, Caspase-9 activity markedly increased. Wortmannin suppressed growth and potentiated apoptosis caused by etoposide. Potentiation of apoptosis by Wortmannin correlated with etoposide-induced PKB and Caspase-9 phosphorylation. Conclusions PKB and Caspase-9 signal transduction pathway promotes human gastric cancer cells survival and resistance to chemotherapy. PKB inhibitor can enhance sensitivity of gastric cancer cells to chemotherapy.

关 键 词：蛋白激酶B 胃癌细胞 化疗敏感性 

分 类 号：R735.2[医药卫生—肿瘤]