PI3K/Akt通路在药物放射增敏中作用的机制  

The Role of PI3K/Akt Pathway in Radiosensitization of HeLa Cells

作　　者：夏曙[1] 赵茵[1] 张孟贤[1] 付强[1] 于世英[1] 

机构地区：[1]华中科技大学同济医学院附属同济医院肿瘤中心,武汉430030

出　　处：《华中科技大学学报（医学版）》2009年第5期636-640,644,共6页Acta Medicinae Universitatis Scientiae et Technologiae Huazhong

基　　金：教育部新教师基金(No.200804871034);湖北省自然科学基金(No.2008cdb133)资助项目

摘　　要：目的进一步探讨PI3K/Akt信号转导途径在药物放射增敏中作用的分子机制。方法体外培养HeLa细胞,多西紫杉醇(docetaxel)和顺铂(cisplatin)单独及分别联合PI3K抑制剂LY294002作用24 h,X线6 Gy剂量照射;Western blot检测Akt、磷酸化Akt(pAkt)、Bad、磷酸化Bad(pBad)蛋白的表达变化;RT-PCR检测Bad、Ku70、Ku80 mR-NA的表达变化;中性彗星电泳检测不同处理组细胞DNA的损伤。结果①docetaxel+LY294002联合照射组、cispla-tin+LY294002联合照射组Bad mRNA表达增高,Ku70 mRNA表达减低,Ku80 mRNA表达无明显变化;②docetaxel+LY294002联合照射组、cisplatin+LY294002联合照射组Bad蛋白表达增高,pAkt、pBad蛋白表达减低,Akt蛋白表达无明显变化;③docetaxel+LY294002联合照射组、cisplatin+LY294002联合照射组细胞彗星电泳尾距明显长于单纯药物增敏照射组。结论①docetaxel和cisplatin药物增敏照射能够明显活化PI3 K/Akt信号转导途径;②抑制PI3 K/Akt信号转导途径能够抑制Ku7 0表达,减少细胞DNA损伤后的再修复,提高促凋亡因子Bad的表达,促进细胞的凋亡。Objective To further explore the biologic mechanism of the role of PI3K/Akt pathway in radiosensitization of HeLa cells.Methods The HeLa cells were cultured in vitro.Using the IC20 of cisplatin and docetaxel in HeLa or combined with LY294002,the cells were radiated by X-ray.The protein expression of pAkt,Akt,Bad and pBad was detected by Western blot,and the mRNA expression of Bad,Ku70 and Ku80 by RT-PCR.The DNA damages were detected by neutro-comet electrophoresis.Results ①The expression level of Bad mRNA in LY294002＋docetaxel/cisplatin group was higher,and that of Ku-70 mRNA was lower,but there was no significant change in Ku-70 mRNA expression.②The expression level of Bad protein in LY294002＋docetaxel/cisplatin group was higher,and that of pBad and pAkt protein was lower,but there was no significant changes in the Akt protein expression.③The comet electrophoresis tail distance in docetaxel＋cisplatin＋LY294002 group was longer than docetaxel＋cisplatin group.Conclusion The radiosensitization of docetaxel and cisplatin could activate the PI3K/Akt pathway.Inhibiting PI3K/Akt pathway may increase radiosensitization of HeLa cells by inhibiting Ku70 to suppress the DNA recovery,and enhancing the expression of Bad to promote cell apoptosis.

关 键 词：PI3K/AKT 放射增敏 多西紫杉醇 顺铂 

分 类 号：R73-36[医药卫生—肿瘤]