抑制PI3K/PKB通路逆转胃癌耐药的作用及其机制  

Suppressing PI3K/PKB signal pathway to reverse drug resistance of gastric carcinoma cell line SGC7901/VCR:efficiency and mechanism

作　　者：谢霞[1] 高青[1] 王艳丽[1] 

机构地区：[1]重庆医科大学附属第一医院消化内科,重庆400016

出　　处：《第三军医大学学报》2009年第3期227-229,共3页Journal of Third Military Medical University

摘　　要：目的观察抑制PI3K/PKB信号通路对胃癌耐药性的逆转作用,并探讨其可能机制。方法通过体内外实验方法检测长春新碱(vincristine,VCR)及联合LY294002(PI3K/PKB通路抑制剂)对SGC7901/VCR细胞的生长抑制作用;采用Western blot及RT-PCR分别检测细胞中PKB、磷酸化PKB的蛋白表达水平及MDR1、Bax、Bcl-2基因表达水平;流式细胞仪检测细胞的凋亡。结果LY294002能明显增加SGC7901/VCR细胞对VCR的敏感性,促进VCR诱导细胞凋亡,使其耐药指数从40.45降至8.50;LY294002可明显降低耐药细胞中磷酸化PKB的蛋白表达和MDR1、Bcl-2的基因表达水平(P<0.01),促进Bax的基因表达(P<0.01);体内实验显示联合用药组的裸鼠移植瘤大小明显小于VCR组(P<0.01)。结论抑制PI3K/PKB通路可逆转胃癌耐药,其机制可能与降低耐药基因MDR1的表达以及调控相关凋亡基因Bax和Bcl-2的表达有关。Objective To investigate the reversing effects on drug resistance of gastric carcinoma by suppressing PI3K/PKB signal pathway, and explore its implicated mechanism. Methods MTT assay was used to test the inhibitory effects of VCR alone or VCR in combination with PI3K/PKB inhibitor, LY294002 on SGC7901/VCR cells. The SGC7901 treated with or without LY294002 served as control. The protein levels of PKB and phospho-PKB in the above VCR cells were determined by Western blot analysis. The mRNA expressions of MDR1, Bax and Bcl-2 were evaluated by semi-quantitative PCR with β-actin as the inner control. The apoptosis was detected by flow cytometry. Tumor volume on the tumor-bearing mice transplanted by SGC7901/ VCR cells or cells treated by VCR, LY294002 and their combination respectively was measure for the in vivo effect of LY294002. Results LY294002 enhanced the sensitivities of SGC7901/VCR cells to VCR significantly, and promoted the apoptosis rate induced by VCR prominently, with their corresponding drug resistant index decreasing from 40.45 to 8.50. The protein level of phospho-PKB was reduced, and the mRNA expression levels of MDR1 and Bcl-2 were inhibited （P 〈 0.01 ）, while that of Bax was improved significantly （P 〈 0.01 ）. LY294002 improved the growth inhibitory effect of VCR on transplanted gastric carcinoma in nude mice. Conclusion Suppressing PI3K/PKB signal pathway by LY294002 reverses the drug resistance of gastric carcinoma cell line SGC7901/VCR. Reduction of MDR1 expression levels, and regulation of apoptosis-related genes, such as Bax and Bcl-2 may play key roles in this progress.

关 键 词：PI3K/PKB LY294002 SGC7901/VCR细胞 SGC7901细胞 凋亡 

分 类 号：R329.28[医药卫生—人体解剖和组织胚胎学] R394-33[医药卫生—基础医学]