雷帕霉素增强子宫内膜癌细胞对阿霉素的敏感性

Rapamycin enhances chemosensitivity of endometrial cancer cells to adriamycin

目的:探讨mTOR抑制剂雷帕霉素联合阿霉素对子宫内膜癌细胞株的影响及其机制。方法:选用2株不同PTEN状态的子宫内膜癌细胞株:HEC-1A(PTEN野生型)和Ishikawa(PTEN突变型),分别给予低浓度雷帕霉素预处理24 h,再使用阿霉素,MTT法检测联合用药前后阿霉素24 h IC50及细胞生存率的变化,计算两药的联合指数;流式细胞术检测细胞凋亡率,Western blotting观察PI3K/Akt通路的蛋白磷酸化和凋亡蛋白caspase-3的变化。结果:(1)雷帕霉素或阿霉素单药使用时均明显抑制2株子宫内膜癌细胞的生长。抑制率与时间、剂量呈正相关。使用10 nmol/L雷帕霉素预处理24 h后,阿霉素作用Ishikawa细胞的IC50由(21.3±3.8)μmol/L降到(11.9±1.2)μmol/L(P<0.05);而HEC-1A细胞的IC50由(14.3±2.8)μmol/L降到(8.2±0.9)μmol/L(P<0.05);2株细胞中阿霉素与雷帕霉素的联合指数均大于1.15,提示在2种细胞株中两药均有协同作用;(2)联合用药后,凋亡率较单药使用组明显升高(P<0.05);同时,p-Akt蛋白表达下降,而活化的caspase-3表达上调。结论:雷帕霉素能增加子宫内膜癌细胞对阿霉素的敏感性,从而降低肿瘤细胞对药物的耐药性,具有良好的抗肿瘤前景。

AIM： To explore the therapeutic effect of adriamycin combined with rapamycin on endometrial cancer cells.METHODS： Two endometrial carcinoma cell lines with different PTEN gene states were chosen： HEC-1A（wild type） and Ishikawa（mutant type）.Before adriamycin administration,the cells were pretreated with low concentration of rapamycin for 24 h.The cell viability and 50% inhibitory concentration（IC50） of adriamycin at 24 h were determined by MTT assay.Multiple drug effect/combination index（CI） was used to evaluate the interaction between adriamycin and rapamycin.Apoptotic rate was measured by flow cytometry.The effects of the drugs on phosphorylation of PI3K/Akt and apoptosis protein caspase-3 were detected by Western blotting.RESULTS： Both adriamycin and rapamycin showed obvious growth inhibitory effects on the 2 endometrial cancer cell lines in a time-and dose-dependent manner.After pretreated with rapamycin,IC50 of adriamycin decreased sharply.In Ishikawa cells,it decreased from（21.3±3.8） μmol/L to（11.9±1.2） μmol/L,P0.05.In HEC-1A cells,it decreased from（14.3±2.8） μmol/L to（8.2±0.9） μmol/L,P0.05.Combination index value of the 2 drugs was more than 1.15 in the 2 endometrial cancer cell lines,indicating synergistic effects.The combination therapy of adriamycin with rapamycin increased apoptotic rates in the 2 cell lines,and induced the down-regulation of phosphorylated Akt and over-expression of caspase-3 as compared with single drug treatment（P0.05）. CONCLUSION： Adriamycin combined with rapamycin significantly enhances the chemosensitivity of endometrial cancer cells and reduces drug resistance,which will become a new trend for treating endometrial cancer.