紫杉醇与mTOR抑制剂雷帕霉素联合抑制非小细胞肺癌增殖

Inhibition of paclitaxel combined with mTOR inhibitor Rapamycin on proliferation of NSCLC cells

目的研究紫杉醇对非小细胞肺癌A549细胞mTOR信号通路的影响,以及紫杉醇与mTOR抑制剂雷帕霉素的联合作用。方法在紫杉醇和/或雷帕霉素处理细胞后,采用流式细胞术分析细胞周期和细胞凋亡;免疫印迹技术分析信号分子表达与磷酸化;采用细胞计数法检测细胞增殖。结果 (5×10^(-6))g/L紫杉醇作用24 h可诱导(31.26±2.52)%细胞发生凋亡;但随紫杉醇浓度增加,细胞凋亡率下降而G_2/M期阻滞效应增加。紫杉醇对mTOR分子的表达无影响,但与其结合的raptor和rictor,以及抗凋亡分子survivin表达随浓度增加而增加,mTOR下游分子S6K1磷酸化也被上调。雷帕霉素与紫杉醇同时或在紫杉醇作用后加入培养体系可增强其对肿瘤增殖的抑制作用,并促进紫杉醇诱导细胞凋亡。结论紫杉醇对A549细胞mTOR信号通路的活化有上调作用,mTOR抑制剂与雷帕霉素可协同抑制非小细胞肺癌增殖。

Objective To study the effect of paclitaxel on mTOR signaling pathway in NSCLC cell A549 and the combination effects of paclitaxel and mTOR inhibitor Rapamycin. Methods Cell cycle and apoptosis were detected by flow cytometry after cells treated by paclitaxel with or without Rapamycin. The expression or phosphorylation of cell signaling molecules were determinated by Western blot, and inhibition rate of tumor cell proliferation was detected by cell counting. Results The apoptosis rate of A549 treated by 5 x 10 -6g/L paclitaxel for 24 hours was （31.26 ___2.52） %. The apoptosis induction effect of higher concentration of paclitaxel decreased, but the cell mitosis blocking effect increased with the concentration. Paclitaxel did not affect the expression of mTOR, but the expression of two molecules bounded with mTOR, raptor and rictor was up-regulated by paclitaxel.Paclitaxel could also increase the mount of survivin and the phosphorylation of S6K1. The apoptosis inducing effect and the antitumor effect of paclitaxel were enhanced by Rapamycin which adding in the cell culture medium with paclitaxel simuteniusly or after the pretreatment for 16 hours. Conclusion Paclitaxel activates mTOR associated pathway. Inhibition of mTOR with Rapamycin can enhance the anti-tumor effect of paclitaxel, and promote the apoptosis induced by palitaxel.