紫杉醇通过mTOR信号通路影响乳腺癌细胞的增殖迁移

Effects of Paclitaxel on proliferation and migration of breast cancer MCF-7 cell via mTOR signaling pathway

目的 探讨紫杉醇通过雷帕霉素靶蛋白（mTOR）信号通路影响乳腺癌MCF-7细胞的增殖迁移.方法 实验分为4组,分别为对照组,紫杉醇低剂量组（0.25 μmol/L）,紫杉醇中剂量组（0.5 μmol/L）,紫杉醇高剂量组（1μmol/L）.MTT法检测各组MCF-7细胞活力;流式细胞术检测各组MCF-7细胞周期变化;Transwell迁移实验检测各组MCF-7细胞迁移能力;Western blot检测各组mTOR信号通路相关蛋白表达水平.结果 与对照组比较,紫杉醇低、中、高剂量组能显著抑制MCF-7细胞活力（P＜0.05）,且在48 h抑制程度最高（P＜0.05）,紫杉醇低、中、高剂量组都能使穿过滤膜进入下腔的乳腺癌MCF-7细胞数目显著减少[（98 ±9.78） vs （86.21 ±6.58）、（53.41 ±3.16）及（42.00 ±4.69）,P＜0.05];紫杉醇低、中、高剂量组能使G1期的细胞明显增多[（52.14±6.13）％vs （67.93±8.16）％、（72.32±3.67）％及（78.53±6.28）％,P＜0.01],使G2期的细胞明显减少[（13.68±0.85）％vs（8.57±1.03）％、（5.30±0.89）％及（3.46±0.78）％,P＜0.01];紫杉醇低、中、高剂量组中4E结合蛋白1（4EBP1）及mTOR磷酸化水平下降,细胞周期蛋白D1（Cyclin D1）及基质金属蛋白酶-9（MMP-9）表达量也降低（P＜0.01）.结论 紫杉醇抑制乳腺癌MCF-7细胞的增殖迁移,与mTOR信号通路有关.

Objective To explore effects of paclitaxel on proliferation and migration of breast cancer Michigan Cancer Foundation-7 （MCF-7） cells via mammalian target of rapamycin （mTOR） signaling pathway.Methods The cases were randomly divided into four groups,including control group,paclitaxel low-dose group （0.25 μmol/L）,paclitaxel medium-dose group （0.5 μmol/L）,and paclitaxel high-dose group （1 μmol/L）.The viability of MCF-7 cells was measured with methyl thiazolyl tetrazolium （MTT） assay.MCF-7 cell cycle was examined with flow cytometry.MCF-7 cell migration was tested with transwell migration assay.The levels of mTOR signalling pathway-related protein were assayed with Western blot.Results Compared to the control group,MCF-7 cell viability was significantly decreased in paclitaxel low,medium and high-dose groups （P 〈 0.05）,and the inhibitory rate was highest at 48 h （P 〈 0.05）.MCF-7 cell migration was significantly inhibited in paclitaxel low,medium and high-dose groups [（98 ± 9.78） vs （86.21 ± 6.58）,（53.41 ± 3.16） and （42.00 ± 4.69）,P 〈 0.05].Moreover,compared to the control group,the number of MCF-7 cells at G1 phase was significantly increased in paclitaxel low,medium and high-dose groups [（52.14±6.13）% vs （67.93 ±8.16）%,（72.32 ±3.67）% and （78.53 ± 6.28）%,P 〈 0.01],the number of MCF-7 cells at G2 phase was significantly reduced in paclitaxel low,medium and high-dose group [（13.68 ± 0.85） % vs （8.57 ± 1.03） %,（5.30 ± 0.89） % and （3.46 ± 0.78） %,P 〈0.01].The phosphorylations of 4E binding protein （4EBP1） and mTOR proteins as well as the expressions of cell-cycle protein D1 （Cyclin D1） and matrix metalloproteinase-9 （MMP-9） were significantly inhibited in paclitaxel low,medium and high-dose groups （P 〈 0.01）.Conclusions These results suggested paclitaxel could inhibit proliferation and migration in breast cancer MCF-7 cells,which might be related to mTOR signal pathway.