依维莫司与PI3K抑制剂联合他莫昔芬对ER阳性乳腺癌细胞系作用的观察

Effects of tamoxifen combining with everolimus and PI3K inhibitor on ER-positive breast cancers

目的:探讨他莫昔芬(TAM)联合mTORC抑制剂依维莫司(EVE)和PI3K抑制剂LY294002(LY)阻断负反馈激活,分析对ER(+)乳腺癌细胞系增殖、凋亡和周期的影响。方法:乳腺癌细胞系MCF-7和BT474分为对照组、TAM、TAM+EVE、TAM+LY和TAM+EVE+LY 5组,分别检测肿瘤细胞的增殖、凋亡与周期以及信号通路的改变情况。结果:MCF-7和BT474接受药物处理以后,EVE明显抑制肿瘤细胞的增殖,A450分别为0.23和0.32,特别是在三药联合组,抑制细胞增殖更加显著,A450分别为0.16和0.20,P<0.05。细胞凋亡的研究显示,EVE可促进肿瘤细胞凋亡,三药联合以后,乳腺癌细胞MCF-7和BT474的凋亡率分别为30.1%和54.2%。细胞周期的研究显示,G1期比例升高,三药联合后MCF-7和BT474G1期比率分别为86.02%和84.91%。EVE可有效阻断mTOR信号通路的活化,但通过负反馈作用可导致磷酸化AKT 473位点的激活,而联合PI3K抑制剂后,这种负反馈作用被阻断。结论:内分泌治疗药物TAM联合mTOR抑制剂EVE和PI3K抑制剂可抑制ER(+)乳腺癌细胞增殖、促进细胞凋亡、阻滞细胞生长,达到更好的治疗效果。

OBJECTIVE：To explore the potential effect of tamoxifen （TAM） combining with everlimus （EVE） and PI3K inhibitor LY294002 （LY） on proliferation, apoptosis, cell cycle and signaling pathway in ER positive breast cancer cell lines. METHODS： Breast cancer cell lines （MCF-7 and BT474） were divided into five groups ： control,TAM, TAM＋ EVE, TAM＋ LY,TAM＋ EVE＋ LY. The proliferation, apoptosis, cell cycle and signaling pathway of breast cancer cell lines were evaluated. RESULTS：The EVE significantly inhibited proliferation of breast cancer cells and the absorbance of A450 was 0.23 and 0.32,respectively. Especially the three agents group got better effect and the absorbance of A450 was 0.16 and 0.20 （P（0.05）. The cell apoptosis research showed that the EVE can reduce apoptosis of breast cancer ceils. When combined with three agents,the apoptosis rate of MCF-7 and BT474 were 30.1% and 54.2%. The cell cycle re- search also showed that the EVE can increase the G1 rate and increased to 86.02% and 84. 91% after treated with the three agents combining. The EVE could inhibit the mTOR signaling pathway, but the negative feedback activation may in- duce AKT （Ser473） phosphorylation. When combined with PI3K inhibitor,the cross-talk was inhibited. CONCLUSIONS： Endocrine therapy agents combined with mTOR inhibitor EVE and PI3K inhibitor may significantly inhibit the proliferationand induce the apoptosis and keep G1 stage of cell cycle for ER-positive breast cancer cell lines,suggesting that the regime may gain more benefit for treatment of breast cancer patients.