氯喹增强乳腺癌细胞对他莫昔芬化疗敏感性的作用研究

目的:探讨氯喹(chloroquine,CQ)增强乳腺癌细胞对他莫昔芬(tamoxifen,TAM)化疗敏感性的作用及其机制.方法:以雌激素受体阳性乳腺癌细胞MCF-7为研究对象,分为空白对照组、TAM组、CQ组和CQ+TAM组,空白对照组不加药物,仅用培养基培养,其余各组加入相应药物培养.采用MTT法检测各组细胞存活率;通过集落克隆形成实验观察低浓度CQ、TAM及其联用对MCF-7细胞增殖的抑制作用;溴化丙啶单染检测各组细胞凋亡率;Western blot法检测各组蛋白表达情况.结果:TAM组、CQ组和TAM+CQ组24 h、48 h、72 h细胞存活率均明显低于空白对照组(P<0.01),TAM+CQ组24 h、48 h、72 h细胞存活率亦均明显低于TAM组和CQ组(P<0.01),TAM组24 h存活率低于CQ组(P<0.05).集落克隆形成实验结果显示,低浓度CQ抑制MCF-7细胞集落形成不明显,但CQ可明显增强TAM的抑制作用.4组间细胞凋亡率差异有统计学意义(P<0.01),其中TAM组、CQ组和TAM+CQ组细胞凋亡率均明显高于空白对照组(P<0.01),TAM+CQ组细胞凋亡率亦均明显高于TAM组和CQ组(P<0.01).Western blot结果显示,随时间增加,TAM组Beclin-1和LC3Ⅱ蛋白表达升高,p62蛋白表达降低;与空白对照组比较,TAM组LC3Ⅱ蛋白表达明显升高,p62蛋白表达降低;而CQ+TAM组LC3Ⅱ、Beclin-1和p62蛋白表达均较TAM组升高,Bcl-2蛋白表达降低.结论:CQ可增强乳腺癌细胞对TAM化疗的敏感性,其机制可能是通过下调Bcl-2表达,抑制细胞自噬反应.

Study on the chloroquine enhancing the chemotherapy sensitivity of breast cancer cells to tamoxifen

Objective:To investigate the effects and mechanism of chloroquine(CQ)enhancing the chemotherapy sensitivity of breast cancer cells to tamoxifen(TAM).Methods:The MCF-7 cells(estrogen-receptor positive breast cancer cells)were divided into the control group,TAM group,CQ group and CQ+TAM group.The control group was cultured with culture medium(no adding drug),and other groups were cultured with corresponding drugs.The survival rate of cells was determined using MTT assay.The inhibiting effects of MCF-7 cells proliferation induced by low concentration CQ,TAM and CQ combined with TAM were observed using colony formation assay.The cell apoptosis rate was determined by propidium bromide staining.The related protein expressions were detected by Western blot.Results:The survival rates of cells in TAM group,CQ group and TAM+CQ group at 24 h,48 h and 72 h of treatment were significantly lower than that in control group(P<0.01).The survival rates of cells in TAM+CQ group at 24 h,48 h and 72 h of treatment were significantly lower than that in TAM group and CQ group(P<0.01),and the survival rate of cells in TAM group at 24 h of treatment was significantly lower than that in CQ group(P<0.05).The results of colony formation assay showed that the effect of low concentration CQ on inhibiting the MCF-7 cells colony formation was not obvious,but CQ could strengthen the inhibiting effect of TAM.The differences of the apoptosis rate of cells between four groups were statistically significant(P<0.01).The apoptosis rates of cells in TAM group,CQ group and TAM+CQ group were significantly higher than that in control group(P<0.01),and the apoptosis rate of cells in TAM+CQ group was significantly higher than that in TAM group and CQ group(P<0.01).The results of Western blot showed that the protein expressions of Beclin-1 and LC3Ⅱ in TAM group increased,and the protein expression of p62 decreased with the increasing of time.Compared with the control group,the expression of LC3Ⅱprotein in TAM group significantly increased,and the expression of p62 protein in TAM group increased.Compared with the TAM group,the protein expressions of LC3Ⅱ,Beclin-1 and p62 in CQ+TAM group increased,and the expression of Bcl-2 protein in CQ+TAM group decreased.Conclusions:CQ can strengthen the chemotherapy sensitivity of breast cancer cells to TAM,the mechanism may be involved in downregulating the expression of Bcl-2 and inhibiting the autophagy.