托瑞米芬和他莫昔芬对MCF7/ADR多药耐药的逆转作用

Reversal effect of toremifene and tamoxifen on multidrug resistance in MCF7/ADR cell

目的:研究托瑞米芬(toremifene,TOR)和他莫昔芬(tamoxifen,TAM)对乳腺癌耐阿霉素细胞株MCF7/ADR多药耐药的逆转作用及其可能作用机制。方法:采用SRB法测量TOR、TAM对MCF7/ADR细胞的耐药逆转倍数;荧光显微镜、流式细胞仪测定加入TOR、TAM前后耐药细胞内荧光含量表达变化;Westernblotting检测TOR、TAM对P-gp表达的影响。结果:(5、10、20)μmol/L的TOR和TAM对MCF7/ADR耐药的逆转倍数分别为(1.5、7.0、35.4)倍和(2.0、5.4、30.7)倍,而对MCF7/S细胞没有显著性作用。加入TOR、TAM后,MCF7/ADR细胞内ADR荧光的呈现由核外进入核内,荧光含量亦具浓度依赖性提高。MCF7/S细胞P-gp表达阴性,而MCF/ADR细胞P-gp表达阳性。TOR[(5、10、20)μmol/L]与TAM[(5、10)μmol/L]对MCF7/ADR细胞株中的P-gp表达未产生显著性抑制作用。结论:TOR可明显逆转MCF7/ADR细胞株对ADR的耐药性,增强其细胞毒作用,逆转强度与TAM相当。其机制可能是通过对P-gp结构功能的调控来逆转耐药性,而不是通过下调MDR1基因的蛋白水平表达。

Objective：To investigate the reversal effect and possible mechanism of toremifene and tamoxifen on multidrug resistance in breast cancer cell line MCF7/ADR. Methods： SRB was used to measure the reversal times of toremifene and tamoxifen on MCF7/ADR. Fluorescent microscope and flow cytometry were applied to analyze the change of the flourescence after added TOR and TAM. The different expression of P-gp in MCF7/ADR and MCF7/S were examined by Western blotting. Results： Toremifene and tamoxifen[（5 ,10 ,20）μmol/L] increased the cytotoxicity of doxorubicin in drug-resistent breast cancer cells in vitro （1.5-fold, 7.0-fold, 35.4-fold and 2.0-fold, 5.4-fold, 30.7-fold,respectively）,but had no signifilent effect on MCF7/S cells. Toremifene and tamoxifen significantly enhanced accumulation of doxorubicin and Rhodamine123 in drug-resistant cells. P-gp expression in MCF7/S was negative,while positive in MCF7/ADR. TOR[（5,10,20）μmol/L] and tamoxifen[（5,10）μmol/L] didn＇t inhibit the expression of P-gp in MCF7/ADR. Conclusion： TOR and tamoxifen could significantly reverse the MDR of MCF7/ADR.The possible mechanism is that the struction and function of p-glycoprotein were changed and regulated by TOR and TAM,instead of dowm-regulating the expression of p-glycoprotein.