水飞蓟素对乳腺癌MCF-7/DOX细胞耐药性的逆转作用及机制研究

摘要

Objective To investigate the reversal effect and mechanism of the traditional medicine monomer silymarin(Sily) on the drug resistance of human breast cancer cell MCF-7/DOX. Methods (1)MTS assay was adopted to determine the toxic effects of doxorubicin(DOX) on MCF-7/S and MCF-7/DOX,the multiple of drug resistance was calculated. When Sily was combined,the reversal effect with Verapamil(Ver) was evaluated as a positive control.(2)To test the changes of multidrug resistance gene MDR1 mRNA and its products P-gp after being treated with Sily and Ver by means of real-time PCR(RT-PCR)and western-blot respectively. Results (1)The IC50 value of sensitive cell and resistant cell with DOX were 1.868μg/ml and 60.6μg/ml respectively,the multiple of drug resistance was 32.45 times. The IC50 value of MCF-7/DOX declined to 12.757μg/ml and the reversal index was 4.75 times(P<0.01) after the effect of Sily(10μg/ml) with a more than 98 percent survival rate, which was detected after 48 hours.(2)The expression level of MRD1 mRNA and the encoded proteins P-gp had significantly decreased(P<0.01). Conclusions Noncytotoxic dose of Sily can reverse the DOX resistance of MCF-7/DOX,and the reversal effect is associated with the down-regulation of MRD1 mRNA and the expression of the encoded proteins P-gp.%目的 探讨中药单体水飞蓟素(Sily)对人乳腺癌耐药细胞MCF-7/DOX耐药性的逆转作用及其机制.方法 (1)用MTS比色法测定阿霉素(DOX)对MCF-7/S和MCF-7/DOX的毒性作用,计算耐药倍数;加入Sily干预后与阳性药物对照组(Ver组)比较,评估Sily的逆转疗效.(2)用实时荧光定量PCR(RT-PCR)及免疫印迹(Western-blot)法分别检测Sily、Ver处理后,MCF-7与MCF-7/DOX细胞中多药耐药基因MDR1 mRNA及其产物P-gp的变化.结果 (1)DOX对敏感细胞和耐药细胞的半数抑制浓度(IC50)分别为1.868μg/ml和60.625μg/ml,耐药倍数为32.45倍,Sily10μg/ml(存活率>98％)作用于MCF-7/DOX 48h后,耐药细胞株的IC50降至12.757μg/ml,逆转倍数为4.75倍(P<0.01);(2)在Sily(10μg/ml)作用下,MDR1 mRNA及其编码的蛋白P-gp表达水平显著下降(P<0.01).结论 无细胞毒性剂量的水飞蓟素能够逆转MCF-7/DOX对DOX的耐药性,其逆转作用可能与下调MDR1 mRNA及其编码的蛋白P-gp的表达有关.