Reversal effect of MDR1 and MDR3 gene silencing by shRNA on resistance of breast carcinoma cells to adriamycin / 国际肿瘤学杂志

ABSTRACT

Objective To investigate the effect of MDR1 and MDR3 gene silence by shRNA of human breast carcinoma cell line MCF-7/Adr,and explore the role of MDR1 and MDR3 in adriamycin-resistance of breast carcinoma cells. Methods shRNA plasmid vector specifically targeting MDR1 and MDR3 gene was transfected into cells. The control group was transfected with empty vector. The concentration of adriamycin was detected by the flow cytometry (FCM). Cell apoptosis was analysed by FITC-Annexin-V/PI double staining. Cell viability and the IC50 of adriamycin on MCF-7/Adr cells were determined by MTT method. MDR1 and MDR3 mRNA were assessed by RT-PCR. P-gp expression was detectedby immunochemistry. Results After treatment with ABCB1 and ABCB4 shRNA plasmid vector, the apoptosis of MCF-7/Adr cells was (30.21±1.65)%and (22.07±2.17)% respectively. Compared with untransfecedgroup and empty vector transfection group the difference was significant(P＜0.01). MDR1 and MDR3 shRNAcould increase cellular adriamycin accumulation of MCF-7/Adr cells. MCF-7/Adr cells viability and the IC50were significantly decreased after transfection. Compared with untransfeced group and empty vector transfectiongroup, the mRNA level of MDR1 and MDR3 in MCF-7/Adr cells were decreased by (89.5±0.8)%and(85.1±1.2)%, the reduction of MDR1 and MDR3 mRNA was in a time-dependent manner. Immunochemistry proved that the expression of p-gp was significantly inhibited. Compared with untransfeced group and empty vector transfection group the difference was significant (P＜0.05). Conclusion The shRNA can effectively and specifically silence the expression of MDR1 and MDR3 gene, reverse the adriamycin-resistance mediated by P-gp in MCF-7/Adr cells. The reversal effect of adriamycin-resistance by shRNA of MDR1 is more effective than that of MDR3.