Reversal effect of cinobufacine on adriamycin resistancehuman breast cancer cells

Aim To investigate the reversal effect of cinobufacine(Cino)on adrimycin(ADM)resistant human breast cancer cell line MCF-7/ADM.Methods The cytotoxic effect of Cino or ADM and the sensitivity of ADM to cells was determined by MTT assay.The intracellular concentration of ADM was detected by HPLC. The expression of P-glycoprotein(P-gp)was examined by flow cytometric(FCM) .Results The maximum non-toxic dose Cino(15 mg·L-1) increased the sensitivity of ADM in MCF-7/ADM,decreased the IC50 of ADM in MCF-7/ADM from 38.14 mg·L-1 to 12.93 mg·L-1, and significantly increased the intracellular concentration of ADM in MCF-7/ADM and reduced the expression of P-glycoprotein.Conclution The results showed that Cino can partially reverse multidrug resistance(MDR)of MCF-7/ADM cells and the mechanism might be associated with the increase of intracellular accumulation of ADM and the reduced expression of P-glycoprotein(P-gp)in MCF-7/ADM cells.