Reversal effect of berbamine on multidrug resistance of K562/A02 cells and its mechanism / 中国实验血液学杂志

ABSTRACT

This preject is to explore the reversal efficacy of calmodulin antagonist berbamine (BBM) on multidrug resistance (MDR) and its mechanism. Human erythroleukemic cell line K562 and its adriamycin-resistant counterpart K562/A02 were used in the study. The cells were co-cultured with ADR and BBM in different concentrations. MTT assay was used to analyze the effect of BBM on cell growth inhibition. According to the MTT assay, the 50% inhibitory concentration (IC(50)), the multiples of drug resistance and increased sensitivity of ADR were calculated. The concentration of intracellular ADR and expression level of P-gp were detected by flow cytometry (FCM). The expression level of mdr1 mRNA and survivin mRNA was detected by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) with beta-actin as internal reference. The results showed that IC(50) of ADR in K562 and K562/A02 cells was 1.16 +/- 0.09 micro mol/L and 37.47 +/- 1.76 micro mol/L, respectively. The resistant multiple of K562/A02 cells to ADR was 32.30 higher than that of K562 cells. BBM increased the chemo-sensitivity of ADR in K562/A02 cells with dose-dependent relationship, i.e. when 5, 10 and 20 micro mol/L BBM was added in the culture the chemo-sensitivity of ADR was increased to 2.01-, 9.68-, and 41.18-fold (P < 0.01), respectively. After treating K562/A02 cells by 5 or 10 micro mol/L BBM for 2 hours the accumulation of intracellular ADR was increased to 1.41- and 1.52-fold (P < 0.01), respectively. Treating by BBM for 72 hours decreased 4.12% (P < 0.05) and 27.09% (P < 0.01) of P-gp expression, respectively, meanwhile down-regulated expression of mdr1 mRNA and survivin mRNA was found. In conclusion, BBM could increase intracellular concentration of ADR in K562/A02 that down-regulated expression level of mdr1 mRNA and P-gp and survivin so that the sensitivity of K562/A02 to ADR was increased significantly.