PDTC逆转K562/AO_2细胞多药耐药性机制研究

The study of the reversal effect of PDTC on multidrug resistance of K562/AO_2 cells and its mechanism

目的研究核因子κB(NF-κB)抑制剂吡咯烷二硫代氨基甲酸盐(PDTC)逆转K562/AO2细胞耐药效应及其机制。方法采用MTT比色法分别检测K562/AO2细胞的耐药性、PDTC对K562/AO2细胞增殖的影响以及非细胞毒剂量PDTC、维拉帕米(Ver)预作用后K562/AO2细胞药物敏感性的变化,采用免疫细胞组织化学法、RT-PCR检测K562、K562/AO2细胞NF-κB、mdr-1 mRNA表达水平以及PDTC作用一定时间对其影响。结果①K562/AO2细胞对阿霉素(ADM)的耐药性是K562细胞的59倍;非细胞毒剂量PDTC预作用后,ADM对K562/AO2细胞的半数抑制浓度(IC50)显著降低,相对逆转耐药效率为93.03%,强于经典耐药逆转剂Ver的作用81.07%(P<0.01);②K562/AO2细胞NF-κB表达水平高于K562细胞(P<0.01);PDTC可有效抑制K562/AO2细胞NF-κB表达,伴随mdr-1 mRNA表达减少,呈时间依赖性。结论抑制NF-κB异常活化可部分逆转K562/AO细胞耐药性,其机制与mdr-1 mRNA转录表达减少有关。

Objective To investigate the effect of pyrrolidine dithioearbama（PDTC）,an inhibitor of nuclear factor κB（NF-κB） activity on reversing the chemoresistance of K562/AO2 cells and its mechanism.Methods Human erythroleukemic cell line K562 and its adriamycin-resistant counterpart K562/AO2 cells were used in the study.MTT assay was employed to detect the multiple drug resistance of K562/AO2 cells,the effect of PDTC on cell proliferation and the variations in drug sensitivity of K562/AO2 cells pretreated with PDTC/Verapamil（Ver） in noncytotoxic dose.Immunocytohistochemical method and RT-PCR were used to detect the relative expression of NF-κB and mdr-1 mRNA in K562 and K562/AO2 cells,respectively,and the effect of PDTC treatment at different time points.Results ①The drug resistance of K562/AO2 cells to ADM was 59 times as much as that of K562 cells.When pretreated with PDTC in noncytotoxic dose,the IC50 of ADM in K562/AO2 cells had a marked decrease,with a relative reverse efficiency of 93.03%,while that of classic modifying agents Ver was 81.07%（P0.01）;②The NF-κB expression level of K562/AO2 cells was significantly higher than that of K562 cells（P0.01）;DTPC effectively inhibited the NF-κB expression of K562/AO2 cells,accompanied by the down-regulated expression of mdr-1 mRNA,in a time dependent manner.Conclusion With its inhibitory effect on the abnormal activity of NF-κB,PDTC can partially reverse the multidrug resistance of K562/AO2 cells,the mechanism of which might be associated with the down-regulation of mdr-1 mRNA.