白血病耐药细胞中多药耐药基因MDR1与核转录因子κB的关系

目的:研究核转录因子κB与多药耐药基因MDR1在白血病化疗耐药中的作用，阐明核转录因子κB(NF-κB)与白血病多药耐药的关系及相关分子机制。方法：白血病细胞K562和阿霉素(ADM)诱导的耐药细胞K562/ADM分别应用ADM（0、0.25、0.50、1.00和2.00 μg·L^-1）或丝裂霉素(MIT)（0、2、4、8和16 mg·L^-1）　作用48 h，通过MTT法检测细胞生存率，计算细胞耐药指数；RT-PCR方法检测MDR1和IκB mRNA表达；Western blotting方法检测P-gp和P65的蛋白表达。结果：ADM和MIT分别作用后，与空白对照组比较，白血病细胞K562细胞生存率下降(P<0.01)，呈剂量依赖性；ADM和MIT对耐药细胞K562/ADM生存率作用不明显；在mRNA水平上，与K562细胞比较，K562/ADM细胞的MDR1 mRNA高表达(P<0.01)。与空白对照组比较，ADM 0.50和1.00　 μg·L^-1>或MIT 4和8 mg·L^-1分别作用K562细胞和K562/ADM细胞，IκBα mRNA表达均下降(P<0.01)，并呈剂量依赖性；在蛋白水平上，与K562细胞比较，K562/ADM细胞的P-gp蛋白高表达(P<0.01)。与空白对照组比较，ADM 0.50和1.00 μg·L^-1或MIT 4和8 mg·L^-1分别作用K562/ADM细胞，P-gp蛋白表达量升高(P<0.01)，同时P65蛋白表达量升高，且呈药物剂量依赖性(P<0.01)。结论：MDR1基因及P-gp蛋白的高表达很可能是白血病细胞K562多药耐药性形成的关键机制，而NF-κB的激活可能参与了多药耐药的调控。

Relationship between multi-drug resistance gene MDR1 and NF-kappa B in human drug-resistance erythroleukemia cells

Objective To observe the effect of nuclear factor kappa B(NF-κB) and multi-drug resistance gene MDR1 on leukemia chemotherapy resistance,to demonstrate the relationship between NF-κB and multidrug-resistance and the related mechanism.Methods Erythroleukemia cells K562 and adriamycin(ADM)-resistance cells K562/ADM were treated with ADM(0,0.25,0.50,1.00,2.00 μg·L-1) or mitomycin(MIT)(0,2,4,8,16 mg·L-1) for 48 h. The cell viability was detected by MTT assay,the cell resistant factor was calculated,MDR1 and IκB mRNA levels were detected by RT-PCR;Pgp and P65 protein levels were detected by Western blotting.Results Compared with control group,0.50 and 1.00 μg·L-1 ADM or 4 and 8 mg·L-1 MIT inhibited the cell viability significantly in erythroleukemia cells K562 in a dose-dependent manner(P<0.01);but had no significant effect on drug-resistance cells;on the mRNA level,compared with K562 cells,the expression level of MDR1 mRNA in K562/ADM cells was higher(P<0.01).Compared with control group,the expressions of IκBα mRNA decreased(P<0.01) in K562 cells or K562/ADM cells treated with 0.50 and 1.00 μg·L-1 ADM or 4 and 8 mg·L-1 MIT respectively in a dose-dependent manner.On the protein level,compared with K562 cells,the expression of P-gp protein increased(P<0.01);compared with control group,the expression of P-gp protein increased(P<0.01),the expression of P65 protein increased at the same time in a dose-dependent manner in K562/ADM cells treated with 0.50 and 1.00 μg·L-1 ADM or 4 and 8 mg·L-1 MIT(P<0.01).Conclusion The high expression of MDR1 gene and P-gp protein may be the essential mechanism of drug resistance in K562 cells,and the activation of NF-κB may be involved in the regulation of multi-drug resistance.