MGC803细胞中MAPK信号传导系统与MDR1关系的研究

Correlation between MAPK signal transduction pathway and MDR1in MGC803 cells

目的:探讨在人胃癌细胞系MGC803中促分裂原激活的蛋白激酶(mitogen-activatedproteinkinase,MAPK)信号传导系统与MDR1基因表达的关系。方法:通过westernblot验证MGC803细胞在长春新碱(vincristine,VCR)作用下MDR1基因编码的P-糖蛋白(P-glycoprotein,P-gp)的表达及特异性MAPK抑制剂PD098059对P-gp表达的抑制,通过流式细胞术对VCR及PD098059作用下的细胞进行周期解析,同时用MTT法验证VCR诱导后及PD098059作用下的药物敏感性。结果:MGC803细胞在VCR短期作用下,P-gp表达增加,在PD098059的作用下其表达受到抑制。通过细胞的周期解析发现VCR和PD098059共同作用的细胞凋亡比例为35.61%,显著高于VCR单独作用引起的凋亡(18.41%)(P<0.05)。VCR刺激后MGC803细胞的IC50为284ng/ml,分别为阴性对照组(127ng/ml)的2.24倍,为VCR+PD098059组(191ng/ml)的1.48倍。结论:MGC803细胞在VCR的短期作用下可诱导产生P-gp,而PD098059可抑制P-gp的表达和逆转其耐药性,从而增加MGC803细胞的凋亡。MAPK有可能通过调节MDR1的转录和翻译而影响细胞的耐药性。

Objective:To investigate the correlation between mitogen -activated protein kinase(MAPK)signal transduction pathway and multidrug resistance in MGC803cells.Methods :Western blot was used to analyzed the expression of P-glycoprotein(P-gp)which is encoded by MDR1in transient induced cells and the inhibition of the expression of P-pg by PD098059.The cells cycle analysis was determined by flow cytometric assays.MTT assay was used to study the drug susceptibility of MGC803cells which were exposed to vincrestine (VCR)and PD098059.Results:Transient exposure to VCR induced P -gp expression in MGC803cells and the expression of P-gp was inhibited by PD098059.The ratio(35.61%)of apoptotic cells treated by VCR and PD098059was significantly higher than that(18.42%)treated by VCR.The IC 50 (284ng /ml)of MGC803cells treated by VCR exhibited2.24-fold higher resistance than that(127ng /ml)of negative group and1.48-fold higher than that(191ng /ml)of the group treated by PD098059.Conclusion:This study shows that the expression of P-gp can be induced by transient exposure to VCR and this induction can be prevented by PD098059.MAPK signal transduction pathway may influence the expression of MDR1.