蛋白激酶C激活剂及抑制剂对紫杉醇耐药的卵巢癌细胞中P-糖蛋白表达及功能的影响

目的:探讨PKC(protein kinase C)激活剂及抑制剂对紫杉醇诱导的卵巢癌耐药细胞系A2780/Taxol中P-gp(P-glyco-protein)的表达及功能的影响。方法:免疫细胞化学SP法检测P-gp和PKC-α在耐药细胞A2780/Taxol及其亲本细胞中的表达;Western Blot检测PKC激动剂佛波脂(PMA)和抑制剂十字孢碱(SP)作用后P-gp在2种细胞上的表达水平;以罗丹明123(Rohdamin123,R123)作为荧光探针用流式细胞仪检测PMA及SP对细胞膜P-gp功能的影响。结果:P-gp在耐药细胞A2780/Taxol中呈阳性表达,在亲本细胞中不表达;PMA处理细胞,细胞内R123的平均荧光强度明显减低,Pgp的功能增强而表达量无明显变化;SP处理细胞,细胞内R123的平均荧光强度明显增加,Pgp的功能减弱而表达也无明显减少。结论:PKC通过对P-gp功能的调节而参与卵巢癌紫杉醇耐药的形成。

The effects of activation and inhibition agents of protein kinase C on the function and expression of P- glyco- protein in taxol- resistant ovarian cancer cells

Objective:To study the effects of activation and inhibition agents of protein kinase C on the function and expression of P-glyco-protein in Taxol-resistant ovarian cancer cell line A2780/Taxol.Methods:Immunohistochemical method was used to determine the expression of P-gp in A2780/Taxol and its parent cells A2780.Western Blot was used to determine the expression of P-gp on the two cell lines,which were treated or not treated by activation or inhibition agents of protein kinase C(PMA or SP).Rohdamin 123 was used as fluorescent probe to observe the effects of PMA and SP on the function of P-gp and drug accumulation in A2780/Taxol.Results:P-gp had positive staining on A2780/Taxol.When treated by PMA,A2780/Taxol cells showed decreasing of drug accumulation,enhancing function of P-gp.When treated by SP,A2780/Taxol cells showed increasing drug accumulation,weakening function of P-gp.The expression had not changed nether when treated by PMA nor SP.Conclusion:Protein kinase C may play a role in taxol resistance of ovarian cancer cells via modulating the function of P-gp.