顺铂对蛋白酶体抑制作用的研究

Inhibitory effect of cisplatin on proteasome

目的 研究顺铂对蛋白酶体的抑制作用。方法 采用蛋白酶体特异性底物S LLVY AMC、B LRR AMC及Z LLE AMC观察了顺铂对纯化的人 2 0S蛋白酶体及CCD 110 3KidTr细胞内蛋白酶体活力的影响 ,同时分析了受蛋白酶体降解的p5 3蛋白在蛋白质及mRNA水平的表达。结果 顺铂对纯化的人 2 0S蛋白酶体具有明显的抑制作用 ,对 3种酶活力抑制作用的半数抑制浓度 (IC50 )分别为 3 2 17(S LLVY AMC)、3 7 96(B LRR AMC)和 3 7 81μg ml(Z LLE AMC)。在 3 0和 60μg ml顺铂作用下 ,CCD 110 3KidTr细胞内蛋白酶体活力也受到显著抑制。在 3 0 μg ml顺铂作用下 ,p5 3mRNA表达在 3、6、12和 2 4h未见明显改变 ,而p5 3蛋白质水平在 3、6h明显增高。结论 顺铂对蛋白酶体活力有抑制作用 ,但对蛋白酶体3种酶活力的抑制没有特异性。顺铂作用CCD 110 3KidTr细胞后p5 3蛋白质表达增高 ,可能与蛋白酶体抑制有关。

Objective To study the inhibitiory effect of cislatin on proteasome.Methods Specific substrates of proteasome,S-LLVY-AMC,B-LRR-AMC,Z-LEEAMC were used to determine the activities of both purified human 20S proteasome and CCD-1103KidTr cellular proteasome treated by cisplatin.p53,one of the proteasome substrates,was analyzed at protein and mRNA levels.Results Cisplatin had a significant inhibitory effect on purified human 20S proteasome.IC_ 50 values of three enzyme activities were 32\^17 μg/ml(S-LLVY-AMC),37\^96 μg/ml(B-LRR-AMC),37\^81 μg/ml(Z-LEE-AMC),respectively.Similar effects were observed in CCD-1103KidTr cells treated by 30 and 60 μg/ml cisplatin.Under 30 μg/ml cisplatin,no obvious changes of p53 mRNA levels were observed at 3,6,12,24 while p53 protein level increased at 3 and 6 h. Conclusion Cisplatin has some but not specific inhibitory effect on proteasome.The increased p53 protein levels of CCD-1103KidTr cells treated with cisplatin may be related to inhibition of proteasome.