Ku80在石英诱导细胞周期改变中作用  

Roles of Ku80 in silica-induced cyclin D1,CDK4,E2F1 expressions and Rb phosphorylation and cell cycle changes in human embryo lung fibroblasts

作　　者：田晓娟 刘海峰[2] 柳建强[2] 

机构地区：[1]唐山市食品化妆品监督所,河北063000 [2]唐山市疾病预防控制中心

出　　处：《中国公共卫生》2015年第1期79-81,共3页Chinese Journal of Public Health

摘　　要：目的探讨Ku80蛋白在石英诱导的人胚肺成纤维细胞(HELF)细胞周期改变中的作用及机制。方法200μg/m L石英按0、3、6、12、24 h处理各组细胞,采用RNAi技术抑制Ku80蛋白表达(H-Ku80),采用流式细胞术检测石英刺激24 h不同细胞系的细胞周期变化情况,免疫印迹技术检测不同细胞系各时间点细胞周期蛋白D1(cyclin D1)、细胞周期蛋白依赖激酶4(CDK4)、E2增强子连接因子1(E2F1)蛋白表达和视网膜母细胞瘤蛋白(Rb)表达及Rb-ser780磷酸化水平。结果石英刺激对照细胞,G1期细胞所占比例从(89.28±2.19)%下降到(68.93±3.79)%;石英刺激H-Ku80,G1期细胞比例进一步减少,从(85.16±3.73)%下降到(59.92±3.31)%,差异均有统计学意义(P<0.05);抑制Ku80蛋白表达后,Rb蛋白表达水平无变化,石英诱导的CyclinD1、CDK4水平增高受抑制,而E2F1、Rb-ser780磷酸化水平进一步增高。结论 Ku80参与石英诱导的细胞周期改变,对CyclinD1、CDK4的表达呈正性调节作用;而对E2F1表达及Rb-ser780磷酸化呈负性调节作用。Objective To study the roles and mechanism of Ku80 in silica-induced cell cycle changes in human em- bryo lung fibroblasts（HELF）. Methods The expression of Ku80 protein was inhibited by siRNA plasmids. Flow cytom- etry was used to detect cell cycle and Western blot was used to determine expression levels of cyclin D1, cyclin dependent kinase-4 （ CDK4 ）, estradiol（ E2 ） promoter binding factor-1 （ E2F1 ） and phosphorylation levels of retinobastoma protein （Rb） after the cells were treated with silica at different time （0,3,6,12, and 24 hours）. Results The proportion of neg- ative control cells in G1 phase decreased from 89. 28±2. 19% to 68. 93±3.79% after exposed to silica and the propor- tion of cells in G1 phase for cells with Ku80 inhibition（H-Ku80） decreased from 85.16 ± 3.73% to 59. 92 ± 3.31%. Silica exposure increased the protein levels of cyclin Dl , CDK4 ,E2F1, and phosphorylation in negative control cells. The expression levels of cyclin D1 and CDK4 were obviously suppressed. However,the protein level of E2F1 and phosphoryl- ation level of Rb-ser780 increased in H-Ku80 cells compared with those in trhe control cells. Conclusion Ku80 may play a role in silica-induced alternations of cell cycle. Ku80 positively regulates silica-induced overexpression of cyclin D1 and CDK4 ,but negatively regulates silica-induced overexpression of E2F1 and phosphorylation increases the level of Rb in human embryo lung fibroblasts.

关 键 词：石英 细胞周期蛋白D1(CyclinD1) 细胞周期蛋白依赖激酶4(CDK4) E2增强子连接因子1(E2F1) 

分 类 号：R135.1[医药卫生—劳动卫生]