^60 Coγ射线辐射致LyGDI断裂对K562细胞的延迟性凋亡作用  

Delayed K562 cell apoptosis promoted by cleaved LyGDI after ^60Co γ-rays irradiation

作　　者：孙华丽[1] 段卫明[2] 邵彦彦[1] 肖海楠[1] 周新文[1] 

机构地区：[1]苏州大学医学部放射医学与公共卫生学院,215123 [2]苏州大学附属第一医院肿瘤科

出　　处：《中华放射医学与防护杂志》2010年第6期643-646,共4页Chinese Journal of Radiological Medicine and Protection

基　　金：国家自然科学基金（30570548）

摘　　要：目的 采用不同剂量的60 Coγ射线照射人红白血病细胞系K562,探究鸟苷酸解离抑制因子-2（LyGDI）在细胞延迟性死亡中的作用以及其调控机制.方法 细胞流式仪PI单染检测细胞周期,藻红B染色观察细胞的凋亡,Western blot分析LyGDI和Rac1蛋白的表达,免疫荧光检测Rac1蛋白在细胞内的分布.结果 K562细胞被阻滞在G2/M期的百分率为71.3%,K562细胞早期凋亡率较低,8 Gy60Co γ射线照射后24 h,凋亡率为14%,呈现出延迟性的细胞凋亡;K562细胞在4 Gy的γ射线照射24 h后,可见LyGDI发生断裂,总的Rac1蛋白表达未发生明显变化,但其在细胞内的分布发生改变,Rac1转移至细胞膜上与少量核内分布,Rac1脱离LyGDI而激活.结论 LyGDI具有增加细胞延迟性凋亡的作用,其断裂使Rac1转移至细胞膜上,诱导Rac1的激活,从而促进了细胞的凋亡.Objective To elucidate the function and regulatory mechanism of LyGDI involved delayed cell death in the human K562 cells and HL-60 cells induced by 60Co γ-rays. Methods Erythrosine B cells staining was used to count the apoptosis rate. PI staining and flow cytometry were applied to check the cell cycle. The expression of LYGDI and Rac1 was resolved by Western blot by using monoclonal antibody of LyGDI and Racl. The distribution of Racl protein in cells was observed with immunofluorescence by using the confocal microscope. Results The K562 cells showed G2/M phase arrest and the percent age was 71.3%. The apoptosis rate was very low at early post-irradiation stage in the K562 cells. The apoptosis rate was 14% in the K562 cells at 24 h post-irradiation with 8 Gy of γ-rays, and delayed cell apoptosis was present. LyGDI was cleaved in the K562 cells irradiated by 4 Gy 60 Co γ-rays after 24 hours post-irradiation. The expression of Racl protein was not altered at all, but the distribution was changed in the irradiated cells while the Racl protein moved to cell membrane and a little in cell nucleus. The Racl was activated with the losing the binding affinity with the LyGDI. Conclusion LyGDI could promote the delayed cell apoptosis, which is through the activation of the Rac1.

关 键 词：60Coγ射线 鸟苷酸解离抑制因子-2 RAC1 凋亡 

分 类 号：R818[医药卫生—放射医学]