UHRF1的高表达降低人乳癌细胞对X射线敏感性的研究  

Alteration of radiosensitivity to X-rays in human breast cancer cells by modified expression of UHRF1

作　　者：李新莉[1] 樊赛军[1] 

机构地区：[1]苏州大学医学部放射医学与公共卫生学院,江苏苏州215123

出　　处：《江苏预防医学》2010年第5期5-8,共4页Jiangsu Journal of Preventive Medicine

基　　金：教育部长江学者和创新团队发展计划资助(IRT0849);国家自然科学基金(30701001);苏州市科技计划项目(YJS0905)

摘　　要：目的:了解基因UHRF1的高表达对乳癌细胞MDA-MB-231辐射敏感性的影响。方法:利用克隆形成实验观察细胞存活;流式细胞术测定细胞周期;利用DNA片段分析和Annexin V试剂盒测定细胞凋亡;Western blot测定蛋白表达变化;利用经典的染色体分析,观察染色体畸变(着丝粒环和双着丝粒)。结果:与对照相比,UHRF1转染可明显降低MDA-MB-231细胞对X射线的敏感性。利用UHRF1-si RNA抑制UHRF1的表达,可显著增强细胞的辐射敏感性。UHRF1的高表达,可诱导G2/M期阻滞,抑制细胞凋亡,下调促凋亡蛋白Bax,上调DNA损伤修复蛋白Ku70和Ku80的表达水平,而且,能抑制X射线诱导的染色体畸变。结论:UHRF1可能通过影响凋亡和DNA损伤修复成为乳癌放疗的新靶标。Objective： To investigate the effect of UHRF1 overexpression on radiosensitivity to X-ray in human breast cancer MDA-MB-231 cells. Methods： Cell survival was determined by colony formation assay; cell cycle distribution was measured by flow cytometry; apoptosis was evaluated by DNA fragmentation assay and Annexin V apoptosis detection kit; protein expression was analyzed by Western blot assay; chromosome aberrations （centric rings and dicentrics） were assayed by conventional chromosomal analysis. Results： A significant decrease of radiosensitivity to X-rays was observed in MDA-MB- 231 cells transfected with a full-length of human UHRF1 cDNA （MDA-MB-231/UHRF1） comapred to the control cells （MDA-MB-231/parental and MDA-MB-231/Neo）. In contrast, a decreased expression of UHRF1 by a specific UHRF1 -siRNA significantly enhanced cell radiosensitivity. The UHRF1-mediated radioresistance was correlated with a G2Ra/M arrest, a decreased induction of apoptosis, a down-regulation of the pro-apoptotic protein Bax and a up-regulation of the DNA damage repair proteins Ku70 and Ku80. Furthermore, chromosomal aberrations （centric rings and dicentrics） by X-ray were less in MDA-MB-231/UHRF1 than in MDA-MB-231/parental ceils and MDA-MB-231/Neo control cells. Conclusion： These results suggested that UHRF1 may be a new target in the radiotherapy of breast cancer via affecting apoptosis and DNA damage repair.

关 键 词：人乳癌细胞 UHRF1基因 X射线 敏感性 

分 类 号：R-33[医药卫生]