DNA损伤对前列腺癌细胞株BRCA1蛋白表达的影响  

DNA Damage Induces BRCA1 Distribution Alteration in Prostate Cancer Cell Lines

作　　者：王春杨[1] 孙圣坤[1] 符伟军[1] 宋涛[1] 蔡伟[1] 高江平[1] 洪宝发[1] 王晓雄[1] 王红 

机构地区：[1]解放军总医院泌尿外科,北京100853 [2]解放军307医院肿瘤科,北京100071

出　　处：《中华男科学杂志》2008年第8期685-689,共5页National Journal of Andrology

基　　金：国家自然科学基金(30600613)

摘　　要：目的:探讨肿瘤抑制基因BRCA1对DNA损伤的反应中的重要作用。明确BRCA1蛋白除了受转录控制、磷酸化和蛋白相互间作用等机制调节外,其功能也受BRCA1的亚细胞分布的功能调节。方法:以乳腺癌细胞株作为阳性对照组,对前列腺癌细胞株LNCaP,DU145和PC-3的BRCA1亚细胞分布免疫荧光染色,并对BRCA1的表达量进行Western印迹检测。结果:BRCA1蛋白存在于LNCaP,DU145和PC-3的前列腺癌细胞株中,而且DNA损伤后能够引起其出核现象,即BRCA1蛋白在细胞质的细胞分布比例由14%增加到40%(P<0.01),相反在细胞核其分布比例由46%减少到21%(P<0.01)。BRCA1这种DNA损伤后的胞质亚细胞分布比例增高仅在p53野生型前列腺癌细胞株出现,在p53突变型前列腺癌细胞株没有此现象。形态学和Western印迹法证实,LNCaP细胞DNA损伤后BRCA1蛋白在胞质、胞核间互动后其凋亡比例高达40%,细胞凋亡的标记蛋白(裂解后caspase-3活性片段)也明显增高。结论:BRCA1的胞质胞核重新分布可能是DNA损伤后的蛋白功能调节机制之一;BRCA1这种亚细胞分布改变需要p53的功能调节,与p53的状态及其功能相关,同时也引起细胞凋亡比例的提高。在前列腺癌细胞株BRCA1引起更高比例的细胞凋亡现象预示,BRCA1可能成为前列腺癌临床治疗的生物靶点。Objective ： To investigate the role of the tumor suppressor gene BRCA 1 in response to DNA damage and to confirm that the function of the BRCA1 protein is regulated by a variety of mechanisms including transcriptional control, phosphorylation and proteinprotein interaction. Methods： With the human breast cell line MCF7 as the positive control, we determined the subcellular distribution of BRCA1 in the prostate cancer cell lines LNCaP, DU145 and PC3 by immunohistochemical staining and Western blotting analyses. Results： BRCA1 was present in the prostate cancer cell lines LNCaP, DU145 and PC3. Ionizing radiation induced BRCA1 nuclear export, increasing from 14% to 40% in the cytoplasma （ P 〈 0.01 ） and decreasing from 46% to 21% in the nuclei （P 〈 0.01 ）. This DNA damage-induced BRCA1 nuclear export occurred only in the p53 wild-type but not in the p53 mutant cell line. The apoptosis rate of LNCaP cells was as high as 40% after nuclear export, with an obvious increase of cleaved caspase-3, which was correlated with BRCA1 nuclear-cytoplasmic shuttling. Conclusion： Cytoplasmic relocalization of the BRCA1 protein may be a mechanism whereby the BRCA1 function is regulated in response to DNA damage. Its induction of a higher rate of cell apoptosis indicates BRCA1 to be another good biomarker for the treatment of prostate cancer.

关 键 词：前列腺癌 BRCA1 DNA损伤 

分 类 号：R737.25[医药卫生—肿瘤]