Trastuzumab对放射诱导下HER-2的入核及DNA损伤的影响  

Effect of Trastuzumab on Radiation-induced Nuclear Transport and DNA Break Repair Process of HER-2

作　　者：张禹[1] 于世英[1] 庄亮[1] 郑祖安[1] 晁腾飞[1] 付强[1] 

机构地区：[1]华中科技大学同济医学院附属同济医院肿瘤中心,武汉市430030

出　　处：《中国肿瘤临床》2011年第23期1430-1434,共5页Chinese Journal of Clinical Oncology

基　　金：国家自然科学基金(编号:30672426;30801351)资助~~

摘　　要：目的:通过观察HER-2单克隆抗体trastuzumab对BT474细胞中HER-2的入核效应和对核内DNA损伤修复的影响,来探讨HER-2直接入核通路上trastuzumab放疗增敏机制。方法:将BT474细胞随机分成单纯照射组和trastuzumab干预组,通过克隆形成实验来观察各剂量下放射后两组BT474细胞的存活分数的差异,共聚焦显微镜下观测trastuzumab对放射后HER-2核转运和DNA DSB标志物γH_2AX表达的影响,免疫印迹实验检测trastuzumab对放射后早期BT474细胞核内HER-2蛋白、DNA-PKcs的表达影响。结果:与单纯照射组相比,trastuzumab干预组可降低放射后各剂量下BT474细胞的存活分数(SF),共聚焦显微镜可观察到trastuzmnab推迟了照射后HER-2蛋白由细胞膜进入核内的过程,并增加放射后12 h时间点的γH_2AX表达,Western blot实验结果显示trastuzumab干预下调了放射后早期核内DNA-PKcs和HER-2的表达。结论:trastuzumab能够通过减少HER-2的入核,并进一步下调DNA-PKcs活性,抑制放射诱导下BT474的早期DSB修复。Objective： To examine the effect oftrastuzumab, a HER-2 inhibitor, on the nuclear transport and DNA break repair process of radiation-induced HER-2 in the breast cancer cell line BT474. The radio-sensitization mechanisms of trastuzumab were also discussed and elucidated. Methods： BT474 cells were randomly divided into two groups. Group one was treated with simple radiotherapy （ simple radiation ）, whereas group two was treated with radiotherapy plus trastuzumab （ intervention ）. Clone formation assay was used to observe the differences in the survival fractions between the two groups following treatments with various irradiation doses. Confocal microscopy was performed to observe the nuclear transport process of HER-2 and 3,H2AX expression after the radiation therapy. Western blot analysis was used to detect the HER-2 and DNA-PKcs expression in the nuclei during an early stage after radiotherapy. Results： Compared with group one, the survival fractions of BT474 cells in group two decreased significantly following radiotherapy with each irradiation dose. The results of confocal microscopy showed that the trastuzumab delayed the nuclear import process of HER-2 at an early stage post-radiation and increased the expression of yH2AX at 12 h after radiation. Western blot analysis revealed that the trastuzumab treatment decreased HER-2 and DNA-PKcs expression in the nuclei during an early stage after radiation. Conclusion： Trastuzumab can inhibit the DNA double-strand break repair in the BT474 cells during an early stage post-radiation by decreasing the HER-2 expression in the nuclei to downregulate the DNA-PKcs activity.

关 键 词：HER-2 TRASTUZUMAB 辐射 核转运 

分 类 号：R73-3[医药卫生—肿瘤]