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目的研究B细胞易位基因2(BTG2)对人乳腺癌细胞T-47D放射敏感性的影响。方法应用脂质体转染的方法提高BTG2基因在人乳腺癌细胞T-47D的表达水平,利用克隆形成实验研究转染后细胞的放射敏感性改变,采用流式细胞术对细胞周期变化进行分析,应用Western blot方法研究相关蛋白的变化。结果克隆形成细胞生存实验结果表明,BTG2稳定高表达的T-47D/BTG2细胞在不同剂量X射线照射后,其存活分数明显低于X射线照射后的未转染的T-47D/Parental(母)细胞以及“空质粒”转染的对照T-47D/Neo细胞的存活分数。细胞平均致死剂量(D_0)值在T-47D/Parental细胞、T-47D/Neo细胞和T-47D/BTG2细胞分别为1.84,1.86和1.57。流式细胞实验结果显示,与T-47D/母细胞和T-47D/Neo细胞相比,T-47D/BTG2细胞在受照射后出现明显的细胞凋亡sub-G1峰。另外,BTG2高表达上调了Bad和Bax促凋亡蛋白的表达水平和下调了协作性的致癌基因Cyclin D1的表达水平。结论增加BTG2基因的表达水平可以明显提高凋亡相关蛋白水平,增加放射治疗所诱导的细胞凋亡,从而提高人类乳腺癌细胞T-47D对电离辐射放射治疗的敏感性。BTG2可能是调节人类乳腺癌细胞放射治疗的有效靶点之一。
Objective To study the effect of B cell translocation gene 2 (BTG2) on the radiosensitivity of human breast cancer T-47D cells. Application methods to improve lipofection BTG2 gene expression levels in human T-47D breast cancer cells, using a colony formation after the change radiosensitivity experimental study of transfected cells by flow cytometry for cell cycle analysis , The application of Western blot method to study the changes of related proteins. Results colony formation assay results showed that cell viability, T-47D BTG2 stable high expression / BTG2 cells irradiated by different doses of X, which is significantly lower than the surviving fraction of transfected after X-ray irradiation T-47D / Parental (parent ) Cells and the “empty plasmid” transfected control T-47D / Neo cells. The mean cell lethal dose (D_0) was 1.84, 1.86 and 1.57 in T-47D / Parental cells, T-47D / Neo cells and T-47D / BTG2 cells, respectively. Flow cytometry results showed that T-47D / BTG2 cells showed obvious apoptotic sub-G1 peak after irradiation compared with T-47D / blastocysts and T-47D / Neo cells. In addition, high expression of BTG2 up-regulated the expression of pro-apoptotic proteins Bad and Bax and down-regulated the expression of the cooperative oncogene Cyclin D1. Conclusion BTG2 increase expression levels of genes can significantly improve the level of apoptosis-related proteins, increased radiation therapy-induced apoptosis, thereby enhancing T-47D human breast cancer cells to ionizing radiation sensitivity of radiation therapy. BTG2 may be one of the effective targets for regulating the radiation of human breast cancer cells.