目的 比较放射性131I与高能X线对人类表皮生长因子受体-2(HER-2)高表达乳腺癌细胞BT474的杀伤效应,为临床放射免疫治疗(rIT)提供依据.方法 采用免疫组化法检测BT474细胞HER-2基因表达.取对数生长期BT474细胞,分别行放射性核素131I培养和高能X线外照射,并按射线吸收剂量分为0、2、4、6、8 Gy5个亚组,以克隆形成实验分析细胞存活率,根据多靶单击模型绘制细胞存活曲线,计算反映放射敏感性的指标准域剂量(Dq)、平均致死剂量(D0)、2Gy照射的存活分数(SF2).结果 免疫组化染色显示BT474细胞呈HER-2蛋白高表达.131I和高能X线外照射后BT474细胞的D0分别为1.725、1.786,Dq分别为0.415、-0.762; SF2分别为22.650％、37.922％,差异无统计学意义(P＞0.05,t=3.643).结论 放射性核素131I低剂量持续辐射与高能X线外照射对乳腺癌BT474细胞可产生相当的杀伤效应,前者因对正常组织损伤小而更适于RIT.%Objective To compare the killing effect of 131I and high-energy X-rays on human epidermal growth factor receptor-2 ( HER-2) overexpression breast cancer cells BT474, to provide basis for clinical radioimmunotherapy ( RIT). Methods To identify the HER2 gene expression of the BT474 cells with immunohistoehemical method. BT474 cells in logarithmic phase were treated with 1311 and high-energy X-ray respectively, then depending on the absorbed dose divided into 0,2,4,6,8 Gy sub groups, the survival rate was analyzed by colonogenic assay, the survival curve was drawn according to multi-target single-hit model, the radiosensitive indexes Dq, DO and SF2 were acqured. Result The immunohistoehemical staining showed BT474 cells were HER-2 overexpression. After cultured with 131 I and radiation with high-energy X-ray the DO were 1.7193, 1. 793, Dq were 0.423, - 0.763, SF2 were 28.120% , 37.922% ; The SF2 of the two groups have no statistical significance(P>0.05, 2=3.643). Conclusion The low-dose-rate of 13! I and high-energy X-ray have considerable cell killing effect on BT474 cells, the former treatment is more suitable for RIT for its little damage to normal tissue.
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