^(131)I和高能X线对HER-2高表达乳腺癌细胞BT474杀伤效应的比较

Comparison of the killing effect of ^(131)I and high-energy X-rays on HER-2 overexpression breast cancer cells

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 Gy 5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)、2 Gy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 ceils with immunohistochemical method. BT474 cells in logarithmic phase were treated with ^131I 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 immunohistochemical staining showed BT474 cells were HER-2 overexpression. After cultured with ^131I 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, t = 3. 643）. Conclusion The low-dose-rate of ^131Iand 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.