^(188)Re-C50对结肠癌细胞的凋亡诱导作用

The apoptotic effect of ^(188)Re-anti-CEA-McAb radioimmunotherapy on colon cancer

目的 观察1 88Re 抗癌胚抗原 (CEA)单克隆抗体 (简称单抗 )C5 0放射免疫治疗 (RIT)对结肠癌细胞的凋亡诱导作用。方法 BALB c小鼠结肠癌模型分为治疗与对照组 ,每组 8只。治疗组每只瘤内注射 18 5MBq1 88Re C5 0 ,对照组每只瘤体内局部注射 0 16mgC5 0。 6h后取新鲜肿瘤组织制备肿瘤单细胞悬液 ,采用流式细胞仪 (FCM)行倍体与S期细胞比例检测 ;取肿瘤组织固定后行透射电镜观察与原位末端标记法 (TUNEL)检测。结果 RIT治疗后 6hC2 6结肠癌细胞在用碘化丙啶 (PI)染色的FCM直方图上出现典型凋亡峰 ,C2 6细胞凋亡百分比为 (16 6 4± 0 12 ) % ,对照组为 0 %。肿瘤S期细胞占 (10 4 1± 1 31) % ,对照组为 (33 14± 2 0 1) %。肿瘤G0 G1 期细胞占 (6 8 6 0± 4 82 ) % ,对照组为 (35 12± 2 6 3) % ,治疗后G1 期细胞呈明显阻滞现象。TUNEL检测肿瘤细胞出现凋亡改变 ,凋亡指数 (AI)为 (2 6 4± 0 97) % ,对照组无凋亡改变发生。电镜下癌细胞出现典型的凋亡细胞形态学改变。结论 诱导结肠癌细胞凋亡是1 88Re C5 0抗肿瘤效应的重要作用机理。

Objective To demonstrate that 188 Re-anti-carcinoembryonic antigen (CEA)-monoclonal antibody (McAb) ( 188 Re-C50) has an anti-tumor effect by inducing apoptosis on colon cancer cells. Methods The model mice of colon cancer (C26) were sacrificed at 6 h after intratumoral injection of 18.5 MBq 188 Re-C50 (treatment group, n =8) or 0.16 mg C50 (control group,n= 8). The single cell suspension of fresh tumor tissue was prepared and the flow cytomytry (FCM) was used to analyze the ploidy and proportion of S-phase cells of the tumor cells in the suspension. Additionally,the tumor tissue samples were examined by transmission electron microscope and terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end-labeling (TUNEL). Results Apoptotic sub-G 1 peak was observed in FCM histogram 6 h after radioimmunotherapy (RIT) in C26 colon cancer cells and the apoptotic index was (16.64±0.12)% vs 0% of control group. The S-phase ratio of RIT group was (10.41±1.31)% and that of control group was (33.14±2.01)%. G 0-G 1 phase ratio of tumor cells in RIT group was (68.60±4.82)% and (35.12±2.63)% in control group. Tumor cells were apparently detained in stage G 1 in RIT group. Apoptosis was also observed in TUNEL assay in RIT group and the apoptosis index was (26.4±0.97)%,but it was not observed in the control group. Typical morphologic transformation such as the apoptotic body was observed by transmission electron microscopy. Conclusion 188 Re-C50 can induce cancer cell apoptosis and probably it's the important mechanism of anti-tumor effect of RIT