^(131)I标记的抗癌胚抗原抗体C50治疗裸鼠结直肠癌移植瘤的疗效观察

Therapeutic efficacy of ^(131) I-labeled anti-carcinoembryonic antigen antibody C50 in colorectal cancer xenografts of nude mice

目的 探讨结直肠癌放射免疫治疗 (RAIT)不同治疗剂量用法与疗效的关系。方法建立表达癌胚抗原 (CEA)的人结直肠癌荷瘤裸鼠模型。接种肿瘤细胞第 9天 ,Ⅰ、Ⅱ和Ⅲ组分别尾静脉注射 5 .5 5× 10 6 、7.40× 10 6 、1.11× 10 7Bq的1 3 1 I标记的抗CEA单克隆抗体C5 0 ( 1 3 1 I C5 0 ) ,Ⅳ组分 2次给予总量 1.11× 10 7Bq的1 3 1 I C5 0 ,计算各组裸鼠肿瘤体积、群体倍增时间及抑瘤率 ,比较接种第 30天肿瘤体积。接种第 15天 ,观察肿瘤组织病理学改变。结果 Ⅰ、Ⅱ、Ⅲ和Ⅳ组两两之间接种第 30天肿瘤体积差异均有非常显著性 (P <0 .0 0 1) ,群体倍增时间依次延长 ,抑瘤率依次增大。光学显微镜下见各治疗组肿瘤组织均有不同程度灶状坏死。结论 结直肠癌RAIT疗效呈剂量依赖性。在总治疗剂量相等的情况下 ,分次RAIT疗效优于单次RAIT。

Objective To investigate the relationship between different dose administration and therapeutic outcome in radioimmunotherapy (RAIT) of colorectal cancer.Methods Human colorectal cancer xenografts with positive CEA expression were established in nude mice. 131I-labeled anti-carcinoembryonic antigen (CEA) monoclonal antibody C50 ( 131I-C50) was given to nude mice via tail vein at 9th day after implantation of tumor cells.Groups Ⅰ,Ⅱ and Ⅲ were given 5.55×106,7.40×106 and 1.11×107 Bq 131 I-C50,respectively.Group Ⅳ was given a total dose of 1.11×107 Bq 131 I-C50 with twice injections.Tumor volume,tumor doubling time and inhibition rate of each group were calculated.Tumor volumes of all the groups at 30th day after implantation were compared among groups.15 days after implantation,pathological change of tumor tissue was examined under light microscope.Results There was remarkable significant difference of tumor volumes at 30th day after implantation among groups (P< 0.001).Tumor doubling time of these groups was prolonged and tumor inhibition rates increased successively.Under light microscope,focal necrosis with varying degrees was found in the tumor tissues of four treatment groups.Conclusion The therapeutic efficacy of RAIT in colorectal cancer is dose-dependent.Therapeutic outcome of fractionated doses RAIT is better than single dose RAIT when the total doses are equal.