Induction of tumor cell apoptosis in colorectal cancer xenografts of nude mice with low dosage of ~(131) I-labelled anti-carcinoembryonic antigen antibody C50 combined with chemotherapy / 中华消化杂志

ABSTRACT

Objective To investigate the outcome of induction of tumor cell apoptosis with low dosage of 131 I labelled anti carcinoembryonic antigen(CEA) monoclonal antibody C50( 131 I C50) and the therapeutic efficacy of combining radioimmunotherapy(RAIT) with chemotherapy in colorectal cancer xenografts. Methods Human colorectal cancer xenografts with positive CEA expression were established in nude mice with LoVo cell line. 5 fluorouracil(5 FU), 75 ?Ci 131 I C50, and 5 FU, combined with 131 I C50 were given to nude mice through tail vein to treat xenografts on 9th day after implantation of tumor cells. Fifteen days after implantation, each mouse was sacrificed and tumor tissues were stained with HE and terminal deoxynucleotidyl transferase mediated X DUTP nick end labeling technique(TUNEL technique). Apoptosis index(AI) of xenograft cells in each mouse was calculated. Results Under light microscope, no obvious cytolysis or necrosis of tumor cells was seen in all four groups. Apoptosis indexes in blank control group, chemotherapy group, radioimmunothera py(RAIT) group, and RAIT+chemotherapy group were (0.29?0.08)%, (18.68? 2.69 )%,(40.88 ?4.54 )% and (62.33?8.00)%, respectively. There were significant difference of apoptosis indexes between any groups( P