[Influence of combination of low dosage 131I-labeled anti-carcinoembryonic antigen antibody C50 and 5-fluorouracil on tumor growth of colorectal cancer xenografts in nude mice].
OBJECTIVE
The aim of this study was to investigate the influence of low dosage (131)I-labeled anti-carcinoembryonic antigen (CEA) monoclonal antibody C50 ((131)I-C50) on tumor growth and the therapeutic efficacy of combination of low dosage (131)I-C50 with chemotherapy using 5-fluorouracil (5-FU) on human colorectal cancer xenografts in nude mice.


METHODS
Human colorectal cancer xenografts with positive CEA expression were established in nude mice with LoVo cell line. 5-FU, 2,775 kBq (131)I-C50, and 5-FU combined with (131)I-C50 were given to nude mice through tail vein to treat xenografts at 9(th) day after implantation of tumor cells. Two of the mice of each group were sacrificed randomly at 7(th) day after the treatment; and cellular ultrastructure of tumor tissues was examined under electron microscope. Pathological changes of tumor tissues were examined under light microscope. Tumor volume, tumor doubling time, and inhibition rate of each group were calculated. Tumor volumes of all groups at 30(th) day after implantation were compared with each other.


RESULTS
There was significant difference of tumor volumes at 30(th) day after implantation between each other among control group, chemotherapy group, radioimmunotherapy (RAIT) group, and RAIT+chemotherapy group (P< 0.001). Tumor doubling time of these groups was prolonged and tumor inhibition rates increased successively.


CONCLUSIONS
Low dosage (131)I-C50 can inhibit tumor growth of human colorectal cancer xenografts in nude mice. Efficacy of tumor growth inhibition can be enhanced by combination of low dosage (131)I-C50 with chemotherapy.
Zheng
Chao-Xu
CX
Department of General Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, PRChina. zcxzd@163.net
Zhan
Wen-Hua
WH
Cai
Shi-Rong
SR
He
Yu-Long
YL
Lin
Zhan-Jiang
ZJ
D000818:Animals; D000906:Antibodies / Q000627:therapeutic use*; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use; D002272:Carcinoembryonic Antigen / Q000276:immunology*; D015179:Colorectal Neoplasms / Q000473:pathology; D004195:Disease Models, Animal; D005472:Fluorouracil / Q000627:therapeutic use*; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000532:radiotherapy*; D016499:Radioimmunotherapy; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays
D000906:Antibodies; D000964:Antimetabolites, Antineoplastic; D002272:Carcinoembryonic Antigen; D007457:Iodine Radioisotopes; D005472:Fluorouracil