Radioimmunotherapy of human colon cancer xenografts by using 131I labeled-CAb1 F(ab')2.
OBJECTIVE
Therapeutic efficacy, suitable dose, and administration times of 131I-CAb1 F(ab')2, a new monoclonal antibody therapeutics specifically directed against a cell surface-associated glycoprotein of colon cancer, were investigated in this article.


METHODS
In human colon cancer xenografts, 131I-CAb1 F(ab')2 at the dose of 125 muCi, 375 muCi, and 1125 muCi were administrated intraperitoneally on Days 6 and 18 after implantation of HR8348 cells with CAb1 high reactivity. Survival time and tumor growth inhibition rate were used to evaluate the efficacy and safety of 131I-CAb1 F(ab')2 in treatment of colon cancer xenografts.


RESULTS
Treatment of 125, 375, and 1125 muCi 131I-CAb1 F(ab')2 did not significantly decrease the mean survival time of nude mice when compared with nontreated groups (p = 0.276, 0.865, 0.582, respectively). Moreover, the mean survival times of nude mice receiving 375 muCi and 1125 muCi 131I-CAb1 F(ab')2 were significantly longer than that of 5-FU-treated groups (p = 0.018 and 0.042). Tumor growth inhibition rates of the first therapy were 35.67% and 41.37%, with corresponding 131I-labeled antibody dosage of 375 muCi and 1125 muCi. After single attack dosage, second reinforcement therapy may rise efficacy significantly. Tumor growth inhibition rates of 125 muCi, 375 muCi, and 1125 muCi 131I-labeled antibody on Day 20 posttherapy were 42.65%, 56.56%, and 84.41%, respectively. Histopathology examination revealed that tissue necrosis of various degrees was found in 131I-CAb1 F(ab')2-treated groups.


CONCLUSIONS
131I-CAb1 F(ab')2 is safe and effective for colon cancer. It may be a novel and potentially adjuvant therapeutics for colon cancer.
Li
Ling
L
Cell Engineering Research Centre and Department of Cell Biology, State Key Laboratory of Cancer Biology, the Fourth Military Medical University, Xi'an, PR China.
Xu
Hui-Yun
HY
Mi
Li
L
Bian
Hui-Jie
HJ
Qin
Jun
J
Xiong
Hua
H
Feng
Qiang
Q
Wen
Ning
N
Tian
Rong
R
Xu
Li-Qing
LQ
Shen
Xiao-Mei
XM
Tang
Hao
H
Chen
Zhi-Nan
ZN
D000818:Animals; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000473:pathology* / Q000532:radiotherapy*; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D016499:Radioimmunotherapy / Q000379:methods*; D016019:Survival Analysis; D015996:Survival Rate; D016896:Treatment Outcome
D000911:Antibodies, Monoclonal; D007457:Iodine Radioisotopes