OBJECTIVETo study the inhibitory effect of CD133 monoclonal antibody labeled with ¹³¹I (¹³¹I-CD133mAb) on Huh-7 human liver cancer cell line overexpressing CD133 antigen in vitro and in mouse models bearing the tumor cell xenograft.

METHODS¹³¹I-CD133mAb was prepared by chloramines-T method and evaluated for its stability. Flow cytometry and immunohistochemistry were used to detect the expression of CD133 in Huh-7 cells and in Huh-7 cell-derived tumors, respectively. Huh-7 cells treated with ¹³¹I-CD133mAb plus cisplatin (DDP), ¹³¹I -CD133mAb, DDP, or no treatment (blank control) were examined for cell proliferation suppression by MTT assay with the IC₅₀ calculated. BALB/c mice bearing subcutaneous Huh-7 cell xenograft in the right forelegs were treated with ¹³¹I -CD133mAb, DDP, or both every two days for two weeks. The tumor size and volume were measured twice a week, and pathological examination of the tumor was carried out after the treatments. The tumor inhibition rate was calculated and tumor cell apoptosis observed with HE staining.

RESULTSThe labeling ratio of ¹³¹I-CD133mAb was 90.25% and the radiochemical purity was 97.78%. Huh-7 cells showed obviously higher CD133 expression than HepG2 cells. ¹³¹I-CD133mAb combined with DDP group resulted in a significantly higher tumor inhibition rate than other treatments in the tumor-bearing mice.

CONCLUSION¹³¹I-CD133mAb can inhibit the growth of liver cancer cells with a high CD133 expression both in vivo and in vitro.