Anti-CD133 Monoclonal Antibody CMab-43 Exerts Antitumor Activity in a Mouse Xenograft Model of Colon Cancer

Cancer stem cells contribute to tumorigenesis, metastasis, recurrence, and chemoresistance. CD133/prominin-1—a pentaspan membrane glycoprotein—has been used as a stem cell biomarker for the isolation of stem-like cells from a variety of normal and pathological tissues. In our previous studies, we developed several anti-CD133 monoclonal antibodies using Cell-Based Immunization and Screening (CBIS) methods, followed by characterization of their efficacy by flow cytometry, western blotting, and immunohistochemical analyses. One of the 100 clones, CMab-43 (IgG 2a , kappa), demonstrated a sensitive and specific reaction against colon cancer cells. This study aimed to investigate the antitumor activity of CMab-43. Caco-2 cells (human colon cancer cell line) were subcutaneously implanted into the flanks of nude mice. CMab-43 and control mouse IgG were injected three times into the peritoneal cavity of mice. Tumor formation was observed in the control and CMab-43-treated mice of Caco-2 xenograft models. CMab-43 significantly reduced tumor development of Caco-2 xenograft in comparison with the control mouse IgG on days 12, 14, and 17. Our results cumulatively suggest that CMab-43 is useful for antibody therapy against CD133-expressing colon cancers.