Cell Surface Antibody Retention Influences In Vivo Antitumor Activity Mediated by Antibody-dependent Cellular Cytotoxicity

• Published in: Anticancer research Vol. 36; no. 11; pp. 5937 - 5944
• Main Authors: Ikeda, Masahiro, Kato, Kazunori, Yamaguchi, Miki, Hamada, Hirofumi, Nakamura, Kazuyasu, Sugimoto, Yoshiyuki
• Format: Journal Article
• Language: English
• Published: Greece 01-11-2016
• Subjects: Antibodies, Monoclonal - immunology; Antibody-Dependent Cell Cytotoxicity - immunology; Antigens, Neoplasm - immunology; Cell Adhesion Molecules - immunology; Cell Line, Tumor; Humans; Xenograft Model Antitumor Assays; solid tumor; monoclonal antibody; TROP2; Antibody-dependent cellular cytotoxicity; cell surface retention
• ISSN: 1791-7530
• DOI: 10.21873/anticanres.11181

Multiple factors affect the in vivo antitumor activity of antibody-based therapeutics; however, the influence of cell surface retention on antibody-dependent cellular cytotoxicity (ADCC) is not fully understood. Here we evaluated the importance of cell surface antibody retention in antitumor activity mediated by ADCC in vivo.
Two mAbs against tumor-associated calcium signal transducer 2 (TACSTD2/TROP2), AR47A6.4.2 and Pr1E11, were used. Antitumor activities against BxPC3 and Colo205 cells were investigated through in vitro and in vivo assays.
Pr1E11 showed better cell surface retention than AR47A6.4.2 in vitro although Pr1E11 and AR47A6.4.2 showed equivalent ADCC activity. Complement-dependent cytotoxicity and antiproliferative activity were not observed for either antibody. Pr1E11 exhibited higher antitumor activity than AR47A6.4.2 in vivo.
Our results suggest that high cell surface retention can result in potent ADCC activity in vivo. This observation could provide novel insight into how effectively screen for antibodies with strong in vivo antitumor activity.