title: In vitro and in vivo antitumor effects of recombinant bispecific antibodies based on humanized anti-EGFR antibody.
abstract: We performed in vitro and in vivo experiments of the anti-epidermal growth factor receptor (EGFR) x anti-CD3 bispecific diabody (hEx3-Db) with the IgG-like bispecific antibodies (BsAbs) (hEx3-scFv-Fc and hEx3-scDb-Fc) and the anti-EGFR therapeutic antibody cetuximab to assess the effect of BsAbs on cancer growth inhibition. In vitro, efficacy of the BsAbs and cetuximab were compared by growth inhibition assays of human cell lines of bile duct (TFK-1, HuCC-T1, OCUCh-LM1), epidermoid (A431), gastric (Kato-III), colon (DLD-1, SW480), and breast (SK-BR-3, MCF-7) cancer. In vivo, in three mouse models, we evaluated the anti-tumor activity of hEx3-Db and cetuximab, assessed the effect of hEx3-Db alone, and compared the antitumor activity of hEx3-Db with the IgG-like BsAbs. In vitro, hEx3-scFv-Fc showed nearly 100% killing activity for all cell lines. Both in vitro and in vivo, hEx3-Db needed CD3-positive phenotypes to induce a growth inhibitory effect. In contrast, IgG-like BsAbs showed monotherapeutic effects in vivo by inducing antibody-dependent cellular cytotoxicity (ADCC) similar to cetuximab. However, enhancement was not observed when lymphokine-activated killer cells with the T-cell phenotype were co-injected. Results suggest that IgG-like BsAbs could not efficiently direct T lymphocytes toward tumor cells to induce ADCC due to steric hindrance on binding to CD3- and Fc-receptor-positive phenotypes. Although hEx3-scFv-Fc showed high cytotoxicity in vitro, its high molecular weight limits its usefulness. With an in vivo effect comparable to hEx3-scFv-Fc and its realistic molecular weight, hEx3-scDb-Fc shows promise as a novel recombinant therapeutic antibody and may be modified to enhance its potency by prevention of steric hindrance.
authors: Division of Gastroenterological Surgery, Department of Surgery, Graduate School of Medicine, Tohoku University, Sendai 980-8574, Japan.
authors: Yasuhiro
authors: Y
authors: Watanabe
authors: Ryutaro
authors: R
authors: Asano
authors: Kyoko
authors: K
authors: Arai
authors: Ippei
authors: I
authors: Shimomura
authors: Hiromi
authors: H
authors: Ogata
authors: Hiroko
authors: H
authors: Kawaguchi
authors: Hiroki
authors: H
authors: Hayashi
authors: Hideo
authors: H
authors: Ohtsuka
authors: Hiroshi
authors: H
authors: Yoshida
authors: Yu
authors: Y
authors: Katayose
authors: Shinichi
authors: S
authors: Egawa
authors: Takeshi
authors: T
authors: Nakanishi
authors: Mitsuo
authors: M
authors: Umetsu
authors: Hiroshi
authors: H
authors: Yasui
authors: Tadao
authors: T
authors: Ishida
authors: Kohzoh
authors: K
authors: Imai
authors: Toshio
authors: T
authors: Kudo
authors: Michiaki
authors: M
authors: Unno
authors: Izumi
authors: I
authors: Kumagai
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology; D018033:Antibodies, Bispecific / Q000276:immunology / Q000494:pharmacology*; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000494:pharmacology; D045744:Cell Line, Tumor; D000068818:Cetuximab; D066246:ErbB Receptors / Q000276:immunology*; D005260:Female; D006801:Humans; D007116:Immunization, Passive; D051379:Mice; D016513:Mice, SCID; D009369:Neoplasms / Q000188:drug therapy / Q000276:immunology / Q000628:therapy*; D023041:Xenograft Model Antitumor Assays
chemical_list: D000888:Antibodies, Anti-Idiotypic; D018033:Antibodies, Bispecific; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D066246:ErbB Receptors; D000068818:Cetuximab