Hersintuzumab: A novel humanized anti-HER2 monoclonal antibody induces potent tumor growth inhibition

• Published in: Investigational new drugs 2018-04, Vol.36 (2), p.171-186
• Main Authors: Amiri, Mohammad Mehdi, Golsaz-Shirazi, Forough, Soltantoyeh, Tahereh, Hosseini-Ghatar, Reza, Bahadori, Tannaz, Khoshnoodi, Jalal, Navabi, Shadi Sadat, Farid, Samira, Karimi-Jafari, Mohammad Hossein, Jeddi-Tehrani, Mahmood, Shokri, Fazel
• Format: Article
• Language: English
• Subjects: AKT protein; Animals; Antibodies; Antibodies, Monoclonal - chemistry; Antibodies, Monoclonal - pharmacology; Antibody-Dependent Cell Cytotoxicity - drug effects; Breast cancer; Cell cycle; Cell Cycle Checkpoints - drug effects; Cell Line, Tumor; Cell proliferation; Cell Proliferation - drug effects; CHO Cells; Complementarity; Constant region; Cricetinae; Cricetulus; Cytometry; Cytotoxicity; Enzyme-linked immunosorbent assay; Epitope Mapping; Epitopes; ErbB-2 protein; Flow cytometry; Gene Amplification; Gene sequencing; Genes; Growth inhibition; Humans; Immunoglobulin Heavy Chains - chemistry; Immunoglobulin Light Chains - chemistry; Immunoglobulin Variable Region - chemistry; Immunotherapy; Inhibition; Medicin och hälsovetenskap; Medicine; Medicine & Public Health; Metastases; Models, Molecular; Monoclonal antibodies; Oncology; Pharmacology/Toxicology; Phosphorylation - drug effects; Preclinical Studies; Receptor, ErbB-2 - immunology; Signal Transduction - drug effects; Signaling; Targeted cancer therapy; Toxicity; Trastuzumab; Tumor cells
• ISSN: 0167-6997; 1573-0646; 1573-0646
• DOI: 10.1007/s10637-017-0518-0

Summary Humanized monoclonal antibodies (mAbs) against HER2 including trastuzumab and pertuzumab are widely used to treat HER2 overexpressing metastatic breast cancers. These two mAbs recognize distinct epitopes on HER2 and their combination induces a more potent blockade of HER2 signaling than trastuzumab alone. Recently, we have reported characterization of a new chimeric mAb (c-1T0) which binds to an epitope different from that recognized by trastuzumab and significantly inhibits proliferation of HER2 overexpressing tumor cells. Here, we describe humanization of this mAb by grafting all six complementarity determining regions (CDRs) onto human variable germline genes. Humanized VH and VL sequences were synthesized and ligated to human γ1 and κ constant region genes using splice overlap extension (SOE) PCR. Subsequently, the humanized antibody designated hersintuzumab was expressed and characterized by ELISA, Western blot and flow cytometry. The purified humanized mAb binds to recombinant HER2 and HER2-overexpressing tumor cells with an affinity comparable with the chimeric and parental mouse mAbs. It recognizes an epitope distinct from those recognized by trastuzumab and pertuzumab. Binding of hersintuzumab to HER2 overexpressing tumor cells induces G1 cell cycle arrest, inhibition of ERK and AKT signaling pathways and growth inhibition. Moreover, hersintuzumab could induce antibody-dependent cell cytotoxicity (ADCC) on BT-474 cells. This new humanized mAb is a potentially valuable tool for single or combination breast cancer therapy.