Journal:Acta Cryst D:S2059798319006995

Structural insight into a matured humanized monoclonal antibody HuA21 against HER2-overexpressing cancer cells

Zhenyi Wang, Liansheng Cheng, Gongrui Guo, Baoyun Cheng, Siyi Hu, Hongmin Zhang, Zhongliang Zhu and Liwen Niu ^[1]

Molecular Tour
HER2, a member of the epidermal growth factor receptor (EGFR) family, has been associated with human breast, ovarian, and gastric cancers. We previously developed a chimeric antibody chA21 that specifically inhibits the growth of HER2-overexpressing cancer cells both in vitro and in vivo. To reduce potential human anti-mouse immune response, humanized antibody HuA21 was developed on the basis of chA21. The crystal structure of HuA21-scFv in complex with the extracellular domain (ECD) of HER2 was determined, which demonstrates that HuA21 binds almost the same epitope as chA21 and also provides insight into how substitutions in HuA21 improve the binding affinity compared with chA21. The binding epitopes of antibodies could contribute to understand their anti-tumor activities. Our HuA21-HER2 structure clearly shows that the epitope of HuA21 is located at the C-terminal part of subdomain I of HER2. This is a new epitope distinct from those described for Trastuzumab and Pertuzumab, which are located at subdomains IV and II, respectively.

References

1. ↑ Wang Z, Cheng L, Guo G, Cheng B, Hu S, Zhang H, Zhu Z, Niu L. Structural insight into a matured humanized monoclonal antibody HuA21 against HER2-overexpressing cancer cells. Acta Crystallogr D Struct Biol. 2019 Jun 1;75(Pt 6):554-563. doi:, 10.1107/S2059798319006995. Epub 2019 May 31. PMID:31205018 doi:http://dx.doi.org/10.1107/S2059798319006995