Identification of an Activating Mutation in the Extracellular Domain of HER2 Conferring Resistance to Pertuzumab

Abstract

Ying Zhang,1 Shanshan Wu,2 Xinlei Zhuang,1 Gaoqi Weng,1 Jiansheng Fan,1 Xiaoyue Yang,1 Yingchun Xu,1 Liqiang Pan,1 Tingjun Hou,1,3 Zhan Zhou,1 Shuqing Chen1 1Institute of Drug Metabolism and Pharmaceutical Analysis and Zhejiang Provincial Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, People’s Republic of China; 2Precision Medicine Center, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325015, People’s Republic of China; 3State Key Laboratory of Computer Aided Design and Computer Graphics (CAD&CG), Zhejiang University, Hangzhou 310058, People’s Republic of ChinaCorrespondence: Zhan Zhou; Shuqing ChenInstitute of Drug Metabolism and Pharmaceutical Analysis and Zhejiang Provincial Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, People’s Republic of ChinaTel [phone]Email [email protected]; [email protected]: The aberrant expression of HER2 is highly associated with tumour occurrence and metastasis, therefore HER2 is extensively targeted for tumour immunotherapy. For example, trastuzumab and pertuzumab are FDA-approved monoclonal antibodies that target HER2-positive tumour cells. Despite their advances in clinical applications, emerging resistance to these two HER2-targeting antibodies has hindered their further application. Somatic mutations in HER2 receptor have been identified as one of the major reasons for resistance to anti-HER2 antibodies.Methods: We analysed the frequency of somatic mutations in various tumour types based on TCGA and COSMIC databases. Then, the effect of the most frequent mutation (S310F) on the interaction between pertuzumab and HER2 was analysed by molecular modelling analysis. The effect of the S310F mutation was further evaluated through multiple in vitro binding experiments and antitumour activity assays.Results: We found through bioinformatics analysis that S310F, an activating mutation in the HER2 extracellular domain, was the most frequent mutation in HER2. The S310F mutation was shown to confer resistance of HER2-positive tumour cells to pertuzumab treatment. With molecular modelling analysis, we confirmed the possibility that the S310F mutation might disrupt the interaction between pertuzumab and HER2 as a result of a significant change in the critical residue S310. Further functional analyses revealed that the S310F mutation completely abolished pertuzumab binding to HER2 receptor and inhibited pertuzumab antitumour efficacy.Conclusion: We demonstrated the loss-of-function mechanism underlying pertuzumab resistance in HER2-positive tumour cells bearing the S310F mutation.Keywords: HER2, mutation, pertuzumab, drug resistance, tumour cells

Keywords

• her2
• mutation
• pertuzumab
• drug resistance
• tumour cells