Construction,Optimization And Characterizat Of Novel Anti-HER2 Antibody For Cancer Therapy

The abnormal activities of the human epidermal growth factor receptor (HER) family, according to the recent studies, are the key factors promoting development and progress of malignant tumors. Recently, together with the development of pre-clinical and clinical studies, as well as the deeply research of HER2 which is one of HER family, HER2 has become a therapeutic target and played an important role in the treatment of cancer. As anti-HER2 monoclonal antibodies, both trastuzumab and pertuzumab have been widely used in clinical treatments. However, the results of clinical treatment show limited efficiency and consequent resistance of trastuzumab, regardless of the potent prospects of monoclonal antibodies. The combination of HER2 inhibitors with different molecular mechanism, especially those with ability to inhibit the activation of HER2/HER3 pathway, not only have obtained significantly therapeutic efficiency in basic research and clinical practice, but also have been a first-line choice for treatment of breast cancer, such as the combination of trastuzumab and pertuzumab.Therefore, development of novel anti-HER2 antibodies for sigle using or combination with chemotherapy or individualized treatment methords in treatment of breast cancer, has very important clinical significance. In our previous work, our research group have obtained several human anti-HER2 single-chain antibodies from a screen of a phage display library. In this research, we converted these single-chain antibodies into full-length antibodies, which, subsequently, were highly expressed in mammalian cell expression system. We selected the antibody with the most significant inhibition of proliferation of breast cancer cells for the followed experiments. By epitope mapping, we optimized this antibody to improve its therapeutic efficiency. F0178C1, the novel antibody after optimization, had significant therapeutic efficiency in breast cancer, as well as a synergistic effect with pertuzumab. Additionally, F0178C1 showed superior efficacy in blocking HER2/HER3 heterodimerization and inhibiting associated signaling pathway. Crystallographic analysis was used to determine the three-dimensional structure of F0178C1-Fab/HER2-ECD complex to 3.5 A resolution, confirming the epitope of F0178C1 and demonstrating the molecular mechanism of the function of F0178C1. All of the results testified that F0178C1 had unique biological function and clinical potential. Moreover, the blocking effect of F0178C1 on HER2/HER3 heterodimerization makes it promising as a potent clinical therapeutic drug.