Bioactivity of recombinant humanized monoclonal antibody against HER2 in-vivo and in-vitro and its mechanism of action in ovarian cancer

BACKGROUND: Human epidermal growth factor receptor 2 (HER2) protein is overexpressed on the surface of various epithelial ovarian cancer tissues, mediates the proliferation, differentiation, metastasis, and signal transduction of tumor cells, and thus is a potential cancer therapeutic target. However, its research in ovarian cancer is still limited, and how to quickly obtain a large number of antibodies remains a concern for researchers. METHODS: In this study, we expressed the recombinant anti-HER2 humanized monoclonal antibody (rhHER2-mAb) in human embryonic kidney 293 (HEK293) cells through transient gene expression (TGE) technology by constructing a mammalian cell expression vector. Firstly, the transfection conditions has been optimized, the ratio of light chain (LC) and heavy chain (HC) was optimized in the range of 4:1 to 1:2 and the ration DNA and polyethyleneimine was optimized in the range of 4:1 to 1:1. The antibody was purified by rProtein A affinity chromatography, and its mediated antibody-dependent cellular cytotoxicity (ADCC) was identified by lactate dehydrogenase release assays. The anti-tumor activity of rhHER2-mAb was evaluated in non-obese diabetic/severe combined immunodeficiency mice. RESULTS: The expression of rhHER2-mAb in the HEK293F cells was at the highest level (100.5 mg/L) when the DNA/polyethyleneimine and light-chain/heavy-chain ratios were 1:4 and 1:2, respectively. The half-maximal inhibitory concentration of the ADCC of the antibodies against the SK-OV-3, OVCAR-3, and A-2780 cells were 12.36, 5.43, and 102.90 ng/mL, respectively. The animal experiments with the mice showed that rhHER2-mAb effectively inhibited the growth (P<0.01) of the SK-OV-3 tumors at a dose of 10 mg/kg. CONCLUSIONS: TGE technology allows us to quickly obtain a large number of anti-HER2 antibodies compared to the traditional method of constructing stable cell lines, and its in vitro and in vivo studied shows that our anti-HER2 antibody have higher affinity and better biological activity bioactivity (P<0.01) compared to Herceptin. Our findings provide novel insights into the development and production of future biotechnology-based drugs using the TGE technology of HEK293F.