Analysis of biological function and efficacy of anti EGFR antibodies isolated from screening of human antibody phage display library specific to human renal cell carcinoma

点击翻译按钮获取中文摘要

Using the ICOS method, AIMS5 library was screened with human RCC cell lines, Caki-1(2 cases), CCF-RC1(2 cases) and ACHN(1 case). RCC-specific antibodies were chosen by immunostaining using clinical samples. We chose two different antibodies(059-152 and 062-130) that exhibited cancer cell-specific staining without staining normal cells on clinical RCC sample. These antibodies also reacted to the cell surface antigen of the selected human RCC cells. Antigens these two antibodies reacted were isolated from immunoprecipitation with CCF-RC1.Consequently, the recognized antigen by these two antibodies was proved to be epidermal growth factor receptor(EGFR). Isolated two different anti-EGFR antibodies were assessed for their functional activity on cell proliferation using Caki-1.At the low concentration(0.1μg/ml), 059-152 and 062-130 exhibited about 70% cell proliferation. At the high concentration(10μg/ml), our two anti-EGFR antibodies(059-152, 062-130) elicited up to 40 to 60% cell prolifer … More ation. In ADCC assay, 059-152 had about 35% ADCC assay. 062-130 had about 40% ADCC assay. The effects of the Ab on the phosphorylation reaction were examined. 059-152 did not inhibit phosphorylation in any cell lines. 062-130 and Cetuximab inhibited phosphorylation using CCF-RC1 and ACHN.To determine if the effects of these antibodies could be translated to inhibition of tumor growth in vivo, the antibody was given to mice transplanted with human RCC cells. Treatment with both antibodies developed significant inhibition on human RCC tumor growth compared with control group. The degree of growth inhibition, however, were dependent on the antibody, administration schedule and doses. Although, synergistic growth inhibitions were observed in combination with chemotherapeutic agents, reduction of host mice body weights reduction were also noted, which meant the necessity of investigation of adverse effects in combination therapy.We expected these antibodies were candidate therapeutic antibodies. We showed, our anti-EGFR antibodies, especially 062-130 had sufficient effect. Because our antibodies were originated from human phage display system, possibility of cross reaction over animals were thought to be limited. We expect that this antibody will become a therapeutic antibody for RCC in clinical use. Less