Abstract 5758: Generation and characterization of novel monoclonal antibodies against overexpressed CD109 on pancreatic cancer cells for use in diagnosis and therapy

Abstract Pancreatic cancer is one of the most aggressive and lethal types of cancer, and more effective therapeutic agents are urgently needed. Overexpressed cell surface antigens are ideal targets for therapy with monoclonal antibody (mAb)-based drugs, and several have been approved for the treatment of human cancers; however, none have approval for pancreatic cancer. Our aim was to discover novel overexpressed cell surface antigens in human pancreatic cancer cells using mAb technology. We have generated two novel mouse mAbs, KU42.33C and KU43.13A, against the human pancreatic cancer cell line BxPC-3. Using ELISA, flow cytometry, competitive assay and mass spectrometry, we discover that these two mAbs target two distinct epitopes on the external domain of CD109 that are overexpressed by varying amounts in human pancreatic cancer cell lines. Treatment with these two naked antibodies alone did not affect tumor cell growth in vitro or cell migration. Of the two mAbs, only KU42.33C was useful in determining the expression of CD109 in tumor cells by Western blot and immunohistochemistry. Immunohistochemistry of human pancreatic carcinoma arrays with mAb KU42.33C showed that 94% of the 65 human pancreatic adenocarcinoma cases were CD109 positive, with no expression in normal pancreatic tissues. Our results suggest that these two novel mAbs are excellent tools for determining the expression level of CD109 in the tumor specimens and sera of patients with a wide range of cancers, in particular pancreatic cancer, and for investigating its diagnostic, prognostic and predictive value. Further research should unravel the therapeutic potential of the humanized forms or the conjugated versions of such antibodies in patients whose tumors overexpress CD109 antigen. Citation Format: Gustavo A. Arias-Pinilla, Angus Dalgleish, Satvinder Mudan, Izhar Bagwan, Tony Walker, Helmout Modjtahedi. Generation and characterization of novel monoclonal antibodies against overexpressed CD109 on pancreatic cancer cells for use in diagnosis and therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5758.