Abstract 5611: Use of ecto-domain vimentin to target brain cancers

Abstract Pritumumab is a natural human IgG1 kappa antibody derived from a regional draining lymph node of a patient with cervical carcinoma. The recognized antigen is an altered form of vimentin, called ecto-domain vimentin (EDV), that is expressed on the cell surface of epithelial tumor cells. For brain cancers, immunohistological analysis showed the binding of pritumumab to EDV to be restricted to tumor cells and not normal cells and tissues suggesting EDV may be a useful biomarker. A recombinant version of the mAb was made using the GPEx® system in CHO cells that showed comparable binding activity by flow cytometry, immunohistochemical analysis, Western blot analysis, and Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC; EC50 of 39.6ng/ml) activity. Further studies include establishing xenograft models with both SCID and athymic nude mice in which pritumumab was effective in preventing tumor growth of both brain cancer stem cells as well as pancreatic cancer in nude mice but not in SCID mice suggesting an active immune response is necessary for optimal treatment. Analysis of a blood brain barrier model suggests pritumumab shows minimal distribution in normal brain tissues and significant binding in tumor areas of brain tissues indicating the mAb crosses the tumor brain barrier. Overall, these data together suggest that EDV is a suitable target and biomarker for brain cancers. Citation Format: Ivan Babic, Rajesh Mukthavaram, Pengfei Jiang, Eric Glassy, Natsuko Nomura, Sandeep Pingle, Mark C. Glassy, Santosh Kesari. Use of ecto-domain vimentin to target brain cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5611. doi:10.1158/1538-7445.AM2017-5611