Abstract 4332: Diagnostic applications of fatty acid synthase monoclonal antibodies

Fatty acid synthase (FASN), is an enzyme capable of de novo fatty acid synthesis and highly expressed and activated in most human carcinomas. Fatty acid synthase is a multi-enzyme protein that catalyzes fatty acid synthesis and is not a single enzyme but a whole enzymatic system composed of two identical 272 KDa multifunctional polypeptides. Fatty-acid synthesis is now associated with clinically aggressive tumor behavior, tumor-cell growth and is associated with poor prognosis in prostate and breast cancer. Its inhibition is selectively cytotoxic to human cancer cells. Thus, FASN and fatty acid metabolism have become an important focus for the diagnostic and treatment of cancer. We have developed a panel of anti-human FASN Mab for application to several diagnostic platforms. Recombinant full length intact FASN protein (rFASN) was used to immunized C57BL/6 mice, sera were collected from pre- and post-immunized mice and tested by ELISA and Western blot on rFASN protein or rFASN immobilized on Western blot. Spleens from mice with the highest anti-FASN antibody titer was fused with a mouse myeloma cell line Sp2/0-Ag14 for hybridoma production. Among the panel of positive anti-FASN clones selected, two clones with isotype of IgG1kappa have shown strong reactivity to the rFASN and native FASN protein on Western analysis. Upon further Western analyses with cell lysates, we have demonstrated specific detection of FASN protein in human embryonic kidney cells (HEK), HEK cells overexpressing the rFASN protein, HOP-62 cells which express low levels of FASN and MALME cells, which express high levels of FASN. Additional biochemical characterization of these antibodies is ongoing, and includes epitope mapping and reactivity to various FASN protein fragments. These anti-FASN antibodies will be tested by IHC, ELISA to compare tissues expression levels of FAS by IHC or circulating levels of the FASN in both normal and cancer patients. With the increasing development of FAS inhibitors these antibodies will be tested as Companion Diagnostics and tested to see if the rise and fall of the FASN circulating levels correspond with cancer progression or therapy response. Citation Format: Walter P. Carney, Wendy Zhang, David Jarosz, Patrick Muraca, Sunny TAM. Diagnostic applications of fatty acid synthase monoclonal antibodies. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4332. doi:10.1158/1538-7445.AM2014-4332