Abstract 4743: Preclinical studies characterize tumor type sensitivity to FASN inhibition and the mechanism and efficacy of novel drug combinations with TVB-2640
Authors: Heuer Timothy S. , Ventura Richard , Lai Julie , Waszczuk Joanna , Rubio Claudia , Hammonds Glenn , O’ Farrell Marie , Buckley Douglas , Kemble George 
Published: July 2016

Tumor cells have an increased dependence on FASN-synthesized palmitate compared to non-tumor cells, which obtain many of their required lipids from the extracellular milieu. Palmitate and palmitate-derived lipids comprise diverse cellular components and function in processes required for tumor cell proliferation and survival. Previously we showed that FASN inhibition results in tumor cell apoptosis in vitro and xenograft tumor growth inhibition in vivo. Our studies demonstrated that diverse tumor types exhibit sensitivity to FASN inhibition and characterized mechanisms of action that associate with the antitumor activity of highly selective small molecule FASN inhibitors. In vitro studies with diverse tumor cell types elucidated a mechanism of action that includes plasma membrane remodeling, signal transduction pathway inhibition, and gene expression reprogramming.

TVB-2640, TVB-3166, and TVB-3664 belong to a series of orally available, reversible, potent, and selective FASN inhibitors discovered and developed by 3-V Biosciences. Analysis of gene expression data from tumor cell lines and human tumors, both primary and patient-derived xenografts, has allowed for the classification of FASN sensitivity by tumor type, histology, and molecular genetic markers. Discoveries from these analyses are being characterized further using in vitro and in vivo studies.

Combined inhibition of FASN and microtubule function with taxane treatment, e.g. paclitaxel, results in synergistic inhibition of tumor growth. Indeed, in Phase I clinical investigation, TVB-2640 combined with paclitaxel has shown promising early signs of clinical activity. Previous in vitro studies revealed that FASN inhibition causes changes in beta-tubulin expression and disrupts the organization of cellular microtubule structures in varied tumor cell types such as CALU-6 non-small-cell lung and 22Rv1 prostate tumor cell lines. Extending our investigation of the mechanism of FASN/taxane synergy, we now show that FASN inhibition prevents beta-tubulin palmitoylation. This likely plays a significant role in the observed effects on beta-tubulin expression and microtubule architecture. As disruption of protein palmitoylation is believed to contribute significantly to the anti-tumor activity of FASN inhibition in general, we expanded the analysis of protein palmitoylation following inhibition of FASN with TVB-3166 and TVB-3664 to include key oncogenic drivers of cell growth, proliferation, and survival such as K-Ras and EGFR. Additionally, the efficacy of FASN inhibition in combination with additional, non-taxane approved cancer therapies, including immunomodulatory agents and bevacizumab, is being investigated.

Citation Format: Timothy S. Heuer, Richard Ventura, Julie Lai, Joanna Waszczuk, Claudia Rubio, Glenn Hammonds, Marie O’ Farrell, Douglas Buckley, George Kemble. Preclinical studies characterize tumor type sensitivity to FASN inhibition and the mechanism and efficacy of novel drug combinations with TVB-2640. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4743.