Inhibition of de novo Palmitate Synthesis by Fatty Acid Synthase Induces Apoptosis in Tumor Cells by Remodeling Cell Membranes, Inhibiting Signaling Pathways, and Reprogramming Gene Expression. Homo sapiens

TVB-3166, an orally available, reversible, potent, and selective FASN inhibitors, was used to investigate FASN as a cancer therapeutic target. FASN inhibition with TVB-3166 induces apoptosis, inhibits anchorage-independent cell growth under lipid-rich conditions, and inhibits in vivo xenograft tumor growth. The effects are dose dependent between 20-200 nM TVB-3166, which agrees with the IC50 value in biochemical FASN and cellular palmitate synthesis assays. Studies to understand the mechanism of action show that FASN inhibition disrupts lipid raft architecture, inhibits biological pathways such as lipid biosynthesis, PI3K-AKT-mTOR and β-catenin signal transduction, and inhibits expression of downstream oncogenic effectors such as c-Myc. These effects are observed in tumor cells but not fibroblast or endothelial cell types. Our results show that FASN inhibition has anti-tumor activities in biologically diverse preclinical tumor models, including those expressing mutant K-Ras, ErbB2, c-Met, and PTEN. The reported findings inform ongoing studies to link specific mechanisms of action with defined tumor types and advance the discovery of biomarkers to support development of FASN inhibitors as novel cancer therapeutics. Overall design: PANC-1 cells were seeded in growth media. The following day, treatment media with DMSO alone or with TVB-3166 (0.1 or 1.0 µM) was added and cells were incubated for an additional 48 (22Rv1) or 72 hours (PANC-1). All treatments were performed in triplicate. For Panc-1 Affymetrix microarray studies (HG-U133 Plus 2.0), cells were lysed using Qiazol (Qiagen, 79306) and processed using the RNeasy microarray kit (Qiagen, 73304). Microarray analysis was performed at Expression Analysis (Durham, NC). Data analysis was performed at 3-V Biosciences using Partek Genomics Suite software (St. Louis, MO).