Acetyl-CoA carboxylase-alpha (ACCA) is a rate-limiting enzyme in long chain fatty acid synthesis, playing a critical role in cellular energy storage and lipid synthesis. ACCA is upregulated in multiple types of human cancers and small interfering RNA-mediated ACCA silencing in human breast and prostate cancer cells results in oxidative stress and apoptosis. This study reports for the first time that TOFA (5-tetradecyloxy-2-furoic acid), an allosteric inhibitor of ACCA, is cytotoxic to lung cancer cells NCl-H460 and colon carcinoma cells HCT-8 and HCT-15, with an IC50 at approximately 5.0, 5.0, and 4.5 mu g/ml, respectively. TOFA at 1.0-20.0 mu g/ml effectively blocked fatty acid synthesis and induced cell death in a dose-dependent manner. The cell death was characterized with PARP cleavage, DNA fragmentation, and annexin-V staining, all of which are the features of the apoptosis. Supplementing simultaneously the cells with palmitic acids (100 mu M), the end-products of the fatty acid synthesis pathway, prevented the apoptosis induced by TOFA. Taken together, these data Suggest that TOFA is a potent cytotoxic agent to lung and colon cancer cells, inducing apoptosis through disturbing their fatty acid synthesis. (C) 2009 Elsevier Inc. All rights reserved.