Inhibition of fatty acid synthase suppresses c-Met receptor kinase and induces apoptosis in diffuse large B-cell lymphoma

Fatty acid synthase (FASN), the enzyme responsible for de novo synthesis of fatty acids, has emerged as a potential therapeutic target for several cancers; however, its role in diffuse large B-cell lymphoma (DLBCL) has not been fully elucidated. In this study, we investigated the role of FASN in a large series of DLBCL tissues in a tissue microarray (TMA) format followed by in vitro studies using DLBCL cell lines. FASN was found to be expressed in 62.6% DLBCL samples and was seen in highly proliferative tumors, manifested by high Ki67 (P < 0.0001). Significant association was found between tumors expressing high FASN and c-Met tyrosine kinase (P < 0.0002), as well as p-AKT (P = 0.0309). In vitro, pharmacological FASN inhibition and small interference RNA (siRNA) targeted against FASN triggered caspase-dependent apoptosis and suppressed expression of c-Met kinase in DLBCL cell lines, which further highlighted the molecular link between FASN and c-Met kinase. Finally, simultaneous targeting of FASN and c-Met with specific chemical inhibitors induced a synergistically stimulated apoptotic response in DLBCL cell lines. These findings provide evidence that FASN, via c-Met tyrosine kinase, plays a critical role in the carcinogenesis of DLBCL and strongly suggest that targeting FASN may have therapeutic value in treatment of DLBCL. Mol Cancer Ther; 9(5); 1244–55. ©2010 AACR.