Increased fatty acid synthase is a therapeutic target in mesothelioma

Many common human cancer tissues express high levels of fatty acid synthase (FAS), the primary enzyme for the synthesis of fatty acids, and the differential expression of FAS between normal and neoplastic tissues has led to the consideration of FAS as a target for anticancer therapy. To investigate the potential of targeting FAS for the treatment of pleural mesothelioma, we first determined whether FAS is overexpressed in human mesothelioma. By immunohistochemistry, we found 22 of 30 human mesothelioma tissue samples tested to express significantly increased levels of FAS compared with normal tissues, including mesothelium. To further explore FAS as a therapeutic target in mesothelioma, we established a nude mouse xenograft model for human mesothelioma using the H-Meso cell line. The i.p. xenografts of this cell line have high levels of FAS expression and fatty acid synthesis pathway activity and grow along mesothelial surfaces in a manner similar to the growth pattern of human mesothelioma. Growth of these tumor xenografts was essentially abolished in mice treated with weekly i.p. injections of C75, a synthetic, small molecule inhibitor of FAS, at levels that resulted in no significant systemic toxicity except for reversible weight loss. These results suggest that FAS may be an effective target for pharmacological therapy in a high proportion of human mesotheliomas.