2194

FASN

fatty acid synthase;FASN;fatty acid synthase

short chain dehydrogenase/reductase family 27X, member 1

17q25

protein-coding

Clinicopathological assessment of the functional relationship between the HER2 oncogene and tumor-associated fatty acid synthase (FASN) is largely precluded because immunohistochemical and/or mRNA studies should be performed in biopsies from breast cancer patients. We here sought to determine whether serum FASN (sFASN) could associate with circulating HER2 extracellular domain (HER2 ECD) in the blood of metastatic breast cancer (MBC) patients. Concentrations of serum FASN and HER2 ECD were measured with ELISA in sera retrospectively obtained from 201 patients with metastatic breast cancer (MBC) and 31 healthy subjects. Mechanistical in vitro studies were performed using pharmacological inhibitors of HER2 and FASN as well as cultured cancer cells engineered to overexpress HER2 and FASN human genes. When the upper limit of normal sFASN was defined as the mean + 2SD of the control group, sFASN was elevated above this cut-off (12 ng/ml) in 70 MBC patients (35%). Eighty-nine MBC patients (44%) had elevated levels of HER2 ECD (HER2 ECD cut-off = 15 ng/ml). HER2 ECD-positive MBC patients slightly increased their sFASN levels compared with HER2 ECD-negative MBC patients. sFASN-positive MBC patients had significantly increased levels of HER2 ECD when compared with sFASN-negative MBC patients (mean HER2 ECD=34 ng/ml, 95%

Fatty acid synthase (FASN) and ATP-citrate lyase, key enzymes of de novo lipogenesis, are significantly upregulated and activated in many cancers and portend poor prognosis. Even though the role of lipogenesis in providing proliferative and survival advantages to cancer cells has been described, the impact of aberrant activation of lipogenic enzymes on cancer progression remains unknown. In this study, we found that elevated expression of FASN is associated with advanced stages of colorectal cancer (CRC) and liver metastasis, suggesting that it may play a role in progression of CRC to metastatic disease. Targeted inhibition of lipogenic enzymes abolished expression of CD44, a transmembrane protein associated with metastases in several cancers including CRC. In addition, inhibition of lipogenic enzymes and reduced expression of CD44 attenuated the activation of MET, Akt, FAK, and paxillin, which are known to regulate adhesion, migration, and invasion. These changes were consistent with an observed decrease in migration and adhesion of CRC cells in functional assays and with reorganization of actin cytoskeleton upon FASN inhibition. Despite the modest effect of FASN inhibition on tumor growth in xenografts, attenuation of lipogenesis completely abolished establishment of hepatic metastasis and formation of secondary metastasis. Together, our findings suggest that targeting de novo lipogenesis may be a potential treatment strategy for advanced CRC.

BACKGROUND: Fatty acid synthase (FASN) is overexpressed in a variety of human cancers, and may be involved in cancer metastasis. Hence, the strategies targeted on FASN may have therapeutic potential for treating cancer metastasis. OBJECTIVES: The aim of this study is to investigate the correlation of FASN expression with metastasis in human osteosarcoma. MATERIALS AND METHODS: Human osteosarcoma cell lines U2-OS and osteosarcoma biopsy specimens were employed in this study. The expression of FASN protein in osteosarcoma specimens was detected by IHC (immunohistochemistry) and the relationship with metastasis was analyzed. We performed the cerulenin, an inhibitor of FASN, to inhibit FASN expression in U2-OS cells. Western blot and RT-PCR were performed to investigate the expression of FASN in U2-OS cells. Cells mobility was detected by wound healing and Transwell assays. RESULTS: Results showed that the FASN expression level in the cases with pulmonary metastases was significantly higher than in those without metastasis. In vitro, the invasion and migration of U2-OS cells were suppressed by inhibiting FASN. Our findings suggested that FASN may be involved in osteosarcoma metastasis.