Elevated expression of fatty acid synthase (FASN) and human epidermal growth factor receptor-2 (HER2) are observed in human osteosarcoma (OS). The aim in this study is to investigate a possible connection between FASN expression and the activity of HER2. The immunohistochemistry staining was conducted on 24 OS specimens from patients, which revealed a significant positive correlation between FASN and HER2 as well as p-HER2 protein expression. Furthermore, the human OS cell lines MG-63 and U2-OS were treated with FASN-specific RNAi Plasmid or Lapatinib (an inhibitor of HER2). The mRNA of HER2 and FASN was measured using RT-PCR. Western blot was performed to detect the protein expression of HER2, p-HER2 and FASN. The results demonstrated that HER2 modulates FASN expression, inhibition of FASN resulted in down-regulation of HER2 and p-HER2 protein in OS cells. Our findings suggested that there was positive feedback regulation between FASN and HER2 expression and phosphorylation in OS cells.
Keywords: FASN; HER2; Osteosarcoma; positive feedback regulation.