Vimentin acetylation is involved in SIRT5-mediated hepatocellular carcinoma migration

Sirtuin 5 (SIRT5) belongs to the sirtuin family of protein deacetylases and contributes to tumorigenesis and migration. However, the underlying molecular mechanism of SIRT5 in hepatocellular carcinoma (HCC) migration is not fully understood. Here we report that SIRT5 was significantly downregulated in HCC, based on analysis of RNA-seq data from the liver HCC dataset of The Cancer Genome Atlas (TCGA). In addition, as compared to adjacent non-tumor tissues, SIRT5 was also significantly downregulated in HCC tissues. In vitro, gain and loss-of-function studies were performed to evaluate the role of SIRT5 in epithelial-mesenchymal transition (EMT). Knockdown of SIRT5 promoted EMT, as indicated by the upregulation of Snail and downregulation of E-cadherin, whereas overexpression of SIRT5 decreased Snail and upregulated E-cadherin. Mechanistically, SIRT5 was found to bind to and deacetylate vimentin at lysine 120. Cell migration was enhanced by overexpression of either wild-type vimentin or acetylation mimetic vimentin (K120Q), whereas cell migration was inhibited by overexpression of the non-acetylation vimentin (K120R). Taken together, these findings indicated that downregulated SIRT5-mediated vimentin acetylation may be involved in the EMT in HCC. Better understanding of SIRT5 may lead to its clinical application as a biomarker for prognosis of prediction of prognosis, as well as a novel therapeutic target.