KIN17 promotes cell migration and invasion through stimulating the TGF-β/Smad2 pathway in hepatocellular carcinoma

KIN17 DNA and RNA binding protein (Kin17) is involved in the regulation of tumorigenesis of diverse human cancers. However, its role in the cancer progression and metastasis in hepatocellular carcinoma (HCC) remains largely unknown. Bioinformatics and immunohistochemistry staining were used to investigate the expression pattern of KIN17 and its prognostic value in HCC patients. The transwell, wound-healing assay was employed to determine the effects of KIN17 on migration and invasion of HCC cells in vitro. The tail veins model was employed to determine the effects of KIN17 on lung metastasis in vivo. The biological mechanisms involved in cell migration and invasion regulated by KIN17 were determined with Western blot analysis method. KIN17 expression was significantly increased in HCC tissues compared with adjacent normal tissues, with particularly higher in portal vein tumor thrombus and intrahepatic metastasis tissues. Patients with higher KIN17 expression experienced poor overall and disease free survival. KIN17 knockdown in HuH7 and HepG2 cells significantly reduced cell migration and invasion abilities, whereas its overexpression promoted migration and invasion in MHCC-97L and HepG2 cells in vitro and in vivo. In HuH7 and HepG2 cells, KIN17 knockdown inhibited the TGF-beta/Smad2 pathway. In contrast, KIN17 overexpression stimulated TGF-beta/Smad2 pathway in MHCC-97L and HepG2 cells, along with the genes involved in the epithelial-mesenchymal transition. These findings suggest that KIN17 promotes migration and invasion in HCC cells by stimulating the TGF-beta/Smad2 pathway. KIN17 could be a promising prognostic biomarker, as well as a potential therapeutic target in HCC.