Stratifin Indicates Worse Prognosis and Promotes Hepatocellular Carcinoma Proliferation, Migration, Invasion and EMT By Modulating Wnt/β-Catenin Pathway

Abstract Background: Stratifin (SFN) is closely related to the tumor progression. However, the role of SFN in hepatocellular carcinoma (HCC) is still unknown. The purpose of this study is to investigate the clinical value, biological role and regulatory mechanisms of SFN in HCC. Methods: Immunohistochemistry and RT-qPCR was used to explore SFN expression in HCC tissues and corresponding adjacent non-tumor tissues. The SFN expression profile data and clinical data of HCC patients were extracted from GEO, TCGA and Oncomine database. The univariate and multivariate analysis were used to investigate the prognosis value of the SFN gene in patients with HCC based on online database. The effects of SFN on HCC cell proliferation, migration, invasion was investigated by preforming CCK-8, colony formation, wound healing and Transwell assays. Xenograft nude mouse were used to observe the role of SFN on tumor growth. Western blotting was used to explore the genes associated with Epithelial mesenchymal transformation (EMT) and Wnt/β-catenin signaling. The luciferase reported assay was used to validate the activity of Wnt signal pathway.Results: In this study, we found SFN was upregulated in HCC cell lines and tissues. Clinically, SFN was positively associated with tumor size, degree of differentiation, TNM stage and vascular invasion. Survival analysis indicated that patients with high SFN levels had worse OS and DFS. SFN was an independent prognostic factor for HCC. Biologically, knockdown of SFN repressed tumor cell proliferation, migration, invasion, epithelial-to-mesenchymal transition (EMT) in vitro and tumor growth in vivo. Conversely, overexpression of SFN promoted these effects. Moreover, SFN promoted matrix metalloproteinases-2 (MMP-2) and MMP-9 expression. Mechanistically, SFN activated Wnt/β-catenin pathway by promoting GSK-3β phosphorylation, decreasing β-catenin phosphorylation, promoting β-catenin nuclear translocation, increasing c-Myc expression and inhibiting Axin2 expression. Furthermore, the TOP/FOP-Flash reporter assays indicated that SFN overexpression or SFN knockdown obviously up-regulated or down-regulated Wnt signaling activity. Conclusions: SFN indicates worse survival in HCC and promotes HCC growth, migration, invasion and EMT by activating Wnt/β-catenin pathway. Our results suggest SFN may become a prognostic factor and therapeutic target for patients with HCC in future.