Abstract
Hepatocellular carcinoma (HCC) is a common malignancy that is associated with a poor prognosis. The extensively studied TGF-β pathway is mediated by SMAD proteins. FXR1, a protein-coding gene belonging to the fragile X-related (FXR) family, is involved in the TGF-β pathway. Previous studies have shown that FXR1 promotes the proliferation, invasion, and migration of colorectal cancer cells. The aim of the present study was to explore the effects of FXR1 on HCC via the TGF-β/SMAD signaling pathway. Immunohistochemical analysis was used to detect the expression of FXR1 in HCC and normal tissues. Western blotting was used to detect protein expression levels in the HCC cell lines, cell migration and invasion were assessed using Transwell assays, and cell proliferation was assessed using a colony formation assay. The ability of the liver cancer cells to grow in vivo was investigated using a nude mouse tumor-bearing model. The results showed that FXR1 expression was upregulated in HCC tissues compared with normal tissues. Knockdown of FXR1 resulted in reduced expression of SMAD2/3 and EMT-related proteins in HCC cells. In addition, FXR1 knockdown inhibited the proliferation, migration, and invasion of HCC cells. FXR1 knockdown also reversed the promoting effect of TGF-β on the invasive ability of HCC cells. Knockdown of SMAD2/3 reversed the increase in HCC cell invasion induced by FXR1 overexpression. Finally, upregulated FXR1 expression was associated with a poorer prognosis in patients with HCC. In conclusion, FXR1 promoted HCC proliferation, migration, and invasion through the regulation of SMAD2/3.