The effect of hepatitis C virus p7 trans-regulated protein 3 (P7TP3) in the development of hepatocellular carcinoma (HCC) is still unknown. The present study aimed to investigate the role and mechanism of P7TP3 in HCC. P7TP3 was significantly decreased in HCC tissues when compared with corresponding liver tissues immediately around the tumor (LAT) from seven HCC patients. Fewer and smaller colonies originated from HepG2-P7TP3 cells when compared to HepG2-NC cells. Overexpression of P7TP3 in HepG2 cells significantly repressed the growth of HCC xenografts in nude mice. Furthermore, wound-healing tests, Transwell assays, Matrigel Transwell assays, adhesion assays, CCK-8 assays, flow cytometry and western blotting analysis showed that P7TP3 protein expression inhibited migration, invasion, adhesion, proliferation and cell cycle progression in HCC cell lines. Moreover, P7TP3 suppressed the activity of the Wnt/β-catenin signaling pathway, and was restored by Wnt3a, which is an activator of the Wnt/β-catenin signaling pathway. Consistently, β-catenin was highly expressed by P7TP3 silencing, and restored by XAV939, an inhibitor of the Wnt/β-catenin signaling pathway. Finally, microRNA (miR)-182-5p suppressed the expression of target gene P7TP3 by directly interacting with the 3'-UTR region. Taken together, P7TP3, the direct target gene of miR-182-5p, inhibited HCC by regulating migration, invasion, adhesion, proliferation and cell cycle progression of liver cancer cell through the Wnt/β-catenin signaling pathway. These findings provide strong evidence that P7TP3 functions as a new promising tumor suppressor in HCC.
Keywords: P7TP3; Wnt; liver cancer; miR-182-5p; β-catenin signaling pathway.
© 2019 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.