Role of Wnt5a in suppressing invasiveness of hepatocellular carcinoma via epithelial mesenchymal transition.

Abstract

573 Background: Wnt signaling pathway includes canonical pathway and non-canonical pathway. Wnt/β-Catenin pathway as canonical pathway is associated with the development of hepatocellular carcinoma (HCC). On the other hand, the association between aberrant activation of non-canonical pathway activated by Wnt5a and tumor progression of HCC is not well-known. We investigated the significance of the expression of Wnt5a in HCC. Methods: Immunohistochemical staining of Wnt5a was performed on the specimen of 243 patients who underwent hepatic resection for HCC. We investigated whether the expression of Wnt5a correlated with the clinicopathological factors, survival, and recurrence in HCC patients. The expression of Wnt5a in human HCC cell lines HLE, HLF, HepG2 and Huh7 was investigated by western blotting. The effects of overexpression or knockdown of Wnt5a on cell lines were evaluated by proliferation assay and invasion assay and changes in epithelial mesenchymal transition (EMT) related molecules were studied by western blotting. Results: The Wnt5a expression was positive in 63 patients (25.9%) and negative in 180 patients (74.1%). The Wnt5a negative was significantly associated with poorly differentiation (P = 0.003) and vascular invasion positive (P = 0.046). By univariate analysis, Wnt5a negative (P = 0.020) was identified as a significant prognostic factor of OS. Multivariate analysis of OS showed that Wnt5a negative (HR 1.895, 95% CI 1.053-3.409, P = 0.033) was identified as an independent prognostic factor. In the HCC cell lines, the Wnt5a expression was lower in HLE and HLF than in HepG2 and Huh7. Knockdown of Wnt5a by shRNA increased the proliferation and invasiveness in Huh7 with high expression of Wnt5a. As a result, the expression of E-cadherin decreased. In HLF with low expression of Wnt5a, overexpression of Wnt5a inhibited the invasiveness and the expression of vimentin decreased. Conclusions: Wnt5a negative was associated with poorly differentiation and vascular invasion, and was independent poor prognostic factor in HCC patients. Wnt5a may be a tumor suppressor involved in EMT mediated changes of invasiveness.