Chibby is an antagonist of β-catenin and is considered a potential tumor suppressor protein, but the role of Chibby in hepatocellular carcinoma (HCC) has not been characterized. The expression patterns of Chibby and β-catenin in HCC specimens and paired adjacent noncancerous tissues were measured by Western blotting and immunohistochemistry. The correlations between Chibby expression and clinicopathological parameters were analyzed. Then the biological functions of Chibby were analyzed in vitro. The Chibby protein was significantly downexpressed in human primary HCC tissues compared to that in matched adjacent normal liver tissue and is a risk factor for HCC recurrence and shorter survival. Furthermore, we found that in HCC tissues the high expression of β-catenin with low expression of Chibby in the nuclei was an independent predictor for disease-free survival (DFS) (p = 0.012) and overall survival (OS) (p = 0.005). Subsequent genetic manipulation in vitro studies revealed that Chibby knockdown induced the expression of β-catenin and C-myc, cyclin D1 protein, which promoted cell proliferation and invasiveness. In contrast, overexpression of Chibby decreased β-catenin expression and inhibited the cell proliferation and invasiveness. Our results suggest that low expression of Chibby was associated with advanced tumor-node-metastasis (TNM) stage and poor differentiation. Furthermore, the combination of Chibby and β-catenin can predict poor prognosis in patients with HCC. Chibby inhibited HCC progression by blocking β-catenin signaling in vitro. Chibby is a biomarker and may be a potential therapeutic target for HCC.
Keywords: Chibby; hepatocellular carcinoma; β-catenin.