PURPOSE: To examine the expression profile and promoter methylation status of WIF-1 in hepatocellular carcinoma (HCC) and identify the possible relationship between the WIF-1 expression pattern and promoter methylation status. METHODS: Quantitative real-time PCR was performed to detect mRNA level of WIF-1 in 4 HCC cell lines, 15 paired HCC clinical samples and 3 normal liver tissues. Methylation-specific PCR and bisulfite DNA sequencing were used in methylation analysis. In vitro assays for HCC cells, colony formation and cell proliferation assay were carried out to observe the effect of WIF-1 on cell growth; TOP-flash luciferase analysis was employed to determine its role in the Wnt pathway. RESULTS: Quantitative real-time PCR analysis showed the extensive low expression of WIF-1 mRNA in HCC, and this down-regulation was generally dependent on the degree of methylation at its promoter region. In vitro assays indicated WIF-1 can inhibit cell growth by blocking Wnt signaling in HCC cells. CONCLUSIONS: WIF-1 silencing as a result of its promoter hypermethylation may be a frequent event in HCC.
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