Oncogenic activation of the Wnt/β-catenin signaling pathway is common in human cancers. The secreted frizzled-related proteins (SFRPs) function as negative regulators of Wnt signaling and have important implications in carcinogenesis. Because there have been no reports about the role ofSFRP3in hepatocellular carcinoma (HCC), we investigated the level of methylation and transcription ofSFRP3. Four HCC cell lines, 60 HCCs, 23 cirrhosis livers, 37 chronic hepatitis livers, and 30 control livers were prescreened forSFRP3promoter methylation by methylation-specific polymerase chain reaction (MS-PCR) and bisulfite sequencing.SFRP3promoter methylation was observed in 100%, 60%, 39.1%, 16.2%, and 0% in HCC cell lines, primary HCCs, cirrhosis livers, chronic hepatitis livers, and control livers, respectively. Demethylation treatment with 5-aza-2′-deoxycytidine in HCC cells restored or increased theSFRP3mRNA expression. We next used quantitative MS-PCR (QMSP) to analyze the methylation level ofSFRP3in 60 HCCs and their corresponding nontumor tissues. Methylation ofSFRP3promoter region in HCCs increased significantly compared with control tissues. There is a positive correlation between promoter hypermethylation andSFRP3mRNA downregulation. Our data suggest that promoter hypermethylation ofSFRP3is a common event in HCCs and plays an important role in regulation ofSFRP3mRNA expression.
Promoter Methylation ofSFRP3Is Frequent in Hepatocellular Carcinoma