title: Frequent concomitant epigenetic silencing of SOX1 and secreted frizzled-related proteins (SFRPs) in human hepatocellular carcinoma.
abstract: OBJECTIVE
  Except for genetic mutations, epigenetic changes are also involved in the development of human cancers. Recently, we have identified SOX1, SRY (sex determining region Y)-box 1, is hypermethylated in cervical cancer and ovarian cancer. Therefore, we investigated whether promoter hypermethylation of SOX1 is common in hepatocellular carcinoma (HCC).
  
  
  METHODS
  We used methylation-specific polymerase chain reaction (MS-PCR) and bisulfite sequencing to analyze the methyaltion level of the SOX1 promoter in seven HCC cell lines, 54 clinical HCCs, 42 cirrhotic livers, 21 livers with chronic hepatitis, and 15 control livers. Then, we employed quantitative MS-PCR (QMSP) to validate in an independent set of samples (60 paired HCCs and 30 control livers). Finally, we used luciferase reporter and colony formation assay to check the effect of SOX1 in HCC.
  
  
  RESULTS
  Promoter methylation of SOX1 was significantly frequent in HCC cell lines and clinical HCCs, cirrhotic livers, but not in control livers (P < 0.0001). There is a significant correlation between downregulation of SOX1 expression and promoter methylation. QMSP results confirmed that promoter hypermethylation of SOX1 is significantly more frequent in HCCs than control livers (P < 0.0001). The frequency of SOX1 methylation in patients with secreted frizzled-related proteins (SFRPs) methylation is significantly higher than in patients without SFRPs methylation (P < 0.0001). Furthermore, ectopic expression of SOX1 could suppress T-cell factor-dependent transcriptional activity and colony formation number in HCCs.
  
  
  CONCLUSIONS
  Concomitant epigenetic silencing of SOX1 and SFRPs through promoter hypermethylation is frequent in HCCs, and this might contribute to abnormal activation of canonical Wnt signal pathway.
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taiwan.
authors.forename: Yu-Lueng
authors.initials: YL
authors.lastname: Shih
authors.forename: Chung-Bao
authors.initials: CB
authors.lastname: Hsieh
authors.forename: Ming-De
authors.initials: MD
authors.lastname: Yan
authors.forename: Chun-Ming
authors.initials: CM
authors.lastname: Tsao
authors.forename: Tsai-Yuan
authors.initials: TY
authors.lastname: Hsieh
authors.forename: Chang-Hsin
authors.initials: CH
authors.lastname: Liu
authors.forename: Ya-Wen
authors.initials: YW
authors.lastname: Lin
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics*; D006528:Carcinoma, Hepatocellular / Q000235:genetics*; D016022:Case-Control Studies; D045744:Cell Line, Tumor; D019175:DNA Methylation; D005136:Eye Proteins / Q000235:genetics; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D006521:Hepatitis, Chronic / Q000235:genetics; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics; D008103:Liver Cirrhosis / Q000235:genetics; D008113:Liver Neoplasms / Q000235:genetics*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055748:SOXB1 Transcription Factors / Q000235:genetics*; D017422:Sequence Analysis, DNA; D000094742:Secreted Frizzled-Related Proteins
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D014408:Biomarkers, Tumor; D005136:Eye Proteins; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D055748:SOXB1 Transcription Factors; C117636:SFRP1 protein, human; D000094742:Secreted Frizzled-Related Proteins; C109618:SFRP2 protein, human; C118511:SFRP5 protein, human; C490906:SOX1 protein, human