Transcriptional silencing of Dickkopf gene family by CpG island hypermethylation in human gastrointestinal cancer

Tadateru Maehata, Hiroaki Taniguchi, Hiroyuki Yamamoto, Kutsuhiko Nosho, Yasushi Adachi, Nobuki Miyamoto, Chie Miyamoto, Noriyuki Akutsu, Satoshi Yamaoka, Fumio Itoh

Research output: Contribution to journalArticlepeer-review

73 Citations (Scopus)


Aim: To clarify alterations of Dickkopfs (Dkks) and Kremen2 (Krm2) in gastrointestinal cancer. Methods: We investigated the expression profiles and epigenetic alterations of Dkks and Krm2 genes in gastrointestinal cancer using RT-PCR, tissue microarray analysis, and methylation specific PCR (MSP). Cancer cells were treated with the demethylating agent and/or histone deacetylase inhibitor. WST-8 assays and in vitro invasion assays after treatment with specific siRNA for those genes were performed. Results: Dkks and Krm2 expression levels were reduced in a certain subset of the gastrointestinal cancer cell lines arvd cancer tissues. This was correlated with promoter hypermethylation. There were significant correlations between Dkks over-expression levels and beta-catenin over-expression in colorectal cancer. In colorectal cancers with beta-catenin over-expression, Dkk-1 expression levels were significantly lower in those with lymph node metastases than in those without. Down-regulation of Dkks expression by siRNA resulted in a significant increase in cancer cell growth and invasiveness in vitro. Conclusion: Down-regulation of the Dkks associated to promoter hypermethylation appears to be frequently involved in gastrointestinal tumorigenesis.

Original languageEnglish
Pages (from-to)2702-2714
Number of pages13
JournalWorld Journal of Gastroenterology
Issue number17
Publication statusPublished - 2008 May 7
Externally publishedYes


  • Dickkopf genes
  • Gastrointestinal cancer
  • Kremen2 gene
  • Methylation
  • Wnt signaling

ASJC Scopus subject areas

  • Gastroenterology


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