Upregulation of DNA methyltransferase - mediated gene silencing, anchorage-independent growth, and migration of colon cancer cells by interleukin-6

Eilis Foran, Megan M. Garrity-Park, Coralie Mureau, John Newell, Thomas C. Smyrk, Paul J. Limburg, Laurence J. Egan

Research output: Contribution to journalArticle

102 Scopus citations

Abstract

Inflammatory bowel disease is characterized by chronic inflammation which predisposes to colorectal cancer. The mechanisms by which inflammation promotes tumorigenesis are not fully known. We aimed to investigate the links between colonic inflammation and tumorigenesis via epigenetic gene silencing. Colon cancer specimens were assessed for the expression of DNA methyltransferase-1 (DNMT-1) using immunohistochemistry. Colorectal carcinoma cell lines were assessed for DNMT1 expression, methylcytosine content, promoter methylation, gene expression, and tumorigenesis in response to interleukin (IL)-6. DNMT1 was expressed at higher levels in both the peritumoral stroma and tumor in inflammatory bowel disease-associated cancers compared with sporadic colon cancers. IL-6 treatment of colon cancer cells resulted in an increase in DNMT1 expression, independent of de novo gene expression. IL-6 increased the methylation of promoter regions of genes associated with tumor suppression, adhesion, and apoptosis resistance. Expression of a subset of these genes was downregulated by IL-6, an effect that was prevented by preincubation with 5-azadeoxycytidine, a DNMT1 inhibitor. Anchorage-independent growth and migration of colon cancer cells was also increased by IL-6 in a 5-azadeoxycytidine-sensitive manner. Our results indicate that DNMT-mediated gene silencing may play a role in inflammation-associated colon tumorigenesis.

Original languageEnglish (US)
Pages (from-to)471-481
Number of pages11
JournalMolecular Cancer Research
Volume8
Issue number4
DOIs
StatePublished - Apr 1 2010

ASJC Scopus subject areas

  • Molecular Biology
  • Oncology
  • Cancer Research

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