Cytokine induction of tumor necrosis factor receptor 2 is mediated by STAT3 in colon cancer cells

Mol Cancer Res. 2011 Dec;9(12):1718-31. doi: 10.1158/1541-7786.MCR-10-0210. Epub 2011 Oct 12.

Abstract

The IL-6/STAT3 and TNFα/NFκB pathways are emerging as critical mediators of inflammation-associated colon cancer. TNF receptor (TNFR) 2 expression is increased in inflammatory bowel diseases, the azoxymethane/dextran sodium sulfate (AOM/DSS) model of colitis-associated cancer, and by combined interleukin (IL) 6 and TNFα. The molecular mechanisms that regulate TNFR2 remain undefined. This study used colon cancer cell lines to test the hypothesis that IL-6 and TNFα induce TNFR2 via STAT3 and/or NFκB. Basal and IL-6 + TNFα-induced TNFR2 were decreased by pharmacologic STAT3 inhibition. NFκB inhibition had little effect on IL-6 + TNFα-induced TNFR2, but did inhibit induction of endogenous IL-6 and TNFR2 in cells treated with TNFα alone. Chromatin immunoprecipitation (ChIP) revealed cooperative effects of IL-6 + TNFα to induce STAT3 binding to a -1,578 STAT response element in the TNFR2 promoter but no effect on NFκB binding to consensus sites. Constitutively active STAT3 was sufficient to induce TNFR2 expression. Overexpression of SOCS3, a cytokine-inducible STAT3 inhibitor, which reduces tumorigenesis in preclinical models of colitis-associated cancer, decreased cytokine-induced TNFR2 expression and STAT3 binding to the -1,578 STAT response element. SOCS3 overexpression also decreased proliferation of colon cancer cells and dramatically decreased anchorage-independent growth of colon cancer cells, even cells overexpressing TNFR2. Collectively, these studies show that IL-6- and TNFα-induced TNFR2 expression in colon cancer cells is mediated primarily by STAT3 and provide evidence that TNFR2 may contribute to the tumor-promoting roles of STAT3.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Cell Line, Tumor
  • Cell Proliferation
  • Colonic Neoplasms / genetics
  • Colonic Neoplasms / metabolism
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Interleukin-6 / genetics
  • Interleukin-6 / metabolism*
  • NF-kappa B / genetics
  • NF-kappa B / metabolism
  • Promoter Regions, Genetic
  • Protein Binding
  • Receptors, Tumor Necrosis Factor, Type II / genetics
  • Receptors, Tumor Necrosis Factor, Type II / metabolism*
  • Response Elements / genetics
  • STAT3 Transcription Factor / genetics
  • STAT3 Transcription Factor / metabolism*
  • Suppressor of Cytokine Signaling 3 Protein
  • Suppressor of Cytokine Signaling Proteins / metabolism
  • Tumor Necrosis Factor-alpha / genetics
  • Tumor Necrosis Factor-alpha / metabolism*

Substances

  • Interleukin-6
  • NF-kappa B
  • Receptors, Tumor Necrosis Factor, Type II
  • SOCS3 protein, human
  • STAT3 Transcription Factor
  • Suppressor of Cytokine Signaling 3 Protein
  • Suppressor of Cytokine Signaling Proteins
  • Tumor Necrosis Factor-alpha