A novel IL-17 signaling pathway controlling keratinocyte proliferation and tumorigenesis via the TRAF4-ERK5 axis

J Exp Med. 2015 Sep 21;212(10):1571-87. doi: 10.1084/jem.20150204. Epub 2015 Sep 7.

Abstract

Although IL-17 is emerging as an important cytokine in cancer promotion and progression, the underlining molecular mechanism remains unclear. Previous studies suggest that IL-17 (IL-17A) sustains a chronic inflammatory microenvironment that favors tumor formation. Here we report a novel IL-17-mediated cascade via the IL-17R-Act1-TRAF4-MEKK3-ERK5 positive circuit that directly stimulates keratinocyte proliferation and tumor formation. Although this axis dictates the expression of target genes Steap4 (a metalloreductase for cell metabolism and proliferation) and p63 (a transcription factor for epidermal stem cell proliferation), Steap4 is required for the IL-17-induced sustained expansion of p63(+) basal cells in the epidermis. P63 (a positive transcription factor for the Traf4 promoter) induces TRAF4 expression in keratinocytes. Thus, IL-17-induced Steap4-p63 expression forms a positive feedback loop through p63-mediated TRAF4 expression, driving IL-17-dependent sustained activation of the TRAF4-ERK5 axis for keratinocyte proliferation and tumor formation.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism
  • Animals
  • Carcinoma, Squamous Cell / metabolism
  • Carcinoma, Squamous Cell / pathology
  • Cell Proliferation / genetics
  • Feedback, Physiological
  • Humans
  • Interleukin-17 / genetics
  • Interleukin-17 / metabolism*
  • Keratinocytes / metabolism*
  • Keratinocytes / pathology*
  • MAP Kinase Kinase Kinase 3 / genetics
  • MAP Kinase Kinase Kinase 3 / metabolism
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mice, Transgenic
  • Mitogen-Activated Protein Kinase 7 / genetics
  • Mitogen-Activated Protein Kinase 7 / metabolism*
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism
  • Receptors, Interleukin-17 / genetics
  • Receptors, Interleukin-17 / metabolism
  • Signal Transduction
  • Skin Neoplasms / metabolism
  • Skin Neoplasms / pathology
  • TNF Receptor-Associated Factor 4 / genetics
  • TNF Receptor-Associated Factor 4 / metabolism*
  • Trans-Activators / genetics
  • Trans-Activators / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • Interleukin-17
  • Membrane Proteins
  • Phosphoproteins
  • Receptors, Interleukin-17
  • TNF Receptor-Associated Factor 4
  • Tiarp protein, mouse
  • Traf3ip2 protein, mouse
  • Traf4 protein, mouse
  • Trans-Activators
  • Trp63 protein, mouse
  • Mitogen-Activated Protein Kinase 7
  • MAP Kinase Kinase Kinase 3
  • Map3k3 protein, mouse