NF-kappaB protects human papillomavirus type 38 E6/E7-immortalized human keratinocytes against tumor necrosis factor alpha and UV-mediated apoptosis

J Virol. 2011 Sep;85(17):9013-22. doi: 10.1128/JVI.00002-11. Epub 2011 Jun 29.

Abstract

Constitutive activation of NF-κB signaling is a key event in virus- and non-virus-induced carcinogenesis. We have previously reported that cutaneous human papillomavirus type 38 (HPV38) displays transforming properties in in vitro and in vivo experimental models. However, the involvement of NF-κB signaling in HPV38-induced cell growth transformation remains to be determined. In this study, we showed that HPV38 E6 and E7 activate NF-κB and that inhibition of the pathway with the IκBα superrepressor sensitizes HPV38E6E7-immortalized human keratinocytes to tumor necrosis factor alpha (TNF-α)- and UVB radiation-mediated apoptosis. Accordingly, inhibition of NF-κB signaling resulted in the downregulation of NF-κB-regulated antiapoptotic genes, including cIAP1, cIAP2, and xIAP genes. These findings demonstrate a critical role of NF-κB activity in the survival of HPV38E6E7-immortalized human keratinocytes exposed to cytokine or UV radiation. Our data provide additional evidence for cooperation between beta HPV infection and UV irradiation in skin carcinogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis*
  • Cell Line
  • Cell Survival / drug effects
  • Cell Survival / radiation effects
  • Humans
  • Keratinocytes / drug effects*
  • Keratinocytes / radiation effects*
  • NF-kappa B / metabolism*
  • Oncogene Proteins, Viral / metabolism*
  • Papillomaviridae / pathogenicity*
  • Tumor Necrosis Factor-alpha / toxicity*

Substances

  • NF-kappa B
  • Oncogene Proteins, Viral
  • Tumor Necrosis Factor-alpha