HPV-18 confers resistance to TNF-alpha in organotypic cultures of human keratinocytes.
The proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) inhibits normal keratinocytes proliferation. However, many human papillomavirus (HPV)-immortalized or transformed cell lines are resistant to TNF-alpha antiproliferative effect. The present study analyzes the effects of TNF-alpha on organotypic cultures of primary human keratinocytes (PHKs) that express HPV-18 oncogenes. Raft cultures prepared with PHKs acutely transfected with HPV-18 whole genome or infected with recombinant retroviruses containing only E6/E7 or E7 were treated with 2 nM TNF-alpha. While BrdU incorporation into basal/parabasal cells of normal PHKs cultures was markedly inhibited by TNF-alpha cultures transfected with HPV-18 whole genome showed proliferation in all cell strata. Furthermore, BrdU incorporation into cultures expressing E6/E7 or E7 was not significantly reduced, indicating that E7 alone confers partial resistance to TNF-alpha. Besides, TNF-alpha treatment did not alter p16ink4a, p21cip1, p27kip1, or cyclin E levels, but did reduce cyclin A and PCNA levels in sensitive cells.
Ludwig Institute for Cancer Research, 1509-010 São Paulo, SP, Brazil. eboccardo@lugwig.org.br
Enrique
E
Boccardo
Francisco
F
Noya
Thomas R
TR
Broker
Louise T
LT
Chow
Luisa L
LL
Villa
D002472:Cell Transformation, Viral / Q000187:drug effects*; D019925:Cyclin A / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D015603:Keratinocytes / Q000473:pathology / Q000821:virology*; D009856:Oncogene Proteins, Viral / Q000096:biosynthesis / Q000235:genetics; D027383:Papillomaviridae / Q000235:genetics / Q000472:pathogenicity*; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D016196:S Phase; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D019925:Cyclin A; D004268:DNA-Binding Proteins; C052603:E6 protein, Human papillomavirus type 18; C052633:E7 protein, Human papillomavirus type 18; D009856:Oncogene Proteins, Viral; D018809:Proliferating Cell Nuclear Antigen; D014409:Tumor Necrosis Factor-alpha