Effects of tumor necrosis factor-alpha (TNF-α) on HPV - immortalized cells

Author(s)

Enrique Mario Boccardo Pierulivo

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ)
• Defense date: 2002-07-05

Examining board members

Luisa Lina Villa; Hugo Aguirre Armelin; Rafael Linden; Ronaldo Bento Quaggio; Bryan Eric Strauss

• Advisor: Luisa Lina Villa

Abstract

Infection by Human papillomavirus (HPV) is the major etiologic factor in the development of cervical intra-epithelial neoplasia, the precursor of carcinoma of the uterine cervix. Tumor necrosis factor-alpha (TNF-α) is one of the main mediators of skin and mucosa inflamation and has a potent anti-proliferative effect on normal and HPV16 immortalized keratinocytes. On the other hand, HPV-18 immortalized and HPV-16 or -18 transformed keratinocytes are resistant to TNF-α. However the molecular basis of this difference is not well understood. In the present study we observed and increase in the CDK inhibitor p21, reduced levels of cyclin A and activation of NF-κB factor only in cells sensitive to this cytokine. Conversely, no alterations in the p16, p27, p65, cyclins D1, E and CDKs -4 and -6 levels was observed in any of the cell lines analyzed. Proliferation of normal primary human keratinocytes (PHK) raft cultures was markedly inhibited after treatment with TNF-α. This was not observed in cultures transfected with HPV-18 whole genome. Cultures transduced retroviral vectors carrying the E7 viral gene showed an intermediate phenotype suggesting that this protein contribute to TNF-α resistance. (AU)