TGF-beta1 and IL-4 downregulate human papillomavirus-16 oncogene expression but have differential effects on the malignant phenotype of cervical carcinoma cells

Virus Res. 2008 Mar;132(1-2):253-6. doi: 10.1016/j.virusres.2007.12.003.

Abstract

Host immune response to human papillomavirus (HPV) is a crucial factor in viral clearance and control of persistent infections. The existence of an intercellular control mechanism mediated by cytokines to suppress HPV-gene transcription and to prevent malignant conversion of HPV-infected cells, has been postulated. In a previous study, we demonstrated the inhibitory activity of several cytokines on the HPV-16 long control region (LCR)-driven transcription; among these, IL-4 was reported as a LCR inhibitor for the first time and proposed as a candidate for further studies. Here, we addressed the question of whether IL-4 represses HPV-16 oncogene transcription and exerts antitumor activity in HPV-16 positive cervical carcinoma cell lines. Results indicated that downregulation of E6 and E7 levels by IL-4 in CaSki cells is weaker than that exerted by TGF-beta1, a known LCR inhibitor, although both cytokines are equally active in suppressing LCR-driven transcriptional activity in a reporter cell line. Moreover, only TGF-beta rescued p53 expression, Rb response pathway, and induced cellular senescence. SiHa cells were unresponsive to both cytokines. These findings suggest that the two cytokines may play a role in the control of HPV infections, however, cervical carcinoma cells developed a partial or a total resistance to their inhibitory activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line, Tumor
  • Cellular Senescence
  • Down-Regulation*
  • Female
  • Gene Expression Regulation, Viral
  • Human papillomavirus 16 / genetics*
  • Human papillomavirus 16 / metabolism
  • Humans
  • Interleukin-4 / metabolism*
  • Oncogene Proteins, Viral / genetics*
  • Papillomavirus E7 Proteins
  • Phenotype
  • Repressor Proteins / genetics*
  • Transcription, Genetic
  • Transforming Growth Factor beta1 / metabolism*
  • Tumor Suppressor Protein p53 / metabolism
  • Uterine Cervical Neoplasms / genetics
  • Uterine Cervical Neoplasms / metabolism

Substances

  • E6 protein, Human papillomavirus type 16
  • Oncogene Proteins, Viral
  • Papillomavirus E7 Proteins
  • Repressor Proteins
  • Transforming Growth Factor beta1
  • Tumor Suppressor Protein p53
  • oncogene protein E7, Human papillomavirus type 16
  • Interleukin-4