Telomerase activity in head and neck tumors after introduction of wild-type p53, p21, p16, and E2F-1 genes by means of recombinant adenovirus

Head Neck. 2000 Jul;22(4):347-54. doi: 10.1002/1097-0347(200007)22:4<347::aid-hed6>3.0.co;2-j.

Abstract

Background: Telomerase (reverse transcriptase) has been shown to play a role in the process of cellular immortalization.

Methods: Telomerase activity was determined in 11 head and neck squamous cell carcinoma (SCCHN) cell lines. The effects of wild-type p16, p21, E2F-1, and p53 genes on telomerase activity were examined by introducing the wild-type genes into two SCCHN cell lines by means of a recombinant adenovirus.

Results: We found elevated telomerase activity in 10 of the 11 SCCHN cell lines tested. When we infected Tu-138 and Tu-167 cell lines with wild-type p16, p21, E2F-1, and p53 genes, we found that p16 had little effect on telomerase activity. Both E2F-1 and p53 were known to induce apoptosis in SCCHN cell lines. Significantly reduced telomerase activity by p53 in both cell lines and E2F-1 in Tu-167 cells was in agreement with suppression of cell growth. Overexpression of p21 also exhibited reduction in telomerase activity.

Conclusions: We conclude from this study that overexpression of E2F-1 and p53 can reverse telomerase activity in SCCHN cell lines and that telomerase activity may be involved in cancer cell immortalization.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenoviridae / genetics
  • Blotting, Western
  • Carcinoma, Squamous Cell
  • Carrier Proteins*
  • Cell Cycle Proteins*
  • Cyclin-Dependent Kinase Inhibitor p16 / genetics*
  • DNA-Binding Proteins*
  • E2F Transcription Factors
  • E2F1 Transcription Factor
  • Gene Expression
  • Genes, p53 / genetics*
  • Head and Neck Neoplasms / enzymology*
  • Humans
  • Oncogene Protein p21(ras) / genetics*
  • Recombination, Genetic
  • Retinoblastoma-Binding Protein 1
  • Sensitivity and Specificity
  • Telomerase / genetics*
  • Telomerase / metabolism*
  • Transcription Factor DP1
  • Transcription Factors / genetics*
  • Tumor Cells, Cultured

Substances

  • Carrier Proteins
  • Cell Cycle Proteins
  • Cyclin-Dependent Kinase Inhibitor p16
  • DNA-Binding Proteins
  • E2F Transcription Factors
  • E2F1 Transcription Factor
  • E2F1 protein, human
  • Retinoblastoma-Binding Protein 1
  • Transcription Factor DP1
  • Transcription Factors
  • Telomerase
  • Oncogene Protein p21(ras)