Oral Oncology
Volume 39, Issue 5 , Pages 445-452, July 2003

Gene expression of telomerase related proteins in human normal oral and ectocervical epithelial cells

  • R. Fujimoto

      Affiliations

    • First Department of Oral and Maxillofacial Surgery, School of Dentistry, Tokushima University, 3-18-15 Kuramoto-cho, Tokushima 770 8504, Japan
    • ,
  • N. Kamata

      Affiliations

    • First Department of Oral and Maxillofacial Surgery, School of Dentistry, Tokushima University, 3-18-15 Kuramoto-cho, Tokushima 770 8504, Japan
    • Corresponding Author InformationCorresponding author. Tel.: +81-88-633-7352; fax: +81-88-633-7388
    • ,
  • M. Taki

      Affiliations

    • First Department of Oral and Maxillofacial Surgery, School of Dentistry, Tokushima University, 3-18-15 Kuramoto-cho, Tokushima 770 8504, Japan
    • ,
  • K. Yokoyama

      Affiliations

    • First Department of Oral and Maxillofacial Surgery, School of Dentistry, Tokushima University, 3-18-15 Kuramoto-cho, Tokushima 770 8504, Japan
    • ,
  • M. Tomonari

      Affiliations

    • First Department of Oral and Maxillofacial Surgery, School of Dentistry, Tokushima University, 3-18-15 Kuramoto-cho, Tokushima 770 8504, Japan
    • ,
  • M. Nagayama

      Affiliations

    • First Department of Oral and Maxillofacial Surgery, School of Dentistry, Tokushima University, 3-18-15 Kuramoto-cho, Tokushima 770 8504, Japan
    • ,
  • S. Yasumoto

      Affiliations

    • Laboratory of Molecular Cell Biology, Kanagawa Cancer Center Research Institute, Yokohama, Japan

Received 18 November 2002; accepted 13 December 2002.

Abstract 

We analyzed telomerase activities and gene expressions of telomerase components: hTERT, hTR, hTEP1, telomeric repeat binding factors: TRF1, TRF2, and c-myc, Max and Mad in human normal oral and ectocervical epithelial keratinocytes, comparing with those of squamous carcinoma cells and HPV16- or SV40-immortalized cells. Significant telomerase activity and hTERT expression were detected in primary keratinocytes. However, both were dramatically down-regulated during serial passages. The down-regulation of hTERT mRNA was associated with augmented expression of TRF1. Expression of c-myc was slightly decreased, whereas Mad was expressed in parallel with that of hTERT during passages. We also detected an alternate splicing of hTERT transcript in two of four cancer cells and normal aged epithelial cells. These results suggest that the senescence of normal oral and ectocervical keratinocytes is accompanied with up-regulation of TRF1 and down-regulation of telomerase activity due to transcriptional suppression of active form of hTERT in vitro.

Keywords:  Telomerase, hTERT, Alternate splicing, Telomeric repeat binding factor (TRF), Aging, Normal oral keratinocytes, c-Myc, TRAP assay, RT-PCR

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PII: S1368-8375(03)00003-4

doi:10.1016/S1368-8375(03)00003-4

Oral Oncology
Volume 39, Issue 5 , Pages 445-452, July 2003

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