Absence of hamTERT gene expression is associated with promoter hypermethylation in immortal hamster buccal pouch epithelial cells

  • Authors:
    • Ayako Kameta
    • Mo K. Kang
    • Ki-Hyuk Shin
    • No-Hee Park
  • View Affiliations

  • Published online on: June 1, 2003     https://doi.org/10.3892/ijo.22.6.1351
  • Pages: 1351-1356
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Abstract

This study describes the first example of spontaneously immortalized, telomerase-negative hamster cells which replicated in the absence of telomere shortening. Primary hamster buccal pouch epithelial (HBPE) cells were subcultured for approximately 10 population doublings (PDs) before they ceased to divide. Among the non-replicating HBPE cells, a colony of proliferating cells had appeared. These cells named HBPE-SI (spontaneously immortalized) replicated with a mean doubling time of 27 h for 120 PDs in culture and are still replicating. Surprisingly, telomerase activity and hamTERT (hamster telomerase gene) expression were not detectable in HBPE-SI, although an exogenous hamTERT promoter showed promoter activity in these cells. HBPE-SI cells replicated in the apparent absence of apparent telomere shortening during their entire in vitro culture, indicating telomerase-independent mode of telomere maintenance. Analysis of the hamTERT promoter in HBPE-SI cells revealed hypermethylation. Exposure of the cells to 5-aza-2'-deoxycytidine (5-aza CdR) restored expression of endogenous hamTERT mRNA. These results indicated that HBPE-SI cells maintained their telomere length in the absence of telomerase activity, and that hamTERT gene expression in these cells was silenced by hypermethylation of the promoter.

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June 2003
Volume 22 Issue 6

Print ISSN: 1019-6439
Online ISSN:1791-2423

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Spandidos Publications style
Kameta A, Kang MK, Shin K and Park N: Absence of hamTERT gene expression is associated with promoter hypermethylation in immortal hamster buccal pouch epithelial cells. Int J Oncol 22: 1351-1356, 2003
APA
Kameta, A., Kang, M.K., Shin, K., & Park, N. (2003). Absence of hamTERT gene expression is associated with promoter hypermethylation in immortal hamster buccal pouch epithelial cells. International Journal of Oncology, 22, 1351-1356. https://doi.org/10.3892/ijo.22.6.1351
MLA
Kameta, A., Kang, M. K., Shin, K., Park, N."Absence of hamTERT gene expression is associated with promoter hypermethylation in immortal hamster buccal pouch epithelial cells". International Journal of Oncology 22.6 (2003): 1351-1356.
Chicago
Kameta, A., Kang, M. K., Shin, K., Park, N."Absence of hamTERT gene expression is associated with promoter hypermethylation in immortal hamster buccal pouch epithelial cells". International Journal of Oncology 22, no. 6 (2003): 1351-1356. https://doi.org/10.3892/ijo.22.6.1351