Expression of human telomerase reverse transcriptase splice variants is well correlated with low telomerase activity in osteosarcoma cell lines

  • Authors:
    • Hitomi Fujiwara-Akita
    • Chihaya Maesawa
    • Takehisa Honda
    • Seiichiro Kobayashi
    • Tomoyuki Masuda
  • View Affiliations

  • Published online on: April 1, 2005     https://doi.org/10.3892/ijo.26.4.1009
  • Pages: 1009-1016
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Abstract

The human telomerase reverse transcriptase (hTERT) gene is a catalytic subunit of telomerase that plays an important role in maintaining telomere length. Recently, post-transcriptional (alternative splicing) and epigenetic (promoter methylation) mechanisms affecting expression of the hTERT gene have been reported as negative regulators of telomerase activity (TA). To elucidate the significance of the telomere maintenance mechanism (TMM) in osteosarcoma (OS), we examined hTERT mRNA/protein expression and methylation status in 16 OS cell lines and compared them with TA. Five (31%) of 16 OS cell lines expressed both full-length and splice variants of hTERT mRNA/protein, and 3 (19%) exhibited only full-length hTERT mRNA/protein. No hTERT mRNA/protein expression was observed in 8 cell lines (50%). TA in OS cell lines exhibiting full-length hTERT mRNA/protein without any splice variants was higher than in cell lines expressing splice variants. The promoters of the 16 OS cell lines were relatively hypermethylated, but no inverse relationship between frequency of methyl-CpG sites and hTERT expression was observed. Treatment with a demethylating agent induced hTERT mRNA/protein in only one cell line. These results suggest that the epigenetic mechanism might contribute to the regulation of the hTERT gene in a small subset of OSs, and that alternative splicing might be involved in controlling the TA of OS cell lines, thereby contributing to their TMM.

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April 2005
Volume 26 Issue 4

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

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Spandidos Publications style
Fujiwara-Akita H, Maesawa C, Honda T, Kobayashi S and Masuda T: Expression of human telomerase reverse transcriptase splice variants is well correlated with low telomerase activity in osteosarcoma cell lines. Int J Oncol 26: 1009-1016, 2005.
APA
Fujiwara-Akita, H., Maesawa, C., Honda, T., Kobayashi, S., & Masuda, T. (2005). Expression of human telomerase reverse transcriptase splice variants is well correlated with low telomerase activity in osteosarcoma cell lines. International Journal of Oncology, 26, 1009-1016. https://doi.org/10.3892/ijo.26.4.1009
MLA
Fujiwara-Akita, H., Maesawa, C., Honda, T., Kobayashi, S., Masuda, T."Expression of human telomerase reverse transcriptase splice variants is well correlated with low telomerase activity in osteosarcoma cell lines". International Journal of Oncology 26.4 (2005): 1009-1016.
Chicago
Fujiwara-Akita, H., Maesawa, C., Honda, T., Kobayashi, S., Masuda, T."Expression of human telomerase reverse transcriptase splice variants is well correlated with low telomerase activity in osteosarcoma cell lines". International Journal of Oncology 26, no. 4 (2005): 1009-1016. https://doi.org/10.3892/ijo.26.4.1009