Alternative lengthening of telomeres in the human adrenocortical carcinoma cell line H295R

  • Authors:
    • Masachika Fujiwara
    • Hiroshi Kamma
    • Wenwen Wu
    • Yukiko Yano
    • Shinsuke Homma
    • Hiroaki Satoh
  • View Affiliations

  • Published online on: August 1, 2006     https://doi.org/10.3892/ijo.29.2.445
  • Pages: 445-451
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Abstract

Telomere maintenance can occur in the absence of telomerase by a mechanism referred to as alternative lengthening of telomeres (ALT). ALT is considered to be rare in tumors of epithelial origin. The biological significance and molecular mechanism of ALT have not been well studied in human cancers. It has been reported that clinical samples of adrenocortical carcinoma show a low incidence of telomerase positivity. We characterized an adrenocortical carcinoma cell line, H295R, focusing on the telomere maintenance mechanism, and compared it with telomerase-positive 293 cells and HeLa cells. Telomerase activity could not be detected in H295R cells by the TRAP assay. Among the essential components of the telomerase holoenzyme, only hTERT expression was undetectable by RT-PCR, indicating that the lack of telomerase activity is due to suppression of hTERT. H295R cells had long and heterogeneous telomere DNA, and FISH revealed large nuclear bodies in a few interphase nuclei, which presumably represented ALT-associated PML bodies. These results suggest that H295R cells have the ALT phenotype. Several proteins that are possibly associated with the telomere maintenance mechanism were examined. TRF1 and TRF2 were expressed in H295R cells as well as in 293 cells and HeLa cells. The ratio of hnRNP B1 to A2 was higher in H295R cells than in 293 cells and HeLa cells. In conclusion, the H295R adrenocortical carcinoma cell line is negative for telomerase and maintains its telomeres by the ALT mechanism. We anticipate that H295R cells will be a good model for understanding the significance and mechanism of ALT in human cancers.

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August 2006
Volume 29 Issue 2

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

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Spandidos Publications style
Fujiwara M, Kamma H, Wu W, Yano Y, Homma S and Satoh H: Alternative lengthening of telomeres in the human adrenocortical carcinoma cell line H295R. Int J Oncol 29: 445-451, 2006
APA
Fujiwara, M., Kamma, H., Wu, W., Yano, Y., Homma, S., & Satoh, H. (2006). Alternative lengthening of telomeres in the human adrenocortical carcinoma cell line H295R. International Journal of Oncology, 29, 445-451. https://doi.org/10.3892/ijo.29.2.445
MLA
Fujiwara, M., Kamma, H., Wu, W., Yano, Y., Homma, S., Satoh, H."Alternative lengthening of telomeres in the human adrenocortical carcinoma cell line H295R". International Journal of Oncology 29.2 (2006): 445-451.
Chicago
Fujiwara, M., Kamma, H., Wu, W., Yano, Y., Homma, S., Satoh, H."Alternative lengthening of telomeres in the human adrenocortical carcinoma cell line H295R". International Journal of Oncology 29, no. 2 (2006): 445-451. https://doi.org/10.3892/ijo.29.2.445