Telomerase activity, expression of Bcl-2 and cell cycle regulation in doxorubicin resistant gastric carcinoma cell lines

  • Authors:
    • Kyong-Ah Yoon
    • Ja-Lok Ku
    • Jung Ok Yang
    • Jae-Gahb Park
  • View Affiliations

  • Published online on: March 1, 2003     https://doi.org/10.3892/ijmm.11.3.343
  • Pages: 343-348
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Abstract

As telomeres play a role in protecting DNA, there is the possibility that telomerase activity is involved with cellular response to DNA-damaging agents. This study was designed to investigate the association between telomerase and the doxorubicin altered cell cycle in drug resistant gastric carcinoma cell lines. Three doxorubicin resistant gastric carcinoma cell lines and their parent cell lines (SNU-1, SNU-16 and SNU-620) were incubated with doxorubicin at the final concentration induced resistance and ten times final concentration for 24 h. Telomerase activity and hTERT mRNA expression were lowered by doxorubicin treatment in parent cell lines, but in drug resistant cell lines, telomerase activity and hTERT mRNA expression were not repressed by doxorubicin treatment. Bcl-2 protein expression, which is known to regulate telomerase activity, did not change in doxorubicin resistant cell lines but decreased in parent cell lines by doxorubicin treatment. Cell cycle analysis revealed that the parent cell lines had an increased fraction of cells in G2/M phase after doxorubicin treatment and doxorubicin resistant cell lines had maintained fractions in G0/G1 phase. Doxorubicin treatment did not alter cyclin B or cdc2 protein level, which is known as the essential component of G2/M transition. G2/M arrest in the parent cell lines was associated with an increase in inhibitory phosphorylation of Tyr15 on cdc2. In summary, the parent cell lines showed G2/M arrest and a reduction of telomerase activity after doxorubicin treatment. In contrast, reduced telomerase activity, Bcl-2 expression and G2/M arrest after doxorubicin treatment did not appear in resistant cell lines. Therefore, relative resistance to doxorubicin may be related to high levels of bcl-2 or intact cell cycle and consequently high telomerase activity.

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March 2003
Volume 11 Issue 3

Print ISSN: 1107-3756
Online ISSN:1791-244X

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Spandidos Publications style
Yoon K, Ku J, Yang JO and Park J: Telomerase activity, expression of Bcl-2 and cell cycle regulation in doxorubicin resistant gastric carcinoma cell lines. Int J Mol Med 11: 343-348, 2003.
APA
Yoon, K., Ku, J., Yang, J.O., & Park, J. (2003). Telomerase activity, expression of Bcl-2 and cell cycle regulation in doxorubicin resistant gastric carcinoma cell lines. International Journal of Molecular Medicine, 11, 343-348. https://doi.org/10.3892/ijmm.11.3.343
MLA
Yoon, K., Ku, J., Yang, J. O., Park, J."Telomerase activity, expression of Bcl-2 and cell cycle regulation in doxorubicin resistant gastric carcinoma cell lines". International Journal of Molecular Medicine 11.3 (2003): 343-348.
Chicago
Yoon, K., Ku, J., Yang, J. O., Park, J."Telomerase activity, expression of Bcl-2 and cell cycle regulation in doxorubicin resistant gastric carcinoma cell lines". International Journal of Molecular Medicine 11, no. 3 (2003): 343-348. https://doi.org/10.3892/ijmm.11.3.343