Apoptosis induction by glycoprotein isolated from Laminaria japonica is associated with down-regulation of telomerase activity and prostaglandin E2 synthesis in AGS human gastric cancer cells

  • Authors:
    • Min Ho Han
    • Gi Young Kim
    • Sung-Kwon Moon
    • Wun-Jae Kim
    • Taek-Jeong Nam
    • Yung Hyun Choi
  • View Affiliations

  • Published online on: December 3, 2010     https://doi.org/10.3892/ijo.2010.853
  • Pages: 577-584
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Abstract

Glycoprotein isolated from Laminaria japonica (LJGP) is known to exhibit significant cytotoxic activity against human cancer cells; however, the mechanisms of its cytoxicity are poorly understood. In this study, we investigated further possible mechanisms by which LJGP exerts its anti-cancer action in cultured human gastric carcinoma AGS cells. LJGP treatment of AGS cells resulted in inhibition of growth and induction of apoptosis in a time- and concentration-dependent manner, as determined by MTT assay, fluorescence microscopy, and flow cytometry analysis. The increase in apoptosis was associated with up-regulation of pro-apoptotic Bax expression, down-regulation of anti-apoptotic Bcl-2 and IAP family members, and activation of caspase-3 and -9. LJGP treatment markedly down-regulated the activity of telomerase and expression of human telomerase reverse transcriptase, a main determinant of telomerase enzymatic activity, with inhibition of Sp1 and c-Myc expression in a concentration-dependent manner. Furthermore, LJGP treatment also caused a progressive decrease in the expression levels of cyclooxygenase (COX)-2 without significant changes in the levels of COX-1, which was correlated with a decrease in prostaglandin E2 synthesis. These results provide important new insights into the possible molecular mechanisms of the anti-cancer activity of LJGP.

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February 2011
Volume 38 Issue 2

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

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Spandidos Publications style
Han MH, Kim GY, Moon S, Kim W, Nam T and Choi YH: Apoptosis induction by glycoprotein isolated from Laminaria japonica is associated with down-regulation of telomerase activity and prostaglandin E2 synthesis in AGS human gastric cancer cells. Int J Oncol 38: 577-584, 2011
APA
Han, M.H., Kim, G.Y., Moon, S., Kim, W., Nam, T., & Choi, Y.H. (2011). Apoptosis induction by glycoprotein isolated from Laminaria japonica is associated with down-regulation of telomerase activity and prostaglandin E2 synthesis in AGS human gastric cancer cells. International Journal of Oncology, 38, 577-584. https://doi.org/10.3892/ijo.2010.853
MLA
Han, M. H., Kim, G. Y., Moon, S., Kim, W., Nam, T., Choi, Y. H."Apoptosis induction by glycoprotein isolated from Laminaria japonica is associated with down-regulation of telomerase activity and prostaglandin E2 synthesis in AGS human gastric cancer cells". International Journal of Oncology 38.2 (2011): 577-584.
Chicago
Han, M. H., Kim, G. Y., Moon, S., Kim, W., Nam, T., Choi, Y. H."Apoptosis induction by glycoprotein isolated from Laminaria japonica is associated with down-regulation of telomerase activity and prostaglandin E2 synthesis in AGS human gastric cancer cells". International Journal of Oncology 38, no. 2 (2011): 577-584. https://doi.org/10.3892/ijo.2010.853