Constitutive histone H2AX phosphorylation on Ser-139 in cells untreated by genotoxic agents is cell-cycle phase specific and attenuated by scavenging reactive oxygen species

  • Authors:
    • Xuan Huang
    • Toshiki Tanaka
    • Akira Kurose
    • Frank Traganos
    • Zbigniew Darzynkiewicz
  • View Affiliations

  • Published online on: August 1, 2006     https://doi.org/10.3892/ijo.29.2.495
  • Pages: 495-501
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Abstract

DNA damage, particularly when it involves formation of double-strand breaks (DSBs), triggers phosphorylation of histone H2AX on Ser-139. Phosphorylated H2AX has been named γH2AX, and induction of γH2AX in cells exposed to genotoxic agents is considered a sensitive and specific reporter of DNA damage. However, in untreated normal cells as well in the cells of various tumor lines cells, a fraction of histone H2AX molecules remain phosphorylated. In the present study, we observed that the extent of this constitutive H2AX phosphorylation varies depending on the cell type (line) and on cell cycle phase and, in most cell types, S and G2/M phase cells exhibit greater levels of H2AX phosphorylation than do cells in the G1 phase. Furthermore, constitutive H2AX phosphorylation in human pulmonary carcinoma A549, lymphoblastoid TK6, and in normal bronchial epithelial cells was reduced following cell exposure to N-acetyl-L-cysteine, a scavenger of reactive oxygen intermediates; the reduction was most pronounced for G2M cells. Growth of A549 cells in the presence of buthionine sulfoximine, an inhibitor of glutathione synthetase, amplified the level of constitutive H2AX phosphorylation in A549 cells. The observed constitutive H2AX phosphorylation may be a reflection of the ongoing DNA damage mediated by reactive oxygen species (ROS) generated by metabolic activity during progression through the cell cycle, leading to formation of DSBs during the S phase. Because cumulative DNA damage in proliferating cells mediated by ROS is considered the key mechanism for cell ageing, the present approach to estimate the degree of attenuation of constitutive H2AX phosphorylation by antioxidants may provide a convenient tool to assess the DNA-protective and possible anti-ageing properties of other agents.

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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
Huang X, Tanaka T, Kurose A, Traganos F and Darzynkiewicz Z: Constitutive histone H2AX phosphorylation on Ser-139 in cells untreated by genotoxic agents is cell-cycle phase specific and attenuated by scavenging reactive oxygen species. Int J Oncol 29: 495-501, 2006
APA
Huang, X., Tanaka, T., Kurose, A., Traganos, F., & Darzynkiewicz, Z. (2006). Constitutive histone H2AX phosphorylation on Ser-139 in cells untreated by genotoxic agents is cell-cycle phase specific and attenuated by scavenging reactive oxygen species. International Journal of Oncology, 29, 495-501. https://doi.org/10.3892/ijo.29.2.495
MLA
Huang, X., Tanaka, T., Kurose, A., Traganos, F., Darzynkiewicz, Z."Constitutive histone H2AX phosphorylation on Ser-139 in cells untreated by genotoxic agents is cell-cycle phase specific and attenuated by scavenging reactive oxygen species". International Journal of Oncology 29.2 (2006): 495-501.
Chicago
Huang, X., Tanaka, T., Kurose, A., Traganos, F., Darzynkiewicz, Z."Constitutive histone H2AX phosphorylation on Ser-139 in cells untreated by genotoxic agents is cell-cycle phase specific and attenuated by scavenging reactive oxygen species". International Journal of Oncology 29, no. 2 (2006): 495-501. https://doi.org/10.3892/ijo.29.2.495