Open Access

Okadaic acid activates the PKR pathway and induces apoptosis through PKR stimulation in MG63 osteoblast-like cells

  • Authors:
    • Tatsuji Haneji
    • Kanji Hirashima
    • Jumpei Teramachi
    • Hiroyuki Morimoto
  • View Affiliations

  • Published online on: April 17, 2013     https://doi.org/10.3892/ijo.2013.1911
  • Pages: 1904-1910
  • Copyright: © Haneji et al. This is an open access article distributed under the terms of Creative Commons Attribution License [CC BY_NC 3.0].

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Abstract

Double-stranded RNA-dependent protein kinase (PKR) is one of the players in the cellular antiviral responses and is involved in transcriptional stimulation through activation of NF-κB. Treatment of the human osteosarcoma cell line MG63 with the protein phosphatase inhibitor okadaic acid stimulated the expression and phosphorylation of IκBα, as judged from the results of real-time PCR and western blot analysis. We investigated the functional relationship between PKR and signal transduction of NF-κB by establishing PKR-K/R cells that produced a catalytically inactive mutant of PKR. Phosphorylation of eIF-2α, a substrate of PKR, was not stimulated by okadaic acid in the PKR-K/R cells, whereas okadaic acid induced phosphorylation of eIF-2α in MG63 cells. Phosphorylation of NF-κB in MG63 cells was stimulated by okadaic acid; however, okadaic acid did not induce phosphorylation of NF-κB in the PKR-K/R cells. Finally, okadaic acid-induced apoptosis was inhibited in the PKR-K/R cells. Our results suggest that okadaic acid-induced phosphorylation of IκBα was mediated by PKR kinase activity, thus, indicating the involvement of this kinase in the control mechanism governing the activation of NF-κB and induction of apoptosis.
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June 2013
Volume 42 Issue 6

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

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Spandidos Publications style
Haneji T, Hirashima K, Teramachi J and Morimoto H: Okadaic acid activates the PKR pathway and induces apoptosis through PKR stimulation in MG63 osteoblast-like cells. Int J Oncol 42: 1904-1910, 2013
APA
Haneji, T., Hirashima, K., Teramachi, J., & Morimoto, H. (2013). Okadaic acid activates the PKR pathway and induces apoptosis through PKR stimulation in MG63 osteoblast-like cells. International Journal of Oncology, 42, 1904-1910. https://doi.org/10.3892/ijo.2013.1911
MLA
Haneji, T., Hirashima, K., Teramachi, J., Morimoto, H."Okadaic acid activates the PKR pathway and induces apoptosis through PKR stimulation in MG63 osteoblast-like cells". International Journal of Oncology 42.6 (2013): 1904-1910.
Chicago
Haneji, T., Hirashima, K., Teramachi, J., Morimoto, H."Okadaic acid activates the PKR pathway and induces apoptosis through PKR stimulation in MG63 osteoblast-like cells". International Journal of Oncology 42, no. 6 (2013): 1904-1910. https://doi.org/10.3892/ijo.2013.1911