Open Access

The combination of rapamycin and MAPK inhibitors enhances the growth inhibitory effect on Nara-H cells

  • Authors:
    • Osamu Nakamura
    • Toshiaki Hitora
    • Yoshiki Yamagami
    • Masaki Mori
    • Hideki Nishimura
    • Ryosuke Horie
    • Konosuke Yamaguchi
    • Tetsuji Yamamoto
  • View Affiliations

  • Published online on: March 27, 2014     https://doi.org/10.3892/ijmm.2014.1715
  • Pages: 1491-1497
  • Copyright: © Nakamura 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

The inhibition of the mammalian target of rapamycin (mTOR) signaling pathway promotes the initiation of autophagy, and the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated protein kinase (ERK) is well known to induce autophagy. Autophagy is a self-defense mechanism of cancer cells that are subjected to antitumor agents, and blocking autophagy can trigger apoptosis. In the present study, we demonstrate that an mTOR inhibitor, rapamycin, induces autophagy in the Nara-H malignant fibrous histiocytoma (MFH) cell line through the activation of ERK1/2. Rapamycin-induced apoptosis was enhanced following the inhibition of the MEK/ERK pathway. In the Nara-H cells, we examined the effects of rapamycin treatment on cell proliferation and on the phosphorylation of the mTOR pathway components and autophagy by western blot analysis. Furthermore, we examined the effects of rapamycin with or without the MEK inhibitor, U0126, on the induction of apoptosis by using fluorescence microscopy. Rapamycin inhibited Nara-H cell proliferation and decreased the phosphorylation of the mTOR pathway in the Nara-H cells. Rapamycin induced the apoptosis of Nara-H cells, and this apoptosis was enhanced by U0126. Simultaneously, phospho-ERK1/2 was activated by rapamycin. The present study demonstrates that rapamycin induces autophagy in Nara-H cells by activating the MEK/ERK signaling pathway, and the rapamycin-induced apoptosis can be enhanced by the MEK inhibitor, U0126. These results suggest that self‑protective mechanisms involving mTOR inhibitors in Nara-H cells are prevented by the inhibition of the MEK/ERK pathway. The combination of an mTOR inhibitor (e.g., rapamycin) and an MEK inhibitor (e.g., U0126) may offer effective treatment for MFH, as this combination effectively activates apoptotic pathways.
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June-2014
Volume 33 Issue 6

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

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Spandidos Publications style
Nakamura O, Hitora T, Yamagami Y, Mori M, Nishimura H, Horie R, Yamaguchi K and Yamamoto T: The combination of rapamycin and MAPK inhibitors enhances the growth inhibitory effect on Nara-H cells. Int J Mol Med 33: 1491-1497, 2014.
APA
Nakamura, O., Hitora, T., Yamagami, Y., Mori, M., Nishimura, H., Horie, R. ... Yamamoto, T. (2014). The combination of rapamycin and MAPK inhibitors enhances the growth inhibitory effect on Nara-H cells. International Journal of Molecular Medicine, 33, 1491-1497. https://doi.org/10.3892/ijmm.2014.1715
MLA
Nakamura, O., Hitora, T., Yamagami, Y., Mori, M., Nishimura, H., Horie, R., Yamaguchi, K., Yamamoto, T."The combination of rapamycin and MAPK inhibitors enhances the growth inhibitory effect on Nara-H cells". International Journal of Molecular Medicine 33.6 (2014): 1491-1497.
Chicago
Nakamura, O., Hitora, T., Yamagami, Y., Mori, M., Nishimura, H., Horie, R., Yamaguchi, K., Yamamoto, T."The combination of rapamycin and MAPK inhibitors enhances the growth inhibitory effect on Nara-H cells". International Journal of Molecular Medicine 33, no. 6 (2014): 1491-1497. https://doi.org/10.3892/ijmm.2014.1715