Growth arrest by activated BRAF and MEK inhibition in human anaplastic thyroid cancer cells

  • Authors:
    • Kento Kurata
    • Naoyoshi Onoda
    • Satoru Noda
    • Shinichiro Kashiwagi
    • Yuka Asano
    • Kosei Hirakawa
    • Masaichi Ohira
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  • Published online on: October 7, 2016     https://doi.org/10.3892/ijo.2016.3723
  • Pages: 2303-2308
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Abstract

Anaplastic thyroid cancer (ATC) is a rare malignancy that progresses extremely aggressively and often results in dismal prognosis. We investigated the efficacy of inhibiting the activated RAS/RAF/MEK pathway in ATC cells aiming to clarify the mechanism of effect and resistance. Four human ATC cell lines (ACT-1, OCUT-2, OCUT-4 and OCUT-6) were used. OCUT-4 had a BRAF mutation. OCUT-2 had both BRAF and PI3KCA mutations. ACT-1 and OCUT-6 had wild-type BRAF and NRAS mutations. The effects of dabrafenib, a selective inhibitor of the BRAFV600E kinase, and trametinib, a reversible inhibitor of MEK activity, were investigated. Dabrafenib strongly inhibited the viability in BRAF mutated cells by demonstrating G0/G1-arrest via the downregulation of MEK/ERK phosphorylation. Upregulated phosphorylation of MEK was observed in RAS mutated cells after dabrafenib treatment and caused VEGF upregulation, but was not related to the cellular proliferation. Trametinib inhibited the cellular viability to variable degrees in every cell by downregulating ERK phosphorylation. Dual blockade by both inhibitors demonstrated clear cytostatic effect in all the cells. OCUT-4 showed the weakest sensitivity to trametinib, no additional effect of either inhibitor in combination with the other, and an increase of SNAI1 mRNA expression after treatment with inhibitors, suggesting a mechanism for resistance. Our findings demonstrated the efficacy of a mutation-selective BRAF inhibitor and a MEK inhibitor in human ATC cells in a genetic alteration-specific manner.
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December-2016
Volume 49 Issue 6

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

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Spandidos Publications style
Kurata K, Onoda N, Noda S, Kashiwagi S, Asano Y, Hirakawa K and Ohira M: Growth arrest by activated BRAF and MEK inhibition in human anaplastic thyroid cancer cells. Int J Oncol 49: 2303-2308, 2016.
APA
Kurata, K., Onoda, N., Noda, S., Kashiwagi, S., Asano, Y., Hirakawa, K., & Ohira, M. (2016). Growth arrest by activated BRAF and MEK inhibition in human anaplastic thyroid cancer cells. International Journal of Oncology, 49, 2303-2308. https://doi.org/10.3892/ijo.2016.3723
MLA
Kurata, K., Onoda, N., Noda, S., Kashiwagi, S., Asano, Y., Hirakawa, K., Ohira, M."Growth arrest by activated BRAF and MEK inhibition in human anaplastic thyroid cancer cells". International Journal of Oncology 49.6 (2016): 2303-2308.
Chicago
Kurata, K., Onoda, N., Noda, S., Kashiwagi, S., Asano, Y., Hirakawa, K., Ohira, M."Growth arrest by activated BRAF and MEK inhibition in human anaplastic thyroid cancer cells". International Journal of Oncology 49, no. 6 (2016): 2303-2308. https://doi.org/10.3892/ijo.2016.3723