Context: The V600E mutation accounts for the vast majority of thyroid carcinoma-associated BRAF mutations. Objective: The aim was to study the effects of the two BRAF V600E ATP-competitive kinase inhibitors, PLX4032 and PLX4720, in thyroid carcinoma cell lines. Experimental Design:Weexaminedtheactivity ofPLX4032andPLX4720in thyroidcarcinomacell lines harboring BRAF V600E (8505C, BCPAP, SW1736, BHT101), NRAS Q61R (HTH7), KRAS G12R (CAL62), HRAS G13R (C643), or RET/PTC1 (TPC-1) oncogenes. Normal thyrocytes (PC Cl 3) were used as control. Results: Both compounds inhibited the proliferation of BRAF mutant cell lines, but not normal thyrocytes, with a half maximal effective concentration (EC 50) ranging from 78-113 nM for PLX4720 and from 29-97 nM for PLX4032. Doses equal to or higher than 500 nM were required to achieve a similar effect in BRAF wild-type cancer cells. Phosphorylation of ERK1/2 and MAPK kinase (MEK)1/2 decreased upon PLX4032 and PLX4720 treatment in BRAF mutant thyroid carcinoma cells but not in normal thyroid cells or in cell lines harboring mutations of RAS or RET/PTC1 rearrangements. PLX4032 and PLX4720 treatment induced a G1 block and altered expression of genes involved in the control of G1-S cell-cycle transition. 8505C cell tumor xenografts were smaller in nude mice treated with PLX4032 than in controlmice.This inhibition was associated with reduction of phospho-ERK and phospho-MEK levels. Conclusions: This study provides additional evidence of the promising nature of mutant BRAF as a molecular target for thyroid carcinoma cells. Copyright © 2010 by The Endocrine Society.
CITATION STYLE
Salerno, P., De Falco, V., Tamburrino, A., Nappi, T. C., Vecchio, G., Schweppe, R. E., … Salvatore, G. (2010). Cytostatic activity of adenosine triphosphate-competitive kinase inhibitors in BRAF mutant thyroid carcinoma cells. Journal of Clinical Endocrinology and Metabolism, 95(1), 450–455. https://doi.org/10.1210/jc.2009-0373
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