Analysis of A375 and A375 clones that acquired resistance to GSK2118436 after treatment with GSK2118436 (GSK436), GSK1120212 (GSK212), or the combination of GSK2118436 and GSK1120212 for 24 hour

In an effort to understand the mechanisms of acquired resistance to BRAF inhibitors, we isolated clones that acquired resistance to the BRAF inhibitor GSK2118436 derived from the A375 BRAF V600E mutant melanoma cell line. This resistance clones acquired mutations in NRAS and MEK1. One clones, 16R6-4, acquired two mutations in NRAS Q61K and A146T. Proliferation and western blot analyses demonstrated that these clones were insensitive to single agent GSK2118436 or GSK1120212 (an allosteric MEK inhibitor) but were sensitive to the combination of GSK2118436 and GSK1120212. To further characterize this combination, global transcriptomic analysis was performed in A375 and 16R6-4 after 24 hour treatment with GSK2118436, GSK1120212 or the combination of GSK2118436 and GSK1120212.

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Greger JG, Eastman SD, Zhang V, Bleam MR, Hughes AM, Smitheman KN, Dickerson SH, Laquerre SG, Liu L, Gilmer TM