Fig. 5: SOX10 loss induces tolerance to MAPK targeting agents.

a Cells were treated with 50 or 100 nM trametinib. Treatment was renewed three times per week. Shown is the mean ± SD from three independent experiments. p-values were calculated using two-sided model-based t-test tests and adjusted for multiple testing using the Hochberg method and represent statistical analysis comparing growth inhibition of MeWo parental vs MeWo #2.1 and MeWo #4.11 from day 0 to day 10. p-values are shown. b mCherry-MeWo and GFP-MeWo SOX10 knockout #2.1 or #4.11 cells were co-mixed at the ratio of 2:1. Cells were co-cultured for 90 days in the presence or absence of 50 nM trametinib. Co-cultures were collected and analyzed by FACS for mCherry and GFP positivity. c Cells were treated with 1 µM PLX4720 plus 35 nM PD325901 for 24 h. Cells were lysed and western blotted as indicated. The experiment was repeated independently three times with similar results. d Cells were treated with BRAFi (500 nM PLX8394). Cells were lysed and western blotted as indicated. The experiment was repeated independently three times with similar results. e Venn diagrams showing the commonality of enriched gene sets (BHFDR < 0.05) from the Hallmark gene set collection (n = 50) for comparisons between A375 gSOX10 or CRTs in the presence of BRAFi+MEKi and parental control groups. f A scatter plot showing differential gene expression for gSOX10 and CRT groups over parental A375. Wald’s test statistic was averaged across the gSOX10 #2 and gSOX10 #4, and the CRT34 and CRT35, conditions. Red dots and gene names indicate the top 10 most significantly up and downregulated genes for the CRT and gSOX10 groups, and genes that are common between CRT and gSOX10are labeled in red. g Cells were treated with 1 µM PLX4720 + 35 nM PD0325901. Treatment was renewed every 48 h. Cells were stained for FN1 and collagen IV. The experiment was performed independently twice, and representative images are shown. Scale bars, 50 μm. h Enrichment plot of EMT (BHFDR < 0.001) comparing patient samples before and after MAPK targeting treatment from the Sun. et al. dataset. i Proliferative/invasive signature (Verfaille, et al.) for patients post vs pretreatment, controlled for patient (Sun, et al.).