Figure 6: AXL and other RTKs are inversely correlated with MITF.
From: Low MITF/AXL ratio predicts early resistance to multiple targeted drugs in melanoma
(a) RNA sequencing was performed in three MITFendo_hi and three MITFendo_lo BRAFV600E mutant melanoma cell lines. The genes in the heatmap were selected based on the MITF expression, expression of MITF-target genes and expression of the RTKs AXL, EGFR and PDGFRβ. (b) A phospho-RTK array was performed comparing one MITFendo_hi and one MITFendo_lo melanoma cell line untreated or treated with 5 μM PLX4720 for 2 days. (c) MITFendo_hi and MITFendo_lo cell lines were immunoblotted for the RTKs PDGFRβ, AXL and EGFR. HSP90 served as a loading control. (d) Protein extracts from treatment-naïve BRAF mutant PDX tumours were immunoblotted for the indicated antibodies. (e) Analysis of 356 TCGA melanoma transcriptomes confirming anticorrelation between MITF and RTKs including AXL. P values were computed by a one-sided Wilcoxon ranksum test on the expression levels of AXL, EGFR and PDGFRB between the top quartile (MITF high, n=89) and bottom quartile (MITF low, n=89) of MITF expression across the samples.
