Fig. 2. Cell autonomous dependence on MITF in models of acquired resistance to MAPK inhibitors.

a Impact of MITF KD on cell survival of MELHO cells, sensitive (S) or resistant to DT (R). Cells were seeded at low density and treated with dox for 10-14 days, before fixing and staining by crystal violet, to enable image acquisition. The impact on cell survival was benchmarked with depletion of Polo-Like Kinase (PLK1). One representative experiment (of 3 biological replicates) is illustrated. A different set of models is shown in Supplementary Fig. 2. b Impact of dox-inducible MITF KD on MITF-M (melanocyte specific transcript) and on selected MITF target genes. MELHO cells (S, R) were treated with dox for 3 days, before being collected for qRT-PCR analysis. Data referring to impact of dox-inducible shMITF is reported in green, for comparison with shNT (non-targeting shRNA), used as control, in gray. c Cell growth dependence on MITF in additional melanoma models. MELHO, UACC-257, and SKMEL-30 cells (either parental or resistant to the indicated treatment) were seeded at 1000 cells/well. Dox was added to the medium to induce MITF depletion and viable cells were quantified using the resazurin assay, after 10 days. Data in b and c is reported as mean ± s.d. of n = 3 independent biological replicates. Source data are provided as a Source Data file. d GSEA from RNA-seq transcriptomic profiling of MELHO cells that are either treatment-naive (S) or resistant to DT combination (R). Differential gene expression analyses represented as heatmaps refer to the following comparisons: MELHO R versus S at baseline (right); MELHO R versus S following dox-inducible MITF KD by shRNA (left). Data in (b–d) is derived from at least 3 experimental replicates.