Figure 4. SC-2001 combined with ABT-737 targeted the MIC population of melanoma cells regardless of the mutation status.

Melanoma spheres were treated with indicated compounds, and then subjected to A. Bright field analysis, Scale bar = 100μm; B. Quantification of the number of primary spheres; For primary sphere assay, the spheres were treated with the indicated concentration of drug for 48 hrs before counting. The combination severely disrupted the primary spheres compared with the control, ABT-737 or SC-2001 treatment alone (P< 0.05 or less) regardless their mutation status in thirteen out of fourteen lines. The p-values for all comparisons are separately listed in Supplementary Table S2. C. Quantification of ALDH assay. For ALDH assay, the cells were treated with the indicated concentration of drug for 48 hrs before conducting the assay. The combination of SC-2001 and ABT-737 significantly decreased the percentage of ALDH^high cells compared with the DMSO control and ABT-737 alone regardless their mutation status (P < 0.05 or less) in seven lines. Unfortunately, we did not have enough material to do additional replicates for last four samples, so we could not statistically analyze the data. The p-values for all comparisons are separately listed in Supplementary Table S3.