Effects of vemurafenib, metformin or the combination on cell proliferation and viability. a) Example of growth curves of BRAFV600E and NRASQ61 mutant melanoma cell lines. BRAFV600E cell lines included M263 (synergistic) and M308 (antagonistic). As representatives for NRASQ61 mutants M207 (synergistic) and SKMEL173 (antagonistic) are shown. The black line represents the data obtained with vemurafenib treatment, the blue line with metformin, and the red line with combination treatment. b) Combination index for the combination of 5 μM vemurafenib and 10 mM metformin of all melanoma cell lines tested. The green cell lines harbor BRAFV600E, red shows NRASQ61 mutant cell lines, and black the wild type cell line M257.