Fig. 5

Effect of VB1 on BRAFi-resistant melanoma cells. a BRAFi-resistant melanoma cells (RA) from parental A375 were generated as described in the Methods. RA and parental A375 cells were seeded into 96-well plates and then treated with PLX4072. Cell viability was determined by the CCK-8 assay. The results represent the mean (n = 6) ± SD of each group, and an asterisk (*) indicates a significant difference using one-way ANOVA (p < 0.05). b RA cells were treated with 0–20 μM VB1 for 0–72 h. Cell viability was determined by the CCK-8 assay. The IC50 values of VB1 in the RA cells were automatically generated by the GraphPad Prism software. c RA cells were seeded into 6-well plates and then treated with various dosages of VB1 as indicated for 24 h. After 10–14 days, the number of colonies was assessed and quantified by crystal violet staining as described in the Methods. d RA cells were seeded into 6-well plates after being treated with VB1 at various dosages, and the apoptosis was determined by flow cytometry with Annexin V and PI double staining. The cell lysates were prepared from RA cells treated with VB1 at various dosages, and western-blotting was performed by various antibodies as indicated. e RA cells were seeded into 6-well plates after being treated with VB1 at various dosages, and the distribution of the cell cycle was determined by flow cytometry as described in the Methods. The results represent the mean (n = 4) ± SD of each group, and an asterisk (*) indicates a significant difference using one-way ANOVA (p < 0.05)