Colony formation assay

The stable Lv-PEAK1 shRNA transfected SKMEL28 cells or the stable PEAK1 transfected SKMEL19 cells or their controls (1 × 10³) were seeded into 6-well plates and cultured for 10 days. To explore the effect of P6 on colony formation, the stable PEAK1 transfected SKMEL19 cells were seeded (1 × 10³) in six well plates and treated with vehicle (DMSO) or P6 (500 nM) for 3 days. Fresh media without P6 was then added to the cells and cultured for another 7 days. After which, the cells were fixed and stained with May-Grunwald-Giemsa. The number of colonies was counted and reported in graphs.