Colony formation assay

Tumor cells and control cells were plated in triplicate in 6-well plates at a density of 1,000 cells/well. After 7 days of culture, the cells were fixed with 4% paraformaldehyde for 30 min at room temperature, and then stained with 0.1% crystal violet solution for 30 min at room temperature. Finally, images were captured and the number of cell colonies was counted, and clones with ≥50 cells were scored as actual colonies. At least three determinations were performed in triplicate.