Colony formation assay
Cells were seeded in 6-well plates (400-600 cells/well) and treated with different concentrations of icariin. After incubation for an additional 6-8 days, the cells were fixed with methanol for 5 min and stained with 0.5% crystal violet for 20 min. Colonies that contained more than 50 cells were counted using a microscope (Olympus, Japan), and the data presented was the average of three experiments.