Colony-forming assay

Cells (n=1000) were plated in 60-mm tissue culture plates in triplicate. Cells were grown in complete DMEM medium for 14 days, with medium changed every 2–3 days. Cells were fixed with 4% paraformaldehyde for 1 h, which was followed by staining with crystal violet for 1 h at room temperature. Stained plates were then washed with running water for 1 min and dried in the air, and images were captured using a high-resolution Nikon D70 camera (Nikon, Tokyo, Japan).