*2.7. Colony Formation Assays*

Cells were seeded in 6-well plates at low density (1000 cells/plate), and cultured both in the absence or presence of drugs as indicated, for 6 days, and then incubated for 14 to 21 days to enable colony formation, after which they were fixed with 4% formaldehyde in PBS and stained with 0.1% crystal violet (Sigma-Aldrich). Relative quantification of colony number was performed using ImageJ Software (U.S. National Institute of Health, Bethesda, MD, USA).
