2.6. Cell Clonogenic Assay

Cell clonogenic assay is a cell viability assay based on live cell ability to proliferate—form colonies. After cell incubation, 330 cells were loaded into 4.1 cm² tissue culture dishes (TPP, Switzerland) containing 2 mL of growth medium. The cells were allowed to grow for 6 days, and then fixed in 1 mL of 96% ethanol for 10 min and stained using crystal violet solution (Sigma Aldrich, St. Louis, MO, USA) that contained 2.3% crystal violet, 0.1% ammonium oxalate, and 20% ethanol. The number of cell colonies was assessed using light microscope (MBS 9, LOMO, St. Petersburg, Russia) and then normalized to the control (no treatment).