A549 holoclone and paraclone cells, as also parental A549 cells transfected with either control siRNA (siCTRL) or siCDA, were seeded into 6-well plates at a density of 10′000 cells/well. Different concentrations of 5′-DFCR or 100 μM tetrahydrouridine (THU) were added into plates after cells attached for 6-day treatment. Subsequently, the media were removed, and cell colonies were gently washed with PBS and stained by 1% crystal violet solution (in 50% Ethanol), which was prepared from 2.3% crystal violet solution (HT901-8FOZ, Sigma). After 30 min-staining, the dye solution was pipetted back for recycling and excess dye was gently rinsed off with tap water. After the plates were air-dried, pictures were captured with a standard photo camera. Crystal violet-stained cells were dissolved in 10% acetic acid solution (2 mL/ well) for 30 min on a shaker and the concentration of the extracted dye (100 μL/ well) was quantified with a spectrophotometer at 590 nm [39 (link)].
Free full text: Click here
