Optimization of p120 siRNA knockdown regimen based on BrdU labeling. BrdU labeling was performed in HCEC cultures treated with scRNA (○) or p120 siRNA (•) at concentrations from 10 to 160 nM starting from day 14 of culturing ([A], *P < 0.05 for each concentration between scRNA and p120 siRNA, and #P < 0.05 between 40–100 nM p120 siRNA, n = 3), or with 100 nM of p120 siRNA starting from day 14 of culturing once, twice, or three times a week ([B], P > 0.05 between groups, n = 3), or starting from day 7, 10, 14, and 17 of culturing ([C], P > 0.05 between each group, n = 3). All cultures were treated for 48 hours.