Knocking down PCNA expression by siRNA sensitizes DMF-differentiated PLB985 cells to apoptosis. DMF-differentiated PLB985 cells were transfected twice with control (CT) siRNA or with PCNA siRNA on days 3 and 4 after DMF. (A) Cytosolic PCNA expression was evaluated by Western blot analysis using the Ab5 pAb (β-actin expression was used as loading control). (B) Quantification of PCNA expression by densitometric scanning using ImageJ software. Data are means ± SEM of six independent experiments (*, P < 0.05; Student’s t test). (C) Effect of PCNA siRNA on the percentage of apoptotic PLB985 cells as measured by mitochondrial depolarization after DiOC6 labeling. PLB985 cells were incubated with 2 µg/ml gliotoxin (n = 6), 10 ng/ml TRAIL (n = 5), or in basal conditions (n = 10) for 15 h. Data are means ± SEM of n independent experiments (*, P < 0.05; **, P < 0.01; Student’s t test).
