(a) HUVECs were transiently transfected with 100 nmol/L of PP2Ac siRNA or control siRNA for 12 h. PP2Ac protein expression was detected to confirm the knockdown effect. A representative western blot was shown. (b) Densitometry analysis of PP2Ac protein expression was plotted (n≥3). (c, d, e, f) After transfection of PP2Ac siRNA, cells were incubated with TGF-β1 for 15 min and 60 min, respectively. A representative western blot of p-c-Raf (Ser 259), T-c-Raf, p-ERK 1/2, T-ERK 1/2 in each group were shown. The histograms showed the ratio of p-c-Raf/T-c-Raf and p-ERK/T-ERK (n≥3).*P<0.05 compared to control group. Bars represented means ±SEM.