Role of PI3K signaling.

<p>(A) Effects of PI3K or MEK inhibition on phosphorylated Akt (Ser-473) and phosphorylated ERK1/2 expression in the presence or absence of H₂O₂ (200 µM). rCMECs were incubated with LY294002 (50 µM) or U0126 (10 µM) for 1 h and then exposed to H₂O₂ for 30 min. Blot shown is representative of at least three independent experiments. (B) Phosphorylated Akt (Ser-473) and phosphorylated c-Raf (Ser-259) expressions in rCMECs incubated with Sal B (20 µM) for the indicated times. (C) Effect of PI3K inhibition on phosphorylated Akt (Ser-473) and phosphorylated c-Raf (Ser-259) expressions induced by Sal B. rCMECs were incubated with LY294002 (50 µM) and/or Sal B (20 µM) for 1 h. (D) Effect of c-Raf inhibition on phosphorylated Akt (Ser-473) and phosphorylated ERK1/2 activation induced by H₂O₂. rCMECs were incubated with GW5074 (5 µM) and/or H₂O₂ (200 µM) for 1 h. (E) Effect of PI3K inhibition on H₂O₂-induced apoptosis in the presence or absence of Sal B (20 µM). rCMECs were incubated with LY294002 (50 µM) and/or Sal B (20 µM) for 1 h and then exposed to H₂O₂ for 12 h. LY, indicates LY294002. S, indicates Sal B. *<i>P</i><0.05; **<i>P</i><0.01 versus H₂O₂ alone; n.s., not significant. Data are representative of three independent experiments.