Inhibition of epithelial outgrowth by LY294002 and SR13668. Epithelial outgrowth was dose-dependently inhibited by LY294002, an inhibitor of PI3K, from 5 to 50 μM (A). Compared with the control, complete inhibition of epithelial outgrowth was noted at 20 (not shown) and 50 μM of LY294002 (B). The addition of 10 μM SR13668, a phosphor-Akt inhibitor, partially suppressed the outgrowth (C), but 50 μM of SR13668 completely abolished the outgrowth (D).