Effect of corosolic acid on VEGFR2-mediated downstream signaling and actin rearrangement.

(A) Huh7 cells were treated with 0.1% DMSO (control) or corosolic acid for 30 min, and the phosphorylation level of VEGFR2 (Tyr1058), Src (Tyr416), and FAK (Tyr397) were analyzed by western blot. (n = 3, *P < 0.05, **P < 0.01 compared with the DMSO treated group) (B) Huh7 cells were treated with 0.1% DMSO (control) or corosolic acid for 6 h, and Rho-GTPase activity was examined with a GST pull-down assay and western blot analysis. (For cdc42, n = 3, **P < 0.01 compared with the DMSO treated group) (C) Huh7 cells were treated with 0.1% DMSO (control) or corosolic acid for 6 h, and fractions containing either F-actin or G-actin were separated by procedures outlined in materials and methods. The ratio of F-actin and G-actin were then calculated. (n = 3, ***P < 0.001 compared with the DMSO treated group) (D) Huh7 cells were treated with 0.1% DMSO (control) or corosolic acid for 6 h followed by immunocytochemistry staining. The phalloidin-stained F-actin (red) and p-FAK (green) co-localized at the leading edge of control cells.