Figure 4

Inhibition of PI3K/AKT and MEK/ERK pathways synergistically enhanced EGCG-induced FOXO activity in HUVEC cells. HUVEC cells were transiently transfected with 6X DBE-luciferase and pRL-TK plasmids for 24 h [69]. After transfection, HUVEC cells were pretreated with AKT inhibitor IV (1 μM) and/or MEK1/2 inhibitor PD98059 (10 μM) for 2 h, followed by treatment with or without EGCG (40 μM) for 24 h. Cells were harvested for firefly/Renilla luciferase assays using the Dual-Luciferase Reporter Assay System (Promega). Luciferase counts were normalized using Renilla luciferase transfection control. Data represent the mean ± S.D. *, #, ** = significantly different from respective controls, P < 0.05.