Fig. 2.

Curcumin inhibits MDP-induced transactivation of IL-8. HCT116 cells were cotransfected with IL-8-luciferase and β-galactosidase reporter constructs. After 24 h, the cells were pretreated with curcumin (10, 20, and 30 μM) (A and D), parthenolide (5, 10, and 15 μM) (B and E), or EGCG (10, 30, and 50 μM) (C and F) for 1 h and then coincubated with 50 μM MDP for additional 6 h. Cell lysates (A–C) were prepared and luciferase and β-galactosidase enzyme activities were measured as described under Materials and Methods. Medium supernatants (D–F) were collected from IL-8-luciferase-transfected cells, and the levels of IL-8 protein were measured as described under Materials and Methods. RLA was normalized with β-galactosidase activity. Values are mean ± S.E.M (n = 3). Statistical significant difference (p < 0.05) is indicated between cells treated with MDP alone and cells treated with MDP plus the indicated phytochemicals. Abbreviations are the same as described in Fig. 1.