Effect of genistein (Gen) on TPA-induced MMP-9 −, NF-κB −, and AP-1 –dependent luciferase reporter gene expression. HepG2 cells treated with increasing concentrations of Gen were transfected with (A) MMP-9−, (B) AP-1−, or (C) NF-κB containing plasmids linked to the luciferase gene. After 16-h treatment with 80 μM TPA, cell lysates were assayed for luciferase activity. Results are expressed as fold activity over that of untreated transfected cells. Values represent the mean ± SEM of 3 independent experiments. *p < 0.01 compared to TPA-treated cells.