Bifunctional effect of resveratrol on the expression of ErbB2 in human breast cancer cell

This study evaluated the effect of resveratrol on the expression of ErbB2 in a human breast cancer cell line, MCF-7. Low concentrations of resveratrol (1–10 μM) reduced the basal expression level of ErbB2 in MCF-7 cells cultured in an estrogen-free medium. When cells were cultured in a medium containing estrogen, resveratrol increased the ErbB2 protein levels in a dose-dependent manner. Resveratrol increased the luciferase reporter gene activity in cells transfected with the −756 bp flanking region of the human erbB2 gene. Resveratrol increased the nuclear levels of AP-2α and AP-2γ, and the induction of the luciferase reporter gene by resveratrol was inhibited by a mutation of two AP-2 binding sites in the promoter region of the human erbB2 gene. Blocking the ERK, p38 kinase or PI3-kinase activity had no effect on the resveratrol-inducible transactivation of the erbB2 gene and the ErbB2 expression level.