ABSTRACT
Our goals were to examine the dual-directional regulation effects of resveratrol (1) in vitro by using MCF-7 cells (estradiol receptor-positive cells), study its mechanism of action, and give a systematical analysis of the regulatory networks of each related factor. An MTT test and growth curve showed that the proliferation of MCF-7 cells was inhibited by a high concentration of 1, and that its IC(50) was 8.70 x 10(-5) +/- 0.23 mol/l. However, 1 induced the proliferation of MCF-7 cells at 10(-7)-10(-5) mol/l, and resulted in a peak proliferation at 1.0 x 10(-7) mol/l. A high concentration of 1 arrested cell cycle progression at the G(1) phase, and a typical "sub-G(1) peak" of apoptotic cells was also observed by flow cytometry. The proliferation index of MCF-7 cells increased significantly with a low concentration of 1 (p < 0.05). 1 in high concentrations induced Bax, caspase-3, and cyclin-dependent kinase (CDK) inhibitor P21 expression, whereas the expressions of cyclin CDK2, Bcl-2, and proliferating cell nuclear antigen (PCNA) were decreased by 1 treatment. Conversely, treatment with low concentrations of 1 decreased the expression of P21 and Bax, while the expressions of cyclin CDK2, Bcl-2, and PCNA were increased. These results suggest that 1 had a dual-regulatory effect on MCF-7 cells. CDK-associated protein was a key factor at both the high and low concentrations used in this study.
