Figure 6.

Effects of icariin on ERα or ERβ-mediated ERE-dependent luciferase activity in UMR 106 cells. Cells were co-transfected with 0.4 µg ERα or ERβ plasmid, 0.4 µg ERE-containing luciferase reporter plasmid and 0.1 µg pRL-TK luciferase internal reporter plasmid using the Lipofectamine™ 2000 reagent according to the manufacture's instructions. Transfected cells were treated with vehicle (C), 17β-oestradiol (E2; 10⁻⁸ M) or icariin (ICA; 10⁻⁸ M) for 24 h. Activities of luciferase encoded by experimental and internal control plasmid were measured sequentially with the DLR assay reagents. The ERE firefly luciferase activities were normalized for pRL-TK Renilla luciferase values. 100% represents the ERE luciferase activity of the control. Results were obtained from three independent experiments and expressed as mean ± SEM. ***P < 0.001 versus control (C). ER, oestrogen receptor; ERE, oestrogen response element.