Effect of SWT and its components on the ERE luciferase activity in MCF-7 cells. The hormone-deprived MCF-7 cells were transiently co-transfected with the ERE-luc construct and a plasmid encoding renillar luciferase (pGL4.74) using FuGENE® HD transfection reagent. (A) The transfected cells were incubated in DMEM supplemented with 10% CD-FBS with E2 (10 nM), SWT or Paeoniae, Chuangxiong, Angelicae or Rehmanniae (1.5 and 3 mg/ml) for 24 h prior to measurement of firefly and renillar luciferase activities using the dual luciferase reporter gene assay. *, P < 0.05; **, P < 0.01, treatment versus control. (B) The transfected cells were treated with SWT 3 mg/ml or 1.5 mg/ml alone or + 1 μM tamoxifen. *, P < 0.05 tamoxifen + SWT versus SWT alone. Data represent the mean + SE of experiments performed in triplicate.