Fig. 1.

Effects of ER agonists/antagonists on ERE activity in HEC-1-A cells. HEC-1-A cells were transiently transfected with expression plasmid vectors for ERα (A, B) or ERβ (C, D) together with a luciferase reporter plasmid ((ERE)₃-Luc) containing three copies of tandem-arrayed ERE inserted upstream of a TATA promoter. Transfected cells were treated with E2, PPT and DPN (A, C) or with MPP or PHTPP in the absence or presence of E2 (B, D). The dual luciferase activity was assayed after incubation for 24 h. Values are means ± SEM of four wells. Independent experiments were performed twice, and similar results were obtained. *P < 0.05; **P < 0.01 and ***P < 0.001 compared with the control; ^#P < 0.001 compared with E2 (10⁻⁹ M) alone.