Overexpression of ERRα increases the aromatase expression and its promoter activity induced by PGE2 in WPMY-1 cells. A, Western blot analysis of ERRα protein expression after transfection with ERRα expression plasmid into WPMY-1 cells for 24 h. B, Cells in six-well plates were transfected with ERRα expression plasmid and then treated with PGE2 (1 μm) or vehicle. After 24 h, total RNA was extracted and aromatase mRNA levels were determined by real-time RT-PCR (B, upper panel). Values represent mean ± sd (n = 4). **, P < 0.01 compared with untreated controls. After 48 h, cells were lysed and Western blot was performed using antibodies to aromatase and GAPDH in duplicate (B, lower panel). Similar results were obtained from separate experiments. C, ERRα expression plasmid or vector were transfected into WPMY-1 cells together with the aromatase promoter luciferase plasmid and then stimulated with PGE2 (1 μm) or vehicle for 24 h. Luciferase activity was measured and normalized to renilla control activity. Results are the mean ± sd of three values. *, P < 0.05; **, P < 0.01 compared with untreated controls.