STAT5 is involved in antiestrogen-induced Cyclin D1 promoter activity.

<p>(A). The involvement of STAT5 in antiestrogens-induced Cyclin D1 promoter activity. Cells were transfected with the luciferase reported plasmid Cyclin D1 pl-963 together with an empty expression vector or two dominant-negative STAT5a mutants, STAT5aΔ713 and STAT5aΔ740, respectively. Transfected cells were treated with vehicle (ethanol), 1 nM or 5 µM of antiestrogens. Columns: means of the relative luciferase activity from four independent experiments. Luciferase activity in the cells transfected with an empty expression vector and treated with vehicle is arbitrarily set as 1.0; bars, SE. *, p<0.05, for cells treated with vehicle (V) vs 1 nM of antiestrogens. (B). The GAS1 is involved in induction of the Cyclin D1 promoter activity by antiestrogens. Cells were transiently transfected with either the wild-type Cyclin D1 promoter (CycD1) or the same promoter construct containing mutated GAS1 (GAS1mut) or GAS2 (GAS2mut) sequence, respectively. Transfected cells were treated with vehicle or 1 nM of antiestrogens, and the luciferase activity was presented relative to the wild-type Cyclin D1 promoter-transfected cells treated with vehicle that is arbitrarily set as 1.0. *, p<0.05, for cells treated with vehicle (V) vs 1 nM of antiestrogens.