Objective: To evaluate the effects of tamoxifen on human endometrial vascular endothelial growth factor (VEGF) gene expression in vitro and in vivo.
Study design: Ishikawa cells were transiently co-transfected with plasmids expressing human estrogen receptor (ER)-alpha or -beta and a 2.3-kb human VEGF promoter-luciferase construct. Transfected cells were treated with tamoxifen and the increase in luciferase activity was compared to controls. In addition, immunohistochemical analysis of VEGF expression in endometrial biopsies from 11 postmenopausal women receiving tamoxifen was compared to 24 postmenopausal women on no hormone replacement.
Results: In transfected cells expressing ERalpha, tamoxifen induced a significant VEGF promoter activation (3.2-fold, p < 0.01), whereas cells expressing ERbeta showed a 1.6-fold stimulation (p = NS). No significant differences in VEGF immunostaining were observed in tamoxifen-exposed women.
Conclusions: Although tamoxifen exposure increases VEGF expression in vitro, a significant increase in VEGF expression is not apparent in endometrial biopsies of postmenopausal women treated with this drug.
Copyright 2003 S. Karger AG, Basel