Progestins activate vascular endothelial growth factor gene transcription in endometrial adenocarcinoma cells

Objective: To determine whether progestins activate vascular endothelial growth factor (VEGF) gene transcription in endometrial adenocarcinoma cells. Design: In vitro study. Setting: University reprodictive biology laboratories. Patient(s): None. Intervention(s): Ishikawa cells were transfected with VEGF promoter-luciferase reporter constructs and expression vectors encoding human progesterone receptors (hPR) A or B. The cells were treated with different progestins and antiprogestins, and luciferase activity was compared with controls. Main Outcome Measure(s): Three functional progesterone response elements (PREs) in the VEGF promoter were identified by electrophoretic mobility-shift assay, and different constructs were created to assess each PRE. Result(s): In cells expressing hPRA or B, treatment with 10 nM R5020 or 100 nM medroxyprogesterone acetate statistically significantly increased luciferase activity (3.3- to 4.8-fold). Pretreatment with 100 nM RU486 blunted the effect of 10 nM R5020, resulting only in a slight, statistically nonsignificant increase in luciferase activity (1.3- to 1.7-fold). Although three different functional PREs could be identified, no single PRE accounted for the preponderance of the luciferase activity. Full VEGF promoter activation required all three PREs. Conclusion(s): Progestins have a direct effect on VEGF gene transcription. However, hPR-mediated transcriptional regulation of the VEGF promoter is complex and cannot be localized to confined PRE sequences. Other response element motifs are likely to play a contributory role. (C) 2003 by American Society for Reproductive Medicine.