Regulation of the expression of the angiogenic enzyme platelet-derived endothelial cell growth factor/thymidine phosphorylase in endometrial isolates by ovarian steroids and cytokines

Abstract

The angiogenic enzyme platelet-derived endothelial cell growth factor/thymidine phosphorylase (PD-ECGF/TP) was strongly expressed in the endometrial glands in the luteal and menstrual, but not the proliferative, phases of the cycle. The converse was seen in the stroma, where expression was strong in the proliferative, but not the luteal or menstrual, phases. Inflammatory cytokines induced PD-ECGF/TP expression in primary cultures of human normal endometrial epithelial (NEE) and normal endometrial stromal cells. The profile of cytokine induction of PD-ECGF/TP was cell dependent. Thus, in NEE cells, PD-ECGF/TP expression was strongly induced by the combination tumor necrosis factor-α and interferon-γ. In contrast, in normal endometrial stromal cells, interferon-γ gave, by far, the strongest induction of PD-ECGF/TP. Expression of the enzyme was not regulated by ovarian hormones alone. Although treatment of NEE cells with a physiological concentration of progesterone (5 x 10-5 M) or transforming growth factor- β1 (10 ng/ml/alone had no effect on PD-ECGF/TP expression, when delivered together at the same dose they induced a 48-fold increase in expression. This expression correlates with cyclic changes in progesterone and transforming growth factor-β1 levels in the uterus.