Regulation of vascular endothelial growth factor secretion in human meningioma cells

Previously, we induced vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) secretion in glioma cell lines by using physiologic concentrations of epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), or platelet-derived growth factor-BB (PDGF-BB). We hypothesized that VEGF/VPF might enhance the blood supply required for the unregulated growth of tumors, and that it acts as the central mediator of tumor angiogenesis. The objective of this study was to determine whether the expression of VEGF/VPF by meningiomas is regulated by growth factors or sex hormones. By means of an enzyme-linked immunosorbent assay of CH-157MN meningioma cell supernatants, we demonstrated that EGF and bFGF similarly induce VEGF secretion by CH-157MN meningioma cells. At the maximum concentrations of EGF (50 ng/mL) and bFGF (50 ng/mL) used in this study, VEGF secretion was induced to 140% to 160% above baseline constitutive secretion. PDGF-BB homodimer did not enhance VEGF secretion significantly. Estradiol (up to 10(-7) mol/L), progesterone (up to 10(-5) mol/L), or testosterone (up to 10(-5) mol/L) did not stimulate or inhibit VEGF secretion in CH-157MN meningioma cells (p > 0.05). Furthermore, we demonstrated that dexamethasone decreased VEGF secretion to 32% of baseline constitutive secretion. This might explain the effect of corticosteroids in alleviating peritumoral brain edema in meningiomas. These results suggest that VEGF secretion in CH-157MN meningioma cells is mainly regulated by growth factors and corticosteroids, but not by sex hormones. Understanding the regulation of VEGF/VPF secretion in meningiomas might contribute to the development of a new therapeutic strategy.