The quinazoline-derived alpha1-adrenoceptor antagonists, doxazosin and terazosin have been recently shown to induce an anoikis effect in human prostate cancer cells and to suppress prostate tumor vascularity in clinical specimens [Keledjian and Kyprianou, 2003]. This study sought to examine the ability of doxazosin to affect the growth of human vascular endothelial cells and to modulate vascular endothelial growth factor (VEGF)-mediated angiogenesis. Human umbilical vein endothelial cells (HUVECs) were used as an in vitro model to determine the effect of doxazosin on cell growth, apoptosis, adhesion, migration, and angiogenic response of endothelial cells. The effect of doxazosin on cell viability and apoptosis induction of human endothelial cells, was evaluated on the basis of trypan blue and Hoechst 33342 staining, respectively. Doxazosin antagonized the VEGF-mediated angiogenic response of HUVEC cells, by abrogating cell adhesion to fibronectin and collagen-coated surfaces and inhibiting cell migration, via a potential downregulation of VEGF expression. Furthermore there was a significant suppression of in vitro angiogenesis by doxazosin on the basis of VEGF-mediated endothelial tube formation (P < 0.01). Fibroblast growth factor-2 (FGF-2) significantly enhanced HUVEC cell tube formation (P < 0.01) and this effect was suppressed by doxazosin. These findings provide new insight into the ability of doxazosin to suppress the growth and angiogenic response of human endothelial cells by interfering with VEGF and FGF-2 action. This evidence may have potential therapeutic significance in using this quinazoline-based compound as an antiangiogenic agent for the treatment of advanced prostate cancer.
2004 Wiley-Liss, Inc.