KR-31372 inhibits KDR/Flk-1 tyrosine phosphorylation via K +ATP channel opening in its antiangiogenic effect

Abstract

The aim of this study was to identify the signaling pathway of the antiangiogenesis by (2 R,3 R,4 S)- Nʺ-cyano- N-(6-nitro-3,4-dihydro-hydroxy-2-methyl-2-dimethoxymethyl 2 H-1-benzopyran-4yl)- N′-benzylguanidine (KR-31372). KR-31372 inhibited the in vitro basal tube formation using Matrigel-coated plate and in vivo neovascularizations in mice induced by Matrigel containing vascular endothelial growth factor (VEGF 165, 5 ng/ml). VEGF 165 markedly increased cell proliferation using 5-bromo-2′-deoxyuridine incorporation and chemotactic migration using transwell chamber in human umbilical vein endothelial cells, those of which were significantly suppressed by pretreatment with KR-31372 and levcromakalim concentration dependently. The suppression of all these variables were strongly antagonized by glibenclamide, ATP-sensitive K + channel blocker. KR-31372 (10 −6–10 −4 M) and levcromakalim (10 −5 M) concentration-dependently suppressed the VEGF 165-induced increases in KDR/Flk-1 tyrosine phosphorylation as well as the extracellular signal-related kinase 1/2 (ERK1/2), p38 MAK and p125 FAK tyrosine phosphorylation. These variables were significantly antagonized by glibenclamide. In conclusion, KR-31372 significantly inhibited the KDR/Flk-1 tyrosine phosphorylation-linked ERK1/2, p38 MAPK and p125 FAK tyrosine phosphorylation via mediation of K + ATP channel opening, thereby resulting in antiangiogenesis.