HGF/NK4 inhibited VEGF-induced angiogenesis in in vitro cultured endothelial cells and in vivo rabbit model.

As vascular endothelial growth factor (VEGF) plays a pivotal role in the development of diabetic retinopathy, inhibition of angiogenesis induced by VEGF is crucial to treat diabetic retinopathy. HGF (hepatocyte growth factor)/NK4, containing the N-terminal hairpin domain and the four subsequent kringle domains of HGF, is considered as a specific antagonist for HGF. Our aim was to explore the inhibitory effects of HGF/NK4 on angiogenesis induced by VEGF. To analyze the in vivo angiogenesis, we used rabbit corneal micropocket assay. Proliferation and migration of human endothelial cells, expression of ets-1, an essential transcription factor for angiogenesis, and the phosphorylation of extracellular signal-regulated kinase (ERK) was examined with or without HGF/NK4. Using corneal micropocket assay, in vivo administration of HGF/NK4 inhibited angiogenesis induced by VEGF. HGF/NK4 inhibited proliferation and migration of human endothelial cells induced by VEGF in a dose-dependent manner. Interestingly, VEGF-mediated phosphorylation of ERK was significantly attenuated by HGF/NK4. Of importance, HGF/NK4 attenuated the increase in ets-1 protein stimulated by VEGF. Nevertheless, HGF/NK4 did not affect phosphorylation of VEGF receptor-2 [kinase domain region (KDR)/foetal liver kinase (Flk)-1]. Although tyrosine phosphatase inhibitor (Na(3)VO(4)), or okadaic acid, serine-threonin kinase inhibitor, did not prevent the inhibition of ERK phosphorylation by HGF/NK4, co-incubation of HGF/NK4 with VEGF significantly diminished mitogen-activated protein (MAP) ERK kinase (MEK) phosphorylation (p<0.01). Overall, HGF/NK4 inhibited angiogenesis induced by VEGF through inhibition of phosphorylation of ERK and ets-1 expression in in vitro cultured endothelial cells and in vivo rabbit model.

Nakabayashi M ，Morishita R ，Nakagami H ，Kuba K ，Matsumoto K ，Nakamura T ，Tano Y ，Kaneda Y ... -  《DIABETOLOGIA》

HGF/NK4, a four-kringle antagonist of hepatocyte growth factor, is an angiogenesis inhibitor that suppresses tumor growth and metastasis in mice.

Kuba K ，Matsumoto K ，Date K ，Shimura H ，Tanaka M ，Nakamura T ... -  《CANCER RESEARCH》

Antagonistic effect of NK4, a novel hepatocyte growth factor variant, on in vitro angiogenesis of human vascular endothelial cells.

Jiang WG ，Hiscox SE ，Parr C ，Martin TA ，Matsumoto K ，Nakamura T ，Mansel RE ... -  《CLINICAL CANCER RESEARCH》

Kringle 1-4 of hepatocyte growth factor inhibits proliferation and migration of human microvascular endothelial cells.

Kuba K ，Matsumoto K ，Ohnishi K ，Shiratsuchi T ，Tanaka M ，Nakamura T ... -  《BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS》

Mechanisms of hepatocyte growth factor-induced retinal endothelial cell migration and growth.

Cai W ，Rook SL ，Jiang ZY ，Takahara N ，Aiello LP ... -  《INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE》