ZM 323881 HCl

ZM323881 is a novel VEGF-R2 selective inhibitor with IC50 of <2nM.

The Different Effects of VEGFA121 and VEGFA165 on Regulating Angiogenesis Depend on Phosphorylation Sites of VEGFR2.[Pubmed:28296822]

Inflamm Bowel Dis. 2017 Apr;23(4):603-616.

The effects of VEGFA isoforms on the vascular permeability and structure are still unclear. In this study, we found that VEGFA121 and VEGFA165, 2 isoforms of VEGFA, exerted the opposing effects of antiangiogenesis and proangiogenesis on regulating vascular endothelia cells proliferation and tube formation. The 2 isoforms affected the protein expression of Ras-related protein 1-GTPase-activating protein 1 (Rap1GAP) and thrombospondin 1, 2 important signal molecules of Rap1GAP/thrombospondin 1 signal pathway in primary human umbilical vein endothelial cells by regulating 2 different phosphorylating sites of VEGFR2, Tyr(1175) and Tyr(1214). We also found that VEGFA121 and VEGFA165 regulating angiogenesis was related to their regulating VEGFR2 and Rap1GAP/thrombospondin 1 signal pathway with the technology of RNA intervening the gene expression of VEGFR2 and Rap1GAP. Meanwhile, 2 inhibitors of VEGFR2, cabozantinib malate and ZM 323881 HCl (ZM), were used to investigate the relationship among VEGFA(121 and 165), VEGFR2, and angiogenesis. It was demonstrated that cabozantinib malate blocked VEGFA121 and VEGFA165 binding to VEGFR2 and inhibited angiogenesis by specifically binding to VEGFR2 rather than changing VEGFR2 phosphorylation or regulating the expression of VEGFR2. However, ZM antagonized the effect of VEGFA on angiogenesis by specifically reversing the phosphorylation induced by VEGFA121 and VEGFA165. The experiments in vivo also demonstrated that obvious abnormality of VEGFA121 and VEGFA165 presented in the serum of ulcerative colitis (UC) rats compared with that of the normal rats. ZM could promote the repairation of the injuries of the vessels and tissues of colonic mucosa of UC rats and caused mild inflammation in colonic mucosa of normal rats. On the contrary, cabozantinib malate caused injury of vessels and inflammation in the colonic mucosa of normal rats and aggravated the injuries of the vessels and inflammation in the colonic mucosa of UC rats. Hence, our data indicated that the activation of different phosphorylation sites of VEGFR2 leaded to VEGFA121 and VEGFA165 exerting opposing effects on angiogenesis, and it might be an underlying pathogenesis of UC and a potential target for UC treatment.

Selective inhibition of vascular endothelial growth factor receptor-2 (VEGFR-2) identifies a central role for VEGFR-2 in human aortic endothelial cell responses to VEGF.[Pubmed:14626450]

J Recept Signal Transduct Res. 2003;23(2-3):239-54.

Vascular endothelial growth factor receptors (VEGFR) are considered essential for angiogenesis. The VEGFR-family proteins consist of VEGFR-1/Flt-1, VEGFR-2/KDR/Flk-1, and VEGFR-3/Flt-4. Among these, VEGFR-2 is thought to be principally responsible for angiogenesis. However, the precise role of VEGFRs1-3 in endothelial cell biology and angiogenesis remains unclear due in part to the lack of VEGFR-specific inhibitors. We used the newly described, highly selective anilinoquinazoline inhibitor of VEGFR-2 tyrosine kinase, ZM323881 (5-[[7-(benzyloxy) quinazolin-4-yl]amino]-4-fluoro-2-methylphenol), to explore the role of VEGFR-2 in endothelial cell function. Consistent with its reported effects on VEGFR-2 [IC(50) < 2 nM], ZM323881 inhibited activation of VEGFR-2, but not of VEGFR-1, epidermal growth factor receptor (EGFR), platelet-derived growth factor receptor (PDGFR), or hepatocyte growth factor (HGF) receptor. We studied the effects of VEGF on human aortic endothelial cells (HAECs), which express VEGFR-1 and VEGFR-2, but not VEGFR-3, in the absence or presence of ZM323881. Inhibition of VEGFR-2 blocked activation of extracellular regulated-kinase, p38, Akt, and endothelial nitric oxide synthetase (eNOS) by VEGF, but did not inhibit p38 activation by the VEGFR-1-specific ligand, placental growth factor (PIGF). Inhibition of VEGFR-2 also perturbed VEGF-induced membrane extension, cell migration, and tube formation by HAECs. Vascular endothelial growth factor receptor-2 inhibition also reversed VEGF-stimulated phosphorylation of CrkII and its Src homology 2 (SH2)-binding protein p130Cas, which are known to play a pivotal role in regulating endothelial cell migration. Inhibition of VEGFR-2 thus blocked all VEGF-induced endothelial cellular responses tested, supporting that the catalytic activity of VEGFR-2 is critical for VEGF signaling and/or that VEGFR-2 may function in a heterodimer with VEGFR-1 in human vascular endothelial cells.

ZM323881, a novel inhibitor of vascular endothelial growth factor-receptor-2 tyrosine kinase activity.[Pubmed:12483548]

Microcirculation. 2002 Dec;9(6):513-22.

OBJECTIVE: Vascular endothelial growth factor (VEGF) increases vascular permeability and angiogenesis in many pathological conditions including cancer, arthritis, and diabetes. VEGF activates VEGF-Receptor 1(VEGF-R1) and VEGF-Receptor 2 (VEGF-R2), which autophosphorylate to initiate a signaling cascade resulting in angiogenesis and increased microvascular permeability. Here we describe a novel VEGF-R2 selective inhibitor, ZM323881 (5-[[7-(benzyloxy) quinazolin-4-yl]amino]-4-fluoro-2-methylphenol), that is a potent and selective inhibitor of VEGF-R2 tyrosine kinase in vitro (IC(50) < 2 nM), compared with other receptor tyrosine kinases, including VEGF-R1 (IC(50) > 50 microM). METHODS: Endothelial cell proliferation was assayed by (3)H-thymidine incorporation in response to VEGF-A +/- ZM323881. The effect of ZM323881 on VEGF-mediated permeability was measured in frog microvessels using the Landis Michel technique. To ensure that ZM323881 was effective in frogs, western analysis was performed on protein extracted from frog lungs incubated in the presence or absence of VEGF-A or VEGF-A with ZM323881. RESULTS: ZM323881 inhibits VEGF-A-induced endothelial cell proliferation (IC(50) = 8 nM) and VEGF-R2 tyrosine phosphorylation in vitro. VEGF-A-mediated increases in vascular permeability in perfused mesenteric microvessels in vivo were reversibly abolished by both ZM323881 and the class III receptor tyrosine kinase inhibitor PTK787/ZK222584. CONCLUSIONS: These data suggest that VEGF-R2 phosphorylation is necessary for VEGF-A-mediated increases in microvascular permeability in vivo.