(Z)-Semaxinib (SU5416) is a potent and selective VEGFR(Flk-1/KDR) inhibitor (IC50: 1.23 μM), 20-fold more selective for VEGFR over PDGFRβ, no inhibition for FGFR, InsR, and EGFR. (Z)-Semaxinib is a quinolone derivative with potential antineoplastic activity.

VEGFR2/Flk1:1.23 μM

在10种测试肿瘤细胞系中,Semaxanib对其中8种(A431,Calu-6,C6,LNCAP,EPH4-VEGF,3T3HER2,488 g2M2以及SF763T细胞)的皮下生长均有明显抑制作用,平均死亡率为2.5%.Semaxanib剂量依赖性抑制体内A375肿瘤的生长.Semaxanib（25 mg/kg/day）具有较强抗血管生成活性,显著降低肿瘤微血管系统的总功能性血管密度.Semaxanib（i.p.）可抑制>85%的皮下肿瘤生长,且无可检测的毒性.

Semaxanib剂量依赖性抑制VEGF（IC50：0.04 μM）和FGF（IC50：50 μM）诱导的有丝分裂。Semaxanib不影响C6胶质瘤,Calu 6肺癌,A375黑素瘤,A431 鳞状细胞癌,和SF767T 神经胶质瘤细胞在体外的生长（IC50s>20 μM）。在Flk-1过表达的NIH 3T3细胞中,Semaxanib对Flk-1受体的VEGF-依赖性磷酸化具有抑制作用（IC50：1.04 μM）。Semaxanib可抑制NIH 3T3细胞中PDGF依赖性自身磷酸化（IC50：20.3 μM）。

Biochemical kinase assays: Solubilized membranes from 3T3 Flk-1 cells are added to polystyrene ELISA plates that had been precoated with a monoclonal antibody that recognizes Flk-1. After an overnight incubation with lysate at 4 ℃, serial dilutions of SU5416 are added to the immunolocalized receptor. To induce autophosphorylation of the receptor, various concentrations of ATP are added to the ELISA plate wells containing serially diluted solutions of SU5416. The autophosphorylation is allowed to proceed for 60 min at room temperature and then stopped with EDTA. The amount of phosphotyrosine present on the Flk-1 receptors in the individual wells is determined by incubating the immunolocalized receptor with a biotinylated monoclonal antibody directed against phosphotyrosine. After removal of the unbound anti-phosphotyrosine antibody, avidin-conjugated horseradish pero-idase H is added to the wells. A stabilized form of 3,3 9,5,5 9-tetramethyl benzidine dihydrochloride and Water2 is added to the wells. The color readout of the assay is allowed to develop for 30 min, and the reaction is stopped with H2SO4.

HUVECs are plated in 96-well, flat-bottomed plates (1×104 cells/100 μL/well) in F-12K media containing 0.5% heat-inactivated FBS and cultured at 37 ℃ for 24 h to quiesce the cells. Serial dilutions of compounds prepared in medium containing 1% DMSO are then added for 2 h, followed by the addition of mitogenic concentrations of either VEGF at 5 ng/mL or 20 ng/mL or acidic fibroblast growth factor at 0.25–5 ng/mL in media. The final concentration of DMSO in the assay is 0.25%. After 24 h, either [3H]thymidine (1 μCi/well) or BrdUrd is added, and the cell monolayers are incubated for another 24 h. The uptake of either [3H]thymidine or BrdUrd into cells is quantitated using a liquid scintillation counter or a BrdUrd ELISA, respectively.(Only for Reference)