EGT022, an RGD-containing recombinant disintegrin, inhibits the VEGF-induced angiogenic process by targeting integrin 3 in endothelial cells

Objectives: EGT022, an RGD-containing recombinant disintegrin from human ADAM metallopeptidase domain 15 (ADAM15), has been reported to stimulate vascular maturation of retinal blood vessels with promotion of pericyte coverage through binding to integrin aIIb ss 3. Previous studies have reported that angiogenesis can be inhibited by several RGD motif-containing disintegrins; however, the effect of EGT022 on Vascular endothelial growth factor (VEGF)-induced angiogenesis has not yet been determined. This study was conducted in order to evaluate the anti-angiogenic function of EGT022 in VEGF-induced endothelial cells. Methods: A proliferation and migration assay was performed using human umbilical vein endothelial cells (HUVEC) cells stimulated with VEGF to determine whether the angiogenic process was suppressed by EGT022. An in vitro trans-well assay and Mile's permeability assay were performed to determine the effect of EGT022 on permeability. Western blot was performed in order to further determine whether EGT022 can inhibit phosphorylation of VEGF receptor-2 (VEGFR2) and Phospholipase C gamma1 (PLC-.1). An integrin binding assay and luciferase assay were performed for identification of the integrin target of EGT022. Results: Angiogenesis including proliferation, migration, tube formation, and permeability was significantly inhibited by EGT022 in HUVEC cells. Our findings also demonstrated that EGT022 binds directly to integrin av ss 3, induces dephosphorylation of integrin ss 3, and inhibits phosphorylation of VEGFR2. In addition, phosphorylation of PLC-.1 and activation of Nuclear Factor of Activated T-cell (NFAT), a downstream pathway of VEGF, are inhibited by EGT022 in HUVEC cells. Conclusion: These results clearly demonstrate the anti-angiogenic role played by EGT022 as a potent antagonist of integrin ss 3 in endothelial cells.