| In Vitro | In vitro activity: Cilengitide is a cyclized pentapeptide peptidomimetic designed to compete for the arginine-glycine-aspartic acid (RGD) peptide sequence that regulates integrin-ligand binding. Cilengitide selectively and potently blocks the ligation of theαvβ3 andαvβ5 integrins to provisional matrix proteins such as vitronectin, fibronectin, fibrinogen, von Willebrand factor, osteopontin, and others. Cilegitide inhibits angiogenesis in vitro. 10 μM Cilengitide completely inhibits attachment of BAE, BME and HUVE cells on vitronectin and fibronectin. Cilengitide inhibits in vitro angiogenesis of BAE cells on three-dimensional collagen and fibrin gels pretreated with FGF-2(or VEGF-A) with IC50 of 15 μM and 8 μM, 4 μM and 3 μM, respectively. Cilengitide blocks proliferation and induces apoptosis of endothelial cells as well as differentiation of human endothelial precursor cells (EPCs). 50 μg/mL Cilengitide completely inhibits the proliferation of human microvascular endothelial cell line HMEC-1 and leads to apoptosis in ~30% cells. 1.0 μM Cilengitide treating for 9 days inhibits the proliferation of EPCs by nearly 40%. 1 μM Cilengitide inhibits the differentiation of EPCs by more than 80% at 14 days. Cilengitide inhibits adhesion and induces apoptosis of tumor cells. 25 μg/mL Cilengitide causes detachment of DAOY cells (medulloblastoma) and U87MG cells (glioblastoma) from vitronectin and tenascin by more than 60%. 25 μg/mL Cilengitide induces a nearly 50% apoptosis rate of these cells.
Kinase Assay: Recombinant soluble integrins are immobilized, and peptides, which are serially diluted in Tris-buffered saline (TBS++) (0.1% (w/v) BSA, 150 mM NaCl, 1 mM CaCl2, 1 mM MgCl2 10 μM MnCl2, 20 mM Tris-HCl; pH 7.4), are added in parallel with biotinylated vitronectin (to 1μg/mL). After a 3-h incubation at 37℃ and washing with Tris–buffered saline, bound ligand is detected by incubation with an antibiotin alkaline phosphatase-conjugated antibody (BioRad) followed by development with p-nitrophenyl phosphatase substrate. The reaction is stopped by the addition of NaOH and the color intensity read at 405 nm.
Cell Assay: HMEC-1 (1×104 per well) are seeded on uncoated 48 well plates and incubated in medium containing 4% FCS with Cilengitide. After incubation for 72 hours at 37℃, cells are trypsinized and counted. |
|---|
