Table 1.
IC50 values measured from competitive binding assays to αvβ3 and α5β1 integrins.
| Compound | αvβ3 IC50 [nM] [a] | α5β1 IC50 [nM] [a] |
|---|---|---|
| Cilengitide (1a) | 0.71 ± 0.06 | 14.4 ± 3.1 |
| cyclo-[-Arg-Gly-Asp-d-Phe-Val-] (1b) | 3.2 ± 1.3 | 166 ± 28 |
| cyclo-[-DKP-Arg-Gly-Asp-] (4) | 4.5 ± 1.1 | 532 ± 35 |
| cyclo-[-Arg-Gly-Asp-(1S,2R)-β-ACPC-Val-] (8) | 44.3 ± 4.0 | 3227 ± 1468 |
| cyclo-[-Arg-Gly-Asp-(1R,2S)-β-ACPC-Val-] (9) | 39.0 ± 1.1 | 468 ± 114 |
| cyclo-(-DKP-isoAsp-Gly-Arg-) (7) | 9.2 ± 1.1 | 1066 ± 228 |
| cyclo-[-isoAsp-Gly-Arg-(1R,2S)-β-ACPC-Val-] (10) | 5362 ± 281 | 2331 ± 134 |
[a] IC50 values were calculated as the concentration of compound required for 50% inhibition of biotinylated vitronectin or fibronectin binding. Screening assays were performed by incubating the immobilized integrin αvβ3 or α5β1 with increasing concentrations (10−12–10−5 M/10−11–10−4 M) of the RGD and isoDGR ligands in the presence of the corresponding biotinylated ECM (extracellular matrix) protein (1 μg mL−1), and measuring bound protein in the presence of the competitive ligand. Each data point is the result of the average of triplicate wells and was analyzed by nonlinear regression analysis with the GraphPad Prism software. Each experiment was repeated in duplicate. All values shown are the arithmetic mean ± the standard deviation (SD) of these duplicate determinations.