Table 1.

Inhibition of biotinylated fibronectin binding to α_Vβ₆ integrin compared with inhibition of biotinylated vitronectin binding to α_Vβ₃.

Compound	αVβ6 IC50 [nM] 1	αVβ3 IC50 [nM] 2	IC50 (αVβ6)/IC50 (αVβ3)
1a c[RGDf(N-Me)V]	82.8 ± 4.9	0.71 ± 0.06	117
1b c[RGDfV]	104.7 ± 18.9	3.2 ± 1.3	33
1c c[RGDfK]	52.0 ± 23.8	1.4 ± 0.2	37
2	345.0 ± 1.0	3.2 ± 2.7	108
3	95.6 ± 24.6	4.5 ± 1.1	21
4	95.3 ± 4.9	7.6 ± 4.3	13
5	173.5 ± 52.5	12.6 ± 5.0	14
6	76.6 ± 4.2	2.1 ± 0.6	37
7	2.3 ± 0.8	0.2 ± 0.09	12
8 c[DKP-3-RAD]	4095 ± 1425	1500 ± 540	3

¹ IC₅₀ values were calculated as the concentration of compound required for 50% inhibition of biotinylated fibronectin binding as estimated by GraphPad Prism software; all values are the arithmetic mean ± SD of triplicate determinations. ² Calculated as the concentration of compound required for 50% inhibition of biotinylated vitronectin binding [24].