Figure 1.

Examples of RGD peptide (1–4) or peptidomimetic (5) integrin ligands recognized by integrins expressed on cancer cells (e.g., αvβ3, α5β1). Functional groups exploitable for peptide conjugation are rendered in red. The α4β1-integrin selective antagonist BIO1211 contains the LDV binding motif and a diphenylurea moiety. The α/β-hybrid DS70 (6), designed as an analogue of BIO1211, includes a central β²-Pro scaffold.