Selective avb3 receptor peptide antagonist for therapeutic and diagnostic applications.

Peptide contg. a cyclic RGD motif and two echistatin C-terminal moieties covalently linked by a spacer having the following formula: AA1-Arg-Gly-Asp-AA2-(Xaa)n-L-(Yaa)m [AA1 and AA2 = a-amino acid contg. at least three functional groups, selected from Cys, Asp, Glu, Lys, Orn, Pen, Dab or Dab; L = linker sequence consisting of 0 - 2 amino acid residues from; (Xaa)n = amino acid sequence in which n = 1 - 3 , which sequence is substantially homolog to that of 28-30 of echistatin: MDD; (Yaa)m = amino acid sequence in which m = 2 - 9, which sequence is substantially homolog to that of C-terminus (41-49) of echistatin: RNPHKGPAT] were prepd. as selective avb3 integrin antagonists for therapeutic and diagnostic applications. All peptides were prepd. by solid phase peptide synthesis using Fmoc (Fmoc = 9-fluorenylmethoxycarbonyl) strategy and were tested for their ability to inhibit cell adhesion to vitronectin.