An all-D amino acid peptide model of alpha 1(IV)531-543 from type IV collagen binds the alpha(3)beta(1) integrin and mediates tumor cell adhesion, spreading, and motility

Type IV collagen promotes integrin-mediated cell adhesion, spreading, and motility. Several regions within the triple-helical domain of type IV collagen have been identified as tumor cellular recognition sites, Among these regions, the (alpha 1(IV)531-543 sequence, designated L-Hep-III, promotes integrin-mediated tumor cell adhesion and directly binds to the alpha(3) beta(1) integrin [Miles, A. J., et al. (1994) J. Biot. Chem. 269, 30939-30945; Miles, A, J.,, et al, (1995) J. Biol. Chem. 270, 29047-29050]. We have presently compared the activities of the all-D enantiomeric peptide model of alpha 1(IV)531-543, designated D-Hep-III, with L-Hep-III, for promoting the adhesion, spreading, and motility of metastatic melanoma and breast carcinoma cells, D-Hep-III was found to support melanoma and breast carcinoma cell adhesion, spreading, and motility in a dose-dependent fashion similar to that of L-Hep-m. The adhesions of melanoma and breast carcinoma cells to both type IV collagen and fibronectin were effectively inhibited by L-Hep-m and D-Hep-III, Melanoma cell invasion of the basement membrane was also inhibited by D-Hep-III, Characterization of the cell surface receptor for D-Hep-III was acheived via cell adhesion assays and affinity chromatography using monoclonal antibodies against integrin subunits, Immunoprecipitation analysis following EDTA elution from a D-Hep-III affinity column indicated that D-Hep-III binds to the alpha(3) beta(1) integrin but not to the alpha(2) or alpha(6) integrin subunits, In summary, these studies demonstrate that an all-D model of the alpha 1(IV)531-543 sequence mimics the biological activities of the all-L peptide. D-Hep-IU. is the first all-D peptide that has been shown to promote tumor cell adhesion, spreading, and migration, inhibit tumor cell adhesion and migration on type IV collagen and invasion of the basement membrane, and bind directly to an integrin. Due to the resistance to proteolysis, all-D receptor-binding peptides such as D-Hep-III have great potential for in vivo studies and as therapeutic agents.