Truncated dipeptidyl peptidase IV is a potent anti-adhesion and anti-metastasis peptide for rat breast cancer cells.

A novel adhesion receptor/ligand pair was shown recently to mediate lung vascular arrest and metastasis of rat breast cancer cells. The interacting adhesion molecules are endothelial dipeptidyl peptidase IV (DPP IV) and tumor cell surface-associated, polymeric fibronectin (FN). A truncated DPP IV (DPP IV(31-767): amino acids 31-767) in which the FN-binding site is preserved is shown here to mask the breast cancer cell surface-associated FN complexes, causing a dose-dependent inhibition of adhesion to endothelial DPP IV and impeding lung colony formation by approximately 80%. Since surface accumulation of FN is chiefly occurring during dissemination in the blood and since many cancer cell types have surface receptors by which they may initiate FN accumulation on their surfaces, the present anti-metastatic treatment modality may extend its efficacy farther than appreciated by this study.