The peptide mimicking small extracellular loop domain of CD82 inhibits tumor cell migration, adhesion and induces apoptosis by inhibiting integrin mediated signaling

Within the extracellular domains of metastasis suppressor CD82, the large extracellular loop (EC2) has received much of the attention and its structure and function have been studied in detail. However, little attention has been given to the small extracellular loop (EC1 domain). To investigate the function role of EC1 in metastasis suppression of CD82, the peptide mimicking EC1 amino acid sequence (EC1-mP) was synthesized and its effect on cancer cells behavior was examined. Here, we reported that EC1-mP strongly inhibited cancer cell migration in vitro, attnuated the ability of cancer cells adhesion to fibronectin, and induced the apoptosis. Furthermore, the EC1-mP was showed to supprese the expressions of integrins α5 and β1, as well as decreased the phosphorylation of FAK and expression of ILK in SW620 cells. Taken together, these results demonstrate that this small peptide has the functional role of CD82 intact molecule. This novel finding will improve our understanding of the mechanism by which CD82 inhibits metastasis, and suggested that EC1 mimic peptide may be a promising candidate for developing anti-metastasis drugs.