Inhibition of Cell Adhesion by Peptides Derived from the EC-4 Domain of E-Cadherin

The objective of this project was to evaluate the biological activity of peptides derived from the EC-4 domain of E-cadherin in inhibiting E-cadherin-mediated cell-cell adhesion. The activity of these peptides was determined by inhibition of Caco-2 single cells that bind to a Caco-2 monolayer and inhibition of junction resealing of MDCK II cell monolayers. The results showed that peptide 6 (LVVQAADLQG) derived from the EC-2 domain and peptide 8 derived from the EC-4 domain (YTALIIATDN) of E-cadherin were more effective in inhibiting single cell adhesion than peptides from other domains (EC-1, EC-3) of E-cadherin. Peptide 8 had better activity than peptide 6. From overlapping hexapeptides derived from peptide 8, it was found that peptide 12 with ALIIAT sequence had the best activity, suggesting that it was the activity sequence of peptide 8. Alanine-scanning and mutation experiments found that peptide 22 (TEIIAT) had the best activity compared to other hexapeptides derived from peptide 8 in inhibiting cell adhesion of Caco-2 cells and junction resealing of MDCK-II cell monolayers