Inhibition of E-Cadherin-Mediated Homotypic Adhesion of Caco-2 Cells: A Novel Evaluation Assay for Peptide Activities in Modulating Cell-Cell Adhesion

Transient modulation of E-cadherin-mediated cell-cell adhe-sion may improve paracellular drug delivery through biological barriers. Therefore, there is a need to develop an efficient method to evaluate cadherin peptides that can modulate the intercellular junctions. The objective of this study was to estab-lish a novel assay to evaluate peptide activity in modulating E-cadherin-mediated homophilic interactions, based on the homotypic adhesion of Caco-2 cells. Fluorescence-labeled Caco-2 single cells were incubated with Caco-2 monolayers that were treated beforehand with Ca2-free medium. The ho-motypic adhesion in the presence or absence of peptide and antibody was determined fluorometrically. The Ca2-deficient pretreatment dramatically increased the number of single cells bound to the monolayers. Immunofluorescence stainin