N-cadherin involvement in the heterotypic adherence of malignant T-cells to epithelia.

N-cadherin, a cell adhesion molecule normally found in neural cell tissue, has been found recently to be expressed on the surface of malignant T-cells. The function of N-cadherin on these cells remains unclear. Heterotypic assays between Molt-3 T lymphoblastic leukemia cells and Caco-2 epithelial monolayers were examined under different conditions to assess the functional role of N-cadherin. The results indicate that adherence of Molt-3 cells to Caco-2 monolayers was reduced significantly following pretreatment of Molt-3 cells with 100 microM of an N-cadherin-derived antagonist decapeptide. In contrast, pretreatment of Molt-3 cells with an anti-N-cadherin antibody raised against the first 20 amino acids of N-cadherin sequence led to a surprisingly marked enhancement of Molt-3 cell adherence to Caco-2 monolayers. In addition, the presence of anti-N-cadherin antibody neutralized the inhibitory effect of anti-ICAM-1 on Molt-3 adhesion to Caco-2 monolayers. This novel finding demonstrates that external stimulus through the N-cadherin amino terminus can modulate adhesion of malignant T-cells to epithelia and may promote their ability to invade or metastasize to inflammatory sites.