title: Induction of apoptosis in cultured endothelial cells by a cadherin antagonist peptide: involvement of fibroblast growth factor receptor-mediated signalling.
abstract: Cadherins are a family of transmembrane glycoproteins mediating calcium-dependent, homophilic cell-cell adhesion. In addition, these molecules are involved in signaling events, regulating such processes as cell motility, proliferation, and apoptosis. Members of the cadherin subfamily, called either classical or type I cadherins, contain a highly conserved sequence at their homophilic binding site consisting of the three amino acids--histidine-alanine-valine (HAV). Previous studies have shown that peptides containing the HAV motif inhibit cadherin-dependent events such as cell aggregation, compaction, and neurite outgrowth. We report here that a cyclic peptide, N-Ac-CHAVC-NH2 can perturb cadherin-mediated endothelial cell interactions, resulting in a progressive apoptotic cell death. This effect depends on cell density, as it is only observed when dense cultures are treated with the peptide. Adherens junction (AJ)-associated cadherin and catenins are differentially affected by the N-Ac-CHAVC-NH2 treatment, as judged by double immunofluorescence labeling followed by immunofluorescence-ratio imaging. However, cell-cell adhesions are largely retained during the first few hours after addition of the peptide. It was also observed that following treatment, actin filaments partially lose their plasma membrane anchorage at AJs and translocate towards the cell center. Interestingly, addition of basic fibroblast growth factor to confluent, peptide-treated, endothelial cell cultures, completely blocks apoptosis and the inhibitory peptide reduce the phosphorylation of the FGF receptor target protein FRS2, suggesting that the peptide exerts its effect by inhibiting cadherin-mediated activation of fibroblast growth factor receptor signaling. We propose that cadherin-mediated signaling is essential for maintaining viability of confluent endothelial cells, and that its perturbation by N-Ac-CHAVC-NH2 drives these cells to apoptosis.
authors.affiliation: Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Noam
authors.initials: N
authors.lastname: Erez
authors.forename: Eli
authors.initials: E
authors.lastname: Zamir
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Gour
authors.forename: Orest W
authors.initials: OW
authors.lastname: Blaschuk
authors.forename: Benjamin
authors.initials: B
authors.lastname: Geiger
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing; D022005:Adherens Junctions / Q000187:drug effects / Q000378:metabolism; D020816:Amino Acid Motifs / Q000502:physiology; D000595:Amino Acid Sequence / Q000502:physiology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D015820:Cadherins / Q000187:drug effects / Q000378:metabolism*; D002417:Cattle; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology*; D002450:Cell Communication / Q000187:drug effects / Q000502:physiology*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D008565:Membrane Proteins / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D010455:Peptides / Q000494:pharmacology; D010750:Phosphoproteins / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D017468:Receptors, Fibroblast Growth Factor / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D015820:Cadherins; C106534:FRS2 protein, human; D008565:Membrane Proteins; D010455:Peptides; D010750:Phosphoproteins; D017468:Receptors, Fibroblast Growth Factor; D016222:Fibroblast Growth Factor 2