title: RGD binding to integrin alphavbeta3 affects cell motility and adhesion in primary human breast cancer cultures.
abstract: Integrins mediate cell adhesion to the extracellular matrix. Integrin alphavbeta3 recognizes the RGD motif as a ligand-binding site and has been associated with high malignant potential in breast cancer cells, signaling the onset of widespread metastasis. In recent years, several antagonists of integrin alphavbeta3, including RGD peptides, have been used as potential anti-cancer agents. In the present work, the effect of the linear RGD hexapeptide GRGDSP was studied, for the first time, on breast tumor explants, as well as on well-spread human breast cancer cells from primary cultures, using the explant technique, to clarify the role of this peptide in the suppression of breast cancer cell migration. The results showed that incubation of breast tumor explants with RGD peptide at the beginning of culture development inhibited completely the migration of cancer cells out of the tissue fragment as revealed by electron microscopy. RGD incubation of well-spread breast cancer cells from primary culture resulted in rounding and shrinkage of the cells accompanied by altered distribution of integrin alphavbeta3 and concomitant F-actin cytoskeletal disorganization, as revealed by immunofluorescence. Electron immunocytochemistry showed aggregation of integrin alphavbeta3 at the cell periphery and its detection in noncoated vesicles. However, Western immunoblotting showed no change in beta3 subunit expression, despite the altered distribution of the integrin alphavbeta3. In light of the above, it appears that the RGD peptide plays an important role in the modulation of cell motility and in the perturbation of cell attachment affecting the malignant potential of breast cancer cells in primary cultures.
authors.affiliation: Laboratory of Histology and Embryology, Medical School, University of Athens, Athens, Greece.
authors.forename: Anastasios
authors.initials: A
authors.lastname: Georgoulis
authors.forename: Sophia
authors.initials: S
authors.lastname: Havaki
authors.forename: Yiannis
authors.initials: Y
authors.lastname: Drosos
authors.forename: Nikos
authors.initials: N
authors.lastname: Goutas
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Vlachodimitropoulos
authors.forename: Vassiliki
authors.initials: V
authors.lastname: Aleporou-Marinou
authors.forename: Christos
authors.initials: C
authors.lastname: Kittas
authors.forename: Evangelos
authors.initials: E
authors.lastname: Marinos
authors.forename: Mirsini
authors.initials: M
authors.lastname: Kouloukoussa
mesh_terms: D000199:Actins / Q000378:metabolism; D000970:Antineoplastic Agents / Q000378:metabolism / Q000494:pharmacology*; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000378:metabolism* / Q000648:ultrastructure; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism* / Q000648:ultrastructure; D002448:Cell Adhesion / Q000187:drug effects*; D002465:Cell Movement / Q000187:drug effects*; D048430:Cell Shape / Q000187:drug effects; D005260:Female; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D016253:Microscopy, Immunoelectron; D009842:Oligopeptides / Q000378:metabolism / Q000494:pharmacology*; D061251:Primary Cell Culture; D011485:Protein Binding; D046509:Tissue Culture Techniques; D014407:Tumor Cells, Cultured
chemical_list: D000199:Actins; D000970:Antineoplastic Agents; D039302:Integrin alphaVbeta3; D009842:Oligopeptides; C058161:glycyl-arginyl-glycyl-aspartyl-seryl-proline