title: Agonist monoclonal antibodies against HGF receptor protect cardiac muscle cells from apoptosis.
abstract: Hepatocyte growth factor (HGF), a pleiotropic cytokine with mitogenic, motogenic, morphogenic, and antiapoptotic effects in various cell types, is a cardioprotective growth factor that can counteract the loss of cardiomyocytes usually observed in cardiac diseases. HGF is a quite unstable molecule in its biologically active heterodimeric form. Since all HGF-induced biological responses are mediated by its high-affinity tyrosine kinase receptor (Met/HGF-R) encoded by the Met gene, we asked whether a monoclonal antibody (MAb) that displays receptor full agonist activity could protect cardiac muscle cell lines from hydrogen peroxide-induced apoptosis. We report that the MAb efficiently inhibited hydrogen peroxide-induced cell shrinkage, DNA fragmentation, annexin V positivity, mitochondrial translocation of bax, and caspase activation. The MAb was thus able to counteract apoptosis evaluated by both morphological and biochemical criteria. The agonist activity of the MAb was mediated by Met/HGF-R, since a Met/HGF-R-specific short hairpin RNA (shRNA) inhibited both activation of transduction pathways and motility triggered by MAb DO-24. The protective antiapoptotic effect of MAb DO-24 was dependent on activation of the ras-MAPK Erk1/2 and phosphatidylinositol 3-kinase (PI3-kinase)-Akt transduction pathways, since it was abrogated by treatments with their specific pharmacological inhibitors, PD-98059 and wortmannin. Moreover, the MAb induced a motogenic, but not mitogenic, response in these cells, mimicking in all aspects the natural ligand HGF but displaying a significant higher stability than HGF in culture. This MAb may thus be a valuable substitute for HGF, being more easily available in a biologically active, highly stable, and purified form.
authors.affiliation: Dept. of Medical Sciences, Università del Piemonte Orientale "A. Avogadro," Novara, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Pietronave
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Forte
authors.forename: Deborah
authors.initials: D
authors.lastname: Locarno
authors.forename: Simone
authors.initials: S
authors.lastname: Merlin
authors.forename: Andrea
authors.initials: A
authors.lastname: Zamperone
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Nicotra
authors.forename: Ciro
authors.initials: C
authors.lastname: Isidoro
authors.forename: Paolo Di
authors.initials: PD
authors.lastname: Nardo
authors.forename: Maria
authors.initials: M
authors.lastname: Prat
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D004285:Dogs; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000494:pharmacology; D051379:Mice; D023421:Models, Animal; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D041681:NIH 3T3 Cells; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000187:drug effects / Q000378:metabolism; D019859:Proto-Oncogene Proteins c-met / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D016283:Proto-Oncogene Proteins p21(ras) / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D000911:Antibodies, Monoclonal; D006861:Hydrogen Peroxide; D019869:Phosphatidylinositol 3-Kinases; D019859:Proto-Oncogene Proteins c-met; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D016283:Proto-Oncogene Proteins p21(ras)