title: Sorafenib blocks tumour growth, angiogenesis and metastatic potential in preclinical models of osteosarcoma through a mechanism potentially involving the inhibition of ERK1/2, MCL-1 and ezrin pathways.
abstract: BACKGROUND
  Osteosarcoma (OS) is the most common primary bone tumour in children and young adults. Despite improved prognosis, metastatic or relapsed OS remains largely incurable and no significant improvement has been observed in the last 20 years. Therefore, the search for alternative agents in OS is mandatory.
  
  
  RESULTS
  We investigated phospho-ERK 1/2, MCL-1, and phospho-Ezrin/Radixin/Moesin (P-ERM) as potential therapeutic targets in OS. Activation of these pathways was shown by immunohistochemistry in about 70% of cases and in all OS cell lines analyzed. Mutational analysis revealed no activating mutations in KRAS whereas BRAF gene was found to be mutated in 4/30 OS samples from patients. Based on these results we tested the multi-kinase inhibitor sorafenib (BAY 43-9006) in preclinical models of OS. Sorafenib inhibited OS cell line proliferation, induced apoptosis and downregulated P-ERK1/2, MCL-1, and P-ERM in a dose-dependent manner. The dephosphorylation of ERM was not due to ERK inhibition. The downregulation of MCL-1 led to an increase in apoptosis in OS cell lines. In chick embryo chorioallantoic membranes, OS supernatants induced angiogenesis, which was blocked by sorafenib and it was also shown that sorafenib reduced VEGF and MMP2 production. In addition, sorafenib treatment dramatically reduced tumour volume of OS xenografts and lung metastasis in SCID mice.
  
  
  CONCLUSIONS
  In conclusion, ERK1/2, MCL-1 and ERM pathways are shown to be active in OS. Sorafenib is able to inhibit their signal transduction, both in vitro and in vivo, displaying anti-tumoural activity, anti-angiogenic effects, and reducing metastatic colony formation in lungs. These data support the testing of sorafenib as a potential therapeutic option in metastatic or relapsed OS patients unresponsive to standard treatments.
authors.affiliation: Division of Medical Oncology, University of Torino Medical School, A,O, Ordine Mauriziano, Institute for Cancer Research and Treatment Candiolo, and Regina Margherita Children's Hospital, Torino, Italy. ymera.pignochino@ircc.it
authors.forename: Ymera
authors.initials: Y
authors.lastname: Pignochino
authors.forename: Giovanni
authors.initials: G
authors.lastname: Grignani
authors.forename: Giuliana
authors.initials: G
authors.lastname: Cavalloni
authors.forename: Manuela
authors.initials: M
authors.lastname: Motta
authors.forename: Marta
authors.initials: M
authors.lastname: Tapparo
authors.forename: Stefania
authors.initials: S
authors.lastname: Bruno
authors.forename: Alessia
authors.initials: A
authors.lastname: Bottos
authors.forename: Loretta
authors.initials: L
authors.lastname: Gammaitoni
authors.forename: Giorgia
authors.initials: G
authors.lastname: Migliardi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Camussi
authors.forename: Marco
authors.initials: M
authors.lastname: Alberghini
authors.forename: Bruno
authors.initials: B
authors.lastname: Torchio
authors.forename: Stefano
authors.initials: S
authors.lastname: Ferrari
authors.forename: Federico
authors.initials: F
authors.lastname: Bussolino
authors.forename: Franca
authors.initials: F
authors.lastname: Fagioli
authors.forename: Piero
authors.initials: P
authors.lastname: Picci
authors.forename: Massimo
authors.initials: M
authors.lastname: Aglietta
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D001557:Benzenesulfonates / Q000494:pharmacology / Q000627:therapeutic use*; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D003598:Cytoskeletal Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis; D061965:Matrix Metalloproteinase Inhibitors; D051379:Mice; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009362:Neoplasm Metastasis / Q000517:prevention & control; D009389:Neovascularization, Pathologic / Q000517:prevention & control; D009536:Niacinamide / Q000031:analogs & derivatives; D012516:Osteosarcoma / Q000098:blood supply / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D010671:Phenylurea Compounds; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology / Q000627:therapeutic use*; D000077157:Sorafenib; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D000099149:Ezrin
chemical_list: D000970:Antineoplastic Agents; D001557:Benzenesulfonates; D003598:Cytoskeletal Proteins; D048049:Extracellular Signal-Regulated MAP Kinases; D020778:Matrix Metalloproteinase 2; D061965:Matrix Metalloproteinase Inhibitors; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009536:Niacinamide; D010671:Phenylurea Compounds; D019253:Proto-Oncogene Proteins c-bcl-2; D011725:Pyridines; D000077157:Sorafenib; D042461:Vascular Endothelial Growth Factor A; D000099149:Ezrin; C579094:Mcl1 protein, mouse