title: CD99 triggering in Ewing sarcoma delivers a lethal signal through p53 pathway reactivation and cooperates with doxorubicin.
abstract: OBJECTIVE
  The paucity of new drugs for the treatment of Ewing sarcoma (EWS) limits the cure of these patients. CD99 has a strong membranous expression in EWS cells and, being also necessary for tumor survival, is a suitable target to aim at. In this article, we described a novel human monospecific bivalent single-chain fragment variable diabody (dAbd C7) directed against CD99 of potential clinical application.
  
  
  METHODS
  In vitro and in vivo evaluation of cell death and of the molecular mechanisms triggered by anti-CD99 agents were performed alone or in combination with doxorubicin to demonstrate efficacy and selectivity of the new dAbd C7.
  
  
  RESULTS
  The dAbd C7 induced rapid and massive EWS cell death through Mdm2 degradation and p53 reactivation. Mdm2 overexpression as well as silencing of p53 in p53wt EWS cells decreased CD99-induced EWS cell death, whereas treatment with nutlin-3 enhanced it. Furthermore, cell death was associated with induction of p21, bax, and mitochondrial depolarization together with substantial inhibition of tumor cell proliferation. Combined treatment of anti-CD99 dAbd C7 with doxorubicin was additive both in vitro and in vivo against EWS xenografts. Normal mesenchymal stem cells showed no p53 activation and were resistant to cell death, unless transformed by EWS-FLI, the oncogenic driver of EWS.
  
  
  CONCLUSIONS
  These results indicate that dAbd C7 is a suitable candidate tool to target CD99 in patients with EWS able to spare normal stem cells from death as it needs an aberrant genetic context for the efficient delivery of CD99-triggered cell death.
authors.affiliation: CRS Development of Biomolecular Therapies, Experimental Oncology Laboratory, Istituto Ortopedico Rizzoli, Bologna, Italy. PROMETEO Laboratory, STB, RIT Department, Istituto Ortopedico Rizzoli, Bologna, Italy.
authors.forename: Clara
authors.initials: C
authors.lastname: Guerzoni
authors.affiliation: DIATHEVA s.r.l., Fano, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Fiori
authors.affiliation: CRS Development of Biomolecular Therapies, Experimental Oncology Laboratory, Istituto Ortopedico Rizzoli, Bologna, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Terracciano
authors.affiliation: CRS Development of Biomolecular Therapies, Experimental Oncology Laboratory, Istituto Ortopedico Rizzoli, Bologna, Italy. PROMETEO Laboratory, STB, RIT Department, Istituto Ortopedico Rizzoli, Bologna, Italy.
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Manara
authors.affiliation: DIATHEVA s.r.l., Fano, Italy.
authors.forename: Diego
authors.initials: D
authors.lastname: Moricoli
authors.affiliation: CRS Development of Biomolecular Therapies, Experimental Oncology Laboratory, Istituto Ortopedico Rizzoli, Bologna, Italy. PROMETEO Laboratory, STB, RIT Department, Istituto Ortopedico Rizzoli, Bologna, Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Pasello
authors.affiliation: CRS Development of Biomolecular Therapies, Experimental Oncology Laboratory, Istituto Ortopedico Rizzoli, Bologna, Italy.
authors.forename: Marika
authors.initials: M
authors.lastname: Sciandra
authors.affiliation: PROMETEO Laboratory, STB, RIT Department, Istituto Ortopedico Rizzoli, Bologna, Italy.
authors.forename: Giordano
authors.initials: G
authors.lastname: Nicoletti
authors.affiliation: Department of Medicine Research and Evaluation, Italian National Institute of Health, Rome, Italy.
authors.forename: Mara
authors.initials: M
authors.lastname: Gellini
authors.affiliation: Deparment of Biomolecular Sciences, Section of Biochemistry and Molecular Biology University of Urbino "Carlo Bo," Urbino, Italy.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Dominici
authors.affiliation: Molecular Immunology Unit, Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS "Istituto Nazionale dei Tumori," Milan, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Chiodoni
authors.affiliation: PROMETEO Laboratory, RIT Department, Istituto Ortopedico Rizzoli, Bologna, Italy.
authors.forename: Pier Maria
authors.initials: PM
authors.lastname: Fornasari
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine, Laboratory of Immunology and Biology of Metastasis, Bologna, Italy.
authors.forename: Pier-Luigi
authors.initials: PL
authors.lastname: Lollini
authors.affiliation: Molecular Immunology Unit, Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS "Istituto Nazionale dei Tumori," Milan, Italy.
authors.forename: Mario P
authors.initials: MP
authors.lastname: Colombo
authors.affiliation: CRS Development of Biomolecular Therapies, Experimental Oncology Laboratory, Istituto Ortopedico Rizzoli, Bologna, Italy. PROMETEO Laboratory, STB, RIT Department, Istituto Ortopedico Rizzoli, Bologna, Italy.
authors.forename: Piero
authors.initials: P
authors.lastname: Picci
authors.affiliation: Department of Medicine Research and Evaluation, Italian National Institute of Health, Rome, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Cianfriglia
authors.affiliation: DIATHEVA s.r.l., Fano, Italy. Deparment of Biomolecular Sciences, Section of Biochemistry and Molecular Biology University of Urbino "Carlo Bo," Urbino, Italy. katia.scotlandi@ior.it mauro.magnani@uniurb.it.
authors.forename: Mauro
authors.initials: M
authors.lastname: Magnani
authors.affiliation: CRS Development of Biomolecular Therapies, Experimental Oncology Laboratory, Istituto Ortopedico Rizzoli, Bologna, Italy. PROMETEO Laboratory, STB, RIT Department, Istituto Ortopedico Rizzoli, Bologna, Italy. katia.scotlandi@ior.it mauro.magnani@uniurb.it.
authors.forename: Katia
authors.initials: K
authors.lastname: Scotlandi
mesh_terms: D000071443:12E7 Antigen; D000888:Antibodies, Anti-Idiotypic / Q000008:administration & dosage / Q000276:immunology; D015703:Antigens, CD / Q000096:biosynthesis* / Q000276:immunology; D000971:Antineoplastic Combined Chemotherapy Protocols; D017209:Apoptosis / Q000187:drug effects*; D015815:Cell Adhesion Molecules / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000276:immunology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004317:Doxorubicin / Q000008:administration & dosage; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051736:Proto-Oncogene Proteins c-mdm2 / Q000096:biosynthesis / Q000235:genetics; D012512:Sarcoma, Ewing / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D057127:Single-Chain Antibodies / Q000008:administration & dosage*; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics; D023041:Xenograft Model Antitumor Assays
chemical_list: D000071443:12E7 Antigen; D000888:Antibodies, Anti-Idiotypic; D015703:Antigens, CD; C061828:CD99 protein, human; D015815:Cell Adhesion Molecules; D057127:Single-Chain Antibodies; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D004317:Doxorubicin; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2