title: Insulin-like growth factor I receptor pathway inhibition by ADW742, alone or in combination with imatinib, doxorubicin, or vincristine, is a novel therapeutic approach in Ewing tumor.
abstract: OBJECTIVE
  Ewing tumor cell survival and proliferation depends on several autocrine loops. Targeting these loops is a promising therapeutic approach. We recently showed the cytostatic role of imatinib, an inhibitor of the SCF-KIT loop, on Ewing tumor cells, and in this study, we intend to analyze the inhibition of the insulin-like growth factor I receptor (IGF1R) loop.
  
  
  METHODS
  We analyzed IGF1R blockade by ADW742, a small molecule specific for this receptor, alone and in combination with imatinib, vincristine, and doxorubicin on Ewing tumor cell lines. We studied the effect on proliferation, apoptosis, cell cycle, pathway phosphorylation, soft-agar growth, motility, and vascular endothelial growth factor expression levels.
  
  
  RESULTS
  Treatment with ADW742 induced down-regulation of IGF1R/AKT/mammalian target of rapamycin (mTOR) phosphorylation, which was deeper in cell lines having higher IGF1R activation levels. Treatment also induced dose-dependent inhibition of cell proliferation (IC50 = 0.55-1.4 micromol/L), inducing a G1 phase blockage and apoptosis. Addition of imatinib to ADW742 synergistically augmented these effects and was especially effective in inhibiting AKT/mTOR phosphorylation and reducing vascular endothelial growth factor expression in cell lines having high IGF1R activation levels. Combination with usual chemotherapeutic agents vincristine and doxorubicin showed synergistic interactions.
  
  
  CONCLUSIONS
  Inhibition of Ewing tumor cell proliferation by ADW742 is mediated through blockade of IGF1R signaling. Combination of ADW742 with imatinib, vincristine, and doxorubicin induces a significant reduction of tumor cell growth, mainly by the increase in apoptosis with a pattern depending on IGF1R activation levels. This study supports a potential role for ADW742 in the treatment of Ewing tumor and AKT/mTOR as a possible surrogate marker of response to therapy.
authors.affiliation: Laboratory 20-Molecular Pathology, Centro de Investigación del Cáncer Instituto de Biología Molecular y Celular del Cáncer, Universidad de Salamanca-Consejo Superior de Investigaciones Cientificas, Salamanca, Spain.
authors.forename: Ana S
authors.initials: AS
authors.lastname: Martins
authors.forename: Carlos
authors.initials: C
authors.lastname: Mackintosh
authors.forename: David Herrero
authors.initials: DH
authors.lastname: Martín
authors.forename: Maria
authors.initials: M
authors.lastname: Campos
authors.forename: Teresa
authors.initials: T
authors.lastname: Hernández
authors.forename: Jose-Luis
authors.initials: JL
authors.lastname: Ordóñez
authors.forename: Enrique
authors.initials: E
authors.lastname: de Alava
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D001549:Benzamides; D001859:Bone Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects; D004317:Doxorubicin / Q000008:administration & dosage*; D004354:Drug Screening Assays, Antitumor; D016193:G1 Phase / Q000187:drug effects; D006801:Humans; D000068877:Imatinib Mesylate; D010766:Phosphorylation / Q000187:drug effects; D010879:Piperazines / Q000008:administration & dosage*; D011494:Protein Kinases / Q000187:drug effects / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000378:metabolism; D011743:Pyrimidines / Q000008:administration & dosage* / Q000494:pharmacology* / Q000627:therapeutic use; D011758:Pyrroles / Q000494:pharmacology* / Q000627:therapeutic use; D017526:Receptor, IGF Type 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D012512:Sarcoma, Ewing / Q000188:drug therapy* / Q000378:metabolism; D013329:Structure-Activity Relationship; D058570:TOR Serine-Threonine Kinases; D014750:Vincristine / Q000008:administration & dosage*
chemical_list: D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D011758:Pyrroles; D014750:Vincristine; D004317:Doxorubicin; D000068877:Imatinib Mesylate; D011494:Protein Kinases; C546842:MTOR protein, human; D017526:Receptor, IGF Type 1; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; C502355:NVP ADW742