title: Crizotinib Synergizes with Chemotherapy in Preclinical Models of Neuroblastoma.
abstract: OBJECTIVE
  The presence of an ALK aberration correlates with inferior survival for patients with high-risk neuroblastoma. The emergence of ALK inhibitors such as crizotinib has provided novel treatment opportunities. However, certain ALK mutations result in de novo crizotinib resistance, and a phase I trial of crizotinib showed a lack of response in patients harboring those ALK mutations. Thus, understanding mechanisms of resistance and defining circumvention strategies for the clinic is critical.
  
  
  METHODS
  The sensitivity of human neuroblastoma-derived cell lines, cell line-derived, and patient-derived xenograft (PDX) models with varying ALK statuses to crizotinib combined with topotecan and cyclophosphamide (topo/cyclo) was examined. Cultured cells and xenografts were evaluated for effects of these drugs on proliferation, signaling, and cell death, and assessment of synergy.
  
  
  RESULTS
  In neuroblastoma murine xenografts harboring the most common ALK mutations, including those mutations associated with resistance to crizotinib (but not in those with wild-type ALK), crizotinib combined with topo/cyclo enhanced tumor responses and mouse event-free survival. Crizotinib + topo/cyclo showed synergistic cytotoxicity and higher caspase-dependent apoptosis than crizotinib or topo/cyclo alone in neuroblastoma cell lines with ALK aberrations (mutation or amplification).
  
  
  CONCLUSIONS
  Combining crizotinib with chemotherapeutic agents commonly used in treating newly diagnosed patients with high-risk neuroblastoma restores sensitivity in preclinical models harboring both sensitive ALK aberrations and de novo-resistant ALK mutations. These data support clinical testing of crizotinib and conventional chemotherapy with the goal of integrating ALK inhibition into multiagent therapy for ALK-aberrant neuroblastoma patients.
authors.affiliation: Division of Oncology and Center for Childhood Cancer Research, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.
authors.forename: Kateryna
authors.initials: K
authors.lastname: Krytska
authors.affiliation: Division of Oncology and Center for Childhood Cancer Research, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.
authors.forename: Hannah T
authors.initials: HT
authors.lastname: Ryles
authors.affiliation: Division of Oncology and Center for Childhood Cancer Research, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.
authors.forename: Renata
authors.initials: R
authors.lastname: Sano
authors.affiliation: Division of Oncology, The Center for Biomedical Informatics (CBMi), The Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania.
authors.forename: Pichai
authors.initials: P
authors.lastname: Raman
authors.affiliation: Division of Oncology and Center for Childhood Cancer Research, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.
authors.forename: Nicole R
authors.initials: NR
authors.lastname: Infarinato
authors.affiliation: Division of Oncology and Center for Childhood Cancer Research, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.
authors.forename: Theodore D
authors.initials: TD
authors.lastname: Hansel
authors.affiliation: Cancer Center, Texas Tech University Health Sciences Center School of Medicine, Lubbock, Texas.
authors.forename: Monish R
authors.initials: MR
authors.lastname: Makena
authors.affiliation: Cancer Center, Texas Tech University Health Sciences Center School of Medicine, Lubbock, Texas.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Song
authors.affiliation: Cancer Center, Texas Tech University Health Sciences Center School of Medicine, Lubbock, Texas.
authors.forename: C Patrick
authors.initials: CP
authors.lastname: Reynolds
authors.affiliation: Division of Oncology and Center for Childhood Cancer Research, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania. mosse@chop.edu.
authors.forename: Yael P
authors.initials: YP
authors.lastname: Mossé
mesh_terms: D000077548:Anaplastic Lymphoma Kinase; D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology / Q000627:therapeutic use*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D000077547:Crizotinib; D003520:Cyclophosphamide / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005260:Female; D006801:Humans; D020128:Inhibitory Concentration 50; D016513:Mice, SCID; D009154:Mutation; D009447:Neuroblastoma / Q000188:drug therapy* / Q000235:genetics; D011720:Pyrazoles / Q000008:administration & dosage; D011725:Pyridines / Q000008:administration & dosage; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics; D019772:Topotecan / Q000008:administration & dosage; D016159:Tumor Suppressor Protein p53 / Q000235:genetics; D023041:Xenograft Model Antitumor Assays
chemical_list: D011720:Pyrazoles; D011725:Pyridines; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D000077547:Crizotinib; D019772:Topotecan; D003520:Cyclophosphamide; C000626173:ALK protein, human; C000626174:Alk protein, mouse; D000077548:Anaplastic Lymphoma Kinase; D020794:Receptor Protein-Tyrosine Kinases