title: Outcome of the p53-mediated DNA damage response in neuroblastoma is determined by morphological subtype and MYCN expression.
abstract: BACKGROUND
  MYCN oncogene amplification occurs in 20-25% of neuroblastoma and is associated with a poor prognosis. We previously reported that MYCN amplified (MNA) p53 wild-type neuroblastoma cell lines failed to G1 arrest in response to irradiation, but this could not be attributed to MYCN alone.
  
  
  OBJECTIVE
  Genes co-amplified with MYCN and/or the predominant cell type, neuronal (N) or substrate adherent (S) phenotypes determine the downstream response to DNA damage in neuroblastoma cell lines.
  
  
  METHODS
  The MYCN amplicons of five MNA and two non-MNA cell line were mapped using 50K Single Nucleotide Polymorphism (SNP) arrays. One MNA (NBL-W) and one non-MNA neuroblastoma cell line (SKNSH) were sub-cloned into N and S-type cells and the p53 pathway investigated after irradiation induced DNA damage. To determine the role of p53 it was knocked down using siRNA.
  
  
  RESULTS
  No genes with a potential role in cell cycle regulation were consistently co-amplified in the MNA cell lines studied. High MYCN expressing NBLW-N cells failed to G1 arrest following irradiation and showed impaired induction of p21 and MDM2, whereas low MYCN expressing NBLW-S cells underwent a G1 arrest with induction of p21 and MDM2. Conversely N type cells underwent higher levels of apoptosis than S type cells. Following p53 knockdown in SHSY5Y N-type cells there was a decrease in apoptosis.
  
  
  CONCLUSIONS
  The downstream response to DNA damage in p53 wild-type neuroblastoma cell lines is p53 dependent, and determined both by the morphological sub-type and MYCN expression.
authors: Newcastle Cancer Centre, Northern Institute for Cancer Research, Newcastle University, Newcastle, UK.
authors: Jane
authors: J
authors: Carr-Wilkinson
authors: Rebecca
authors: R
authors: Griffiths
authors: Rebecca
authors: R
authors: Elston
authors: Laura D
authors: LD
authors: Gamble
authors: Bojidar
authors: B
authors: Goranov
authors: Christopher P F
authors: CP
authors: Redfern
authors: John
authors: J
authors: Lunec
authors: Deborah A
authors: DA
authors: Tweddle
mesh_terms: D045744:Cell Line, Tumor; D004249:DNA Damage; D004260:DNA Repair / Q000502:physiology*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D000071447:N-Myc Proto-Oncogene Protein; D009447:Neuroblastoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D015513:Oncogene Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D020641:Polymorphism, Single Nucleotide; D034622:RNA Interference; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors / Q000502:physiology*
chemical_list: C459801:MYCN protein, human; D000071447:N-Myc Proto-Oncogene Protein; D009687:Nuclear Proteins; D015513:Oncogene Proteins; D016159:Tumor Suppressor Protein p53