title: UBE4B levels are correlated with clinical outcomes in neuroblastoma patients and with altered neuroblastoma cell proliferation and sensitivity to epidermal growth factor receptor inhibitors.
abstract: BACKGROUND
  The UBE4B gene, which is located on chromosome 1p36, encodes a ubiquitin ligase that interacts with hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs), a protein involved in epidermal growth factor receptor (EGFR) trafficking, suggesting a link between EGFR trafficking and neuroblastoma pathogenesis. The authors analyzed the roles of UBE4B in the outcomes of patients with neuroblastoma and in neuroblastoma tumor cell proliferation, EGFR trafficking, and response to EGFR inhibition.
  
  
  METHODS
  The association between UBE4B expression and the survival of patients with neuroblastoma was examined using available microarray data sets. UBE4B and EGFR protein levels were measured in patient tumor samples, EGFR degradation rates were measured in neuroblastoma cell lines, and the effects of UBE4B on neuroblastoma tumor cell growth were analyzed. The effects of the EGFR inhibitor cetuximab were examined in neuroblastoma cells that expressed wild-type and mutant UBE4B.
  
  
  RESULTS
  Low UBE4B gene expression is associated with poor outcomes in patients with neuroblastoma. UBE4B overexpression reduced neuroblastoma tumor cell proliferation, and UBE4B expression was inversely related to EGFR expression in tumor samples. EGFR degradation rates correlated with cellular UBE4B levels. Enhanced expression of catalytically active UBE4B resulted in reduced sensitivity to EGFR inhibition.
  
  
  CONCLUSIONS
  The current study demonstrates associations between UBE4B expression and the outcomes of patients with neuroblastoma and between UBE4B and EGFR expression in neuroblastoma tumor samples. Moreover, levels of UBE4B influence neuroblastoma tumor cell proliferation, EGFR degradation, and response to EGFR inhibition. These results suggest UBE4B-mediated growth factor receptor trafficking may contribute to the poor prognosis of patients who have neuroblastoma tumors with 1p36 deletions and that UBE4B expression may be a marker that can predict responses of neuroblastoma tumors to treatment.
authors.affiliation: Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Houston, Texas, USA. zage@bcm.tmc.edu
authors.forename: Peter E
authors.initials: PE
authors.lastname: Zage
authors.forename: Natalie
authors.initials: N
authors.lastname: Sirisaengtaksin
authors.forename: Yin
authors.initials: Y
authors.lastname: Liu
authors.forename: Monica
authors.initials: M
authors.lastname: Gireud
authors.forename: Brandon S
authors.initials: BS
authors.lastname: Brown
authors.forename: Shana
authors.initials: S
authors.lastname: Palla
authors.forename: Kristen N
authors.initials: KN
authors.lastname: Richards
authors.forename: Dennis P M
authors.initials: DP
authors.lastname: Hughes
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Bean
mesh_terms: D000911:Antibodies, Monoclonal / Q000494:pharmacology; D061067:Antibodies, Monoclonal, Humanized; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D000068818:Cetuximab; D002872:Chromosome Deletion; D002878:Chromosomes, Human, Pair 1; D066246:ErbB Receptors / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006801:Humans; D009447:Neuroblastoma / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D016896:Treatment Outcome; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000378:metabolism*; D043743:Ubiquitin-Protein Ligase Complexes / Q000235:genetics* / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D025521:Tumor Suppressor Proteins; D043743:Ubiquitin-Protein Ligase Complexes; C473697:UBE4B protein, human; D044767:Ubiquitin-Protein Ligases; C512478:EGFR protein, human; D066246:ErbB Receptors; D000068818:Cetuximab