title: Exosome-like Extracellular Vesicles from MYCN-amplified Neuroblastoma Cells Contain Oncogenic miRNAs.
abstract: BACKGROUND
  In recent years, evidence has accumulated indicating that both normal and cancer cells communicate via the release and delivery of macromolecules packed into extracellular membrane vesicles.
  
  
  METHODS
  We isolated nano-sized extracellular vesicles from MYCN-amplified neuroblastoma cell lines using ultracentrifugation and exosome precipitation (Exoquick) protocols. These vesicles were characterized by transmission electron microscopy (TEM), nanoparticle tracking analysis and western blotting. Exosomal miRNA profiles were obtained using a reverse transcription-polymerase chain reaction (RT-PCR) ready-to-use panel measuring a total of 742 miRNAs.
  
  
  RESULTS
  In this study, we showed that MYCN-amplified neuroblastoma cell lines secrete populations of miRNAs inside small exosome-like vesicular particles. These particles were shown to be taken-up by recipient cells. By profiling the miRNA content, we demonstrated high expression of a group of established oncomirs in exosomes from two MYCN-amplified neuroblastoma cell lines. Despite the fact that other studies have demonstrated the ability of exosomal miRNAs both to repress mRNA targets and to stimulate Toll-like receptor-8 (TLR8) signaling in recipient cells, we did not observe these effects with exosomes from MYCN-amplified neuroblastoma cells. However, functional enrichment analysis reveals that mRNA targets of highly expressed exosomal miRNAs are associated with a range of cellular and molecular functions related to cell growth and cell death.
  
  
  CONCLUSIONS
  MYCN-amplified neuroblastoma cell lines secrete exosome-like particles containing oncogenic miRNAs. This work showed for the first time that neuroblastoma cells secrete exosome-like particles containing miRNAs with potential roles in cancer progression. These findings indicate a new way for MYCN-amplified neuroblastoma cells to interact with the tumor environment.
authors.affiliation: Department of Pediatrics, University-Hospital of Northern-Norway (UNN), Tromsø, Norway.
authors.forename: Bjørn Helge
authors.initials: BH
authors.lastname: Haug
authors.affiliation: Pediatric Research Group, Department of Clinical Medicine, University of Tromsø, Tromsø, Norway.
authors.forename: Øyvind H
authors.initials: ØH
authors.lastname: Hald
authors.affiliation: Department of Pediatrics, University-Hospital of Northern-Norway (UNN), Tromsø, Norway.
authors.forename: Peter
authors.initials: P
authors.lastname: Utnes
authors.affiliation: Pediatric Research Group, Department of Clinical Medicine, University of Tromsø, Tromsø, Norway.
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Roth
authors.affiliation: Pediatric Research Group, Department of Clinical Medicine, University of Tromsø, Tromsø, Norway.
authors.forename: Cecilie
authors.initials: C
authors.lastname: Løkke
authors.affiliation: Department of Pediatrics, University-Hospital of Northern-Norway (UNN), Tromsø, Norway Pediatric Research Group, Department of Clinical Medicine, University of Tromsø, Tromsø, Norway.
authors.forename: Trond
authors.initials: T
authors.lastname: Flægstad
authors.affiliation: Department of Pediatrics, University-Hospital of Northern-Norway (UNN), Tromsø, Norway Pediatric Research Group, Department of Clinical Medicine, University of Tromsø, Tromsø, Norway christer.einvik@uit.no.
authors.forename: Christer
authors.initials: C
authors.lastname: Einvik
mesh_terms: D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000235:genetics; D055354:Exosomes / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D035683:MicroRNAs / Q000096:biosynthesis / Q000235:genetics*; D000071447:N-Myc Proto-Oncogene Protein; D009447:Neuroblastoma / Q000235:genetics* / Q000473:pathology; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics*; D015513:Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D051200:Toll-Like Receptor 8 / Q000096:biosynthesis
chemical_list: C459801:MYCN protein, human; D035683:MicroRNAs; D000071447:N-Myc Proto-Oncogene Protein; D009687:Nuclear Proteins; D015513:Oncogene Proteins; D012333:RNA, Messenger; C495349:TLR8 protein, human; D051200:Toll-Like Receptor 8
keywords: Exosome; miRNA; microRNA; neuroblastoma