Proteome profiling of neuroblastoma-derived exosomes reveal the expression of proteins potentially involved in tumor progression

PLoS One. 2013 Sep 19;8(9):e75054. doi: 10.1371/journal.pone.0075054. eCollection 2013.

Abstract

Neuroblastoma (NB) is the most common extracranial solid tumor in childhood, with grim prognosis in a half of patients. Exosomes are nanometer-sized membrane vesicles derived from the multivesicular bodies (MVBs) of the endocytic pathway and released by normal and neoplastic cells. Tumor-derived exosomes have been shown in different model systems to carry molecules that promote cancer growth and dissemination. In this respect, we have here performed the first characterization and proteomic analysis of exosomes isolated from human NB cell lines by filtration and ultracentrifugation. Electron microscopy demonstrated that NB-derived exosomes exhibited the characteristic cup-shaped morphology. Dynamic light scattering studies showed a bell-shaped curve and a polydispersity factor consistent with those of exosomes. Zeta potential values suggested a good nanoparticle stability. We performed proteomic analysis of NB-derived exosomes by two dimension liquid chromatography separation and mass spectrometry analyses using the multidimensional protein identification technology strategy. We found that the large majority of the proteins identified in NB derived exosomes are present in Exocarta database including tetraspanins, fibronectin, heat shock proteins, MVB proteins, cytoskeleton-related proteins, prominin-1 (CD133), basigin (CD147) and B7-H3 (CD276). Expression of the CD9, CD63 and CD81 tetraspanins, fibronectin, CD133, CD147 and CD276 was validated by flow cytometry. Noteworthy, flow cytometric analysis showed that NB-derived exosomes expressed the GD2 disialoganglioside, the most specific marker of NB. In conclusion, this study shows that NB-derived exosomes express a discrete set of molecules involved in defense response, cell differentiation, cell proliferation and regulation of other important biological process. Thus, NB-derived exosomes may play an important role in the modulation of tumor microenvironment and represent potential tumor biomarkers.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line, Tumor
  • Disease Progression
  • Exosomes / chemistry
  • Exosomes / metabolism*
  • Flow Cytometry
  • Gangliosides / chemistry
  • Gangliosides / metabolism
  • Humans
  • Neuroblastoma / genetics
  • Neuroblastoma / metabolism*
  • Proteome*
  • Proteomics* / methods
  • Reproducibility of Results

Substances

  • Gangliosides
  • Proteome
  • ganglioside, GD2

Grants and funding

This study was supported by: “Cinque per mille dell’IRPEF - Finanziamento della ricerca sanitaria”, Finanziamento Ricerca Corrente, Ministero Salute and by Associazione Italiana per la Ricerca sul Cancro (AIRC) project IG 13003 to Vito Pistoia; funds from Associazione Italiana per la Ricerca sul Cancro (AIRC) and Fondazione Compagnia San Paolo to Carlo Tacchetti. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.