Monitoring the Rab27 associated exosome pathway using nanoparticle tracking analysis

Exp Cell Res. 2013 Jul 15;319(12):1706-1713. doi: 10.1016/j.yexcr.2012.10.006. Epub 2012 Oct 22.


Exosomes are secreted by many cell types and display multiple biological functions. The ability to both rapidly detect and quantify exosomes in biological samples would assist in the screening of agents that interfere with their release, and which may therefore be of clinical relevance. Nanoparticle tracking analysis, which detects the size and concentration of exosomes, was used to monitor the inhibition of exosome secretion from MDA-MB-231 breast cancer cells expressing inhibitory RNA targeted for Rab27a, a known component of the exosome pathway. Inhibition of both Rab27a and Rab27b was observed, resulting in alterations to intracellular CD63+ compartments and the release of fewer exosomes into the culture medium, as determined by nanoparticle tracking analysis and confirmed by immunoblotting and protein quantification. These data show that nanoparticle tracking analysis can be used effectively and rapidly to monitor the disruption of exosome secretion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line, Tumor
  • Exosomes / metabolism*
  • Humans
  • Nanoparticles*
  • RNA, Small Interfering
  • Secretory Pathway*
  • Tetraspanin 30 / genetics
  • Tetraspanin 30 / metabolism
  • rab GTP-Binding Proteins / genetics
  • rab GTP-Binding Proteins / metabolism*
  • rab27 GTP-Binding Proteins


  • CD63 protein, human
  • RNA, Small Interfering
  • Tetraspanin 30
  • rab27 GTP-Binding Proteins
  • RAB27A protein, human
  • Rab27B protein, human
  • rab GTP-Binding Proteins