An optimized procedure for exosome isolation and analysis using serum samples: Application to cancer biomarker discovery

Methods. 2015 Oct 1:87:26-30. doi: 10.1016/j.ymeth.2015.03.009. Epub 2015 Mar 24.

Abstract

Exosomes are RNA and protein-containing nanovesicles secreted by all cell types and found in abundance in body fluids, including blood, urine and cerebrospinal fluid. These vesicles seem to be a perfect source of biomarkers, as their cargo largely reflects the content of parental cells, and exosomes originating from all organs can be obtained from circulation through minimally invasive or non-invasive means. Here we describe an optimized procedure for exosome isolation and analysis using clinical samples, starting from quick and robust extraction of exosomes with Total exosome isolation reagent, then isolation of RNA followed by qRT-PCR. Effectiveness of this workflow is exemplified by analysis of the miRNA content of exosomes derived from serum samples - obtained from the patients with metastatic prostate cancer, treated prostate cancer patients who have undergone prostatectomy, and control patients without prostate cancer. Three promising exosomal microRNA biomarkers were identified, discriminating these groups: hsa-miR375, hsa-miR21, hsa-miR574.

Keywords: Biomarker; Blood; Exosome; Extracellular vesicle; Prostate cancer; miRNA; microRNA.

MeSH terms

  • Biomarkers, Tumor / blood*
  • Biomarkers, Tumor / genetics
  • Biomarkers, Tumor / isolation & purification
  • Case-Control Studies
  • Exosomes / chemistry*
  • Gene Expression
  • Humans
  • Indicators and Reagents / chemistry
  • Male
  • MicroRNAs / blood*
  • MicroRNAs / genetics
  • Prostate-Specific Antigen / blood
  • Prostate-Specific Antigen / genetics
  • Prostatectomy
  • Prostatic Neoplasms / chemistry*
  • Prostatic Neoplasms / diagnosis
  • Prostatic Neoplasms / genetics
  • Prostatic Neoplasms / surgery
  • RNA, Neoplasm / blood
  • RNA, Neoplasm / genetics
  • RNA, Neoplasm / isolation & purification
  • Reverse Transcriptase Polymerase Chain Reaction

Substances

  • Biomarkers, Tumor
  • Indicators and Reagents
  • MIRN21 microRNA, human
  • MIRN375 microRNA, human
  • MIRN574 microRNA, human
  • MicroRNAs
  • RNA, Neoplasm
  • Prostate-Specific Antigen