Comparative Study of Extracellular Vesicles from the Urine of Healthy Individuals and Prostate Cancer Patients

PLoS One. 2016 Jun 15;11(6):e0157566. doi: 10.1371/journal.pone.0157566. eCollection 2016.

Abstract

Recent studies suggest that extracellular vesicles may be the key to timely diagnosis and monitoring of genito-urological malignancies. In this study we investigated the composition and content of extracellular vesicles found in the urine of healthy donors and prostate cancer patients. Urine of 14 PCa patients and 20 healthy volunteers was clarified by low-speed centrifugation and total extracellular vesicles fraction was obtain by high-speed centrifugation. The exosome-enriched fraction was obtained by filtration of total extracellular vesicles through a 0.1 μm pore filter. Transmission electron microscopy showed that cell-free urine in both groups contained vesicles from 20 to 230 nm. Immunogold staining after ultrafiltration demonstrated that 95% and 90% of extracellular vesicles in healthy individuals and cancer patients, respectively, were exosomes. Protein, DNA and RNA concentrations as well as size distribution of extracellular vesicles in both fractions were analyzed. Only 75% of the total protein content of extracellular vesicles was associated with exosomes which amounted to 90-95% of all vesicles. Median DNA concentrations in total extracellular vesicles and exosome-enriched fractions were 18 pg/ml and 2.6 pg/ml urine, correspondingly. Urine extracellular vesicles carried a population of RNA molecules 25 nt to 200 nt in concentration of no more than 290 pg/ml of urine. Additionally, concentrations of miR-19b, miR-25, miR-125b, and miR-205 were quantified by qRT-PCR. MiRNAs were shown to be differently distributed between different fractions of extracellular vesicles. Detection of miR-19b versus miR-16 in total vesicles and exosome-enriched fractions achieved 100%/93% and 95%/79% specificity/sensitivity in distinguishing cancer patients from healthy individuals, respectively, demonstrating the diagnostic value of urine extracellular vesicles.

Publication types

  • Comparative Study

MeSH terms

  • Aged
  • Aged, 80 and over
  • Centrifugation / methods
  • DNA, Neoplasm / genetics
  • DNA, Neoplasm / urine
  • Exosomes / metabolism*
  • Exosomes / ultrastructure
  • Extracellular Vesicles / metabolism*
  • Extracellular Vesicles / ultrastructure
  • Humans
  • Male
  • MicroRNAs / genetics
  • MicroRNAs / urine
  • Microscopy, Electron, Transmission
  • Middle Aged
  • Neoplasm Proteins / metabolism
  • Neoplasm Proteins / urine
  • Prostatic Neoplasms / diagnosis
  • Prostatic Neoplasms / urine*
  • RNA, Neoplasm / genetics
  • RNA, Neoplasm / urine
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sensitivity and Specificity

Substances

  • DNA, Neoplasm
  • MIRN16 microRNA, human
  • MIRN19 microRNA, human
  • MicroRNAs
  • Neoplasm Proteins
  • RNA, Neoplasm

Grants and funding

This work was supported by Russian Science Foundation (project № 16-15-00124). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.