Detection of prostate cancer-specific transcripts in extracellular vesicles isolated from post-DRE urine

• Type of Material: Article
• Authors: Kathryn L. Pellegrini, Emory University; Dattatraya Patil, Emory University; Kristen J.S. Douglas, Emory University; Grace Lee, Emory University; Kathryn Wehrmeyer, Emory University; Mersiha Torlak, Emory University; Jeremy Clark, University of East Anglia; Colin S. Cooper, University of East Anglia; Carlos S Moreno, Emory University; Martin Sanda, Emory University
• Language: English
• Date: 2017-06-01
• Publisher: Wiley: 12 months
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2017 Wiley Periodicals, Inc.
• Final Published Version (URL): http://dx.doi.org/10.1002/pros.23355
• Title of Journal or Parent Work: Prostate
• ISSN: 0270-4137
• Volume: 77
• Issue: 9
• Start Page: 990
• End Page: 999
• Grant/Funding Information: Funding from the National Cancer Institute Early Detection Research Network (U01 CA113913) and the Movember Foundation (as part of the GAP1 Global Prostate Cancer Biomarker Initiative) supported this study.; The protocols for urine processing, EV purification, and RNA extraction from cell pellet and EVs were provided by the Cooper lab at the University of East Anglia, UK as part of the Movember Foundation GAP1 Global Prostate Cancer Biomarker Initiative.; Movember Foundation; National Cancer Institute, Grant number: U01 CA113913; NIH, Grant number: P30 CA138292, UL1 TR000454, S10 RR025679; Research reported in this publication was also supported in part by the Emory Integrated Genomics Core Shared Resource of the Winship Cancer Institute of Emory University (NIH/NCI award P30 CA138292), and the Robert P. Apkarian Integrated Electron Microscopy Core (subsidized by the Emory College of Arts and Sciences and Emory University School of Medicine with additional support provided by NIH UL1 TR000454) with data described here gathered on the JEOL JEM-1400 120 kV TEM (supported by NIH S10 RR025679).
• Keywords: DISEASE; GENE; PCA3; prostate cancer; EXOSOMES; Life Sciences & Biomedicine; BIOPSY; Urology & Nephrology; DIAGNOSIS; biomarkers; ERG; TMPRSS2-ERG FUSION TRANSCRIPTS; SEDIMENTS; BIOMARKERS; ASSAY; Endocrinology & Metabolism; Science & Technology
• Research Categories: Health Sciences, Pathology; Health Sciences, Oncology; Biology, Genetics

Abstract

Background: The measurement of gene expression in post-digital rectal examination (DRE) urine specimens provides a non-invasive method to determine a patient's risk of prostate cancer. Many currently available assays use whole urine or cell pellets for the analysis of prostate cancer-associated genes, although the use of extracellular vesicles (EVs) has also recently been of interest. We investigated the expression of prostate-, kidney-, and bladder-specific transcripts and known prostate cancer biomarkers in urine EVs. Methods: Cell pellets and EVs were recovered from post-DRE urine specimens, with the total RNA yield and quality determined by Bioanalyzer. The levels of prostate, kidney, and bladder-associated transcripts in EVs were assessed by TaqMan qPCR and targeted sequencing. Results: RNA was more consistently recovered from the urine EV specimens, with over 80% of the patients demonstrating higher RNA yields in the EV fraction as compared to urine cell pellets. The median EV RNA yield of 36.4 ng was significantly higher than the median urine cell pellet RNA yield of 4.8 ng. Analysis of the post-DRE urine EVs indicated that prostate-specific transcripts were more abundant than kidney- or bladder-specific transcripts. Additionally, patients with prostate cancer had significantly higher levels of the prostate cancer-associated genes PCA3 and ERG. Conclusions: Post-DRE urine EVs are a viable source of prostate-derived RNAs for biomarker discovery and prostate cancer status can be distinguished from analysis of these specimens. Continued analysis of urine EVs offers the potential discovery of novel biomarkers for pre-biopsy prostate cancer detection.