title: Isolation of prostate cancer-related exosomes.
abstract: OBJECTIVE
  Exosomes have been demonstrated to be useful non-invasive biomarkers for several cancers including prostate cancer. Since normal cells also secrete exosomes, isolation of cancer-derived exosomes from blood is a prerequisite for their better understanding. The aim of this study is to establish the method for isolation of prostate cancer-related exosomes from blood.
  
  
  METHODS
  Exosomes were collected from prostate cancer LNCaP and PC-3 cell lines by ultracentrifugation and by using magnetic beads conjugated with anti-CD9 antibody and anti-prostate-specific membrane antigen (PSMA) antibody. Prostate cancer-related exosomes were also isolated from the plasma of prostate cancer patients by anti-PSMA beads. Isolated exosomes were analyzed by western blotting.
  
  
  RESULTS
  Exosomes were isolated from LNCaP cells by ultracentrifugation, contained PSMA and androgen receptor (AR). AR was also detected in exosomes isolated from LNCaP cells by anti-PSMA and anti-CD9 beads, showing that AR is present in prostate cancer-related exosomes. The amount of CD9 in isolated exosomes was much higher in advanced and chemo-resistant prostate cancer patients than in prostate cancer patients without metastasis and healthy volunteers, indicating that patients with aggressive prostate cancer exhibit higher levels of prostate cancer-related exosomes in blood.
  
  
  CONCLUSIONS
  The immunoaffinity-based method we developed is capable of isolating prostate cancer-related exosomes from blood, the use of which will enhance investigation processes on exosomes in prostate cancer.
authors: Department of Urology, Gifu University Graduate School of Medicine, Gifu, Japan mizutech@gifu-u.ac.jp.
authors: Kosuke
authors: K
authors: Mizutani
authors: Department of Urology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors: Riyako
authors: R
authors: Terazawa
authors: Department of Urology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors: Koji
authors: K
authors: Kameyama
authors: Department of Urology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors: Taku
authors: T
authors: Kato
authors: Department of Urology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors: Kengo
authors: K
authors: Horie
authors: Department of Urology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors: Tomohiro
authors: T
authors: Tsuchiya
authors: Department of Urology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors: Kensaku
authors: K
authors: Seike
authors: Urology, Asahi University Murakami Memorial Hospital, Gifu, Japan.
authors: Hidetoshi
authors: H
authors: Ehara
authors: Research Team for Mechanism of Aging, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo, Japan.
authors: Yasunori
authors: Y
authors: Fujita
authors: Research Team for Mechanism of Aging, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo, Japan.
authors: Kyojiro
authors: K
authors: Kawakami
authors: Research Team for Mechanism of Aging, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo, Japan.
authors: Masafumi
authors: M
authors: Ito
authors: Department of Urology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors: Takashi
authors: T
authors: Deguchi
mesh_terms: D015153:Blotting, Western; D016022:Case-Control Studies; D045744:Cell Line, Tumor; D055354:Exosomes / Q000737:chemistry* / Q000473:pathology*; D006801:Humans; D008297:Male; D009367:Neoplasm Staging; D064129:Prostatic Neoplasms, Castration-Resistant / Q000097:blood* / Q000648:ultrastructure*; D014461:Ultracentrifugation
keywords: LNCaP; Prostate cancer; androgen receptor; exosome; microvesicle; prostate-specific membrane antigen