title: Malignant cell-derived extracellular vesicles express different chromogranin epitopes compared to prostasomes.
abstract: BACKGROUND
  Prostasomes are nanosized extracellular vesicles exocytosed by prostate epithelial cells. They have been assigned many roles propitious to sperm in favor of fertilization. Prostatic cancer cells can also produce and secrete extracellular vesicles.
  
  
  METHODS
  We assessed using ELISA, the surface expression of chromogranin proproteins on prostasomes and malignant extracellular vesicles of four different prostate cancer cell-lines, two hormone sensitive and two hormone refractory. We used a panel of chromogranin A and chromogranin B antibodies against peptides in-between hypothetical cleavage sites along the proproteins.
  
  
  RESULTS
  A diverging pattern of chromogranin peptides was apparent when comparing prostasomes and malignant extracellular vesicles indicating a phenotypical change. We also compared western blot patterns (prostasomes and malignant extracellular vesicles) for selected antibodies that displayed high absorbances in the ELISA. Western blot analyses revealed various cleavage patterns of those proproteins that were analyzed in prostasomes and extracellular vesicles.
  
  
  CONCLUSIONS
  Chromogranins are constituents of not only prostasomes but also of malignant prostate cell-derived extracellular vesicles with different amino acid sequences exposed at the membrane surface giving rise to a mosaic pattern. These findings may be of relevance for designing new assays for detection or even possible treatment of prostate cancers.
authors.affiliation: Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Louise
authors.initials: L
authors.lastname: Dubois
authors.affiliation: Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Mats
authors.initials: M
authors.lastname: Stridsberg
authors.affiliation: Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Pedram
authors.initials: P
authors.lastname: Kharaziha
authors.affiliation: Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Dimitris
authors.initials: D
authors.lastname: Chioureas
authors.affiliation: ERASMUS Student, KAHO Hogeschool, Ghent, Belgium.
authors.forename: Niels
authors.initials: N
authors.lastname: Meersman
authors.affiliation: Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Theocharis
authors.initials: T
authors.lastname: Panaretakis
authors.affiliation: Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: K Göran
authors.initials: KG
authors.lastname: Ronquist
mesh_terms: D015153:Blotting, Western; D045744:Cell Line, Tumor; D002864:Chromogranins / Q000032:analysis* / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells / Q000737:chemistry / Q000648:ultrastructure; D005089:Exocytosis; D055354:Exosomes / Q000737:chemistry* / Q000648:ultrastructure; D005110:Extracellular Space; D006801:Humans; D008297:Male; D046529:Microscopy, Electron, Transmission; D011471:Prostatic Neoplasms / Q000648:ultrastructure*; D012661:Semen
chemical_list: D002864:Chromogranins
keywords: DU145; LNCaP; PC3; chromogranins; extracellular vesicles; prostasomes; prostate cancer; synaptophysin