title: Androgen receptor (AR) inhibitor ErbB3-binding protein-1 (Ebp1) is not targeted by the newly identified AR controlling signaling axis heat-shock protein HSP27 and microRNA miR-1 in prostate cancer cells.
abstract: OBJECTIVE
  Androgen receptor (AR) networks are predominantly involved in prostate cancer (PCa) progression; consequently, factors of AR regulation represent promising targets for PCa therapy. The ErbB3-binding protein 1 (Ebp1) is linked to AR suppression and chemoresistance by so far unknown mechanisms. In this study, an assumed regulation of Ebp1 by the newly identified AR controlling signaling axis heat-shock protein 27 (HSP27)-microRNA-1 (miR-1) was examined.
  
  
  METHODS
  Transfection experiments were carried out overexpressing and knockdown HSP27 and miR-1, respectively, in LNCaP and PC-3 cells. Afterward, HSP27- and miR-1-triggered Ebp1 protein expression was monitored by Western blotting.
  
  
  RESULTS
  AR-positive LNCaP cells and AR-negative PC-3 cells possessed diverse basal expression levels of Ebp1. However, subsequent studies revealed no differences in cellular Ebp1 concentrations after modulation of HSP27 and miR-1. Furthermore, docetaxel incubation experiments exhibited no effects on Ebp1 protein synthesis.
  
  
  CONCLUSIONS
  In PCa, Ebp1 has been described as a regulator of AR functionality and as an effector of PCa therapy resistance. Our data suggest that Ebp1 functionality is independent from heat-shock-protein-regulated progression networks in PCa.
authors.affiliation: Department of Urology, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, 17475, Greifswald, Germany, matthias.stope@uni-greifswald.de.
authors.forename: Matthias B
authors.initials: MB
authors.lastname: Stope
authors.forename: Stefanie
authors.initials: S
authors.lastname: Peters
authors.forename: Hannah
authors.initials: H
authors.lastname: Großebrummel
authors.forename: Uwe
authors.initials: U
authors.lastname: Zimmermann
authors.forename: Reinhard
authors.initials: R
authors.lastname: Walther
authors.forename: Martin
authors.initials: M
authors.lastname: Burchardt
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000502:physiology*; D000230:Adenocarcinoma / Q000473:pathology / Q000503:physiopathology*; D000970:Antineoplastic Agents / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000502:physiology; D002478:Cells, Cultured; D018450:Disease Progression; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology; D055551:HSP27 Heat-Shock Proteins / Q000502:physiology*; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000502:physiology*; D011471:Prostatic Neoplasms / Q000473:pathology / Q000503:physiopathology*; D016601:RNA-Binding Proteins / Q000502:physiology*; D011944:Receptors, Androgen / Q000187:drug effects / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D014162:Transfection
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000970:Antineoplastic Agents; D055551:HSP27 Heat-Shock Proteins; C544547:MIRN1 microRNA, human; D035683:MicroRNAs; C101633:PA2G4 protein, human; D016601:RNA-Binding Proteins; D011944:Receptors, Androgen