title: Alterations in the expression of inhibitors of apoptosis during differentiation of prostate epithelial cells.
abstract: OBJECTIVE
  To investigate alterations in the apoptotic phenotype, specifically the inhibitors of apoptosis (IAP) family, in prostate epithelial cells after differentiation from an apoptotic-resistant basal cell to an apoptotic-susceptible secretory cell.
  
  
  METHODS
  Cells of the immortalized human prostate epithelial line HPr-1AR were cultured with and with no 5alpha-dihydrotestosterone (DHT) to drive differentiation. Western blotting and reverse transcription-polymerase chain reaction (RT-PCR) were used to determine changes in differentiation markers such as cytokeratins (CK) 14 and 18, and in XIAP, cIAP-1 and cIAP-2. Flow cytometry was used to assess viability and apoptosis, by propidium iodide DNA staining of the cells during differentiation.
  
  
  RESULTS
  Morphological changes and the increased CK-18 and decreased CK-14 expression confirmed differentiation of cells towards a secretory phenotype. Real-time PCR and Western blotting confirmed the expression of the IAPs in the HPr-1AR cells. There was a time-dependent decrease in the mRNA expression of XIAP, cIAP-1 and cIAP-2 after treatment with DHT. Differentiation also resulted in decreased cIAP-1 and XIAP protein expression, but cIAP-2 remained unchanged. Spontaneous apoptosis was significantly increased during cellular differentiation.
  
  
  CONCLUSIONS
  We show for the first time that differentiation of HPr-1AR prostate epithelial cells results in the development of a transient end-stage cell that might be explained by the loss of the IAP family of proteins.
authors.affiliation: UCD School of Medicine and Medical Science, Conway Institute of Biomolecular and Biomedical Research, University College Dublin and Dublin Molecular Medicine Centre, Dublin, Ireland. ronanlong@hotmail.com
authors.forename: Ronan M
authors.initials: RM
authors.lastname: Long
authors.forename: Colm
authors.initials: C
authors.lastname: Morrissey
authors.forename: Sinead
authors.initials: S
authors.lastname: Walsh
authors.forename: Hilary J
authors.initials: HJ
authors.lastname: Hamilton
authors.forename: Nicole
authors.initials: N
authors.lastname: Farrell
authors.forename: Amanda
authors.initials: A
authors.lastname: O'Neill
authors.forename: John M
authors.initials: JM
authors.lastname: Fitzpatrick
authors.forename: William R
authors.initials: WR
authors.lastname: Watson
mesh_terms: D017209:Apoptosis / Q000502:physiology*; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism*; D000075747:Baculoviral IAP Repeat-Containing 3 Protein; D015153:Blotting, Western; D002454:Cell Differentiation / Q000502:physiology*; D004847:Epithelial Cells / Q000502:physiology*; D005434:Flow Cytometry; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins / Q000378:metabolism; D053547:Keratin-14 / Q000378:metabolism; D053538:Keratin-18 / Q000378:metabolism; D008297:Male; D011467:Prostate / Q000166:cytology*; D011471:Prostatic Neoplasms / Q000473:pathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D044767:Ubiquitin-Protein Ligases; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000378:metabolism
chemical_list: D051017:Apoptosis Regulatory Proteins; D051034:Inhibitor of Apoptosis Proteins; D053547:Keratin-14; D053538:Keratin-18; D051636:X-Linked Inhibitor of Apoptosis Protein; C494832:BIRC3 protein, human; D000075747:Baculoviral IAP Repeat-Containing 3 Protein; D044767:Ubiquitin-Protein Ligases