title: A novel androgen signalling pathway uses dihydrotestosterone, but not testosterone, to activate the EGF receptor signalling cascade in prostate stromal cells.
abstract: OBJECTIVE
  Human prostate growth and function are tightly controlled by androgens that are generally thought to exert their effects by regulating gene transcription. However, a rapid, non-genomic steroid action, often involving an elevation of intracellular calcium ([Ca(2+) ]i ), has also been described in a number of cell types. In this study we investigate whether androgens acutely regulate [Ca(2+) ]i in stromal cells derived from the human prostate.
  
  
  METHODS
  Human-cultured prostatic stromal cells (HCPSCs) were loaded with the calcium-sensitive fluorophore, fura-2-acetoxymethyl ester (FURA-2AM) (10 μM). Changes in [Ca(2+) ]i in response to the androgens, dihydrotestosterone (DHT) and testosterone, as well as EGF were measured by fluorescence microscopy.
  
  
  RESULTS
  DHT, but not testosterone (0.03-300 nM), elicited concentration-dependent elevations of [Ca(2+) ]i within 1 min of addition. These responses were blocked by the androgen receptor antagonist, flutamide (10 μM); the sarcoplasmic reticulum ATPase pump inhibitor, thapsigargin (1 μM); the inositol trisphosphate receptor inhibitor, 2-aminoethyldiphenyl borate (50 μM) and the PLC inhibitor, U-73122 (1 μM). Responses were also blocked by the L-type calcium channel blocker, nifedipine (1 μM), and by removal of extracellular calcium. A similar transient elevation of [Ca(2+) ]i was elicited by EGF (100 ng·mL(-1) ). The EGF receptor inhibitor, AG 1478 (30 nM), and the MMP inhibitor, marimastat (100 nM), blocked the DHT-induced elevation of [Ca(2+) ]i .
  
  
  CONCLUSIONS
  These studies show that DHT elicits an androgen receptor-dependent acute elevation of [Ca(2+) ]i in HCPSC, most likely by activating EGF receptor signalling.
authors.affiliation: Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), Parkville, Vic., Australia.
authors.forename: V L
authors.initials: VL
authors.lastname: Oliver
authors.forename: K
authors.initials: K
authors.lastname: Poulios
authors.forename: S
authors.initials: S
authors.lastname: Ventura
authors.forename: J M
authors.initials: JM
authors.lastname: Haynes
mesh_terms: D059002:Androgen Receptor Antagonists / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects*; D002478:Cells, Cultured; D013196:Dihydrotestosterone / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006801:Humans; D008297:Male; D061965:Matrix Metalloproteinase Inhibitors / Q000494:pharmacology; D011467:Prostate / Q000187:drug effects* / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011944:Receptors, Androgen / Q000187:drug effects / Q000378:metabolism; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000037:antagonists & inhibitors / Q000378:metabolism; D017154:Stromal Cells / Q000187:drug effects* / Q000378:metabolism; D013739:Testosterone / Q000494:pharmacology*; D013997:Time Factors; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: C410798:AR protein, human; D059002:Androgen Receptor Antagonists; D061965:Matrix Metalloproteinase Inhibitors; D047428:Protein Kinase Inhibitors; D011944:Receptors, Androgen; D013196:Dihydrotestosterone; D013739:Testosterone; C512478:EGFR protein, human; D066246:ErbB Receptors; D010738:Type C Phospholipases; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases
keywords: EGF; dihydrotestosterone; human-cultured prostatic stromal cells; intracellular calcium; non-genomic androgen signalling