Characterization of 5alpha-reductase gene expression in stroma and epithelium of human prostate.
The expression of 5alpha-reductase type 1 and type 2 isoenzymes in hyperplastic human prostate tissue and several human prostate cell lines was investigated by Northern blot analyses, reverse transcription-polymerase chain reaction (RT-PCR), and enzyme activity. Separation of stroma and epithelium was confirmed histologically and only preparations with no apparent contamination were employed in the subsequent studies. Poly(A)+ RNA was isolated from stromal and epithelial fractions and analysed by Northern blot and RT-PCR. Inhibition of epithelial and stromal 5alpha-reductase activities by 17beta-N,N-diethylcarbamoyl-4-methyl-4-aza-5alpha-androstan- 3-one (4MA) was assessed using a range of concentrations between 10(-13) and 10(-5) M. Results from Northern blot analyses and RT-PCR showed that the prostate stroma expressed 5alpha-reductase type 1 and type 2 isoenzymes, whereas the prostate epithelium only expressed 5alpha-reductase type 1. This was consistent with biphasic inhibition of 5alpha-reductase activity by 4MA in stroma and monophasic inhibition in epithelium. Cultured epithelial cells derived from human prostate only expressed 5alpha-reductase type 1 and had Vmax and Km values that approximated the lower end of the range reported for surgically removed prostate epithelium. The foregoing data explains the disparate activities of 5alpha-reductase, previously reported, in stroma and epithelium. The differential localization of these isoenzymes in the prostate suggests that future therapy of androgen-sensitive disease may be more successful through the use of selective inhibitors of the different 5alpha-reductase isoenzymes.
Bruchovsky
N
N
Department of Cancer Endocrinology, British Columbia Cancer Agency, Vancouver, Canada.
Sadar
M D
MD
Akakura
K
K
Goldenberg
S L
SL
Matsuoka
K
K
Rennie
P S
PS
D000368:Aged; D000726:Androgen Antagonists / Q000494:pharmacology; D001378:Azasteroids / Q000494:pharmacology; D015152:Blotting, Northern; D042944:Cholestenone 5 alpha-Reductase; D013196:Dihydrotestosterone / Q000031:analogs & derivatives / Q000494:pharmacology; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D006965:Hyperplasia / Q000201:enzymology / Q000235:genetics; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D010088:Oxidoreductases / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism*; D016133:Polymerase Chain Reaction / Q000379:methods; D011467:Prostate / Q000166:cytology* / Q000378:metabolism* / Q000473:pathology; D011471:Prostatic Neoplasms / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D012333:RNA, Messenger / Q000096:biosynthesis; D017154:Stromal Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D014407:Tumor Cells, Cultured
D000726:Androgen Antagonists; D001378:Azasteroids; D007527:Isoenzymes; D012333:RNA, Messenger; D013196:Dihydrotestosterone; C031563:17-N,N-diethylcarbamoyl-4-methyl-4-azaandrostane-3-one; D010088:Oxidoreductases; D042944:Cholestenone 5 alpha-Reductase