Characterization of type I 5α-reductase activity in DU145 human prostatic adenocarcinoma cells

Martin Kaefer, James E. Audia, Nicholas Bruchovsky, Robin L. Goode, Kenneth C. Hsiao, Ilan Y. Leibovitch, Joseph H. Krushinski, Chung Lee, Christopher P. Steidle, Debra M. Sutkowski, Blake Lee Neubauer

Research output: Contribution to journalArticle

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Abstract

The conversion of testosterone (T) to dihydrotestosterone (DHT) has been demonstrated to be catalysed by at least two isoforms of human steroid 5α-reductase, designated types I and II. Type II 5α-reductase expression predominates in human accessory sex tissues, localized to the fibromuscular stromal compartment. The type I isoform predominates in skin, prostatic epithelia and, to a lesser extent, in prostatic fibromuscular stroma. The significance of the type I isoform to prostatic cellular growth and function remains undefined. In cultured DU145 cells, we evaluated the metabolism of [14C]-T and demonstrated the time-dependent formation of [14C]-DHT. Oxidative metabolism (conversion of [14C]-T to [14C]-androstenedione) and the formation of conjugated androgen metabolites occurred at a relatively low rate in the DU145 cells. Using human type I 5α-reductase cDNA, Northern blot analysis of DU145 cell mRNA revealed high levels of type I isoform expression. Analogous probing of the DU145 cells with a human 5α-reductase II cDNA failed to reveal expression of the type II isoform. The expression of functional type I activity has been confirmed pharmacologically using isoform-selective 5α-reductase inhibitors. Reductive metabolism of [3H]-T in the DU145 cells was inhibited in a concentration-dependent manner by LY306089, a potent non-steroidal type I-selective inhibitor (IC50 = 10.0 nM). SKF105657, a steroidal type II-specific inhibitor was distinctly less active at inhibiting [3H]-DHT formation. LY306089 was a non-competitive inhibitor of type I 5α-reductase in DU145 cellular homogenates with an apparent K(i) value of 4.0 nM. These studies have identified and pharmacologically defined type I 5α-reductase activity in an androgen-insensitive prostatic cancer cell line and provide the basis for additional investigations into the significance of type I 5α-reductase to human prostatic pathophysiology.

Original languageEnglish
Pages (from-to)195-205
Number of pages11
JournalJournal of Steroid Biochemistry and Molecular Biology
Volume58
Issue number2
DOIs
StatePublished - May 1996

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Oxidoreductases
Adenocarcinoma
Protein Isoforms
LY 306089
Dihydrotestosterone
Metabolism
Castration-Resistant Prostatic Neoplasms
Androgens
Complementary DNA
Androstenedione
Accessories
Metabolites
Northern Blotting
Inhibitory Concentration 50
Testosterone
Cultured Cells
Skin
Epithelium
Steroids
Cells

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology

Cite this

Characterization of type I 5α-reductase activity in DU145 human prostatic adenocarcinoma cells. / Kaefer, Martin; Audia, James E.; Bruchovsky, Nicholas; Goode, Robin L.; Hsiao, Kenneth C.; Leibovitch, Ilan Y.; Krushinski, Joseph H.; Lee, Chung; Steidle, Christopher P.; Sutkowski, Debra M.; Neubauer, Blake Lee.

In: Journal of Steroid Biochemistry and Molecular Biology, Vol. 58, No. 2, 05.1996, p. 195-205.

Research output: Contribution to journalArticle

Kaefer, M, Audia, JE, Bruchovsky, N, Goode, RL, Hsiao, KC, Leibovitch, IY, Krushinski, JH, Lee, C, Steidle, CP, Sutkowski, DM & Neubauer, BL 1996, 'Characterization of type I 5α-reductase activity in DU145 human prostatic adenocarcinoma cells', Journal of Steroid Biochemistry and Molecular Biology, vol. 58, no. 2, pp. 195-205. https://doi.org/10.1016/0960-0760(96)00020-9
Kaefer, Martin ; Audia, James E. ; Bruchovsky, Nicholas ; Goode, Robin L. ; Hsiao, Kenneth C. ; Leibovitch, Ilan Y. ; Krushinski, Joseph H. ; Lee, Chung ; Steidle, Christopher P. ; Sutkowski, Debra M. ; Neubauer, Blake Lee. / Characterization of type I 5α-reductase activity in DU145 human prostatic adenocarcinoma cells. In: Journal of Steroid Biochemistry and Molecular Biology. 1996 ; Vol. 58, No. 2. pp. 195-205.
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AU - Goode, Robin L.

AU - Hsiao, Kenneth C.

AU - Leibovitch, Ilan Y.

AU - Krushinski, Joseph H.

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