Abstract
The UDP-glucuronosyltransferases (UGTs) 2B15 and 2B17 are the major UGTs involved in the inactivation and elimination of the active androgens, dihydrotestosterone and testosterone. Although regulation of these UGT genes by various endogenous and exogenous ligands, including steroid hormones and bile acids, is well documented, the mechanisms controlling their basal gene expression are poorly understood. We recently reported that Forkhead box protein A1 (FOXA1) regulates the basal expression of the UGT2B17 gene in prostate cancer cells. In this study, we show that FOXA1 also regulates basal expression of the UGT2B15 gene in the prostate cell line LNCaP (lymph node carcinoma of the prostate). FOXA1 binds to a site −208 to −217 base pairs relative to the UGT2B15 translation start site, as shown by electromobility shift and chromatin immunoprecipitation assays. Mutation of this site prevents binding and substantially decreases basal UGT2B15 promoter activity. Silencing of FOXA1 expression by small interfering RNA significantly reduced UGT2B15 transcript levels, further confirming a crucial role of FOXA1 in controlling UGT2B15 gene expression. Because local inactivation of active androgens by UGT2B15 and UGT2B17 has been shown to be a major determinant of androgen response and signaling activity, regulation of the UGT2B15 and UGT2B17 genes by FOXA1 may have an important role in the maintenance of androgen homeostasis within prostate cancer cells.
Footnotes
The work was supported by the National Health and Medical Research Council of Australia [Grant 426705].
Article, publication date, and citation information can be found at http://dmd.aspetjournals.org.
doi:10.1124/dmd.110.035436.
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ABBREVIATIONS:
- HSD
- hydroxysteroid dehydrogenase
- DHT
- dihydrotestosterone
- ADT
- androsterone
- 3α-diol
- 5α-androstane-3α,17β-diol
- UGT
- UDP-glucuronosyltransferase
- R1881
- 17β-hydroxy-17α-methyl-19-norandrost-4,9,11-trien-3-one
- FOX
- Forkhead box
- PCR
- polymerase chain reaction
- FBS
- fetal bovine serum
- EMSA
- electrophoretic mobility shift assay
- ChIP
- chromatin immunoprecipitation
- RT-qPCR
- reverse transcription-quantitative real-time PCR
- HNF
- hepatocyte nuclear factor
- siRNA
- small interfering RNA
- bp
- base pair
- SNP
- single nucleotide polymorphism
- ERα
- estrogen receptor α
- rRNA
- ribosomal RNA
- LNCaP
- lymph node carcinoma of the prostate
- GW4064
- 3-(2,6-dichlorophenol)-4-(3′-carboxy-2-chlorostilben-4-yl-)oxymethyl-5-isopropyl-isoxazole.
- Received July 13, 2010.
- Accepted August 23, 2010.
- Copyright © 2010 by The American Society for Pharmacology and Experimental Therapeutics
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