Androgen regulation of prostasin gene expression is mediated by sterol-regulatory element-binding proteins and SLUG.
BACKGROUND
Prostasin is downregulated in hormone-refractory prostate cancers (HRPC). The mechanisms by which androgens regulate prostasin expression are unclear.


METHODS
LNCaP cells were treated with dihydrotestosterone (DHT), and mRNA expression of prostasin, SREBPs, SNAIL, and SLUG was examined by real-time PCR following reverse transcription. A human prostasin promoter was evaluated in HEK-293 cells co-transfected with transcription factor cDNAs. Regulation of endogenous prostasin expression by transfected SREBP-2 or SLUG was evaluated. Expression of SNAIL and SLUG mRNA in DU-145 cells treated with epidermal growth factor (EGF) was examined.


RESULTS
Prostasin mRNA expression in LNCaP cells was not responsive to DHT treatment. DHT marginally upregulated mRNA expression of SREBP-1c, SREBP-2, and SNAIL, but not SREBP-1a, while dramatically increased SLUG mRNA expression, in a dose-dependent manner. Co-transfection of prostasin promoter and SREBP cDNA in HEK-293 cells resulted in stimulation of promoter activity at approximately twofold by SREBP-1c, and up to sixfold by SREBP-2; while co-transfection with SNAIL or SLUG cDNA resulted in repression of promoter activity to 43% or 59%, respectively. Co-transfection of the SLUG cDNA negated SREBP-2's stimulation of prostasin promoter in a dose-dependent manner. Transfection of an SREBP-2 cDNA in HEK-293 and DU-145 resulted in upregulation of prostasin while transfection of a SLUG cDNA in LNCaP repressed prostasin expression. EGF upregulated SNAIL and SLUG mRNA in DU-145.


CONCLUSIONS
DHT regulates prostasin expression in prostate cells via SREBP stimulation and SLUG repression of prostasin promoter. SLUG is upregulated by DHT and EGF, providing a molecular mechanism by which epithelial cell-specific genes are silenced during prostate cancer development and progression.
Chen
Mengqian
M
Department of Molecular Biology and Microbiology, University of Central Florida, Orlando, Florida 32816-2364, USA.
Chen
Li-Mei
LM
Chai
Karl X
KX
D000728:Androgens / Q000494:pharmacology* / Q000502:physiology; D002460:Cell Line; D045744:Cell Line, Tumor; D018076:DNA, Complementary / Q000032:analysis / Q000235:genetics; D013196:Dihydrotestosterone / Q000494:pharmacology; D018450:Disease Progression; D004305:Dose-Response Relationship, Drug; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005786:Gene Expression Regulation; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects* / Q000502:physiology; D020868:Gene Silencing; D006801:Humans; D008297:Male; D011401:Promoter Regions, Genetic / Q000502:physiology; D011467:Prostate / Q000737:chemistry / Q000166:cytology / Q000502:physiology; D011471:Prostatic Neoplasms / Q000737:chemistry / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012697:Serine Endopeptidases / Q000032:analysis / Q000235:genetics* / Q000502:physiology; D000071250:Snail Family Transcription Factors; D051782:Sterol Regulatory Element Binding Protein 2 / Q000235:genetics / Q000502:physiology; D051779:Sterol Regulatory Element Binding Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D014162:Transfection; D000099271:Prostasin
D000728:Androgens; D018076:DNA, Complementary; D013196:Dihydrotestosterone; D004815:Epidermal Growth Factor; D012333:RNA, Messenger; D012697:Serine Endopeptidases; D000071250:Snail Family Transcription Factors; D051782:Sterol Regulatory Element Binding Protein 2; D051779:Sterol Regulatory Element Binding Proteins; D014157:Transcription Factors; D000099271:Prostasin; C000604407:SNAI1 protein, human; C497390:SREBF2 protein, human