Regulation of prostasin expression and function in the prostate.
BACKGROUND
The invasion suppressor prostasin is down-regulated in prostate cancer, but the mechanism is unknown. A prostasin-binding protein (PBP) was found in the seminal vesicles, but its identity remains unclear.


METHODS
Genomic Southern blot analysis using methylation sensitive restriction endonucleases was employed to examine the prostasin gene promoter region in prostate cancer cell lines. RT-PCR was employed to examine prostasin expression under demethylation, histone deacetylase inhibition, and nerve growth factor (NGF) treatment. Liquid column chromatography was employed to purify the PBP from mouse seminal vesicles. The PBP was further characterized by amino acid sequence analysis, recombinant protein expression, protease inhibition and binding assays. Immunohistochemistry and Western blot analysis were used to evaluate PBP expression in the prostate and prostate cancer cells.


RESULTS
Promoter DNA methylation partly causes the prostasin down-regulation in DU-145 and PC-3 cells, while prostasin expression can be induced by NGF. The PBP is identified to be protease nexin-1 (PN-1), a serpin. PN-1 inhibits prostasin's serine protease activity, is expressed by prostate epithelial cells (PrECs) and prostate cancer cells, and capable of binding to membrane-anchored prostasin.


CONCLUSIONS
Prostasin's expression and function are regulated by factors in the prostate tissue environment.
Department of Molecular Biology and Microbiology, University of Central Florida, Orlando, Florida 32816, USA.
Li-Mei
LM
Chen
Xiaochun
X
Zhang
Karl X
KX
Chai
D016564:Amyloid beta-Protein Precursor; D000818:Animals; D015153:Blotting, Western; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D019175:DNA Methylation; D004847:Epithelial Cells; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology*; D006801:Humans; D008297:Male; D051379:Mice; D011401:Promoter Regions, Genetic; D011471:Prostatic Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D058255:Protease Nexins; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012669:Seminal Vesicles / Q000378:metabolism; D020539:Sequence Analysis, Protein; D012697:Serine Endopeptidases / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D058258:Serpin E2; D000099271:Prostasin
D016564:Amyloid beta-Protein Precursor; D002352:Carrier Proteins; D058255:Protease Nexins; D012334:RNA, Neoplasm; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D012697:Serine Endopeptidases; D058258:Serpin E2; D000099271:Prostasin; C545486:SERPINE2 protein, human