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Updated: Aug 19, 2026

Laser-capture Microdissection of Human Prostatic Epithelium for RNA Analysis
Published on: November 26, 2015
LNCaP produces both putative zymogen and inactive, free form of prostate-specific antigen
E Corey1, L G Brown, M J Corey
1Department of Urology, School of Medicine, University of Washington, Seattle 98195, USA. ecorey@u.washington.edu
Background:
Our objective was to investigate the presence of prostate specific antigen (PSA) and alpha-1-antichymotrypsin (ACT) mRNA and protein in prostate cancer cell lines, and the complexing characteristics of expressed PSA.
Methods:
RT-PCR, immunohistochemistry, and Western blots were employed. Trypsin treatment of PSA was performed to establish the possible presence of an activatable form of PSA.
Results:
ACT mRNA and protein were detected in LNCaP, PC-3, and DU 145 by RT-PCR and by immunohistochemistry, respectively. Only LNCaP cells were positive for PSA mRNA and protein. LNCaP expressed approximately 30% active PSA, approximately 40% putative zymogen form of PSA, and approximately 30% stably inactive PSA.
Conclusions:
We have shown that the majority of PSA expressed by LNCaP cells is present in free, noncomplexed forms in the conditioned media. A portion (40%) can be activated by trypsin, while the rest is stably inactive PSA. LNCaP cells may serve as a source of the "unreactive" PSA present in prostate cancer patients' serum.
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