PRESENCE OF 11-BETA-HYDROXYSTEROID DEHYDROGENASE ENZYME IN THE HUMAN PROSTATE TUMOR-CELL LINE LNCAP

11 beta-Hydroxysteroid dehydrogenase (11 beta-HSD) is the enzyme that catalyzes the reversible oxidation of the biologically active steroid cortisol and corticosterone to their inactive metabolites cortisone an d dehydrocorticosterone. We report its presence in significant levels in the human prostate carcinoma cell line LNCaP cultured in medium RPM I-1640 with 10% fetal calf serum (FCS). The 11-dehydrogenase activity of 11 beta-HSD is present, while the 11-reductase activity is undetect able in these tumor cells under the present culture conditions. The en zyme activity is found to be linear with time of incubation, and is pr oportional to plated cell density. The enzymatic activity can be deter mined in cultures maintained for longer times. Carbenoxolone, the pote ntial inhibitor of the 11 beta-HSD, inhibits 95% of the dehydrogenase activity of the tumor cells when used in nM concentration. The presenc e of this enzyme in tumor cell line indicates that 11 beta-HSD plays a n important role in maintaining the active glucocorticoid levels in th e prostate. (C) 1993 Wiley-Liss, Inc.