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 and dehydrocorticosterone. We report its presence in significant levels in the human prostate carcinoma cell line LNCaP cultured in medium RPMI-1640 with 10% fetal calf serum (FCS). The 11-dehydrogenase activity of 11 beta-HSD is present, while the 11-reductase activity is undetectable in these tumor cells under the present culture conditions. The enzyme activity is found to be linear with time of incubation, and is proportional to plated cell density. The enzymatic activity can be determined in cultures maintained for longer times. Carbenoxolone, the potential inhibitor of the 11 beta-HSD, inhibits 95% of the dehydrogenase activity of the tumor cells when used in nM concentration. The presence of this enzyme in tumor cell line indicates that 11 beta-HSD plays an important role in maintaining the active glucocorticoid levels in the prostate.