Pergamon fr. Steroid Biochern. Molec. Biol. Vol. 61, No. 3-6, pp. 287-292, 1997 © 1997 Elsevier Science Ltd. All rights reserved Printed in Great Britain PII: S0960-0760(96)00213-0 0960-0760/97 $17.00 + 0.00 Product of Aromatase Activity in lntact LNCaP and MCF-7 Human Cancer Cells Luigi A. M. Castagnetta, 1'2. Orazia M. Granata, 1 Vincenzo Bellavia, 2 Rosalba Amodio, 1 Eugenia Scaccianoce, 1 Monica Notarbartolo, 2 Maria R. Follari, 1 M. Dora Miceli 2 and Giuseppe Carruba 2 IExperimental Oncology and Molecular Endocrinology Units, Palermo Branch of the National Cancer Institute of Genoa, c/o "M. Ascoli" Cancer Hospital Center, Palermo, Sicily, Italy and 2Institute of Oncology, School of Medicine, University of Palermo, Palermo, Sicily, Italy We investigated conversion rates of androgens to estrogens in cultured, hormone-responsive pros- tate (LNCaP) and breast (MCF-7) human cancer cells. For this purpose, we adopted an intact cell analysis, whereby cells were incubated for different incubation times in the presence of close-to- physiological (1 nM) or supraphysiological (1/aM) concentrations of labelled androgen precursors, i.e. testosterone (T) and androstenedione (A4Ad). The aromatase activity, as measured by estrogen formation, was detected in LNCaP cells (0.5 pmol/ml), even though to a significantly lower extent than in MCF-7 cells (5.4 pmol/ml), using 1/aM T after 72 h incubation. Surprisingly, LNCaP cells displayed a much higher aromatase activity when T was used as a substrate with respect to A4Ad. In either cell Une, T transformation to A4Ad was relatively low, attaining only 2.8% in LNCaP and 7.5% MCF-7 cells. However, T was mostly converted to conjugates (over 95%), glucuronides and some sulphates, in LNCaP cells, whereas it was only partly ¢onverted to sulphates (<10%) in MCF-7 cells. Aromatase activity seems to be inconsistent in LNCaP cells, being strongly affected by culture con- ditions, especially by fetal calf serum (FCS). Further studies should assess the regulation of aroma- tase expression by serum or growth factors in different human cancer cells, also using anti- aromatase andlor anti-estrogen compounds, in different culture conditions. © 1997 Elsevier Science Ltd ,7. SteroidBiochem. Molec. Biol., Vol. 61, No. 3-6, pp. 287-292, 1997 INTRODUCTION Although androgens are universally assumed to be necessary for development, growth and funcnonal ac- tivity of the human prostate gland, it has been suggested that estrogens may participate in the patho- genesis of prostate diseases, including benign prostatic hyperplasia (BPH) and cancer. Nevertheless, patterns of estrogen formation and metabolism in the human prostate are still uncertain. Because levels of circulat- ing estrogens in the older male are about 100 times lower than those of T, it seems more likely that pro- static tissues use androgen blood supply for local es- trogen production. Therefore, attention has been Proceedings of the IV International Aromatase Conference, Tahoe City, CA, U.S.A., 7-11 June 1996. *Correspondence to L. A. M. Castagnetta. Fax: +39 91 666 4352; e-mail: lucashbl@unipa.it. drawn to the presence of aromatase activity in the human prostate. The growth of cultured human prostate epithelial cells may be either stimulated [1] or inhibited [2] by estrogens being, at least in some cases, typicaUy estro- gen receptor (ER)-mediated [3]. This observation appears to be of special interest, as it has been demonstrated that estrogens and androgens may con- cur in the development and maintenance of the malig- nant prostate [4]. On the other hand, there is concurring evidence, either immunocytochemical or biochemical, for ER in the normal, hyperplastic and cancerous human prostate [5-8]. As tissue levels of estrogens and their receptors are intimately related, cells that grow in response to estrogens via ER are likely to be endowed with the enzymes responsible for estrogen formation from the androgen substrate, namely the aromatase enzymes. 287