RESUMO
CONTEXT: Mammary and placental 17ß-hydroxysteroid dehydrogenase type 1 (17ßHSD1). OBJECTIVE: To assess the impact of testosterone, tibolone, and black cohosh on purified mammary and placental 17ßHSD1. MATERIALS AND METHODS: 17ßHSD1 was purified from human mammary gland and placenta by column chromatography, its activity was monitored by a radioactive activity assay, and the degree of purification was determined by gel electrophoresis. Photometric cofactor transformation analysis was performed to assess 17ßHSD1 activity without or in presence of testosterone, tibolone and black cohosh. RESULTS: 17ßHSD1 from both sources displayed a comparable basal activity. Testosterone and tibolone metabolites inhibited purified mammary and placental 17ßHSD1 activity to a different extent, whereas black cohosh had no impact. DISCUSSION: Studies on purified enzymes reveal the individual action of drugs on local regulatory mechanisms thus helping to develop more targeted therapeutic intervention. CONCLUSION: Testosterone, tibolone and black cohosh display a beneficial effect on local mammary estrogen metabolism by not affecting or decreasing local estradiol exposure.
Assuntos
17-Hidroxiesteroide Desidrogenases/antagonistas & inibidores , Cimicifuga/química , Inibidores Enzimáticos/farmacologia , Norpregnenos/farmacologia , Testosterona/farmacologia , 17-Hidroxiesteroide Desidrogenases/isolamento & purificação , 17-Hidroxiesteroide Desidrogenases/metabolismo , Mama/enzimologia , Mama/metabolismo , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Feminino , Humanos , Estrutura Molecular , Norpregnenos/síntese química , Norpregnenos/química , Placenta/enzimologia , Placenta/metabolismo , Gravidez , Relação Estrutura-Atividade , Testosterona/síntese química , Testosterona/químicaRESUMO
INTRODUCTION: Testosterone (T) is a therapeutic option for women with hypoactive sexual desire disorder. T may have an impact on the mammary gland by altering local estrogen synthesis. The aim of the present study was to measure the effect of T on estrone-sulfate (E1S)-sulfatase (STS) expression, and activity using hormone-dependent BC cells with high and low aggressive potential (BT-474, MCF-7), and HBL-100 as a breast cell line of non-malignant origin. METHODS: Cells were incubated in RPMI 1640 medium containing 5% steroid-depleted fetal calf serum for 3d, and subsequently incubated in absence or presence of T alone, and combined with anastrozole (A) at 10(-8)M, and 10(-6)M at 37 degrees C for either 24h or directly in cell extracts ("direct"). STS protein expression was measured by dot-blot (immunoblotting), and STS, HSD17B1 and HSD17B2 mRNA levels by quantitative RT-PCR. STS activity was evaluated by incubating homogenized breast cells with [(3)H]-E1S and separating the products E1, and E2 by thin layer chromatography. RESULTS: Basal STS mRNA expression did not reveal group differences. However, STS mRNA was decreased by T+A in MCF-7 cells. 17HSDB1 expression was decreased by T+A in BT-474 cells, and 17HSDB2 expression was decreased by A and T+A treatment in MCF-7 cells. Basal and T treated STS protein expression was significantly higher in malignant compared to non-malignant breast cells. However, T did not induce significant intra-cell line differences. Similarly, basal and T treated STS activity was significantly higher in highly malignant compared to non-malignant breast cells. Regardless of cell lines, T slightly decreased STS activity after "direct" incubation, but led to an increase of local estrogen formation after 24h which was attenuated, and partly reversed by A, respectively. CONCLUSIONS: The more aggressive the breast cell line, the higher the local estrogen formation. The transition from normal to malignant seems to be accompanied by an altered autoregulation. The given local endocrine milieu seems to be essential for response to T.
