The Journal of Steroid Biochemistry and Molecular Biology
Mammalian lignans and genistein decrease the activities of aromatase and 17β-hydroxysteroid dehydrogenase in MCF-7 cells
Introduction
Some studies suggest an association between the intake, plasma levels or urinary excretion of phytoestrogens such as the isoflavones genistein (GEN) and daidzein (DAID) and the mammalian lignans enterolactone (EL) and enterodiol (ED) (metabolites of plant lignans) and a reduced risk of breast cancer [1], [2], the etiology and development of which estrogen plays a major role. 17β-Estradiol (E2) has been implicated in both the initiation and the promotion of breast cancer [3], such that lifetime estrogen exposure is considered a major risk factor for the disease [4], [5].
Two thirds of breast cancers occur in postmenopausal women at a time when the major source of estrogen production is outside the ovary and circulating estrogens are low [6], [7]. However, plasma estrogen concentrations are significantly lower than those found in “normal” glandular tissue and cancerous tissue [3], [8], suggesting that circulating estrogen concentrations may not be indicative of tissue exposure.
Aromatase and 17β-HSD are enzymes involved in estrogen production within the breast [9], [10], [11]. Aromatase catalyzes the final step in the production of estrogens, i.e. estrone (E1) from androstenedione (AD) and E2 from testosterone [12], while 17β-HSD (types I and II) control the balance between E2 and the less biologically active E1 [13], [14]. The increased activity and expression of these enzymes are associated with breast cancer [15], [16], [17], [18], with tumors showing elevated activity, relative to normal tissue [19]. Hence, aromatase inhibitors such as anastrozole and letrozole are now used to follow tamoxifen treatment of breast cancer and, in some cases, have been found to be more effective than tamoxifen as a first line treatment [20].
We hypothesize that interference in the normal synthesis and metabolism of estrogen is one mechanism through which the protective effect of these phytoestrogens is mediated. In previous studies, EL has been found to inhibit aromatase activity in human preadipocytes [21] and placental microsomes [22], while GEN and DAID have been shown to inhibit 17β-HSD in human placental microsomes [23], genital skin fibroblasts [24], and granulosa luteal cells [25]. However, GEN is generally considered to have little or no ability to inhibit aromatase activity [23], [25], [26], [27]. In the estrogen receptor-positive human breast cancer cells (MCF-7), GEN modulates the activity and expression of 17β-HSD [28] but not aromatase [27]. Another study found GEN to inhibit 17β-HSD in T47D but not in MCF-7 cells [29]. The effect of EL and ED on aromatase and 17β-HSD has not been examined.
Studies on aromatase activity in MCF-7 cells are often conducted in those transfected with human placental aromatase. Yue et al. [16], however, suggested that these transfected cells may not be the best model for regulation studies because the regulation of aromatase expression and activity is tissue specific. Wild-type MCF-7 cells have been shown to have aromatase activity at levels high enough to elicit an estrogenic response [30]. Because the regulation of both aromatase and 17β-HSD is tissue specific [31], [32], and in the case of aromatase changes with the development of breast cancer [33], it is of interest to examine the effect of the lignans and isoflavones in wild-type MCF-7 cells.
The objective of this study was to first determine whether the MCF-7 cells have measurable aromatase and 17β-HSD type 1 activities, and then to investigate the effect of various concentrations of EL, ED and GEN on these activities. Changes in estrogen production induced by EL, ED or GEN were then related to cell proliferation, since it is well established that E2 dose can dependently increase the proliferation of MCF-7 cells. The results will suggest one potential mechanism whereby GEN, ED and EL may reduce tumor growth of estrogen receptor-positive human breast cancer cells.
Section snippets
Cell culture
MCF-7 cells (American Type Culture Collection, Rockville, MD) were maintained in 75 cm2 culture flasks at 37 °C and in a 5% CO2 humidified atmosphere. Cells were grown in Dulbecco's Modified Eagle Medium (DMEM)/F121:1 (15 nM HEPES, l-glutamine and pyridoxine hydrochloride) (Gibco, Invitrogen Inc., Burlington, Ont., Canada) supplemented with 10% fetal bovine serum (FBS; CanSera Intl. Inc., Etobicoke, Ont.). The medium was replaced every 2 days. Cells at 80% confluence were subcultured every 10–12
Effect on aromatase activity
EL (10 and 20 μM) significantly decreased the amount of E1 produced from AD by 37% and 25%, respectively, when compared to control (AD alone) (Fig. 1A). ED at all concentrations (1, 10, 50 and 100 μM) decreased E1 production from AD with the maximum reduction (86%) at 100 μM relative to control (Fig. 1B). GEN (10 μM) significantly decreased E1 production from AD by 70% (Fig. 1C). The amount of E1 produced in the presence of 4-OHA (50 μM) was 300% that was seen to be in control (mean over all
Discussion
This study demonstrated that aromatase and 17β-HSD type 1 enzyme activities are present in measurable amounts in MCF-7 cells, with the activity of 17β-HSD type 1 being higher than that of aromatase. This is in agreement with data from human specimens from postmenopausal mastectomy patients, which found the activity of 17β-HSD to be higher than that of aromatase both within and surrounding the tumor [19].
This study also demonstrated for the first time that EL and ED reduce the production of E1
Acknowledgement
This study was supported in part by the Natural Sciences and Engineering Research Council of Canada.
References (50)
Phytestrogens and breast cancer
J. Steroid Biochem. Mol. Biol.
(2002)- et al.
Paradoxical effect of estradiol: it can block its own biotransformation in human breast cancer cells
J. Steroid Biochem. Mol. Biol.
(2001) - et al.
The selective estrogen enzyme modulator (SEEM) in breast cancer
J. Steroid Biochem. Mol. Biol.
(2001) - et al.
The conversion of androstenedione to estrone, estradiol and testosterone in breast tissue
J. Steroid Biochem.
(1980) - et al.
Aromatase in the normal breast and breast cancer
J. Steroid Biochem. Mol. Biol.
(1997) - et al.
Aromatase and COX-2 expression in human breast cancers
J. Steroid Biochem. Mol. Biol.
(2001) - et al.
Utilization of oxygen and reduced nicotinamide adenine dinucleotide phosphate by human placental microsomes during aromatizatoin of androstenedione
J. Biol. Chem.
(1974) - et al.
The potential role of estrogen in aromatase regulation in the breast
J. Steroid Biochem. Mol. Biol.
(2001) - et al.
Estrone sulfate-sulfatase and 17β-hydroxysteroid dehydrogenase activities: a hypothesis for their role in the evolution of human breast cancer from hormone-dependent to hormone independent
J. Steroid Biochem. Mol. Biol.
(1995) - et al.
Intratumoral levels of estrogens in breast cancer
J. Steroid Biochem. Mol. Biol.
(1999)
Lignans and flavonoids inhibit aromatase enzyme in human preadipocytes
J. Steroid Biochem. Mol. Biol.
Inhibition of human aromatase by mammalian lignans and isoflavonoid phytoestrogens
J. Steroid Biochem. Mol. Biol.
Effects of phytoestrogens on aromatase, 3β and 17β-hydroxysteroid dehydrogenase activities in human breast cancer cells
Life Sci.
Flavonoid inhibition of aromatase enzyme activity in human preadipocytes
J. Steroid Biochem. Mol. Biol.
Regulation of aromatase by nuclear receptors
J. Steroid Biochem. Mol. Biol.
Role of 17 beta-hydroxysteroid dehydrogenase type 1 in endocrine and introcrine estradiol biosynthesis
J. Steroid Biochem. Mol. Biol.
Analysis of transcriptional regulation of human breast aromatase by in vitro and in vivo studies
J. Steroid Biochem. Mol. Biol.
Overview of naturally occurring endocrine-active substances in the human diet in relation to human health
Nutrition
Enterolactone and estradiol inhibit each other's proliferative effect on MCF-7 breast cancer cells in culture
J. Steroid Biochem. Mol. Biol.
Effect of the aromatase inhibitor 4-OHA on progesterone synthesis by human luteal cells
Fertil. Steril.
White button mushroom phytochemicals inhibit aromatase activity and breast cancer cell proliferation
J. Nutr.
Metabolism of dehydroepiandrosterone by rat hippocampal cells in culture: possible role of aromatization and 7-hydroxylation in neuroprotection
J. Steroid Biochem. Mol. Biol.
A rapid sensitive method for the quantification of microgram quantities of protein utilizing the principle of protein dye binding
Anal. Biochem.
Growth-inhibitory effects of the natural phyto-oestrogen genistein in MCF-7 human breast cancer cells
Eur. J. Cancer
Genistein inactivates bcl-2, delays the G2/M phase of the cell cycle, and induces apoptosis of human breast adenocarcinoma MCF-7 cells
Eur. J. Cancer
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