Life Sci. 2003 Jan 10;72(8):877-83.
The effect of endogenous estradiol metabolites on the proliferation of human breast cancer cells.
Lippert C, Seeger H, Mueck AO.
Section of Endocrinology and Menopause, Department of Obstetrics and Gynecology, University of Tuebingen, Schleichstrasse 4, 72 076 Tuebingen, Germany.
Evidence is accumulating that estradiol metabolites may be involved in carcinogenesis as some metabolites exert proliferative and others anti-proliferative properties on human cancer cells. The present study is the first to investigate the effect of 14 endogenous estradiol metabolites on the proliferation of the human breast cancer cell line, MCF-7, in comparison with the effect of the parent substance 17beta-estradiol with special concern on high pharmacological concentrations. The steroids were tested in the range from 10(-8) to 10(-5) M on MCF-7 cells which were incubated for nine days. Estradiol and almost all A-ring metabolites displayed biphasic reactions on cell proliferation, i.e. stimulatory at low concentrations and inhibitory at the highest concentration, 10(-5) M. The D-ring metabolites did not show such clear biphasic patterns, in most of them the stimulatory effect prevailed at the highest dosage used. The strongest inhibitory effect was seen for the A-ring metabolite 2-methoxyestradiol at the concentrations of 10(-6) and 10(-5) M and the strongest stimulatory effect was noted for the D-ring metabolite estriol at the same concentrations.The results indicate that some A-ring metabolites might be suitable for breast cancer treatment when used in high dosages. This is of special interest, since many of these metabolites have very weak estrogenic activity.
J Control Release. 2003 Dec 12;93(3):319-30.
Controlled release of estradiol solubilized in carbopol/surfactant aggregates.
Barreiro-Iglesias R, Alvarez-Lorenzo C, Concheiro A.
Departamento de Farmacia y Tecnologia Farmaceutica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15872 Santiago de Compostela, Spain.
The potential of carbopol/surfactant dispersions as solubilizing and controlled release systems of estradiol (a poorly water-soluble drug) was evaluated. The solubilization of estradiol in the dispersions of Carbopol 934 (0.25%) and Pluronic F-127, Tween 80, sodium dodecylsulfate (SDS), or benzalkonium chloride (BkCl) was assessed, by differential scanning calorimetry (DSC) of films obtained by desiccation, as a decrease in estradiol melting temperature and enthalpy. The amounts of estradiol solubilized in carbopol/SDS and carbopol/Tween 80 aqueous dispersions were considerably greater (solubilization capacity: 1.3 and 9 times greater) than in the surfactant alone solutions and up to 100 times greater than in water. High aggregates/water equilibrium partition coefficients of estradiol in carbopol/SDS (1768 M(-1)) and carbopol/Tween 80 (14114 M(-1)) dispersions were found. Carbopol/(1%) SDS/(25 mg/dl) estradiol and carbopol/(0.1%) Tween 80/(5 mg/dl) estradiol dispersions had a pH of around 4, were easy flowing, and showed sustained release for at least 1 week. Estradiol diffusion coefficients were greater when the receptor medium was 0.3-1.0% SDS solution than when it was iso-osmotic NaCl solution or pH 7.5 phosphate buffer. At this pH, a viscoelastic gel is formed on the donor side of the membrane and the drug diffusion slowed down. When the receptor medium contains a surfactant, estradiol release seems to happen as a direct exchange between the carbopol/surfactant aggregates and the receptor surfactant micelles. If no surfactant is in the receptor fluid, estradiol/surfactant complexes migrate towards the receptor. Despite the low viscosity of these dispersions, estradiol di
Endocrinology. 2004 Mar;145(3):1444-52. Epub 2003 Nov 26.
Prostaglandin mediates premature delivery in pregnant sheep induced by estradiol at 121 days of gestational age.
Wu WX, Ma XH, Coksaygan T, Chakrabarty K, Collins V, Rose J, Nathanielsz PW.
Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA. wen_xuan_wotmail.com
The experiments reported here were designed for both in vivo and in vitro approaches in the same animals to obtain a better picture of the role of estrogen in the control of parturition. Chronically catheterized pregnant ewes were treated with vehicle (n = 5) or estradiol (n = 6), 5 mg twice a day, im for 2 d starting at d 119 of gestation. Maternal and fetal plasma estradiol, progesterone, and cortisol were measured by RIA and maternal plasma prostaglandin (PG) F2alpha was measured by enzyme immunoassay. Intrauterine PG H synthase 2 mRNA and protein and placental P450(c17)alpha hydroxylase mRNA were determined by Northern, in situ hybridization, Western blot analysis, and immunocytochemistry. Data were analyzed by ANOVA.Five of six estradiol-treated ewes delivered their fetuses within 48 h; however, the placenta was still retained 5-6 h after fetal delivery. Both maternal plasma estradiol and PGF2 alpha increased significantly in the estradiol-treated group. Maternal and fetal plasma progesterone and cortisol were not altered in either group. There were significant increases of PGH synthase 2 mRNA and protein in myometrium, endometrium, and maternal placenta but not in fetal placenta in estradiol-treated ewes. Placental P450(c17)alpha hydroxylase mRNA was not detectable in vehicle or estradiol-treated groups.Estradiol can, in the absence of increase in plasma cortisol, stimulate uterine PG production and induce labor, resulting in fetal delivery in the sheep. Failure of placental delivery after estradiol treatment suggests that estradiol alone is insufficient to stimulate some of the key changes required to complete de
Oestradiol inhibits spontaneous and cisplatin-induced apoptosis in epithelial ovarian cancer cells: relationship to DNA repair capacity.
Murdoch WJ, Van Kirk EA.
Reproductive Biology Program, University of Wyoming, Laramie 82071, USA. wmurdocwyo.edu
A prospective role of sex steroid hormones in the pathogenesis of common epithelial ovarian cancer remains equivocal. We hypothesized that oestradiol can protect ovarian cells from apoptosis by augmenting their DNA repair capacity. Two established oestrogen receptor-positive human cancer cell lines of ovarian surface epithelial origin (OVCAR-3, SKOV-3) were studied during short-term (24 h) subculture in the absence or presence of oestradiol-17beta and/or the DNA-damaging chemotherapeutic agent cisplatin. Apoptosis was monitored among individual cells by in situ DNA fragmentation analysis. Basal rates of apoptosis were diminished by exposure to oestradiol (progesterone or testosterone were without effect). Oestradiol also suppressed apoptosis induced by cisplatin and enhanced the repair of a cisplatin-damaged reporter chloramphenicol-O-acetyltransferase gene transfected into ovarian cells. The ability of oestrogen-responsive ovarian cancer cells to efficiently repair DNA and thereby avoid apoptosis may be related to propensity for clonal expansion and drug resistance.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14646531&dopt=Abstract estradiol [PubMed]
Arch Dermatol Res. 2004 Feb;295(8-9):307-11. Epub 2003 Nov 29.
Effect of 17beta-estradiol on immunosuppression induced by ultraviolet B irradiation.
Hiramoto K, Tanaka H, Yanagihara N, Sato EF, Inoue M.
Department of Biochemistry and Molecular Pathology, Osaka City University Medical School, 1-4-3 Asahimachi, Abeno-ku, 545-8585, Osaka City, Osaka, Japan. hiramotsic.med.osaka-cu.ac.jp
BACKGROUND: The risk of skin cancer is lower in females than in males, and photoimmunosuppression caused by ultraviolet (UV) radiation is thought to be involved in the progression of skin cancer. OBJECTIVES. To determine the effect of 17beta-estradiol on immunosuppression and contact hypersensitivity (CHS) caused by ultraviolet B (UVB) irradiation. METHODS: Systemic immunosuppression was induced in C57BL mice that had been sensitized with 0.5% fluorescein isothiocyanate (FITC) through the skin by a single exposure to UVB (10 kJ/m2). The CHS response was assessed after applying FITC to mice treated intraperitoneally with 17beta-estradiol, tamoxifen (17beta-estradiol antagonist), or antiestradiol antibody. Levels of serum interleukin-10 (IL-10) were measured in treated mice and control mice using an enzyme-linked immunosorbent assay (ELISA). To assess the effect of 17beta-estradiol on keratinocytes, Pam-212 cells were exposed in vitro to UVB radiation and treated for 24 h with 17beta-estradiol. The IL-10 content of the supernatant was measured using an ELISA. RESULTS: The CHS response in UVB-irradiated mice was significantly suppressed in comparison to that in nonirradiated mice. Consecutive intraperitoneal injections of 17beta-estradiol significantly reduced UVB-induced suppression of the CHS response in male mice, whereas injection of tamoxifen or antiestradiol antibody significantly promoted UVB-induced suppression in female mice. Treatment with 17beta-estradiol decreased the serum IL-10 levels in CHS-suppressed male mice after UVB irradiation, but treatment with tamoxifen or antiestradiol antibody increased the serum IL-10 level
J Chromatogr A. 2003 Dec 5;1020(1):99-104.
Analysis of steroid hormones in effluents of wastewater treatment plants by liquid chromatography-tandem mass spectrometry.
Ingrand V, Herry G, Beausse J, de Roubin MR.
Anjou Recherche-Vivendi Water, Emerging Parameters, 1 Place de Turenne, Immeuble Le Dufy, 94417 Saint Maurice Cedex, France. valerie.ingranenerale-des-eaux.net
This paper presents the development of an analytical procedure for the determination of two sexual steroid hormones: 17beta-estradiol and estrone, and the synthetic contraceptive estrogen, 17alpha-ethynylestradiol in effluents of wastewater treatment plants. Samples are extracted via solid-phase extraction using C18 cartridges. Extracts in ethyl acetate are then purified with a liquid-liquid separation with aqueous sodium chloride, then with a clean-up on a Florisil cartridge. Steroids are analyzed using an LC-MS-MS ion trap system. Internal quantification with the corresponding deuterated steroids leads to limits of quantification at 5 ng/l for estrone and 10 ng/l for estradiol and ethynylestradiol. In mineral spiked water, recoveries are 91% for 17beta-estradiol, 97% for estrone and 87% for 17alpha-ethynylestradiol and RSDs are 15% for 17beta-estradiol, 11% for estrone and 23% for 17alpha-ethynylestradiol.
Circulation. 2003 Dec 16;108(24):2974-8. Epub 2003 Dec 08.
Methoxyestradiols mediate the antimitogenic effects of 17beta-estradiol: direct evidence from catechol-O-methyltransferase-knockout mice.
Zacharia LC, Gogos JA, Karayiorgou M, Jackson EK, Gillespie DG, Barchiesi F, Dubey RK.
Center for Clinical Pharmacology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pa, USA.
BACKGROUND: Studies using pharmacological agents suggest but do not prove that the antimitogenic effects of estradiol are caused by conversion of estradiol to hydroxyestradiols (mediated by CYP450s) followed by methylation of hydroxyestradiols to methoxyestradiols (mediated by catechol-O-methyltransferase, COMT). METHODS AND RESULTS: To test this hypothesis more rigorously, we used aortic smooth muscle cells (SMCs) from mice lacking COMT (COMT-KO). Wild-type (WT) but not COMT-KO SMCs efficiently converted 2-hydroxyestradiol to 2-methoxyestradiol. Both WT and COMT-KO SMCs expressed estrogen receptors. Estradiol and 2-hydroxyestradiol concentration-dependently inhibited serum-induced DNA synthesis, cell numbers, and collagen synthesis in WT but not COMT-KO SMCs. 2-Methoxyestradiol inhibited DNA synthesis, cell numbers, and collagen synthesis in both WT and COMT-KO SMCs. CONCLUSIONS: These data provide strong evidence that the vascular antimitogenic effects of estradiol are estrogen receptor-independent and involve the sequential conversion of estradiol to hydroxyestradiols and then to methoxyestradiols.
Clin Exp Obstet Gynecol. 2003;30(4):229-34.
Action of 25 microg 17beta-oestradiol vaginal tablets in the treatment of vaginal atrophy in Greek postmenopausal women; clinical study.
Akrivis Ch, Varras M, Thodos A, Hadjopoulos G, Bellou A, Antoniou N.
Department of Obstetrics and Gynaecology, G. Chatzikosta General State Hospital, Ioannina, Greece.
PURPOSE: To evaluate the clinical efficacy and safety of intravaginal application of 25 microg micronized oestradiol in postmenopausal women from the Greek population suffering from symptoms related to vaginal atrophy. MATERIALS AND METHODS: 91 women suffering from vaginal dryness, vaginal itching and dyspareunea were treated with 25 microg 17beta-oestradiol vaginal tablets. The duration of treatment was 12 weeks. During the first two weeks the women inserted one vaginal tablet intravaginally once daily. Thereafter, the women inserted one tablet twice per week with at least a 3-day interval between treatments to maintain therapeutic response for ten weeks. Efficacy was evaluated by the relief of vaginal symptoms and safety by the concentrations of serum oestradiol (E2) and follicular-stimulating hormone (FSH). Pretreatment and post-treatment findings were compared and each patient served as her own control. RESULTS: The rates of symptoms of vaginal dryness, vaginal itching and dyspareunea showed statistically significant differences over the course of the trial (Cochran Q test, p < 0.001). No one complained of vaginal dryness and vaginal itching after four and six weeks of treatment respectively, while in one patient the sensation of dyspareunea remained constant after the fourth week of treatment. Despite the statistically significant increase in blood oestradiol levels in relation to baseline values (ANOVA model of repeated measures, p < 0.001), these levels were within the normal range for postmenopausal women. Also, serum FSH levels were statistically significantly reduced from 47.4 mIU/ml at entry into the study to 45.5 mIU/ml after two week
J Agric Food Chem. 2003 Dec 17;51(26):7632-5.
Phytoestrogens modulate binding response of estrogen receptors alpha and beta to the estrogen response element.
Kostelac D, Rechkemmer G, Briviba K.
Institute of Nutritional Physiology, Federal Research Centre for Nutrition, Karlsruhe, Germany.
Binding of estrogen receptor (ER) to estrogen response element (ERE) induces gene activation and is an important step in estrogen-induced biological effects. Here, we investigated the effects of some dietary phytoestrogens such as the isoflavones genistein and daidzein, its metabolite equol, and the coumestane coumestrol on the binding rate of ERalpha and ERbeta to ERE by a nonradioactive real-time method, the Biacore Technology. ERalpha and ERbeta were able to bind to ERE immobilized on the surface of a sensor chip even in the absence of estrogens. 17beta-Estradiol and phytoestrogens induced an increase in ER binding to ERE in a concentration-dependent manner. 17beta-Estradiol was a more potent activator of binding than the phytoestrogens studied. The concentrations of 17beta-estradiol inducing an increase in the binding response of ERalpha and ERbeta to ERE by 50% (EC(50)) as compared to unliganded ER were 0.03 and 0.01 microM, respectively. Regarding the efficacy of activation of ERalpha, from the most to the least effective compound, the sequence and the EC(50) were as follows: 17beta-estradiol (0.03 microM) > coumestrol (0.2 microM) > equol (3.5 microM) > genistein (15 microM) > daidzein (>300 microM) and for ERbeta 17beta-estradiol (0.01 microM) > coumestrol (0.025 microM) > genistein (0.03 microM) > daidzein (0.35 microM) > equol (0.4 microM). The ratios EC(50)alpha/EC(50)beta were calculated to be for 17beta-estradiol, 3; coumestrol, 8; equol, 8.8; genistein, 500; daidzein > 850. These ratios indicate that genistein and daidzein preferentially activate the binding of ERbeta to ERE. The endogenous hormone 17beta-estradiol as well as coumestrol and daidzein metabolite equol a
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