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Non-estrogenic Xanthohumol Derivatives Mitigate Insulin Resistance and Cognitive Impairment in High-Fat Diet-induced Obese Mice. Sci Rep 2018; 8:613. [PMID: 29330372 PMCID: PMC5766630 DOI: 10.1038/s41598-017-18992-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 12/20/2017] [Indexed: 01/21/2023] Open
Abstract
Xanthohumol (XN), a prenylated flavonoid from hops, improves dysfunctional glucose and lipid metabolism in animal models of metabolic syndrome (MetS). However, its metabolic transformation into the estrogenic metabolite, 8-prenylnaringenin (8-PN), poses a potential health concern for its use in humans. To address this concern, we evaluated two hydrogenated derivatives, α,β-dihydro-XN (DXN) and tetrahydro-XN (TXN), which showed negligible affinity for estrogen receptors α and β, and which cannot be metabolically converted into 8-PN. We compared their effects to those of XN by feeding C57BL/6J mice a high-fat diet (HFD) containing XN, DXN, or TXN for 13 weeks. DXN and TXN were present at higher concentrations than XN in plasma, liver and muscle. Mice administered XN, DXN or TXN showed improvements of impaired glucose tolerance compared to the controls. DXN and TXN treatment resulted in a decrease of HOMA-IR and plasma leptin. C2C12 embryonic muscle cells treated with DXN or TXN exhibited higher rates of uncoupled mitochondrial respiration compared to XN and the control. Finally, XN, DXN, or TXN treatment ameliorated HFD-induced deficits in spatial learning and memory. Taken together, DXN and TXN could ameliorate the neurocognitive-metabolic impairments associated with HFD-induced obesity without risk of liver injury and adverse estrogenic effects.
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Boonmuen N, Gong P, Ali Z, Chittiboyina AG, Khan I, Doerge DR, Helferich WG, Carlson KE, Martin T, Piyachaturawat P, Katzenellenbogen JA, Katzenellenbogen BS. Licorice root components in dietary supplements are selective estrogen receptor modulators with a spectrum of estrogenic and anti-estrogenic activities. Steroids 2016; 105:42-9. [PMID: 26631549 PMCID: PMC4714869 DOI: 10.1016/j.steroids.2015.11.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 11/09/2015] [Accepted: 11/18/2015] [Indexed: 12/29/2022]
Abstract
Licorice root extracts are often consumed as botanical dietary supplements by menopausal women as a natural alternative to pharmaceutical hormone replacement therapy. In addition to their components liquiritigenin (Liq) and isoliquiritigenin (Iso-Liq), known to have estrogenic activity, licorice root extracts also contain a number of other flavonoids, isoflavonoids, and chalcones. We have investigated the estrogenic activity of 7 of these components, obtained from an extract of Glycyrrhiza glabra powder, namely Glabridin (L1), Calycosin (L2), Methoxychalcone (L3), Vestitol (L4), Glyasperin C (L5), Glycycoumarin (L6), and Glicoricone (L7), and compared them with Liq, Iso-Liq, and estradiol (E2). All components, including Liq and Iso-Liq, have low binding affinity for estrogen receptors (ERs). Their potency and efficacy in stimulating the expression of estrogen-regulated genes reveal that Liq and Iso-Liq and L2, L3, L4, and L6 are estrogen agonists. Interestingly, L3 and L4 have an efficacy nearly equivalent to E2 but with a potency ca. 10,000-fold less. The other components, L1, L5 and L7, acted as partial estrogen antagonists. All agonist activities were reversed by the antiestrogen, ICI 182,780, or by knockdown of ERα with siRNA, indicating that they are ER dependent. In HepG2 hepatoma cells stably expressing ERα, only Liq, Iso-Liq, and L3 stimulated estrogen-regulated gene expression, and in all cases gene stimulation did not occur in HepG2 cells lacking ERα. Collectively, these findings classify the components of licorice root extracts as low potency, mixed ER agonists and antagonists, having a character akin to that of selective estrogen receptor modulators or SERMs.
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Affiliation(s)
- Nittaya Boonmuen
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Department of Physiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Ping Gong
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Zulfiqar Ali
- National Center for Natural Products Research, University of Mississippi, Oxford, MS 38677, United States
| | - Amar G Chittiboyina
- National Center for Natural Products Research, University of Mississippi, Oxford, MS 38677, United States
| | - Ikhlas Khan
- National Center for Natural Products Research, University of Mississippi, Oxford, MS 38677, United States
| | - Daniel R Doerge
- Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, United States
| | - William G Helferich
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Kathryn E Carlson
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Teresa Martin
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Pawinee Piyachaturawat
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand; Chakri Naruebodindra Medical Institute, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - John A Katzenellenbogen
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Benita S Katzenellenbogen
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States.
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Jiang Y, Gong P, Madak-Erdogan Z, Martin T, Jeyakumar M, Carlson K, Khan I, Smillie TJ, Chittiboyina AG, Rotte SCK, Helferich WG, Katzenellenbogen JA, Katzenellenbogen BS. Mechanisms enforcing the estrogen receptor β selectivity of botanical estrogens. FASEB J 2013; 27:4406-18. [PMID: 23882126 DOI: 10.1096/fj.13-234617] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Because little is known about the actions of botanical estrogens (BEs), widely consumed by menopausal women, we investigated the mechanistic and cellular activities of some major BEs. We examined the interactions of genistein, daidzein, equol, and liquiritigenin with estrogen receptors ERα and ERβ, with key coregulators (SRC3 and RIP140) and chromatin binding sites, and the regulation of gene expression and proliferation in MCF-7 breast cancer cells containing ERα and/or ERβ. Unlike the endogenous estrogen, estradiol (E2), BEs preferentially bind to ERβ, but their ERβ-potency selectivity in gene stimulation (340- to 830-fold vs. E2) is enhanced at several levels (coregulator recruitment, chromatin binding); nevertheless, at high (0.1 or 1 μM) concentrations, BEs also fully activate ERα. Because ERα drives breast cancer cell proliferation and ERβ dampens this, the relative levels of these two ERs in target cells and the BE dose greatly affect gene expression and proliferative response and will be crucial determinants of the potential benefits vs. risks of BEs. Our findings reveal key and novel mechanistic differences in the estrogenic activities of BEs vs. E2, with BEs displaying patterns of activity distinctly different from those seen with E2 and provide valuable information to inform future studies.
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Affiliation(s)
- Yan Jiang
- 1Department of Molecular and Integrative Physiology, University of Illinois and College of Medicine at Urbana-Champaign, Urbana, IL 61801, USA.
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Carroll VM, Jeyakumar M, Carlson KE, Katzenellenbogen JA. Diarylpropionitrile (DPN) enantiomers: synthesis and evaluation of estrogen receptor β-selective ligands. J Med Chem 2011; 55:528-37. [PMID: 22122563 DOI: 10.1021/jm201436k] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Two estrogen receptor (ER) subtypes, ERα and ERβ, mediate the actions of estrogens in diverse reproductive and nonreproductive target tissues. ER subtype-selective ligands, which bind to and activate these subtypes differentially, have proved to be useful in elucidating which actions of estrogens proceed through ERα vs ERβ. Some of these ligands show potential as novel therapeutic agents. Diarylpropionitrile (DPN), an ERβ selective ligand that we developed, is a chiral molecule, but it has been studied almost exclusively as the racemic mixture (rac-DPN, 1). Herein we report the development of an efficient enantioselective synthesis of the two isomers, R-DPN (3) and S-DPN (2), and we have compared the in vitro ligand binding affinities, coactivator binding affinities, recruitment potencies, and cellular transcriptional potencies of these isomers. Both enantiomers show a very high affinity and potency preference for ERβ over ERα, typically in the range of 80-300-fold. Although the enantioselectivity is only modest (3-4-fold), the R-enantiomer is the higher affinity and more potent isomer. While ERβ can be effectively and selectively stimulated by rac-DPN or by either R-DPN or S-DPN, R-DPN might be the preferred member of this isomeric series for biological studies of ERβ function.
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Affiliation(s)
- Vincent M Carroll
- Department of Chemistry, University of Illinois, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
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Moore TW, Gunther JR, Katzenellenbogen JA. Probing the topological tolerance of multimeric protein interactions: evaluation of an estrogen/synthetic ligand for FK506 binding protein conjugate. Bioconjug Chem 2011; 21:1880-9. [PMID: 20919698 DOI: 10.1021/bc100266v] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bivalent small molecules composed of a targeting element and an element that recruits endogenous proteins have been shown to block protein-protein interactions in some systems. We have attempted to apply such an approach to disrupt the interaction of the estrogen receptor α with either its associated coactivators or its dimerization partner (i.e., another estrogen receptor). We show here that a conjugate capable of simultaneously binding both the estrogen receptor and a recruited protein (FK506 Binding Protein 12 kDa) is, however, incapable of disrupting the multimeric estrogen receptor dimer/coactivator complex both in vitro and in cell-based reporter gene assays. We postulate why it may not be possible to disrupt this particular protein-protein complex-as well as other systems having high topological tolerance-with such bivalent inhibitors.
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Affiliation(s)
- Terry W Moore
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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Parent EE, Carlson KE, Katzenellenbogen JA. Synthesis of 7alpha-(fluoromethyl)dihydrotestosterone and 7alpha-(fluoromethyl)nortestosterone, structurally paired androgens designed to probe the role of sex hormone binding globulin in imaging androgen receptors in prostate tumors by positron emission tomography. J Org Chem 2007; 72:5546-54. [PMID: 17585812 DOI: 10.1021/jo070328b] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Although prostate cancer growth is regulated by androgens through the androgen receptor (AR), in vitro assays of AR levels in prostate tumors have limited prognostic value. This might be improved by direct measurement of tumor AR in vivo using positron emission tomography (PET) imaging with fluorine-18-labeled androgens. Most AR PET imaging agents have been designed to limit steroid binding to serum proteins, but there is evidence that binding to sex hormone binding globulin (SHBG) might enhance tumor uptake. To probe the role of SHBG in prostate tumor uptake of PET imaging agents, we have synthesized two fluoro steroids, 7alpha-(fluoromethyl)dihydrotestosterone (7alpha-FM-DHT) and 7alpha-(fluoromethyl)nortestosterone (7alpha-FM-norT), by a route amenable to their labeling with [18F]fluoride ion. Both compounds have high affinity for AR, but 7alpha-FM-norT has much lower affinity for SHBG. Thus, these two fluoro steroids are well matched in terms of their site of fluorine labeling, similarity of structure, and equivalent AR binding affinity-but contrasting SHBG binding-and therefore can be used as agents for evaluating the role of SHBG binding in the target tissue uptake of AR PET imaging agents in humans.
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Affiliation(s)
- Ephraim E Parent
- Department of Chemistry, University of Illinois, Urbana, IL 61801, USA
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Rzheznikov VM, Golubovskaya LE, Minailova ON, Ivanenko TI, Fedotov VP. Steroid nitrates. II. Synthesis and hormonal activity of 9α,11β-dihydroxyestra-1,3,5(10)-triene 11-nitrates. Pharm Chem J 2007. [DOI: 10.1007/s11094-007-0070-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Kim SH, Katzenellenbogen JA. Hormone-PAMAM dendrimer conjugates: polymer dynamics and tether structure affect ligand access to receptors. Angew Chem Int Ed Engl 2007; 45:7243-8. [PMID: 17024710 DOI: 10.1002/anie.200601923] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Sung Hoon Kim
- Department of Chemistry, University of Illinois, 600 South Mathews Avenue, Urbana, IL 61801, USA
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Kim SH, Katzenellenbogen JA. Hormone–PAMAM Dendrimer Conjugates: Polymer Dynamics and Tether Structure Affect Ligand Access to Receptors. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200601923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Kim NN, Stankovic M, Armagan A, Cushman TT, Goldstein I, Traish AM. Effects of tamoxifen on vaginal blood flow and epithelial morphology in the rat. BMC WOMENS HEALTH 2006; 6:14. [PMID: 16970814 PMCID: PMC1590006 DOI: 10.1186/1472-6874-6-14] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Accepted: 09/13/2006] [Indexed: 11/24/2022]
Abstract
Background Tamoxifen, a selective estrogen receptor modulator with both estrogenic and anti-estrogenic activity, is widely used as adjuvant therapy in breast cancer patients. Treatment with tamoxifen is associated with sexual side effects, such as increased vaginal dryness and pain/discomfort during sexual activity. There have been limited investigations of the effect of tamoxifen on estrogen-dependent peripheral genital arousal responses. The objective of this study was to investigate the effects of tamoxifen on vaginal physiology in the rat. Methods Female Sprague-Dawley rats were subjected to sham surgery or bilateral ovariectomy. After 2 weeks, sham-operated rats were implanted with subcutaneous osmotic infusion pumps containing vehicle (control) or tamoxifen (150 μg/day). Ovariectomized rats were similarly infused with vehicle. After an additional 2 weeks, vaginal blood flow responses to pelvic nerve stimulation were measured by laser Doppler flowmetry and vaginal tissue was collected for histological and biochemical assay. Results Tamoxifen treatment did not change plasma estradiol concentrations relative to control animals, while ovariectomized rats exhibited a 60% decrease in plasma estradiol. Tamoxifen treatment caused a significant decrease in mean uterine weight, but did not alter mean vaginal weight. Vaginal blood flow was significantly decreased in tamoxifen-infused rats compared to controls. Similar to ovariectomized animals, estrogen receptor binding was increased and arginase enzyme activity was decreased in tamoxifen-infused rats. However, different from control and ovariectomized animals, the vaginal epithelium in tamoxifen-infused rats appeared highly mucified. Periodic acid-Schiff staining confirmed a greater production of carbohydrate-rich compounds (e.g. mucin, glycogen) by the vaginal epithelium of tamoxifen-infused rats. Conclusion The observations suggest that tamoxifen exerts both anti-estrogenic and pro-estrogenic effects in the vagina. These physiological alterations may eventually lead to vaginal atrophy and compromise sexual function.
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Affiliation(s)
- Noel N Kim
- Institute for Sexual Medicine, Department of Urology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Miljan Stankovic
- Institute for Sexual Medicine, Department of Urology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Abdullah Armagan
- Department of Urology, Suleyman Demirel University Faculty of Medicine, Isparta, Turkey
| | - Tulay T Cushman
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Irwin Goldstein
- Institute for Sexual Medicine, Department of Urology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Abdulmaged M Traish
- Institute for Sexual Medicine, Department of Urology, Boston University School of Medicine, Boston, Massachusetts, USA
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts, USA
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Tuccinardi T, Bertini S, Martinelli A, Minutolo F, Ortore G, Placanica G, Prota G, Rapposelli S, Carlson KE, Katzenellenbogen JA, Macchia M. Synthesis of Anthranylaldoxime Derivatives as Estrogen Receptor Ligands and Computational Prediction of Binding Modes. J Med Chem 2006; 49:5001-12. [PMID: 16884312 DOI: 10.1021/jm060560u] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
N-Me-anthranylaldoximes possess a hydrogen-bonded pseudocyclic A' ring in place of the typical phenolic A-ring that is characteristic of most estrogen receptor (ER) ligands. We have investigated the role played by substituents introduced into either one or both of the peripheral 3- and 4-phenyl rings in modulating ER binding affinity. An efficient synthetic strategy was employed for the preparation of differentially substituted 3- and 4-aryl derivatives that involved exploiting the different reactivity of bromo- versus chloro-aryl groups in palladium-catalyzed cross-couplings. The binding data showed that ERalpha affinity could be improved by a single p-OH group in the 4-phenyl ring, whereas the same substitution on the 3-phenyl ring caused a dramatic reduction of ERbeta affinity. The most ERalpha-selective compound was the one with two p-OH groups on both phenyl substituents. To rationalize these results, ligand docking followed by molecular mechanics Poisson-Boltzmann/surface area (MM-PBSA) studies were carried out. These analyses suggested a molecular basis for the interaction of these compounds with the ERs and enabled the development of models able to predict the mode of ligand binding.
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Affiliation(s)
- Tiziano Tuccinardi
- Dipartimento di Scienze Farmaceutiche, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
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Zhou D, Carlson KE, Katzenellenbogen JA, Welch MJ. Bromine- and Iodine-Substituted 16α,17α-Dioxolane Progestins for Breast Tumor Imaging and Radiotherapy: Synthesis and Receptor Binding Affinity. J Med Chem 2006; 49:4737-44. [PMID: 16854080 DOI: 10.1021/jm060348q] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Progesterone receptors (PRs) are present in many breast tumors, and their levels are increased by certain endocrine therapies. We describe the synthesis and PR binding affinities of a series of bromine- and iodine-substituted 16alpha,17alpha-dioxolane progestins, some of which, when appropriately radiolabeled, are potential agents for diagnostic imaging of PR-positive breast tumors using positron emission tomography (PET) and for radiotherapy. These compounds were synthesized from halogenated furanyl, phenyl, and thiophenyl aldehydes and a progestin 16alpha,17alpha,21-triol (5) in the presence of HClO4 or Sc(OTf)3 in high yields under optimized conditions. A new reagent, perfluoro-1-butanesulfonyl fluoride (PBSF), was used to convert the C-21 OH to F in high yields. The relative binding affinities (RBAs) of the most promising compounds for the PR (RBA of R5020 = 100) were 16alpha,17alpha-[(R)-1'-alpha-(5-bromofurylmethylidene)dioxyl]-21-hydroxy-19-norpregn-4-ene-3,20-dione (endo-6; RBA = 65 and moderate lipophilicity), 21-fluoro-16alpha,17alpha-[(R)-1'-alpha-(5-iodofurylmethylidene)dioxyl]-19-norpregn-4-ene-3,20-dione (endo-14; RBA = 40) and 21-fluoro-16alpha,17alpha-[(S)-1'-beta-(4-iodophenylmethylidene)dioxyl]-19-norpregn-4-ene-3,20-dione (exo-16; RBA = 34).
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Affiliation(s)
- Dong Zhou
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Seo JW, Comninos JS, Chi DY, Kim DW, Carlson KE, Katzenellenbogen JA. Fluorine-substituted cyclofenil derivatives as estrogen receptor ligands: synthesis and structure-affinity relationship study of potential positron emission tomography agents for imaging estrogen receptors in breast cancer. J Med Chem 2006; 49:2496-511. [PMID: 16610793 PMCID: PMC2522267 DOI: 10.1021/jm0512037] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In a search for estrogen receptor (ER) ligands to be radiolabeled with fluorine-18 for imaging of ER-positive breast tumors with positron emission tomography (PET), we investigated cyclofenil analogues substituted at the C3 or C4 position of the cyclohexyl group. McMurry coupling of 4,4'-dihydroxybenzophenone with various ketones produced key cyclofenil intermediates, from which C3 and C4 substituents containing alkyl and various oxygen or fluorine-substituted alkyl groups were elaborated. Binding assays to both ERalpha and ERbeta revealed that the C3 site is more tolerant of steric bulk and polar groups than the C4 site, consistent with a computational model of the ERalpha ligand binding pocket. Fluorine substitution is tolerated very well at some sites, giving some compounds having affinities comparable to or higher than that of estradiol. These fluoro and fluoroalkyl cyclofenils merit further consideration as fluorine-18 labeled ER ligands for PET imaging of ERs in breast tumors.
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Affiliation(s)
- Jai Woong Seo
- Department of Chemistry, Inha University, 253 Yonghyundong Namgu, Inchon 402-751, Korea
| | - John S. Comninos
- Department of Chemistry, University of Illinois, Urbana, IL 61801, USA
| | - Dae Yoon Chi
- Department of Chemistry, Inha University, 253 Yonghyundong Namgu, Inchon 402-751, Korea
| | - Dong Wook Kim
- Department of Chemistry, University of Illinois, Urbana, IL 61801, USA
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Yoo J, Dence CS, Sharp TL, Katzenellenbogen JA, Welch MJ. Synthesis of an estrogen receptor beta-selective radioligand: 5-[18F]fluoro-(2R,3S)-2,3-bis(4-hydroxyphenyl)pentanenitrile and comparison of in vivo distribution with 16alpha-[18F]fluoro-17beta-estradiol. J Med Chem 2005; 48:6366-78. [PMID: 16190762 DOI: 10.1021/jm050121f] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Estrogen receptor beta (ERbeta), a less active ER subtype that appears to have a restraining effect on the more active ERalpha, could be a factor that determines the level of estrogen action in certain estrogen target tissues. ERbeta is found in breast cancer, and its levels relative to ERalpha decline with disease progression. Thus, the independent quantification of ERalpha and ERbeta levels in breast cancer by imaging might be predictive of responses to different hormone therapies. To develop an imaging agent for ERbeta, we synthesized a fluoroethyl analogue of DPN (2,3-bis(4-hydroxyphenyl)propanonitrile), a known ERbeta-selective ligand. This analogue, FEDPN (5-fluoro-(2R,3S)-2,3-bis(4-hydroxyphenyl)pentanenitrile), has an 8.3-fold absolute affinity preference for ERbeta. [18F]Fluoride-labeled FEDPN was prepared from a toluenesulfonate precursor, which provided [18F]FEDPN with a specific activity greater than 3100 Ci/mmol after HPLC purification. Biodistribution studies in immature female rats using estradiol as a blocking agent revealed specific uptake of [18F]FEDPN in the uterus and ovaries. Experiments using ERalpha- and ERbeta-knockout mice demonstrated the expected ERalpha-subtype dependence in the tissue uptake of the known 16alpha-[18F]fluoro-17beta-estradiol ([18F]FES), which has a 6.3-fold preference for ERalpha. The tissue uptake of [18F]FEDPN in the ER knockout mice showed some evidence of mediation by ERbeta, but the levels of specific uptake of this agent were relatively modest. Based on our results, imaging of ERalpha can be done effectively with [18F]FES, but imaging of ERbeta will likely require agents with more optimized ERbeta binding affinity and selectivity than [18F]FEDNP.
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Affiliation(s)
- Jeongsoo Yoo
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, Campus Box 8225, 510 South Kingshighway Boulevard, St. Louis, Missouri 63110, USA
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Zhou HB, Comninos JS, Stossi F, Katzenellenbogen BS, Katzenellenbogen JA. Synthesis and Evaluation of Estrogen Receptor Ligands with Bridged Oxabicyclic Cores Containing a Diarylethylene Motif: Estrogen Antagonists of Unusual Structure. J Med Chem 2005; 48:7261-74. [PMID: 16279785 DOI: 10.1021/jm0506773] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new series of ligands for the estrogen receptor (ER) based on a three-dimensional structural motif consisting of a bridged oxabicyclic core (7-oxabicyclo[2.2.1]heptene or heptadiene) were synthesized and examined for their receptor binding activity and as regulators of transcription through the two ER subtypes, ER alpha and ER beta. The prototypical ligands also contain a 1,2-diarylethylene motif, common to many nonsteroidal estrogens, as an embellishment on the oxabicyclic core. Thus, these ligands bear peripheral groups typically found in ER ligands, built here upon an overall three-dimensional core topology that is unusual for these targets. Most of these compounds were conveniently synthesized by a Diels-Alder reaction of various 3,4-diarylfurans with a variety of dienophiles, neat and under mild conditions in the absence of catalysts. Some of the synthesized compounds display good binding affinity for the ER, and in transcription assays, the highest affinity compounds are antagonists on both ERs. Molecular modeling studies suggest a structural basis for the antagonist activity of these compounds. These compounds, based on the bicyclo[2.2.1]core system, expand the structural diversity of ligands that can be antagonists for the estrogen receptors.
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Affiliation(s)
- Hai-Bing Zhou
- Department of Chemistry, University of Illinois, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
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16
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De Angelis M, Stossi F, Carlson KA, Katzenellenbogen BS, Katzenellenbogen JA. Indazole Estrogens: Highly Selective Ligands for the Estrogen Receptor β. J Med Chem 2005; 48:1132-44. [PMID: 15715479 DOI: 10.1021/jm049223g] [Citation(s) in RCA: 174] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The estrogen receptors, ERalpha and ERbeta, are important pharmaceutical targets. To develop ERbeta-selective ligands, we synthesized a series of nonsteroidal compounds having a phenyl-2H-indazole core with different groups at C-3. Several of these show high affinity and good ERbetaselectivity, especially those with polar and/or polarizable substituents at this site (halogen, CF(3), nitrile); the best compounds have affinities for ERbeta comparable to estradiol, with ERbetaaffinity selectivity >100. This potency and ERbeta selectivity is also seen in cell-based transcriptional assays, where several compounds showed ERbeta efficacies equivalent to that of estradiol with ERbeta potency selectivities of 100. These compounds might prove useful as selective pharmacological probes to study the biological actions of estrogens mediated through ERbeta, and they might lead to the development of useful pharmaceuticals. These findings also contribute to an evolving pharmacophore that characterizes certain nonsteroidal ligands having high ERbeta subtype affinity and potency selectivity.
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Affiliation(s)
- Meri De Angelis
- Department of Chemistry, University of Illinois, 600 South Matthews Avenue, Urbana, Illinois 61801, USA
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17
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Compton DR, Sheng S, Carlson KE, Rebacz NA, Lee IY, Katzenellenbogen BS, Katzenellenbogen JA. Pyrazolo[1,5-a]pyrimidines: estrogen receptor ligands possessing estrogen receptor beta antagonist activity. J Med Chem 2005; 47:5872-93. [PMID: 15537344 DOI: 10.1021/jm049631k] [Citation(s) in RCA: 150] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In our search for novel subtype-selective estrogen receptor (ER) ligands, we have examined various heterocyclic units as core structural elements. Here, we have investigated the fused, bicyclic pyrazolo[1,5-a]pyrimidine core, which is a system that allows for analogues to be readily assembled in a library-like fashion. This series of pyrazolo[1,5-a]pyrimidine ER ligands provided us with a new pharmacological profile for an ER ligand: compounds that are passive on both ERs, with a distinct potency selectivity in favor of ERbeta. The most distinctive ligand in this series, 2-phenyl-3-(4-hydroxyphenyl)-5,7-bis(trifluoromethyl)-pyrazolo[1,5-a]pyrimidine, was 36-fold selective for ERbeta in binding. Curiously, on the basis of molecular modeling, the ERbeta binding selectivity of compounds in this series appears to be derived from differing orientations that they adapt in the ligand binding pockets of ERalpha vs ERbeta. In transcription assays this pyrazolopyrimidine was fully effective as an ERbeta antagonist while exhibiting no significant activity on ERalpha. Thus, this ligand functions as a potency- and efficacy-selective ERbeta antagonist that would abrogate estrogen action through ERbeta with minimal effects on its activity through ERalpha; as such, it could be used to study the biological function of ERbeta.
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Affiliation(s)
- Dennis R Compton
- Department of Chemistry and Department of Molecular and Integrative Physiology, University of Illinois, 600 South Matthews Avenue, Urbana, Illinois 61801, USA
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18
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Kim SW, Kim NN, Jeong SJ, Munarriz R, Goldstein I, Traish AM. MODULATION OF RAT VAGINAL BLOOD FLOW AND ESTROGEN RECEPTOR BY ESTRADIOL. J Urol 2004; 172:1538-43. [PMID: 15371887 DOI: 10.1097/01.ju.0000137744.12814.2e] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
PURPOSE The effects of subphysiological and physiological levels of estradiol on vaginal blood flow and estrogen receptor were investigated. MATERIALS AND METHODS Intact or ovariectomized female Sprague-Dawley rats were used. Two weeks after surgery rats were infused with vehicle (polyethyleneglycol), or estradiol at subphysiological (5 microg daily) or physiological (15 microg daily) concentrations for 14 days using osmotic pumps. Changes in vaginal blood flow elicited by pelvic nerve stimulation were assessed by laser Doppler flowmetry. Total levels of functional estrogen receptor were determined by radioligand binding and Western blot analyses were used to assess estrogen receptor (ER) alpha protein. RESULTS Mean plasma estradiol concentration +/- SEM decreased by 63% in the vehicle group (intact 36.5 +/- 10.3 pg/ml). The subphysiological and physiological estradiol groups had plasma levels that were 55% and 83% of the intact group, respectively. Uterine and vaginal wet weight, and vaginal blood flow were significantly decreased in the vehicle group and normalized by physiological levels of estradiol. However, vaginal blood flow was significantly greater in the subphysiological estradiol group compared to intact animals. Specific binding of [H]estradiol in vaginal tissue extracts from intact rats was 0.51 fmol/mg protein and it was increased 30-fold in the vehicle group. ER binding in vaginal tissue in the physiological estradiol group decreased to levels that were comparable to those in intact animals, whereas estrogen receptor binding remained elevated in the subphysiological estradiol group. These changes were paralleled by ERalpha protein levels. CONCLUSIONS Estradiol is crucial for maintaining optimal vaginal blood flow in the rat. Lower levels of plasma estradiol trigger compensatory ERalpha up-regulation.
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Affiliation(s)
- Soo Woong Kim
- Department of Urology, Seoul National University College of Medicine, Seoul, Korea
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19
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Suzuki N, Yamamoto K, Sasayama Y, Suzuki T, Kurokawa T, Kambegawa A, Srivastav AK, Hayashi S, Kikuyama S. Possible direct induction by estrogen of calcitonin secretion from ultimobranchial cells in the goldfish. Gen Comp Endocrinol 2004; 138:121-7. [PMID: 15302261 DOI: 10.1016/j.ygcen.2004.05.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2004] [Accepted: 05/24/2004] [Indexed: 11/18/2022]
Abstract
The plasma level of calcitonin (CT), a calcium (Ca)-regulating hormone, is known to increase in female teleosts during the reproductive period. In the present study, a correlation between plasma CT and Ca and one between plasma CT and the gonad somatic index were demonstrated in the female goldfish but not in the male. To clarify the relationship between CT and Ca, we examined the plasma CT and Ca levels after injecting immature goldfish with estrogen. At day 1, the plasma CT level significantly increased, whereas the plasma Ca level was not changed from its initial level. This result suggests that the trigger of CT secretion is estrogen and that estrogen directly acts on the ultimobranchial gland (UBG), a CT-secreting organ. To determine whether the UBG is equipped with estrogen receptor (ER), an ER binding assay and immunohistochemical staining of UBG cells with an antibody against ER were conducted. As a result, estrogen-specific binding (Kd, 18.52 nM; Bmax, 1.35 pmol/mg protein) and ER-immunoreactivity in the UBG were demonstrated. Furthermore, the expression of alpha, beta, and gamma types of ER in the UBG was also detected by use of the reverse-transcription polymerase chain reaction. Thus, we concluded that estrogen acts on the UBG to induce the release of CT, which in turn plays an important role in reproduction directly and/or indirectly through Ca. This is the first report on the existence of ERs in a teleost UBG and the occurrence of CT secretion caused by estrogen.
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Affiliation(s)
- Nobuo Suzuki
- Noto Marine Laboratory, Institute of Nature and Environmental Technology, Kanazawa University, Uchiura, Ishikawa 927-0553, Japan.
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20
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Kim SH, Tamrazi A, Carlson KE, Daniels JR, Lee IY, Katzenellenbogen JA. Estrogen receptor microarrays: subtype-selective ligand binding. J Am Chem Soc 2004; 126:4754-5. [PMID: 15080660 DOI: 10.1021/ja039586q] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present the first example of a nuclear hormone receptor microarray, using for illustration the ligand-binding domains of the two estrogen receptors, ERalpha-LBD and ERbeta-LBD. The proteins are printed and allowed to attach to aldehyde slides; the efficiency of attachment depends on whether the LBD is liganded with agonists (low attachment) versus liganded with antagonists or unliganded (high attachment). This suggests that attachment is orientation specific and involves principally a single lysine residue. The attached ERs retain good ligand-binding activity that can be assessed using an estradiol-fluorophore conjugate, and specific and ER subtype-selective binding of ligands can be determined conveniently in competitive binding assays. This powerful new, high-throughput technique to study ligand binding to ER-LBDs can be extended to other nuclear hormone receptors and adapted to assay the recruitment of coregulator proteins.
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Affiliation(s)
- Sung Hoon Kim
- Department of Chemistry, University of Illinois, 600 South Matthews Avenue, Urbana, Illinois 61801, USA
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21
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Traish AM, Huang YH, Min K, Kim NN, Munarriz R, Goldstein I. Binding characteristics of [3H]delta(5)-androstene-3beta,17beta-diol to a nuclear protein in the rabbit vagina. Steroids 2004; 69:71-8. [PMID: 14715380 DOI: 10.1016/j.steroids.2003.10.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In this study, we investigated the binding characteristics of [3H]Delta(5)-androstene-3beta,17beta-diol to rabbit vaginal cytosolic and nuclear extracts and in freshly excised intact tissue strips. [3H]delta(5)-Androstene-3beta,17beta-diol bound to a protein(s) in the vaginal nuclear extract with high affinity (K(d)=3-5 nM) and limited capacity (50-100 fmol/mg protein). No specific binding was detected in the cytoplasmic extracts. Competitive binding studies showed that binding of [3H]delta(5)-androstene-3beta,17beta-diol was effectively displaced with unlabeled delta(5)-androstene-3beta,17beta-diol but not with dehydroepiandrosterone, testosterone, dihydrotestosterone, triamcinolone acetonide, or progesterone. However, estradiol at high concentrations partially displaced bound [3H]delta(5)-androstene-3beta,17beta-diol. Incubation of freshly excised vaginal tissue strips with [3H]delta(5)-androstene-3beta,17beta-diol in the absence or presence of excess unlabeled delta(5)-androstene-3beta,17beta-diol for 1h at 37 degrees C resulted in specific binding to a soluble macromolecule in the nuclear KCl extracts. In addition, quantitative measurement of estrogen receptor, androgen receptor and delta(5)-androstene-3beta,17beta-diol binding protein was performed by equilibrium ligand binding assays using extracts of distal vaginal tissue from intact animals or ovariectomized animals treated for 2 weeks with vehicle, estradiol, testosterone, or estradiol plus testosterone. These changes in steroid hormone levels resulted in opposing trends between the estrogen receptor and delta(5)-androstene-3beta,17beta-diol binding protein, suggesting that delta(5)-androstene-3beta,17beta-diol binding protein is regulated differently by the hormonal milieu than the estrogen receptor. These data suggest that rabbit vaginal tissue expresses a novel binding protein which specifically binds delta(5)-androstene-3beta,17beta-diol and is distinct from the androgen and estrogen receptors.
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Affiliation(s)
- Abdulmaged M Traish
- Department of Biochemistry, Boston University School of Medicine, 700 Albany Street, Room W607, Boston, MA 02118, USA.
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22
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Rodriguez AL, Tamrazi A, Collins ML, Katzenellenbogen JA. Design, Synthesis, and in Vitro Biological Evaluation of Small Molecule Inhibitors of Estrogen Receptor α Coactivator Binding. J Med Chem 2003; 47:600-11. [PMID: 14736241 DOI: 10.1021/jm030404c] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nuclear receptors (NRs) complexed with agonist ligands activate transcription by recruiting coactivator protein complexes. In principle, one should be able to inhibit the transcriptional activity of the NRs by blocking this transcriptionally critical receptor-coactivator interaction directly, using an appropriately designed coactivator binding inhibitor (CBI). To guide our design of various classes of CBIs, we have used the crystal structure of an agonist-bound estrogen receptor (ER) ligand binding domain (LBD) complexed with a coactivator peptide containing the LXXLL signature motif bound to a hydrophobic groove on the surface of the LBD. One set of CBIs, based on an outside-in design approach, has various heterocyclic cores (triazenes, pyrimidines, trithianes, cyclohexanes) that mimic the tether sites of the three leucines on the peptide helix, onto which are appended leucine residue-like substituents. The other set, based on an inside-out approach, has a naphthalene core that mimics the two most deeply buried leucines, with substituents extending outward to mimic other features of the coactivator helical peptide. A fluorescence anisotropy-based coactivator competition assay was developed to measure the specific binding of these CBIs to the groove site on the ER-agonist complex with which coactivators interact; control ligand-binding assays assured that their interaction was not with the ligand binding pocket. The most effective CBIs were those from the pyrimidine family, the best binding with K(i) values of ca. 30 microM. The trithiane- and cyclohexane-based CBIs appear to be poor structural mimics, because of equatorial vs axial conformational constraints, and the triazene-based CBIs are also conformationally constrained by amine-substituent-to-ring resonance overlap, which is not the case with the higher affinity alkyl-substituted pyrimidines. The pyrimidine-based CBIs appear to be the first small molecule inhibitors of NR coactivator binding.
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Affiliation(s)
- Alice L Rodriguez
- Department of Chemistry, University of Illinois, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
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23
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Minutolo F, Antonello M, Bertini S, Ortore G, Placanica G, Rapposelli S, Sheng S, Carlson KE, Katzenellenbogen BS, Katzenellenbogen JA, Macchia M. Novel estrogen receptor ligands based on an anthranylaldoxime structure: role of the phenol-type pseudocycle in the binding process. J Med Chem 2003; 46:4032-42. [PMID: 12954056 DOI: 10.1021/jm0308390] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The 3,4-diphenylsalicylaldoxime system 1 is an estrogen receptor (ER) ligand of unusual structure, having a hydrogen-bonded pseudocyclic A'-ring in place of the paradigmatic phenolic A-ring that is characteristic of most estrogens. We have investigated the role played by the pseudocycle A' in binding to the ER by preparing 3,4-diphenylbenzaldoxime (4), a compound that completely lacks this ring but still preserves all of the other features of the original molecule 1, as well as a series of 3,4-diphenylanthranylaldoximes (5a-c) in which the nature of the heteroatom participating in the formation of pseudoring A' has been changed from an oxygen (1) to a nitrogen that is either unsubstituted (5a) or substituted with small alkyl groups (a methyl in 5b, or an ethyl in 5c). The importance of hydrogen-bonded pseudocycle A' in the binding process was confirmed by the fact that benzaldoxime 4 showed a greatly reduced binding affinity compared to salicylaldoxime 1. Moreover, the binding affinity improved considerably when the A'-ring contained either an unsubstituted nitrogen (5a) or an N-Me group (5b). On the other hand, the N-Et-substituted anthranyl derivative 5c showed a marked drop in binding affinity. Molecular modeling docking studies on ERalpha confirmed that compounds 5a and 5b fit nicely in the ligand binding pocket, with an especially comfortable fit for the N-Me group of 5b in a small hydrophobic pocket surrounded by nonpolar residues. The limited size of this pocket does not allow accommodation of N-substituents larger than a methyl group, which is consistent with the low binding affinity of the N-Et compound 5c.
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MESH Headings
- Benzene Derivatives/chemistry
- Benzene Derivatives/metabolism
- Benzene Derivatives/pharmacology
- Binding Sites
- Binding, Competitive
- Dose-Response Relationship, Drug
- Endometrial Neoplasms/metabolism
- Estradiol/chemistry
- Estradiol/metabolism
- Female
- Genes, Reporter/genetics
- Humans
- Hydrogen Bonding
- Ligands
- Models, Molecular
- Oximes/chemistry
- Oximes/metabolism
- Oximes/pharmacology
- Phenols/chemistry
- Phenols/metabolism
- Phenols/pharmacology
- Radioligand Assay
- Receptors, Estrogen/agonists
- Receptors, Estrogen/antagonists & inhibitors
- Receptors, Estrogen/genetics
- Receptors, Estrogen/metabolism
- Structure-Activity Relationship
- Transcription, Genetic/drug effects
- Transcription, Genetic/genetics
- Transfection
- Tumor Cells, Cultured
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Affiliation(s)
- Filippo Minutolo
- Dipartimento di Scienze Farmaceutiche, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
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24
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Arterburn JB, Corona C, Rao KV, Carlson KE, Katzenellenbogen JA. Synthesis of 17-alpha-substituted estradiol-pyridin-2-yl hydrazine conjugates as effective ligands for labeling with Alberto's complex fac-[Re(OH2)3(CO)3]+ in water. J Org Chem 2003; 68:7063-70. [PMID: 12946150 DOI: 10.1021/jo034780g] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The development of (99m)Tc-estradiol radiopharmaceuticals would be advantageous for the detection of estrogen receptor-positive breast tumors. Estradiol derivatives conjugated to organometallic tricarbonyl-Tc(I) and related Re(I) complexes are capable of achieving high receptor binding affinity, but effective methods for synthesizing radiolabeled complexes in water are not available. Our interest in the synthesis of 2-hydrazinopyridines as ligands for Tc and Re led us to investigate Pd-catalyzed amination reactions of halo-pyridine substrates with di-tert-butyl hydrazodiformate. Both 2- and 4-substituted halo-pyridine substrates undergo C-N coupling with di-tert-butyl hydrazodiformate to produce Boc-protected pyridine hydrazine derivatives. Only highly electrophilic 3-pyridine halides were converted to the hydrazine. The Boc-protected 5-bromopyridin-2-yl hydrazine substrate 3 was prepared by regioselective substitution at the 2-position of 2,5-dibromopyridine. This bifunctional chelate was attached to ethynyl or vinyl groups at the 17alpha position of estradiol, using Sonogashira and Suzuki/Miyaura coupling reactions to synthesize 1 and 2 in high yields, respectively. Deprotection of 1 under acidic conditions provided the hydrazine hydrochloride salt 25. The 17alpha-estradiol-tricarbonylrhenium(I) complex 4 was synthesized by labeling 25 with fac-[Re(OH(2))(3)(CO)(3)](+) in aqueous ethanol. This complex exhibited excellent stability and high receptor binding affinity for the estrogen receptor, and it is a promising model for evaluation of the analogous Tc-99m complexes as diagnostic imaging agents for breast tumors.
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Affiliation(s)
- Jeffrey B Arterburn
- Department of Chemistry and Biochemistry MSC 3C, New Mexico State University, P.O. Box 30001, Las Cruces, New Mexico 88003, USA.
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25
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Muthyala RS, Sheng S, Carlson KE, Katzenellenbogen BS, Katzenellenbogen JA. Bridged bicyclic cores containing a 1,1-diarylethylene motif are high-affinity subtype-selective ligands for the estrogen receptor. J Med Chem 2003; 46:1589-602. [PMID: 12699377 DOI: 10.1021/jm0204800] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The actions of estrogens are mediated through the two estrogen receptors, ERalpha and ERbeta. Compounds that interact selectively with ERalpha or ERbeta are of interest because they could be used to explore the biological roles of these ER subtypes and they might be interesting estrogen pharmaceuticals. In a new approach to develop ER subtype-selective ligands, we have embellished the 1,1-diarylethylene motif, common to many nonsteroidal estrogens, with various bridged bicyclic or tricyclic cores, including ones based on bicyclo[3.3.1]nonane, bicyclo[2.2.1]heptane, and selected bi- and tricyclic terpenoids. This design leads to three-dimensional ER ligands of unusual structure that we have used to probe the size and shape of the ligand binding pocket of ERalpha and ERbeta. Many of these compounds have high binding affinities, with the best having a bicyclo[3.3.1]nonane core and binding 3-5 times better than estradiol to both ER subtypes. Some of the compounds show significant affinity selectivity in favor of ERbeta (4- to 5-fold), and in cell-based assays for transcriptional activity most are partial agonists on ERalpha and full antagonists on ERbeta.
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Affiliation(s)
- Rajeev S Muthyala
- Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA
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26
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Minutolo F, Bertini S, Papi C, Carlson KE, Katzenellenbogen JA, Macchia M. Salicylaldoxime moiety as a phenolic "A-Ring" substitute in estrogen receptor ligands. J Med Chem 2001; 44:4288-91. [PMID: 11708930 DOI: 10.1021/jm010948j] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The phenolic "A-ring" of natural and synthetic estrogen receptor (ER) ligands was effectively replaced by a planar six-member ring formed through an intramolecular hydrogen bond within a salicylaldoxime. Thus, oxime 1, a structural analogue of a triarylethylene estrogen, showed a significant binding affinity for the ER. The OH of the oxime function appears to mimic the phenolic OH present in more "classical" ER ligands because the binding reduced when the oxime OH is methylated (2) or absent (3).
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Affiliation(s)
- F Minutolo
- Dipartimento di Scienze Farmaceutiche, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
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27
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Meyers MJ, Sun J, Carlson KE, Marriner GA, Katzenellenbogen BS, Katzenellenbogen JA. Estrogen receptor-beta potency-selective ligands: structure-activity relationship studies of diarylpropionitriles and their acetylene and polar analogues. J Med Chem 2001; 44:4230-51. [PMID: 11708925 DOI: 10.1021/jm010254a] [Citation(s) in RCA: 544] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Through an effort to develop novel ligands that have subtype selectivity for the estrogen receptors alpha (ERalpha) and beta (ERbeta), we have found that 2,3-bis(4-hydroxyphenyl)propionitrile (DPN) acts as an agonist on both ER subtypes, but has a 70-fold higher relative binding affinity and 170-fold higher relative potency in transcription assays with ERbeta than with ERalpha. To investigate the ERbeta affinity- and potency-selective character of this DPN further, we prepared a series of DPN analogues in which both the ligand core and the aromatic rings were modified by the repositioning of phenolic hydroxy groups and by the addition of alkyl substituents and nitrile groups. We also prepared other series of DPN analogues in which the nitrile functionality was replaced with acetylene groups or polar functions, to mimic the linear geometry or polarity of the nitrile, respectively. To varying degrees, all of the analogues show preferential binding affinity for ERbeta (i.e., they are ERbeta affinity-selective), and many, but not all of them, are also more potent in activating transcription through ERbeta than through ERalpha (i.e., they are ERbeta potency-selective). meso-2,3-Bis(4-hydroxyphenyl)succinonitrile and dl-2,3-bis(4-hydroxyphenyl)succinonitrile are among the highest ERbeta affinity-selective ligands, and they have an ERbeta potency selectivity that is equivalent to that of DPN. The acetylene analogues have higher binding affinities but somewhat lower selectivities than their nitrile counterparts. The polar analogues have lower affinities, and only the fluorinated polar analogues have substantial affinity selectivities. This study suggests that, in this series of ligands, the nitrile functionality is critical to ERbeta selectivity because it provides the optimal combination of linear geometry and polarity. Furthermore, the addition of a second nitrile group beta to the nitrile in DPN or the addition of a methyl substitutent at an ortho position on the beta-aromatic ring increases the affinity and selectivity of these compounds for ERbeta. These ERbeta-selective compounds may prove to be valuable tools in understanding the differences in structure and biological function of ERalpha and ERbeta.
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Affiliation(s)
- M J Meyers
- Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA
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28
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Mortensen DS, Rodriguez AL, Carlson KE, Sun J, Katzenellenbogen BS, Katzenellenbogen JA. Synthesis and biological evaluation of a novel series of furans: ligands selective for estrogen receptor alpha. J Med Chem 2001; 44:3838-48. [PMID: 11689070 DOI: 10.1021/jm010211u] [Citation(s) in RCA: 215] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A variety of nonsteroidal systems can function as ligands for the estrogen receptor (ER), in some cases showing selectivity for one of the two ER subtypes, ER alpha or ER beta. We have prepared a series of heterocycle-based (furans, thiophenes, and pyrroles) ligands for the estrogen receptor and assessed their behavior as ER ligands. An aldehyde enone conjugate addition approach and an enolate alkylation approach were developed to prepare the 1,4-dione systems that were precursors to the trisubstituted and tetrasubstituted systems, respectively. All of the diones were easily converted into the corresponding furans, but formation of the thiophenes and pyrroles from the more highly substituted 1,4-diones was problematical. Of the systems investigated, the tetrasubstituted furans proved to be most interesting. They were ER alpha binding- and potency-selective agents, with the triphenolic 3-alkyl-2,4,5-tris(4-hydroxyphenyl)furans (15a-d) displaying generally higher subtype binding selectivity than the bisphenolic analogues (15f-i). Binding selectivity for ER alpha was as high as 50-70-fold, and transcriptional activation studies showed that several members of this series were ER alpha selective agonists, with the best compound [3-ethyl-2,4,5-tris(4-hydroxyphenyl)furan, 15b] having full transcriptional activity on ER alpha while being inactive on ER beta. Comparative binding affinity analysis and molecular modeling were used to investigate the preferred binding mode adopted by the furan ligands, which appears to have the C(2) phenol mimicking the important role of the A-ring of estradiol. These ligands should be useful in studying the biological roles of both ER alpha and ER beta, and they might form the basis for the development of novel estrogen pharmaceuticals.
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Affiliation(s)
- D S Mortensen
- Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA
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29
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Stauffer SR, Coletta CJ, Tedesco R, Nishiguchi G, Carlson K, Sun J, Katzenellenbogen BS, Katzenellenbogen JA. Pyrazole ligands: structure-affinity/activity relationships and estrogen receptor-alpha-selective agonists. J Med Chem 2000; 43:4934-47. [PMID: 11150164 DOI: 10.1021/jm000170m] [Citation(s) in RCA: 614] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have found that certain tetrasubstituted pyrazoles are high-affinity ligands for the estrogen receptor (ER) (Fink et al. Chem. Biol. 1999, 6, 205-219) and that one pyrazole is considerably more potent as an agonist on the ERalpha than on the ERbeta subtype (Sun et al. Endocrinology 1999, 140, 800-804). To investigate what substituent pattern provides optimal ER binding affinity and the greatest enhancement of potency as an ERalpha-selective agonist, we prepared a number of tetrasubstituted pyrazole analogues with defined variations at certain substituent positions. Analysis of their binding affinity pattern shows that a C(4)-propyl substituent is optimal and that a p-hydroxyl group on the N(1)-phenyl group also enhances affinity and selectivity for ERalpha. The best compound in this series, a propylpyrazole triol (PPT, compound 4g), binds to ERalpha with high affinity (ca. 50% that of estradiol), and it has a 410-fold binding affinity preference for ERalpha. It also activates gene transcription only through ERalpha. Thus, this compound represents the first ERalpha-specific agonist. We investigated the molecular basis for the exceptional ERalpha binding affinity and potency selectivity of pyrazole 4g by a further study of structure-affinity relationships in this series and by molecular modeling. These investigations suggest that the pyrazole triols prefer to bind to ERalpha with their C(3)-phenol in the estradiol A-ring binding pocket and that binding selectivity results from differences in the interaction of the pyrazole core and C(4)-propyl group with portions of the receptor where ERalpha has a smaller residue than ERbeta. These ER subtype-specific interactions and the ER subtype-selective ligands that can be derived from them should prove useful in defining those biological activities in estrogen target cells that can be selectively activated through ERalpha.
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Affiliation(s)
- S R Stauffer
- Department of Chemistry, University of Illinois and University of Illinois College of Medicine, Urbana, Illinois 61801, USA
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Stauffer SR, Katzenellenbogen JA. Solid-phase synthesis of tetrasubstituted pyrazoles, novel ligands for the estrogen receptor. JOURNAL OF COMBINATORIAL CHEMISTRY 2000; 2:318-29. [PMID: 10891098 DOI: 10.1021/cc0000040] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Most ligands for the estrogen receptor (ER) are not well suited for synthesis by combinatorial means, because their construction involves a series of carbon-carbon bond forming reactions that are not uniformly high yielding. In previous work directed to overcoming this limitation, we surveyed various phenol-substituted five-membered heterocycles, hoping to find a system that would afford both high ER binding affinity and whose synthesis could be adapted to solid-phase methods (Fink et al. Chem. Biol. 1999, 6, 206-219.) In this report, we have developed a reliable and efficient solid-phase method to prepare the best of these heterocycles, the tetrasubstituted pyrazoles, and we have used this methodology to produce small, discrete libraries of these novel ER ligands. We used a combination of FT-IR and nanoprobe (1)H NMR-MAS to characterize intermediates leading up to the final pyrazole products directly on the bead. We also developed a scavenging resin, which enabled us to obtain products free from inorganic contaminants. We prepared a 12-member test library, and then a 96-member library, and in both cases we determined product purity and ER binding affinity of all of the library members. Several interesting binding affinity patterns have emerged from these studies, and they have provided us with new directions for further exploration, which has led to pyrazoles having high affinity and potency as agonists and antagonists toward the ER alpha subtype.
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Affiliation(s)
- S R Stauffer
- Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA
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31
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Meyers MJ, Sun J, Carlson KE, Katzenellenbogen BS, Katzenellenbogen JA. Estrogen receptor subtype-selective ligands: asymmetric synthesis and biological evaluation of cis- and trans-5,11-dialkyl- 5,6,11, 12-tetrahydrochrysenes. J Med Chem 1999; 42:2456-68. [PMID: 10395487 DOI: 10.1021/jm990101b] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have recently reported that racemic 5,11-cis-diethyl-5,6,11, 12-tetrahydrochrysene-2,8-diol (THC, rac-2b) acts as an agonist on estrogen receptor alpha (ERalpha) and as a complete antagonist on estrogen receptor beta (ERbeta) (Sun et al. Endocrinology 1999, 140, 800-804). To further investigate this novel ER subtype-selective estrogenic activity, we have synthesized a series of cis- and trans-dialkyl THCs. cis-Dimethyl, -diethyl, and -dipropyl THCs 2a-c were prepared in a highly enantio- and diastereoselective manner by the acyloin condensation of enantiomerically pure alpha-alkyl-beta-arylpropionic esters, followed by a Lewis acid-mediated double cyclization under conditions of minimal epimerization. ERalpha and ERbeta binding affinity of both cis and trans isomers of dimethyl, diethyl, and dipropyl THCs was determined in competitive binding assays, and their transcriptional activity was determined in reporter gene assays in mammalian cells. Nearly all THCs examined were found to be affinity-selective for ERbeta. All these THCs are agonists on ERalpha, and THCs with small substituents are agonists on both ERalpha and ERbeta. As substituent size was increased, ERbeta-selective antagonism developed first in the (R,R)-cis enantiomer series and finally in the trans diastereomer and (S,S)-cis enantiomer series. The most potent and selective ligand was identified as (R,R)-cis-diethyl THC 2b, which mimicked the ERbeta-selective antagonist character of racemic cis-diethyl THC 2b. This study illustrates that the antagonist character in THC ligands for ERbeta depends in a progressive way on the size and geometric disposition of substituent groups and suggests that the induction of an antagonist conformation in ERbeta can be achieved with these ligands with less steric perturbation than in ERalpha. Furthermore, antagonists that are selectively effective on ERbeta can have structures that are very different from the typical antiestrogens tamoxifen and raloxifene, which are antagonists on both ERalpha and ERbeta.
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Affiliation(s)
- M J Meyers
- Departments of Chemistry, Molecular and Integrative Physiology, and Cell and Structural Biology, University of Illinois, Urbana, Illinois 61801, USA
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32
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Hanson RN, Napolitano E, Fiaschi R. Synthesis and evaluation of 11beta-substituted 21-chloro/iodo-(17alpha,20E/Z)-19-norpregna-1,3,5(10),20-te traene-3, 17beta-diols: high-affinity ligands for the estrogen receptor. J Med Chem 1998; 41:4686-92. [PMID: 9822539 DOI: 10.1021/jm9801051] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have synthesized six new estrogens substituted at the 11beta-position with a methoxy or vinyl group and at the 17alpha-position with an (E)- or (Z)-chloro/iodovinyl moiety. The products were obtained in good overall yields from the corresponding tri-n-butylstannylvinyl intermediates using the electrophilic halodestannylation methodology. The six new ligands were compared to the 11beta-unsubstituted chloro/iodovinyl derivatives and the 11beta-methoxy (E)- and (Z)-iodovinyl estrogens to evaluate the effects of 11beta-substitution and 20E/Z-stereochemistry. While all the compounds exhibited high affinity for the estrogen receptor, the 20Z-isomers demonstrated higher affinity than the corresponding 20E-isomers. In addition, the presence of the lipophilic 11beta-substituent was favored over either no substituent or a polar (methoxy) group. Within each isomeric series, the presence of the 21-halo substituent had different effects. For the 20E-series, the 21-chloro products had a higher affinity than the 21-iodo analogue, whereas for the 20Z-series the effect was reversed. These results provide additional insights into the interaction of substituted estradiols with the hormone binding domain of the estrogen receptor.
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Affiliation(s)
- R N Hanson
- Department of Pharmaceutical Sciences, Bouve College of Pharmacy and Health Sciences, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115, USA
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33
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El khissiin A, Leclercq G. Exchange of bound estrogens and antiestrogens in MCF-7 cells: evidence for ligand-induced stable configurations of the estrogen receptor. Steroids 1998; 63:565-74. [PMID: 9830682 DOI: 10.1016/s0039-128x(98)00064-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Estrogens and antiestrogens promote specific conformations of the estrogen receptor (ER). To analyze the influence of such configurations on the stability of the ligand-ER complexes, MCF-7 breast cancer cells were exposed for 1 h to either [3H]E2 or an unlabeled estrogen or antiestrogen (E2, DES, E1, BP; OH-Tam, RU 39,411, ICI 164,384, RU 58,668); mutual exchange rates of bound compounds (i.e., [3H]E2-->ligand; ligand-->[3H]E2) were then analyzed in cell extracts by measuring [3H]E2. Addition of cycloheximide (CHX) to the incubation medium eliminated the potential interference of E2-induced ER loss. Extracts from control untreated cells were labeled with [3H]E2 or one of these various ligands and similarly submitted to exchange. Displacement of bound compounds occurred at moderate temperature (18 degrees C) but not at 4 degrees C. Remarkably, exchange proceeded at a lower rate in extracts from cells preincubated with [3H]E2 or a ligand. Antiestrogens RU 39,411 and RU 58,668 appeared especially refractory to displacement. Such low exchange rates were also recorded in experiments conducted on whole cells although to a higher extent than in extracts from preincubated cells. Enzyme immunoassays demonstrated that absence of major exchange could not be attributed to ER loss. Moreover, displacement of bound ligands appeared independent of their binding affinity for the receptor. These data suggest that estrogen and antiestrogen binding is stabilized by at least one factor (coactivators or corepressors) thus fixing the receptor molecules in a configuration that is relatively resistant to subsequent exchange. FPLC and PgR induction revealed that a significant proportion of ER maintained in a sufficiently flexible status was still able to exchange and transduce the transcriptional message of the displacer ligand.
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Affiliation(s)
- A El khissiin
- Laboratoire J.-C. Heuson de Cancérologie Mammaire, Institut Jules Bordet, Brussels, Belgium
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Crain DA, Noriega N, Vonier PM, Arnold SF, McLachlan JA, Guillette LJ. Cellular bioavailability of natural hormones and environmental contaminants as a function of serum and cytosolic binding factors. Toxicol Ind Health 1998; 14:261-73. [PMID: 9460179 DOI: 10.1177/074823379801400116] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Environmental contaminants have been reported to function as hormone mimics in various wildlife species. To investigate a potential mechanism for the interaction of contaminants with the endocrine system, we evaluated the cellular bioavailability of numerous chemicals. Hormone binding proteins from oviductal cytosol of the American alligator (Alligator mississippiensis) and yellow-bellied turtle (Trachemys scripta) were used in competitive binding assays with [3H] 17 beta-estradiol. Most of the environmental contaminants, and the potent, synthetic estrogen diethylstilbestrol (DES), did not interact with the cytosolic binding proteins. Among the compounds tested, o,p'-DDT and toxaphene exhibited the greatest affinity for the binding proteins. The functional consequence of the apparent lack of interaction of most contaminants with binding proteins was studied in a strain of yeast containing the human estrogen receptor (YES assay). The activation of YES with estradiol was reduced 30% in the presence of a physiological concentration (0.01 mg/mL) of human sex hormone binding globulin (SHBG), a hormone binding protein found in the blood. In contrast, the activity of DES was not inhibited by 0.01 mg/mL SHBG. Interestingly, ethinyl estradiol, a major component of contraceptives, did not appear to appreciably interact with SHBG in the YES system. Together, these data suggest that cytosolic and circulating binding proteins bind many environmental contaminants with much less affinity than native steroids. Therefore, such contaminants may be more hormonally active than previously hypothesized.
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Affiliation(s)
- D A Crain
- Department of Zoology, University of Florida, Gainesville, USA.
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Devraj R, Barrett JF, Fernandez JA, Katzenellenbogen JA, Cushman M. Design, synthesis, and biological evaluation of ellipticine-estradiol conjugates. J Med Chem 1996; 39:3367-74. [PMID: 8765520 DOI: 10.1021/jm9602930] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Three ellipticine-estradiol conjugates were synthesized in an effort to target the cytotoxicity of ellipticine to estrogen-receptor positive cells. The three conjugates were prepared with linker chains extending from the 17 alpha position of the estradiol to N-2 (compound 3), N-6 (compound 4), and C-9 (compound 5) positions of ellipticine. The ellipticine-estradiol conjugates were evaluated for their abilities to bind to estrogen receptors, to inhibit topoisomerase II, and for their cytotoxicities in human cancer cell lines. Conjugates 3 and 5 displayed weak binding affinities of 0.132 and 0.303 for the estrogen receptor (relative to estradiol = 100), while conjugate 4 did not show any detectable binding to the estrogen receptor. Compound 3 was a moderate inhibitor of topoisomerase II (IC50 24.1 microM), while 4 and 5 were inactive. Conjugate 3 was consistently more cytotoxic (GI50 values 1-10 microM) than compounds 4 and 5 (GI50 values 10-100 microM) in a variety of human cancer cell lines. None of the compounds displayed any selectivity for estrogen-receptor positive cell lines, which probably reflects their weak affinities for estrogen receptors.
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Affiliation(s)
- R Devraj
- Department of Medicinal Chemistry and Molecular Pharmacology, School of Pharmacy and Pharmacal Sciences, Purdue University, West Lafayette, Indiana 47907, USA
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36
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Davioud E, Fagart J, Souque A, Rafestin-Oblin ME, Marquet A. New steroidal diazo ketones as potential photoaffinity labeling reagents for the mineralocorticoid receptor: synthesis and biological activities. J Med Chem 1996; 39:2860-4. [PMID: 8709117 DOI: 10.1021/jm9601359] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Three diazo ketones in the progesterone series were synthesized as potential photoaffinity reagents. The diazo ketone group was introduced at the C17 (21-diazopregn-4-ene-3,20-dione, 1) or C13 (18-(diazomethyl)-20-hydroxypregn-4-ene-3,18-dione, 2, 18-(diazomethyl)pregn-4-ene-3, 18,20-trione, 3) position of the pregnene skeleton. Whereas compound 1 could be easily obtained from the corresponding acid chloride, preparation of 2 and 3 required a less straightforward route involving reaction of tosyl azide on the formyl derivative of methyl ketone 5. The affinity of the diazo ketones for the human mineralocorticoid receptor (hMR), expressed in Sf9 insect cells using the Baculovirus system, was estimated by competition experiments using [3H]aldosterone as specific ligand. The affinity of 1 for hMR was almost identical with that of aldosterone. The affinities of 2 and 3 were 1, order of magnitude lower than that of aldosterone. The mineralocorticoid activity of the diazo ketones was measured in cis-trans cotransfection assays in CV-1 cells with the mouse mammary tumor virus as DNA target sequence. Compound 1 exhibits an agonist activity (ED50 = 6 x 10(-9) M) with no antagonist activity. In contrast 2 and 3 behave as antagonists, displaying an IC50 of approximately 10(-6) M whether the substituent at the C20 position is a hydroxy (2) or an oxo (3) group.
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Affiliation(s)
- E Davioud
- Laboratorie de Chimie Organique Biologique, CNRS URA 493-', Université P. et M. Curie, Paris, France
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37
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Trivedi RN, Chauhan SC, Dwivedi A, Kamboj VP, Singh MM. Time-related effects of a triphenylethylene antiestrogen on estrogen-induced changes in uterine weight, estrogen receptors, and endometrial sensitivity in rats. Contraception 1995; 51:367-79. [PMID: 7554978 DOI: 10.1016/0010-7824(95)00103-h] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Time-related estrogen antagonistic action of a single oral contraceptive (1.25 mg/kg) dose of the triphenylethylene antiestrogen centchroman was determined in ovariectomized immature rats. Tamoxifen and nafoxidine were used for comparison. A single oral administration of centchroman followed by three doses of estradiol-17 beta (1 microgram/d, s.c.) caused significant dose-dependent inhibition in estradiol-17 beta-induced increase in uterine weight and nuclear and cytosolic estrogen receptors. But the inhibition at antiimplantation dose was evident only if estradiol-17 beta treatment was initiated not later than 48 h post-antiestrogen. Alternatively, when antiestrogen treatment was followed by a single dose of estradiol-17 beta between days 2-7, a synergistic action, typical of antiestrogens possessing weak estrogen agonistic activity, was observed. In immature rats in which a condition mimicking preimplantation was produced by estradiol-17 beta (0.5 microgram/d, s.c.) priming on days -2 and -1, followed by progesterone (1 mg/d, s.c.) and an endometrial sensitizing dose (0.5 microgram/d, s.c.) of estradiol-17 beta at 1600 h on day 4, anti-implantation dose of centchroman administered on day 1, too, failed to inhibit uterine weight gain induced by sensitizing dose of estradiol-17 beta, but caused marked inhibition in endometrial sensitivity to a deciduogenic stimulus and decidualization and weight gain of traumatized uterine horn 96 h post-traumatization over non-traumatized horn was only about 150% (725% in controls). Inhibition in endometrial sensitivity and decidualization was evident when the interval between antiestrogen treatment and sensitizing estradiol was < 126 h. Pinopods were present on endometrial surface on day 5 whether or not priming and/or sensitizing doses of estradiol were administered, but decidual response was mild if either of these doses of estradiol-17 beta was deferred. Findings suggest that: (a) duration of antiestrogenic action of single anti-implantation dose of centchroman in rat was about 126 h, which in ovariectomized immature rats was evident only when a condition mimicking preimplantation was produced and the antiestrogenic response was based on inhibition in estradiol-induced endometrial sensitivity and not uterine weight gain; (b) priming as well as sensitizing estrogen were essential to get optimal decidual responses; (c) appearance of pinopods on endometrial surface may not be related to endometrial sensitivity; and (d) tamoxifen and nafoxidine appear slightly longer acting with duration of antiestrogenic action of approximately 150 h.
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Affiliation(s)
- R N Trivedi
- Central Drug Research Institute, Lucknow, India
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38
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Pulkkinen M, Hämäläinen MM. Myometrial estrogen and progesterone receptor binding in pregnancy: inhibition by the detergent action of phospholipids. J Steroid Biochem Mol Biol 1995; 52:287-94. [PMID: 7696151 DOI: 10.1016/0960-0760(94)00175-l] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We characterized the phospholipid inhibition of estradiol and progesterone binding to guinea-pig and human myometrial receptors. Of twelve compounds studied, phosphatidylinositol (PI), lysophosphatidic acid and lysophosphatidylcholine (lyso-PC) were the most active inhibitors (50% inhibition at 10(-5) M). Lyso-PC with fatty acid chain length C14:0 inhibited ligand binding both to estrogen receptor (ER) and progesterone receptor (PR), C16:0 only to PR and C18:0 neither to ER nor to PR. The lyso-derivates were more inhibitory than the parent compounds. The ionic detergent (sodium taurocholate) inhibited both ER and PR binding, but the non-ionic detergent (Triton X-100) only PR. Triton X-100 enhanced the PI-induced inhibition of ER binding by a factor of 10. PR was more sensitive to inhibition than ER in all cases. The type of inhibition was non-competitive. At term pregnancy, ligand binding to myometrial ER or PR was low or absent in humans, but moderate in the guinea-pig. Phospholipid extracts of human decidua and fetal membranes contained PI and phosphatidylserine rather than lyso-PC. The extract was a potent inhibitor of ligand binding to PR (50% inhibition at 10(-6) M phospholipid phosphorus), but not to ER. The physicochemical environment, modulated by phospholipids acting as detergents, may regulate sex steroid function also in vivo. This might have special significance for pregnancy maintenance.
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Affiliation(s)
- M Pulkkinen
- Department of Obstetrics and Gynecology, University of Turku, Finland
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39
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Shull JD, Pennington KL. Changes in population density elicit quantitative and qualitative changes in the estrogen receptor in intact GH4C1 pituitary tumor cells. J Steroid Biochem Mol Biol 1993; 44:53-60. [PMID: 8424893 DOI: 10.1016/0960-0760(93)90151-l] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We have previously demonstrated that population density alters the responsiveness of GH4C1 pituitary tumor cells to 17 beta-estradiol (E2). At a low population density E2 was observed to increase prolactin mRNA and stimulate cell proliferation, whereas this estrogen was unable to elicit these responses when the cells were maintained at a 4-fold higher population density. In an attempt to determine the mechanism through which population density alters responsiveness to E2, the steady-state level of estrogen receptor (ER), the affinity of ER for E2, and ER down-regulation have been examined in both intact and fractionated cells using ligand binding and ligand exchange assays. Data presented herein demonstrate that (1) GH4C1 cells maintained at low density expressed fewer ER than cells cultured at high density; (2) ER in cells cultured at high density displayed a reduced affinity for E2; (3) ER down-regulation occurring within 1 h of E2 addition appeared to be more pronounced in high density cultures; and (4) steady-state levels of ER were similar in low and high density cells treated with E2 for 1 through 5 days. Although none of these observations appear to correlate with the previously observed effects of population density on the responsiveness of GH4C1 cells to E2, they further illustrate the potential of the culture environment to alter the responsiveness to estrogenic stimuli by altering the properties of the ER.
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Affiliation(s)
- J D Shull
- Eppley Institute for research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha 68198-6805
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40
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Toko T, Matsuo K, Shibata J, Wierzba K, Nukatsuka M, Takeda S, Yamada Y, Asao T, Hirose T, Sato B. Interaction of DP-TAT-59, an active metabolite of new triphenylethylene-derivative (TAT-59), with estrogen receptors. J Steroid Biochem Mol Biol 1992; 43:507-14. [PMID: 1419885 DOI: 10.1016/0960-0760(92)90237-d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
DP-TAT-59, (Z)-2-(4-(1-(4-hydroxyphenyl)-2-(4-isopropylphenyl)-1-butenyl) phenoxy)-N, N-dimethylethylamine, has been reported to inhibit estrogen-stimulated growth of MCF-7 cells as well as rat uterus at lower concentrations than the hydroxymetabolite of tamoxifen (4-OH-TAM). In the present study, the growth of mouse Leydig cell tumor, B-1F cells were also more effectively inhibited by DP-TAT-59 than 4-OH-TAM. Additionally, the expression of estrogen responsive element ligated CAT gene transfected into B-1F cells was also suppressed by DP-TAT-59. Thus, the interaction of DP-TAT-59 with estrogen receptor (ER) was characterized and compared with that of 4-OH-TAM using immature rat and bovine uteri. The dissociation constant of DP-TAT-59 to ER of immature rat uterus was 0.24 nM and was similar to that of 4-OH-TAM (Kd = 0.20 nM) and estradiol (Kd = 0.29 nM). Using sucrose density gradients, the sedimentation constant of DP-TAT-59 with bovine uterus was 4.9S, which was similar to that of estradiol (5.1S) and 4-OH-TAM (5.3S). However, the elution profile of the DP-TAT-59-ER complex from a DEAE-Sephadex column was different for both estradiol-and 4-OH-TAM-ER complexes. These results suggest that ER forms different complexes with DP-TAT-59 than estradiol or 4-OH-TAM, while the ER binding affinity of these compounds are similar to each other.
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Affiliation(s)
- T Toko
- Biological Research Laboratories, Taiho Pharmaceutical Co. Ltd, Tokushima, Japan
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41
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DiZio JP, Carlson KE, Bannochie CJ, Welch MJ, Von Angerer E, Katzenellenbogen JA. Estrogen platinum-diamine complexes: preparation of a non-steroidal estrogen platinum-diamine complex labeled with platinum-191 and a study of its binding to the estrogen receptor in vitro and its tissue distribution in vivo. J Steroid Biochem Mol Biol 1992; 42:363-73. [PMID: 1606047 DOI: 10.1016/0960-0760(92)90141-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We have prepared in radiolabeled form (platinum-191) a non-steroidal estrogen platinum-diamine complex (Pt-diamine complex) that is reported to have selective cytostatic activity in estrogen receptor positive mouse mammary tumors. We then studied the interaction of this metal radiolabeled complex with the estrogen receptor in vitro and its distribution in immature rats in vivo. The radiolabeled complex was prepared by incubation of the non-steroidal estrogen diamine with [191Pt](II)Cl(-2)4 (t 1/2 = 2.96 days, sp. act. 7.54 Ci/mmol) in dimethylformamide (DMF)/H2O, followed by purification by HPLC. The final radiolabeled product coeluted with an authentic standard of the unlabeled Pt-diamine complex, with a retention time distinct from those of the precursor diamine and chloroplatinate. In competitive radiometric receptor binding assays with rat uterine estrogen receptor, samples of the unlabeled diamine and Pt-diamine complex have apparent binding affinities of 53 +/- 3% and 32 +/- 11%, respectively, relative to estradiol (RBA = 100% as standard). However, attempts to observe the binding of the 191Pt-diamine complex with the estrogen receptor were complicated by a very high level of non-receptor binding, an irreversible binding to proteins in the receptor preparation, and a degradation of the platinum complex that, in part, releases the diamine. As a result, it is difficult to be certain whether the binding affinity measured for the Pt-diamine complex in the competitive binding assays is due to the complex itself, or whether it arises from diamine released upon degradation of the complex. In tissue distribution studies in immature female rats, much of the 191Pt-diamine complex was deposited in the liver; there was no evidence of selective uptake of this compound by estrogen target tissues. Thus, it is not clear, from these studies, that the observed bioactivity of this complex arises from the interaction of the Pt complex or the diamine ligand with the estrogen receptor.
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Affiliation(s)
- J P DiZio
- Department of Chemistry, University of Illinois, Urbana 61801
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42
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Leclercq G, Legros N, Piccart MJ. Accumulation of a non-binding form of estrogen receptor in MCF-7 cells under hydroxytamoxifen treatment. J Steroid Biochem Mol Biol 1992; 41:545-52. [PMID: 1562525 DOI: 10.1016/0960-0760(92)90381-r] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
It is well known that MCF-7 cells, when incubated with hydroxytamoxifen (OH-Tam) loose their capacity to bind [3H]estradiol. By using Western blotting and [3H]tamoxifen aziridine labeling of KCl extracts from these cells we found that this loss in binding capacity was not associated with a disappearance of the estrogen receptor (ER) protein, an event known to occur after incubation with estradiol. Attempts to label under exchange conditions these ER molecules, which, on the basis of enzyme immunoassays appear to accumulate under OH-Tam treatment, were unsuccessful. Cell fractionation suggested that their origin is nuclear. Assessment of a few triphenylethylenic antiestrogens, as far as their inhibitory potency towards the in vitro MCF-7 cell growth is concerned, indicated a correlation between accumulation of these non-binding ER molecules and the antiestrogen antiproliferative action. However, we were unable to demonstrate absence of such an ER accumulation in two tamoxifen-resistant variants. Impaired folding of the ER protein or impaired phosphorylation of its hormone-binding domain are attractive hypotheses to account for these non-binding ER molecules. Whether these ER molecules have any physiological role, such as competition with the "normal" receptor molecules for the estrogen responsive elements on the DNA is unknown and deserves further study.
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Affiliation(s)
- G Leclercq
- Institut Jules Bordet, Service de Médecine Interne, Laboratoire J. C. Heuson de Cancérologie Mammaire, Bruxelles, Belgium
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Sreenivasulu S, Singh MM, Dwivedi A, Setty BS, Kamboj VP. CDRI-85/287, a novel antiestrogen and antiimplantation agent: biological profile and interaction with the estrogen receptors in immature rat uterus. Contraception 1992; 45:81-92. [PMID: 1591925 DOI: 10.1016/0010-7824(92)90144-i] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Postcoital antifertility efficacy, estrogenic and antiestrogenic activities of compound 85/287 were determined by the subcutaneous route in rats. It was 100% effective in preventing implantation at 0.5 mg/kg dose when administered within 24 h of mating and at 0.05 mg/kg in the days 1-5 post-coitum regimen. In the immature rat bioassay, it exhibited mild uterotrophic effect at the contraceptive dose but when administered along with estradiol (E2), it caused almost complete inhibition of uterine weight gain and vaginal cornification at the 2 mg/kg dose. E2 administration to immature rats (0.1 microgram, s.c., 3 days) caused 3-5 fold increase in the nuclear as well as cytoplasmic estradiol receptor (ER) content as compared to controls. In contrast, 85/287 (0.5 mg/kg and 2 mg/kg; s.c.), only translocated the ER to the nuclear compartment resulting in a depletion of cytoplasmic ER levels. Concurrent administration of 85/287 and E2 inhibited E2-induced increase in cytoplasmic ER. It is suggested that compound 85/287 exerts its antiestrogenic and antiimplantation action by interfering with the formation of E2-receptor complexes in the uterus.
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Affiliation(s)
- S Sreenivasulu
- Division of Endocrinology, Central Drug Research Institute, Lucknow, India
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Abstract
Breast cancer is the most frequently seen cancer in pregnancy and lactation, but the incidence is low, the disease being seen in approximately 0.03% of pregnancies. Only 1% to 2% of breast cancer overall is diagnosed during pregnancy or lactation. There is no evidence to implicate pregnancy or lactation in either the etiology or the progression of breast cancer. Careful breast examination early in the pregnancy is very important to find solid masses that require biopsy before breast engorgement hides them. Therapeutic options vary, depending on the stage of disease and the stage of the pregnancy. Operable disease in the first 6 to 7 months of the pregnancy should be treated by mastectomy, as irradiation is contraindicated. Late in the pregnancy, a lumpectomy and axillary dissection can be done, with irradiation being delayed until after delivery. General anesthesia is safe if the usual precautions are taken to compensate for the physiologic changes induced by pregnancy. Unfortunately, delay in diagnosis is common, and 70% to 89% of patients with operable primary lesions have positive axillary lymph nodes. Late stage appears to be the only reason for the generally worse prognosis in these patients, as stage for stage, they have a course similar to that of nonpregnant patients. Adjuvant chemotherapy can be considered late in the pregnancy but should usually be delayed until after delivery. In patients with locally advanced or metastatic cancer diagnosed early in the pregnancy, for whom both chemotherapy and radiation therapy would normally be recommended, consideration must be given to termination of the pregnancy. There is no evidence that termination of pregnancy improves the outlook for the patients, but it does permit standard aggressive therapy in advanced disease.
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Affiliation(s)
- H C Hoover
- Surgical Oncology Research, Massachusetts General Hospital, Boston
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Murdoch FE, Meier DA, Furlow JD, Grunwald KA, Gorski J. Estrogen receptor binding to a DNA response element in vitro is not dependent upon estradiol. Biochemistry 1990; 29:8377-85. [PMID: 2252899 DOI: 10.1021/bi00488a026] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Gel shift assays were employed to distinguish between the contribution of 17 beta-estradiol (E2) and a short heating step to the ability of the rat uterine cytosolic estrogen receptor (ER) to bind to the estrogen response element (ERE) from the vitellogenin A2 gene (vitERE). Despite the popularity of models in which the ER is a ligand-activated DNA-binding protein, these studies find that estrogen does not significantly contribute to receptor-DNA complex formation. An avidin-biotin complex with DNA (ABCD) assay was utilized to obtain quantitative measurement of the affinities of the ER for the vitERE and a mutant sequence. Scatchard analysis gave a dissociation constant of 390 +/- 40 pM for the E2-occupied, heated ER to the vitERE. The data fit a one-site model and evidence for cooperatively was not observed. A dissociation constant of 450 +/- 170 pM was obtained for the unoccupied, heated ER, leading to the conclusion that estrogen was not necessary for specific binding to DNA. The percentage of ER capable of binding vitERE varied with each cytosol preparation, ranging from 60 to 100% and estrogen did not appear to affect this variation. Competition against the vitERE with a 2-bp mutant sequence showed a 250-fold lower relative binding affinity of the receptor for the mutant over the vitERE sequence. This ability of the ER to discriminate between target and nonspecific DNA sequences was also not dependent on the presence of estrogen.
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Affiliation(s)
- F E Murdoch
- Department of Biochemistry, University of Wisconsin-Madison 53706
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Miyashita Y, Hirose T, Kouhara H, Kishimoto S, Matsumoto K, Sato B. Identification of unoccupied but transformed nuclear estrogen receptor in cultured mouse Leydig cell. JOURNAL OF STEROID BIOCHEMISTRY 1990; 35:561-7. [PMID: 2355731 DOI: 10.1016/0022-4731(90)90199-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The molecular forms of estrogen receptor (ER) in estrogen-responsive mouse Leydig cell line (B-1) have been examined in relation to their biological activity. ER was predominantly recovered in the nuclear fraction upon homogenization even after cells were precultured in the absence of E2 and Phenol Red. This unoccupied nuclear ER (ERn) whose hormone binding ability was extremely thermostable could be extracted with 0.4 M KCl. This stability enabled us to determine hydrodynamic parameters in the ligand-free condition. The Stokes radius and sedimentation constant of this ERn in high salt condition were 5.5 nm and 6.0S, respectively, resulting in its molecular weight of 140,000. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of ER labeled with [3H]tamoxifen aziridine gave a single band of 65,000 Da, indicating that this ERn had a oligomer structure similar to that of transformed nuclear ER complexed with estrogen in the putative target cells. Therefore, we further examined the possibility that this ERn in B-1 cells can activate estrogen-responsive genes without any aid from estrogen. Estrogen responsive element-thymidine kinase promoter-chloramphenicol acetyltransferase fusion gene (ERE-tk-CAT) was transfected into B-1 cells. CAT activity was enhanced only in cells stimulated with estrogen. It may be concluded from these results that transformed ERn can be formed in the absence of estrogen but that binding to estrogen may be required in order to exert its biological activity.
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Affiliation(s)
- Y Miyashita
- Third Department of Internal Medicine, Osaka University Hospital, Japan
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Samama B, Aron C. Changes in estrogen receptors in the mediobasal hypothalamus mediate the facilitory effects exerted by the male's olfactory cues and progesterone on feminine behavior in the male rat. JOURNAL OF STEROID BIOCHEMISTRY 1989; 32:525-9. [PMID: 2724955 DOI: 10.1016/0022-4731(89)90385-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The purpose of this study was to determine whether facilitory effects exerted by olfactory cues on lordosis behavior in the male rat involved changes in estradiol receptors at the hypothalamic level. Male rats were orchidectomized as adults. They were given either 25 micrograms estradiol benzoate (EB) alone or 25 micrograms EB and 100 micrograms progesterone (P) sequentially and exposed or not to the odor of male urine. Some of them were tested for lordosis behavior at 8 h after P. The other ones were killed 4 h after P and used for estradiol (E2) and P receptor assay in mediobasal hypothalamus (MBH). Olfactory cues were shown to increase the number of E2 receptors in both the animals given EB or EB + P. Progesterone as such appeared to be capable of increasing the number and the rate of occupancy of E2 receptors. A population of constitutive and estrogen-inducible P receptors was detected in the MBH. Since only the animals given EB + P were shown to be sensible to the facilitory effects of male urine on lordosis behavior, it may be assumed that E2 and P on one hand and olfactory cues on the other exert cumulative effects at the level of the MBH and that both a high level and a high rate of occupancy of E2 receptors are necessary for the olfactory cues to facilitate the display of lordosis behavior in the male rat.
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Affiliation(s)
- B Samama
- Institute of Histology, Strasbourg, France
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Senekjian EK, Press MF, Blough RR, Herbst AL, DeSombre ER. Comparison of the quantity of estrogen receptors in human endometrium and myometrium by steroid-binding assay and enzyme immunoassay based on monoclonal antibodies to human estrophilin. Am J Obstet Gynecol 1989; 160:592-7. [PMID: 2467564 DOI: 10.1016/s0002-9378(89)80035-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The recently developed enzyme immunoassay for estrogen receptors is more simple to perform with quality assurance than conventional steroid-binding assays with radioactive labeled estrogen. However, it is not known how well the results of the two assays agree for normal human uterine samples. We compared enzyme immunoassay (Abbott estrogen receptor enzyme immunoassay) and steroid-binding assay of normal human endometrium and myometrium. Low-salt, "cytosol" estrogen receptor determinations were performed by dextran-coated charcoal assay, and high-salt, "nuclear" estrogen receptors were measured by controlled pore glass bead assay. Results showed excellent correlation (p less than 0.0001) for cytosol estrogen receptor of endometrium (r = 0.95) and myometrium (r = 0.79) and also for a smaller number of nuclear estrogen receptors of myometrium (p less than 0.01, r = 0.69). Good agreement between steroid-binding assay and enzyme immunoassay was seen for estrogen receptors of both proliferative and secretory phase samples. Thus the data indicate that the simpler estrogen receptor enzyme immunoassay is useful to measure estrogen receptor in the normal uterus. Furthermore, with this sandwich assay, there is no evidence for the existence of significant quantities of receptor fragments that do not bind estrogen.
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Affiliation(s)
- E K Senekjian
- Department of Obstetrics and Gynecology, University of Chicago, Pritzker School of Medicine, IL
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Steroid receptors and regulation of LH and secretogranin II (GP87) secretion in pituitary cell aggregates. Neurochem Int 1989; 15:277-83. [DOI: 10.1016/0197-0186(89)90133-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/1989] [Accepted: 04/11/1989] [Indexed: 12/22/2022]
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50
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Fanchenko ND, Adamyan LV, Alekseeva ML, Minina LS, Novikov EA. Interaction between labeled estrogens and receptors in human uterine cytosol. Bull Exp Biol Med 1988. [DOI: 10.1007/bf00834671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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