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Min CK, Nwachukwu JC, Hou Y, Russo RJ, Papa A, Min J, Peng R, Kim SH, Ziegler Y, Rangarajan ES, Izard T, Katzenellenbogen BS, Katzenellenbogen JA, Nettles KW. Asymmetric allostery in estrogen receptor-α homodimers drives responses to the ensemble of estrogens in the hormonal milieu. Proc Natl Acad Sci U S A 2024; 121:e2321344121. [PMID: 38830107 PMCID: PMC11181081 DOI: 10.1073/pnas.2321344121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 04/19/2024] [Indexed: 06/05/2024] Open
Abstract
The estrogen receptor-α (ER) is thought to function only as a homodimer but responds to a variety of environmental, metazoan, and therapeutic estrogens at subsaturating doses, supporting binding mixtures of ligands as well as dimers that are only partially occupied. Here, we present a series of flexible ER ligands that bind to receptor dimers with individual ligand poses favoring distinct receptor conformations-receptor conformational heterodimers-mimicking the binding of two different ligands. Molecular dynamics simulations showed that the pairs of different ligand poses changed the correlated motion across the dimer interface to generate asymmetric communication between the dimer interface, the ligands, and the surface binding sites for epigenetic regulatory proteins. By examining the binding of the same ligand in crystal structures of ER in the agonist vs. antagonist conformers, we also showed that these allosteric signals are bidirectional. The receptor conformer can drive different ligand binding modes to support agonist vs. antagonist activity profiles, a revision of ligand binding theory that has focused on unidirectional signaling from the ligand to the coregulator binding site. We also observed differences in the allosteric signals between ligand and coregulator binding sites in the monomeric vs. dimeric receptor, and when bound by two different ligands, states that are physiologically relevant. Thus, ER conformational heterodimers integrate two different ligand-regulated activity profiles, representing different modes for ligand-dependent regulation of ER activity.
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Affiliation(s)
- Charles K. Min
- Department of Immunology and Microbiology, The Herbert Wertheim University of Florida Scripps Institute for Biomedical Innovation and Technology, Jupiter, FL33458
- The Skaggs Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, La Jolla, CA92037
| | - Jerome C. Nwachukwu
- Department of Immunology and Microbiology, The Herbert Wertheim University of Florida Scripps Institute for Biomedical Innovation and Technology, Jupiter, FL33458
| | - Yingwei Hou
- Department of Chemistry and Cancer Center, University of Illinois at Urbana-Champaign, Urbana, IL61801
| | - Robin J. Russo
- Department of Immunology and Microbiology, The Herbert Wertheim University of Florida Scripps Institute for Biomedical Innovation and Technology, Jupiter, FL33458
- The Skaggs Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, La Jolla, CA92037
| | - Alexandra Papa
- Department of Immunology and Microbiology, The Herbert Wertheim University of Florida Scripps Institute for Biomedical Innovation and Technology, Jupiter, FL33458
- Florida Atlantic University, Jupiter, FL33458
| | - Jian Min
- State Key Laboratory of Biocatalysis and Enzyme Engineering, National & Local Joint Engineering Research Center of High-throughput Drug Screening Technology, School of Life Sciences, Hubei University, Wuhan430062, China
| | - Rouming Peng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, National & Local Joint Engineering Research Center of High-throughput Drug Screening Technology, School of Life Sciences, Hubei University, Wuhan430062, China
| | - Sung Hoon Kim
- Department of Chemistry and Cancer Center, University of Illinois at Urbana-Champaign, Urbana, IL61801
| | - Yvonne Ziegler
- Department of Molecular and Integrative Physiology, Cancer Center at University of Illinois at Urbana-Champaign, Urbana, IL61801
| | - Erumbi S. Rangarajan
- Department of Immunology and Microbiology, The Herbert Wertheim University of Florida Scripps Institute for Biomedical Innovation and Technology, Jupiter, FL33458
| | - Tina Izard
- Department of Immunology and Microbiology, The Herbert Wertheim University of Florida Scripps Institute for Biomedical Innovation and Technology, Jupiter, FL33458
- The Skaggs Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, La Jolla, CA92037
| | - Benita S. Katzenellenbogen
- Department of Molecular and Integrative Physiology, Cancer Center at University of Illinois at Urbana-Champaign, Urbana, IL61801
| | - John A. Katzenellenbogen
- Department of Chemistry and Cancer Center, University of Illinois at Urbana-Champaign, Urbana, IL61801
| | - Kendall W. Nettles
- Department of Immunology and Microbiology, The Herbert Wertheim University of Florida Scripps Institute for Biomedical Innovation and Technology, Jupiter, FL33458
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Zouboulis CC, Blume-Peytavi U, Kosmadaki M, Roó E, Vexiau-Robert D, Kerob D, Goldstein SR. Skin, hair and beyond: the impact of menopause. Climacteric 2022; 25:434-442. [PMID: 35377827 DOI: 10.1080/13697137.2022.2050206] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The skin is an endocrine organ and a major target of hormones such as estrogens, androgens and cortisol. Besides vasomotor symptoms (VMS), skin and hair symptoms often receive less attention than other menopausal symptoms despite having a significant negative effect on quality of life. Skin and mucosal menopausal symptoms include dryness and pruritus, thinning and atrophy, wrinkles and sagging, poor wound healing and reduced vascularity, whereas skin premalignant and malignant lesions and skin aging signs are almost exclusively caused by environmental factors, especially solar radiation. Hair menopausal symptoms include reduced hair growth and density on the scalp (diffuse effluvium due to follicular rarefication and/or androgenetic alopecia of female pattern), altered hair quality and structure, and increased unwanted hair growth on facial areas. Hormone replacement therapy (HRT) is not indicated for skin and hair symptoms alone due to the risk-benefit balance, but wider potential benefits of HRT (beyond estrogen's effect on VMS, bone, breast, heart and blood vessels) to include skin, hair and mucosal benefits should be discussed with women so that they will be able to make the best possible informed decisions on how to prevent or manage their menopausal symptoms.
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Affiliation(s)
- C C Zouboulis
- Departments of Dermatology, Venereology, Allergology and Immunology, Dessau Medical Center, Brandenburg Medical School Theodor Fontane and Faculty of Health Sciences, Brandenburg, Germany
| | - U Blume-Peytavi
- Department of Dermatology, Venerology and Allergology, Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Germany
| | | | - E Roó
- Clider Clínica Dermatológica Roó, Universidad Francisco de Vitoria, Madrid, Spain
| | | | - D Kerob
- Laboratoires Vichy, Levallois-Perret, France
| | - S R Goldstein
- School of Medicine, New York University Grossman, New York, NY, USA
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Lovre D, Peacock E, Katalenich B, Moreau C, Xu B, Tate C, Utzschneider KM, Gautier JF, Fonseca V, Mauvais-Jarvis F. Conjugated Estrogens and Bazedoxifene Improve β Cell Function in Obese Menopausal Women. J Endocr Soc 2019; 3:1583-1594. [PMID: 31384719 PMCID: PMC6676076 DOI: 10.1210/js.2019-00074] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 05/31/2019] [Indexed: 12/21/2022] Open
Abstract
CONTEXT Studies suggest that menopausal hormone therapy (MHT) prevents type 2 diabetes (T2D). The combination of conjugated estrogens (CE) with the selective estrogen receptor modulator bazedoxifene (BZA) is an MHT that improves obesity and T2D in preclinical models of menopausal metabolic syndrome. The effect of CE/BZA on adiposity and glucose homeostasis in obese postmenopausal women is unknown. OBJECTIVE To investigate the effect of CE/BZA on body composition, glucose homeostasis, and markers of inflammation in obese postmenopausal women. RESEARCH DESIGN INTERVENTION AND PARTICIPANTS Randomized, double-blind, placebo-controlled pilot trial of 12 obese menopausal women assigned to 12-week treatment with CE 0.45 mg/BZA 20 mg (n = 7) or placebo (n = 5). At baseline and after 12 weeks, we assessed body composition (dual-energy X-ray absorptiometry), glucose homeostasis (IV glucose tolerance test), and inflammation biomarkers. RESULTS Women treated with CE/BZA exhibited increased β cell function using homeostatic model assessment-B [median (interquartile range) CE/BZA vs placebo: 18.5 (-0.9 to 320.6) μU/mM vs -25.5 (-39.9 to -0.1) μU/mM; P = 0.045], and decreased basal glucose concentrations (Gb) [-5.2 (-9.2 to -1.7) mg/dL vs 2.7 (0.9 to 4.9) mg/dL; P = 0.029]. Insulin sensitivity was higher in the placebo arm [1.35 (1.12 to 1.82) (μU/mL) min-1 vs -0.24 (-1.50 to 0.19) (μU/mL) min-1; P = 0.029]. No changes between treatment groups were observed for the acute insulin response to glucose (AIRg), the disposition index (DI), body composition, and inflammatory biomarkers. CONCLUSIONS A 12-week treatment of obese postmenopausal women with CEs/BZA improves fasting β cell function and glucose concentrations without change in AIRg, HOMA-IR, DI, body composition, or markers of inflammation.
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Affiliation(s)
- Dragana Lovre
- Section of Endocrinology and Metabolism, Tulane University Health Sciences Center, New Orleans, Louisiana
- Section of Endocrinology, Southeast Louisiana Veterans Healthcare System, New Orleans, Louisiana
| | - Erin Peacock
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana
| | - Bonnie Katalenich
- Clinical Translational Unit, School of Medicine, Tulane University, New Orleans, Louisiana
| | - Cynthia Moreau
- Clinical Translational Unit, School of Medicine, Tulane University, New Orleans, Louisiana
| | - Beibei Xu
- Section of Endocrinology and Metabolism, Tulane University Health Sciences Center, New Orleans, Louisiana
| | - Chandra Tate
- Section of Endocrinology and Metabolism, Tulane University Health Sciences Center, New Orleans, Louisiana
| | - Kristina M Utzschneider
- Division of Metabolism, Endocrinology and Nutrition, VA Puget Sound Health Care System and University of Washington, Seattle, Washington
| | - Jean-François Gautier
- Department of Diabetes and Endocrinology, Assistance Publique-Hôpitaux de Paris, Lariboisière Hospital, University Paris-Diderot Paris-7, Paris, France
- INSERM UMRS 1138, Cordeliers Research Center, Paris, France
| | - Vivian Fonseca
- Section of Endocrinology and Metabolism, Tulane University Health Sciences Center, New Orleans, Louisiana
- Section of Endocrinology, Southeast Louisiana Veterans Healthcare System, New Orleans, Louisiana
| | - Franck Mauvais-Jarvis
- Section of Endocrinology and Metabolism, Tulane University Health Sciences Center, New Orleans, Louisiana
- Section of Endocrinology, Southeast Louisiana Veterans Healthcare System, New Orleans, Louisiana
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Xu Y, López M. Central regulation of energy metabolism by estrogens. Mol Metab 2018; 15:104-115. [PMID: 29886181 PMCID: PMC6066788 DOI: 10.1016/j.molmet.2018.05.012] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Revised: 05/09/2018] [Accepted: 05/15/2018] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Estrogenic actions in the brain prevent obesity. Better understanding of the underlying mechanisms may facilitate development of new obesity therapies. SCOPE OF REVIEW This review focuses on the critical brain regions that mediate effects of estrogens on food intake and/or energy expenditure, the molecular signals that are involved, and the functional interactions between brain estrogens and other signals modulating metabolism. Body weight regulation by estrogens in male brains will also be discussed. MAJOR CONCLUSIONS 17β-estradiol acts in the brain to regulate energy homeostasis in both sexes. It can inhibit feeding and stimulate brown adipose tissue thermogenesis. A better understanding of the central actions of 17β-estradiol on energy balance would provide new insight for the development of therapies against obesity in both sexes.
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Affiliation(s)
- Yong Xu
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
| | - Miguel López
- NeurObesity Group, Department of Physiology, CiMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, 15706, Spain.
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Time to first occurrence of breast pain and vaginal bleeding in phase 3 trials of CE/BZA. Menopause 2017; 24:1372-1377. [DOI: 10.1097/gme.0000000000000935] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Conjugated estrogens and bazedoxifene in minority populations: pooled analysis of four phase 3 trials. Menopause 2016; 23:611-20. [PMID: 27163519 DOI: 10.1097/gme.0000000000000617] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The aim of the study was to compare efficacy of conjugated estrogens (CE)/bazedoxifene (BZA) for treatment of menopausal symptoms and prevention of postmenopausal osteoporosis in minorities (black/Hispanic) versus whites. METHODS In a post hoc analysis, data were pooled from 3,424 white or minority nonhysterectomized postmenopausal women randomized to CE 0.45 or 0.625 mg/BZA 20 mg or placebo in four double-blind, phase 3 Selective Estrogens, Menopause, and Response to Therapy (SMART) trials. Outcomes included hot flush frequency/severity (daily diary) in women with at least seven moderate-to-severe hot flushes per day (SMART-1, -2), vaginal cytology in women with at most 5% superficial cells (SMART-1, -3), lumbar spine and total hip bone mineral density (BMD) (SMART-1, -5), and the Menopause-Specific Quality of Life (MENQOL) questionnaire (SMART-1, -2, -3, -5). RESULTS The analysis included 2,907 white (84.9%), 315 black (9.2%), and 202 Hispanic (5.9%) women. The reduction in hot flush frequency/severity versus placebo (P < 0.05; week 12) was similar in white and minority women. In both populations, both doses significantly (P < 0.05 vs placebo) improved MENQOL vasomotor function, sexual function, and total scores at 3 months; decreased the percentage of parabasal cells at 2 years; and increased the percentage of BMD responders at 12 and 24 months. Significant differential treatment effects by race/ethnicity were observed only for effects on vaginal superficial cells at month 24 and vaginal pH at month 3. CONCLUSIONS Notwithstanding a limited sample size, CE/BZA had a similar and beneficial impact on hot flushes, MENQOL, and BMD in minorities and whites.
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Selektive Östrogenrezeptormodulatoren (SERM). GYNAKOLOGISCHE ENDOKRINOLOGIE 2015. [DOI: 10.1007/s10304-015-0003-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Abstract
The successful use of high-dose synthetic estrogens to treat postmenopausal metastatic breast cancer is the first effective 'chemical therapy' proven in clinical trial to treat any cancer. This review documents the clinical use of estrogen for breast cancer treatment or estrogen replacement therapy (ERT) in postmenopausal hysterectomized women, which can either result in breast cancer cell growth or breast cancer regression. This has remained a paradox since the 1950s until the discovery of the new biology of estrogen-induced apoptosis at the end of the 20th century. The key to triggering apoptosis with estrogen is the selection of breast cancer cell populations that are resistant to long-term estrogen deprivation. However, estrogen-independent growth occurs through trial and error. At the cellular level, estrogen-induced apoptosis is dependent upon the presence of the estrogen receptor (ER), which can be blocked by nonsteroidal or steroidal antiestrogens. The shape of an estrogenic ligand programs the conformation of the ER complex, which, in turn, can modulate estrogen-induced apoptosis: class I planar estrogens (e.g., estradiol) trigger apoptosis after 24 h, whereas class II angular estrogens (e.g., bisphenol triphenylethylene) delay the process until after 72 h. This contrasts with paclitaxel, which causes G2 blockade with immediate apoptosis. The process is complete within 24 h. Estrogen-induced apoptosis is modulated by glucocorticoids and cSrc inhibitors, but the target mechanism for estrogen action is genomic and not through a nongenomic pathway. The process is stepwise through the creation of endoplasmic reticulum stress and inflammatory responses, which then initiate an unfolded protein response. This, in turn, initiates apoptosis through the intrinsic pathway (mitochondrial) with the subsequent recruitment of the extrinsic pathway (death receptor) to complete the process. The symmetry of the clinical and laboratory studies now permits the creation of rules for the future clinical application of ERT or phytoestrogen supplements: a 5-year gap is necessary after menopause to permit the selection of estrogen-deprived breast cancer cell populations to cause them to become vulnerable to apoptotic cell death. Earlier treatment with estrogen around menopause encourages growth of ER-positive tumor cells, as the cells are still dependent on estrogen to maintain replication within the expanding population. An awareness of the evidence that the molecular events associated with estrogen-induced apoptosis can be orchestrated in the laboratory in estrogen-deprived breast cancers now supports the clinical findings regarding the treatment of metastatic breast cancer following estrogen deprivation, decreases in mortality following long-term antihormonal adjuvant therapy, and the results of treatment with ERT and ERT plus progestin in the Women's Health Initiative for women over the age of 60. Principles have emerged for understanding and applying physiological estrogen therapy appropriately by targeting the correct patient populations.
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Affiliation(s)
- V Craig Jordan
- Departments of Breast Medical Oncology and Molecular and Cellular OncologyMD Anderson Cancer Center, Houston, Texas 77030, USA
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Affiliation(s)
- V Craig Jordan
- Georgetown University Medical Center, 3970 Reservoir Rd NW, Research Building, Suite E501, Washington, DC 20057, United States.
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Naqvi H, Sakr S, Presti T, Krikun G, Komm B, Taylor HS. Treatment with bazedoxifene and conjugated estrogens results in regression of endometriosis in a murine model. Biol Reprod 2014; 90:121. [PMID: 24740602 DOI: 10.1095/biolreprod.113.114165] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Bazedoxifene (BZA), a selective estrogen receptor modulator (SERM), inhibits the action of estrogens on endometrial proliferation. Here, we evaluate the effect of a tissue-selective estrogen complex (TSEC) containing BZA and conjugated estrogens (CE) on ectopic endometrial lesions in a mouse model of endometriosis. Experimental endometriosis was created in 60 female CD-1 mice. The mice were randomly divided into 10 groups that received varying doses of either BZA (1, 2, 3, or 5 mg/kg/day), BZA (1, 2, 3, or 5 mg/kg/day) in combination with CE (3 mg/kg/day), CE treatment alone (3 mg/kg/day), or vehicle control for 8 wk. Treatment with BZA alone or the TSEC containing BZA/CE led to a decrease in endometriotic lesion size compared to controls. The mean surface area of the untreated lesions was 19.6 mm(2). Treatment with BZA or BZA/CE resulted in reduced lesion size (to 8.8 and 7.8 mm(2), respectively). No significant difference was found in lesion size between the BZA and BZA/CE treatment groups or between different doses of either treatment. Ovarian cyst formation was not evident in the treated groups. Treatment with the TSEC containing higher BZA dosages (3 and 5 mg/kg/day) led to significantly lower levels of estrogen receptor (Esr1) mRNA expression compared to the control treatment. No differences were observed in expression of progesterone receptor (Pgr). Immunohistochemical analysis also demonstrated a decrease in ESR protein. The combination of CE and BZA may prove to be a novel treatment option for endometriosis.
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Affiliation(s)
- Hanyia Naqvi
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut
| | - Sharif Sakr
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut
| | - Thomas Presti
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut
| | - Graciela Krikun
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut
| | | | - Hugh S Taylor
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut
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Kim JH, Meyers MS, Khuder SS, Abdallah SL, Muturi HT, Russo L, Tate CR, Hevener AL, Najjar SM, Leloup C, Mauvais-Jarvis F. Tissue-selective estrogen complexes with bazedoxifene prevent metabolic dysfunction in female mice. Mol Metab 2014; 3:177-90. [PMID: 24634829 DOI: 10.1016/j.molmet.2013.12.009] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 12/20/2013] [Accepted: 12/21/2013] [Indexed: 12/11/2022] Open
Abstract
Pairing the selective estrogen receptor modulator bazedoxifene (BZA) with estrogen as a tissue-selective estrogen complex (TSEC) is a novel menopausal therapy. We investigated estrogen, BZA and TSEC effects in preventing diabetisity in ovariectomized mice during high-fat feeding. Estrogen, BZA or TSEC prevented fat accumulation in adipose tissue, liver and skeletal muscle, and improved insulin resistance and glucose intolerance without stimulating uterine growth. Estrogen, BZA and TSEC improved energy homeostasis by increasing lipid oxidation and energy expenditure, and promoted insulin action by enhancing insulin-stimulated glucose disposal and suppressing hepatic glucose production. While estrogen improved metabolic homeostasis, at least partially, by increasing hepatic production of FGF21, BZA increased hepatic expression of Sirtuin1, PPARα and AMPK activity. The metabolic benefits of BZA were lost in estrogen receptor-α deficient mice. Thus, BZA alone or in TSEC produces metabolic signals of fasting and caloric restriction and improves energy and glucose homeostasis in female mice.
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Key Words
- AMPKα, AMP-activated protein kinase α
- AUC, area-under the curve
- Akt, protein kinase B
- BAT, brown adipose tissue
- BZA, bazedoxifene
- Bazedoxifene
- CE, conjugated equine estrogens
- E2, 17β-estradiol
- ER, estrogen receptor
- FAS, fatty acid synthase
- FGF21, fibroblast growth factor 21
- GIR, glucose infusion rate
- H&E, hematoxylin and eosin
- HFD, high-fat diet
- HGP, hepatic glucose production
- ITT, insulin tolerance test
- Insulin resistance
- LPL, lipoprotein lipase
- Lcn2, lipocalin 2
- Menopause
- Metabolic syndrome
- NAFLD, non-alcoholic fatty liver disease
- OGTT, oral glucose tolerance test
- OVX, ovariectomy
- PTT, pyruvate tolerance test
- RBP4, retinol binding protein 4
- RER, respiratory exchange ratio
- Rd, rate of whole-body glucose disappearance
- SERM, selective estrogen receptor modulator
- TBARS, thiobarbituric acid reactive substances
- TG, triacylglycerol
- TSEC, tissue-selective estrogen complex
- Tissue-selective estrogen complexes
- Type 2 diabetes
- UCPs, uncoupling proteins
- VO2, oxygen consumption
- WAT, white adipose tissue.
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Affiliation(s)
- Jun Ho Kim
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Matthew S Meyers
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Saja S Khuder
- Center for Diabetes and Endocrine Research, Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Simon L Abdallah
- Center for Diabetes and Endocrine Research, Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Harrison T Muturi
- Center for Diabetes and Endocrine Research, Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Lucia Russo
- Center for Diabetes and Endocrine Research, Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Chandra R Tate
- Department of Medicine, Division of Endocrinology and Metabolism, Tulane University Health Sciences Center, School of Medicine, New Orleans, LA 70112, USA
| | - Andrea L Hevener
- Department of Medicine, Division of Endocrinology, Diabetes and Hypertension, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Sonia M Najjar
- Center for Diabetes and Endocrine Research, Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Corinne Leloup
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Franck Mauvais-Jarvis
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA ; Department of Medicine, Division of Endocrinology and Metabolism, Tulane University Health Sciences Center, School of Medicine, New Orleans, LA 70112, USA
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Santen RJ, Yue W, Heitjan DF. Occult breast tumor reservoir: biological properties and clinical significance. Discov Oncol 2013; 4:195-207. [PMID: 23632998 DOI: 10.1007/s12672-013-0145-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Accepted: 04/11/2013] [Indexed: 12/31/2022] Open
Abstract
Small, occult, undiagnosed breast cancers are found at autopsy in up to 15.6 % of women dying from unrelated causes with an average of 7 % from eight separate studies. The mammographic detection threshold of breast tumors ranges from 0.88 to 1.66 cm in diameter based on the patient's age. Tumor growth rates, expressed as "effective doubling times," vary from 10 to >700 days. We previously reported two models, based on iterative analysis of these parameters, to describe the biologic behavior of undiagnosed, occult breast tumors. Our models facilitate interpretation of the Women's Health Initiative (WHI) and antiestrogen breast cancer prevention studies. A nude mouse xenograft model was used to validate our assumption that breast tumors grow in a log-linear fashion. We then used our previously reported occult tumor growth (OTG) and computer-simulated tumor growth models to analyze various clinical trial data. Parameters used in the OTG model included a 200-day effective doubling time, 7 % prevalence of occult tumors, and 1.16 cm detection threshold. These models had been validated by comparing predicted with observed incidence of breast cancer in eight different populations of women. Our model suggests that menopausal hormone therapy with estrogens plus a progestogen (E + P) in the WHI trial primarily promoted the growth of pre-existing, occult lesions and minimally initiated de novo tumors. We provide a potential explanation for the lack of an increase in breast cancer incidence in the subgroup of women in the WHI who had not received E + P prior to randomization. This result may have reflected a leftward skew in the distribution of occult tumor doublings and insufficient time for stimulated tumors to reach the detection threshold. Our model predicted that estrogen alone reduced the incidence of breast cancer as a result of apoptosis. Understanding of the biology of occult tumors suggests that breast cancer "prevention" with antiestrogens or aromatase inhibitors represents early treatment rather than a reduction in de novo tumor formation. Our models suggest that occult, undiagnosed tumors are prevalent, grow slowly, and are the biologic targets of a hormone therapy in menopausal women and of antiestrogen therapy for prevention.
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Affiliation(s)
- Richard J Santen
- Department of Internal Medicine, Division of Endocrinology, University of Virginia, Charlottesville, VA 22908-1416, USA.
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