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Zheng J, Chen S, Lu H, Xia M, Wang S, Li X, Li H, Wang Y, Ge RS, Liu Y. Enhanced inhibition of human and rat aromatase activity by benzene ring substitutions in bisphenol A: QSAR structure-activity relationship and in silico docking analysis. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133252. [PMID: 38128231 DOI: 10.1016/j.jhazmat.2023.133252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 12/07/2023] [Accepted: 12/11/2023] [Indexed: 12/23/2023]
Abstract
Bisphenol A (BPA) is a widely used plastic material, but its potential endocrine disrupting effect has restricted its use. The BPA alternatives have raised concerns. This study aimed to compare inhibitory potencies of 11 BPA analogues on human and rat placental aromatase (CYP19A1). The inhibitory potency on human CYP19A1 ranged from bisphenol H (IC50, 0.93 μM) to tetramethyl BPA and tetrabromobisphenol S (ineffective at 100 μM) when compared to BPA (IC50, 73.48 μM). Most of them were mixed/competitive inhibitors and inhibited estradiol production in human BeWo cells. Molecular docking analysis showed all BPA analogues bind to steroid active site or in between steroid and heme of CYP19A1 and form a hydrogen bond with catalytic residue Met374. Pharmacophore analysis showed that there were 4 hydrophobic regions for BPA analogues, with bisphenol H occupying 4 regions. Bivariate correlation analysis showed that LogP (lipophilicity) and LogS (water solubility) of BPA analogues were correlated with their IC50 values. Computerized drug metabolism and pharmacokinetics analysis showed that bisphenol H, tetrabromobisphenol A, and tetrachlorobisphenol A had low solubility, which might explain their weaker inhibition on estradiol production on BeWo cells. In conclusion, BPA analogues mostly can inhibit CYP19A1 and the lipophilicity determines their inhibitory strength.
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Affiliation(s)
- Jingyi Zheng
- Department of Gynecology and Obstetrics, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Anesthesiology of Zhejiang Province, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou, Zhejiang 325027, China; Department of Anesthesiology and Perioperative Medicine, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Environment and Male Reproductive Medicine of Wenzhou, Wenzhou 325000, Zhejiang, China; Key Laboratory of Structural Malformations in Children of Zhejiang Province, Wenzhou 325000, Zhejiang, China
| | - Sailing Chen
- Department of Gynecology and Obstetrics, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Anesthesiology of Zhejiang Province, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou, Zhejiang 325027, China; Department of Anesthesiology and Perioperative Medicine, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Environment and Male Reproductive Medicine of Wenzhou, Wenzhou 325000, Zhejiang, China; Key Laboratory of Structural Malformations in Children of Zhejiang Province, Wenzhou 325000, Zhejiang, China
| | - Han Lu
- Department of Gynecology and Obstetrics, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Anesthesiology of Zhejiang Province, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou, Zhejiang 325027, China; Department of Anesthesiology and Perioperative Medicine, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Environment and Male Reproductive Medicine of Wenzhou, Wenzhou 325000, Zhejiang, China; Key Laboratory of Structural Malformations in Children of Zhejiang Province, Wenzhou 325000, Zhejiang, China
| | - Miaomiao Xia
- Department of Gynecology and Obstetrics, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Anesthesiology of Zhejiang Province, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou, Zhejiang 325027, China; Department of Anesthesiology and Perioperative Medicine, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Environment and Male Reproductive Medicine of Wenzhou, Wenzhou 325000, Zhejiang, China; Key Laboratory of Structural Malformations in Children of Zhejiang Province, Wenzhou 325000, Zhejiang, China
| | - Shaowei Wang
- Department of Gynecology and Obstetrics, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Anesthesiology of Zhejiang Province, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou, Zhejiang 325027, China; Department of Anesthesiology and Perioperative Medicine, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Environment and Male Reproductive Medicine of Wenzhou, Wenzhou 325000, Zhejiang, China; Key Laboratory of Structural Malformations in Children of Zhejiang Province, Wenzhou 325000, Zhejiang, China
| | - Xiaoheng Li
- Department of Gynecology and Obstetrics, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Anesthesiology of Zhejiang Province, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou, Zhejiang 325027, China; Department of Anesthesiology and Perioperative Medicine, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Environment and Male Reproductive Medicine of Wenzhou, Wenzhou 325000, Zhejiang, China; Key Laboratory of Structural Malformations in Children of Zhejiang Province, Wenzhou 325000, Zhejiang, China
| | - Huitao Li
- Department of Gynecology and Obstetrics, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Anesthesiology of Zhejiang Province, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou, Zhejiang 325027, China; Department of Anesthesiology and Perioperative Medicine, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Environment and Male Reproductive Medicine of Wenzhou, Wenzhou 325000, Zhejiang, China; Key Laboratory of Structural Malformations in Children of Zhejiang Province, Wenzhou 325000, Zhejiang, China
| | - Yiyan Wang
- Department of Gynecology and Obstetrics, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Anesthesiology of Zhejiang Province, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou, Zhejiang 325027, China; Department of Anesthesiology and Perioperative Medicine, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Environment and Male Reproductive Medicine of Wenzhou, Wenzhou 325000, Zhejiang, China; Key Laboratory of Structural Malformations in Children of Zhejiang Province, Wenzhou 325000, Zhejiang, China.
| | - Ren-Shan Ge
- Department of Gynecology and Obstetrics, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Anesthesiology of Zhejiang Province, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou, Zhejiang 325027, China; Department of Anesthesiology and Perioperative Medicine, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Environment and Male Reproductive Medicine of Wenzhou, Wenzhou 325000, Zhejiang, China; Key Laboratory of Structural Malformations in Children of Zhejiang Province, Wenzhou 325000, Zhejiang, China.
| | - Yi Liu
- Department of Gynecology and Obstetrics, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China.
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Almutlaq RN, Newell-Fugate AE, Evans LC, Fatima H, Gohar EY. Aromatase inhibition increases blood pressure and markers of renal injury in female rats. Am J Physiol Renal Physiol 2022; 323:F349-F360. [PMID: 35900340 PMCID: PMC9423724 DOI: 10.1152/ajprenal.00055.2022] [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: 03/07/2022] [Revised: 06/22/2022] [Accepted: 07/13/2022] [Indexed: 11/22/2022] Open
Abstract
Aromatase is a monooxygenase that catalyzes the rate-limiting step of estrogen biosynthesis from androgens. Aromatase inhibitors are widely used for the treatment of patients with hormone receptor-positive breast cancer. However, the effects of aromatase inhibitors on cardiovascular and renal health in females are understudied. Given that estrogen is protective against cardiovascular and kidney diseases, we hypothesized that aromatase inhibition elevates blood pressure and induces kidney injury in female Sprague-Dawley rats. Twelve-week-old female rats were implanted with radiotelemetry transmitters to continuously monitor blood pressure. After baseline blood pressure recording, rats were randomly assigned to treatment with the aromatase inhibitor anastrozole (ASZ) or vehicle (Veh) in drinking water. Twenty days after treatment initiation, rats were shifted from a normal-salt (NS) diet to a high-salt (HS) diet for an additional 40 days. Rats were euthanized 60 days after treatment initiation. Body weight increased in both groups over the study period, but the increase was greater in the ASZ-treated group than in the Veh-treated group. Mean arterial pressure increased in ASZ-treated rats during the NS and HS diet phases but remained unchanged in Veh-treated rats. In addition, urinary excretion of albumin and kidney injury marker-1 and plasma urea were increased in response to aromatase inhibition. Furthermore, histological assessment revealed that ASZ treatment increased morphological evidence of renal tubular injury and proximal tubular brush border loss. In conclusion, chronic aromatase inhibition in vivo with ASZ increases blood pressure and markers of renal proximal tubular injury in female Sprague-Dawley rats, suggesting an important role for aromatization in the maintenance cardiovascular and renal health in females.NEW & NOTEWORTHY Aromatase enzyme catalyzes the rate-limiting step in estrogen biosynthesis. Aromatase inhibitors are clinically used for the treatment of patients with breast cancer; however, the impact of inhibiting aromatization on blood pressure and renal function is incompletely understood. The present findings demonstrate that systemic anastrozole treatment increases blood pressure and renal tubular injury markers in female rats fed a high-salt diet, suggesting an important role for aromatization in preserving cardiovascular and renal health in females.
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Affiliation(s)
- Rawan N Almutlaq
- Cardiorenal Physiology and Medicine Section, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Annie E Newell-Fugate
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas
| | - Louise C Evans
- Department of Surgery, Medical School, University of Minnesota, Minneapolis, Minnesota
| | - Huma Fatima
- Division of Anatomic and Clinical Pathology, Department of Pathology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Eman Y Gohar
- Division of Nephrology and Hypertension, Vanderbilt University Medical Center, Nashville, Tennessee
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Heidary DK, Kriger SM, Hachey AC, Glazer EC. A Fluorometric CYP19A1 (Aromatase) Activity Assay in Live Cells. ChemMedChem 2021; 16:2845-2850. [PMID: 34224206 DOI: 10.1002/cmdc.202100326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Indexed: 11/10/2022]
Abstract
Inhibition of estrogen synthesis is an integral component of the frontline pharmacologic therapy for the treatment of estrogen receptor positive cancers. However, there is currently no direct, high-throughput-ready assay for aromatase (also known as CYP19A1) that can be performed in live cells. Herein we present a cell-based assay that allows for multiplexed assessment of enzyme activity, protein half-life, cell viability, and identification of inhibitors with slow off-rates.
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Affiliation(s)
- David K Heidary
- Department of Chemistry, University of Kentucky, 505 Rose St., Lexington, KY 40506, USA
| | - Sarah M Kriger
- Department of Chemistry, University of Kentucky, 505 Rose St., Lexington, KY 40506, USA
| | - Austin C Hachey
- Department of Chemistry, University of Kentucky, 505 Rose St., Lexington, KY 40506, USA
| | - Edith C Glazer
- Department of Chemistry, University of Kentucky, 505 Rose St., Lexington, KY 40506, USA
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A novel GC-MS methodology to evaluate aromatase activity in human placental microsomes: a comparative study with the standard radiometric assay. Anal Bioanal Chem 2019; 411:7005-7013. [DOI: 10.1007/s00216-019-02076-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 07/31/2019] [Accepted: 08/07/2019] [Indexed: 10/26/2022]
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Targeting the Hippo Pathway for Breast Cancer Therapy. Cancers (Basel) 2018; 10:cancers10110422. [PMID: 30400599 PMCID: PMC6266939 DOI: 10.3390/cancers10110422] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 10/31/2018] [Accepted: 11/02/2018] [Indexed: 12/31/2022] Open
Abstract
Breast cancer (BC) is one of the most prominent diseases in the world, and the treatments for BC have many limitations, such as resistance and a lack of reliable biomarkers. Currently the Hippo pathway is emerging as a tumor suppressor pathway with its four core components that regulate downstream transcriptional targets. In this review, we introduce the present targeted therapies of BC, and then discuss the roles of the Hippo pathway in BC. Finally, we summarize the evidence of the small molecule inhibitors that target the Hippo pathway, and then discuss the possibilities and future direction of the Hippo-targeted drugs for BC therapy.
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Alyafee YA, Alaamery M, Bawazeer S, Almutairi MS, Alghamdi B, Alomran N, Sheereen A, Daghestani M, Massadeh S. Preparation of anastrozole loaded PEG-PLA nanoparticles: evaluation of apoptotic response of breast cancer cell lines. Int J Nanomedicine 2017; 13:199-208. [PMID: 29343958 PMCID: PMC5749378 DOI: 10.2147/ijn.s151139] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Purpose Anastrozole (ANS) is an aromatase inhibitor that is widely used as a treatment for breast cancer in postmenopausal women. Despite the wide use of ANS, it is associated with serious side effects due to uncontrolled delivery. In addition, ANS exhibits low solubility and short plasma half-life. Nanotechnology-based drug delivery has the potential to enhance the efficacy of drugs and overcome undesirable side effects. In this study, we aimed to prepare novel ANS-loaded PLA-PEG-PLA nanoparticles (ANS-NPs) and to compare the apoptotic response of MCF-7 cell line to both ANS and ANS-loaded NPs. Method ANS-NPs were synthesized using double emulsion method and characterized using different methods. The apoptotic response was evaluated by assessing cell viability, morphology, and studying changes in the expression of MAPK3, MCL1, and c-MYC apoptotic genes in MCF-7 cell lines. Results ANS was successfully encapsulated within PLA-PEG-PLA, forming monodisperse therapeutic NPs with an encapsulation efficiency of 67%, particle size of 186±27.13, and a polydispersity index of 0.26±0.11 with a sustained release profile extended over 144 hours. In addition, results for cell viability and for gene expression represent a similar apoptotic response between the free ANS and ANS-NPs. Conclusion The synthesized ANS-NPs showed a similar therapeutic effect as the free ANS, which provides a rationale to pursue pre-clinical evaluation of ANS-NPs on animal models.
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Affiliation(s)
- Yusra A Alyafee
- Developmental Medicine Department, King Abdullah International Medical Research Center, King Saud Bin Abdulaziz University for Health Sciences, King AbdulAziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia.,Department of Zoology/College of Science/King Saud University (KSU), Riyadh, Kingdom of Saudi Arabia
| | - Manal Alaamery
- Developmental Medicine Department, King Abdullah International Medical Research Center, King Saud Bin Abdulaziz University for Health Sciences, King AbdulAziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia
| | - Shahad Bawazeer
- Developmental Medicine Department, King Abdullah International Medical Research Center, King Saud Bin Abdulaziz University for Health Sciences, King AbdulAziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia
| | - Mansour S Almutairi
- Developmental Medicine Department, King Abdullah International Medical Research Center, King Saud Bin Abdulaziz University for Health Sciences, King AbdulAziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia
| | - Badr Alghamdi
- Developmental Medicine Department, King Abdullah International Medical Research Center, King Saud Bin Abdulaziz University for Health Sciences, King AbdulAziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia
| | - Nawaf Alomran
- Developmental Medicine Department, King Abdullah International Medical Research Center, King Saud Bin Abdulaziz University for Health Sciences, King AbdulAziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia
| | - Atia Sheereen
- Developmental Medicine Department, King Abdullah International Medical Research Center, King Saud Bin Abdulaziz University for Health Sciences, King AbdulAziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia
| | - Maha Daghestani
- Department of Zoology/College of Science/King Saud University (KSU), Riyadh, Kingdom of Saudi Arabia
| | - Salam Massadeh
- Developmental Medicine Department, King Abdullah International Medical Research Center, King Saud Bin Abdulaziz University for Health Sciences, King AbdulAziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia.,College of Pharmacy, King Saud bin Abdulaziz University for Health Sciences, King Abdullah International Medical Research Center, King Abdulaziz Medical City, Ministry of National Guard, Health Affairs, Riyadh, Kingdom of Saudi Arabia
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Kazemi S, Daryani AS, Abdouss M, Shariatinia Z. DFT computations on the hydrogen bonding interactions between methacrylic acid-trimethylolpropane trimethacrylate copolymers and letrozole as drug delivery systems. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2016. [DOI: 10.1142/s0219633616500152] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The hydrogen bonding interactions between letrozole (Let) anticancer drug and three copolymers of methacrylic acid-trimethylolpropane trimethacrylate (M1–M3 as molecular imprinted polymers) were studied using density functional theory (DFT) at both B3LYP and B3PW91 levels. The binding energies were corrected for the basis set superposition error (BSSE) and zero-point vibrational energies (ZPVE) so that the most negative [Formula: see text] were measured for compounds 7 and 8 formed between M1 copolymer and endocyclic N1 and N2 atoms of drug, respectively. Also, among complexes 13–15 in which two copolymers were contributed in the formation of O–H[Formula: see text]N bonds with the drug, compound 13 (containing two M1 copolymers) showed the highest [Formula: see text] value. The interactions of all copolymers with drug were exergonic (spontaneous interaction) and exothermic. The QTAIM data supported the covalent character of the C–N, C–H, N–N, C–O, O–H and O–H[Formula: see text]N bonds, the intermediate nature of C[Formula: see text]N and C[Formula: see text]O bonds while the electrostatic character of C–H[Formula: see text]O, HC[Formula: see text]HC and CH[Formula: see text]N interactions. According to the [Formula: see text], [Formula: see text] and [Formula: see text] values, it was suggested that t complexes 7 and 8 (among two particles systems) as well as complex 13 (among three particles systems) can be the most promising drug delivery systems.
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Affiliation(s)
- Saeedeh Kazemi
- Department of Chemistry, Amirkabir University of Technology (Tehran Polytechnic), P. O. Box: 15875-4413, Tehran, Iran
| | - Aliasghar Sarabi Daryani
- Department of Polymer Engineering & Color Technology, Amirkabir University of Technology (Tehran Polytechnic), P. O. Box: 15875-4413, Tehran, Iran
| | - Majid Abdouss
- Department of Chemistry, Amirkabir University of Technology (Tehran Polytechnic), P. O. Box: 15875-4413, Tehran, Iran
| | - Zahra Shariatinia
- Department of Chemistry, Amirkabir University of Technology (Tehran Polytechnic), P. O. Box: 15875-4413, Tehran, Iran
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Ghosh D, Lo J, Egbuta C. Recent Progress in the Discovery of Next Generation Inhibitors of Aromatase from the Structure-Function Perspective. J Med Chem 2016; 59:5131-48. [PMID: 26689671 DOI: 10.1021/acs.jmedchem.5b01281] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Human aromatase catalyzes the synthesis of estrogen from androgen with high substrate specificity. For the past 40 years, aromatase has been a target of intense inhibitor discovery research for the prevention and treatment of estrogen-dependent breast cancer. The so-called third generation aromatase inhibitors (AIs) letrozole, anastrozole, and the steroidal exemestane were approved in the U.S. in the late 1990s for estrogen-dependent postmenopausal breast cancer. Efforts to develop better AIs with higher selectivity and lower side effects were handicapped by the lack of an experimental structure of this unique P450. The year 2009 marked the publication of the crystal structure of aromatase purified from human placenta, revealing an androgen-specific active site. The structure has reinvigorated research activities on this fascinating enzyme and served as the catalyst for next generation AI discovery research. Here, we present an account of recent developments in the AI field from the perspective of the enzyme's structure-function relationships.
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Affiliation(s)
- Debashis Ghosh
- Department of Pharmacology, State University of New York Upstate Medical University , 750 East Adams Street, Syracuse, New York 13210, United States
| | - Jessica Lo
- Department of Pharmacology, State University of New York Upstate Medical University , 750 East Adams Street, Syracuse, New York 13210, United States
| | - Chinaza Egbuta
- Department of Pharmacology, State University of New York Upstate Medical University , 750 East Adams Street, Syracuse, New York 13210, United States
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Mwakikunga A, Hosie MJ. Anastrozole is a dose-specific superovulator and favors implantation in rats: a prospective study. Cell Tissue Res 2015; 364:209-17. [PMID: 25971929 DOI: 10.1007/s00441-015-2180-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 03/23/2015] [Indexed: 10/23/2022]
Abstract
An alternative superovulator to replace clomiphene citrate (CC) is needed as it is unsuitable for women with polycystic ovarian syndrome and is associated with low pregnancy rates. Anastrozole is an effective superovulator, but has not been well researched. The aim of this study was to determine the optimal dose of anastrozole as a superovulator and ascertain its effects on implantation and uterine ultrastructure during early pregnancy in Wistar rats using scanning electron microscopy. The uterine morphological characteristics which were studied in day 1 and 6 pregnant rats include microvilli density, length, surface "beads", surface glycocalyx, cell borders and apices, uterine surface fording and large surface protrusions. A significant increase in implantation sites is seen in the 15 mg/kg anastrozole group, compared to control. Day 1 and 6 anastrozole groups have similar morphology to the control and different to the CC group. At day 6, large surface protrusions are mostly noted but not limited to anastrozole-treated rats; anastrozole also appears to retain glycocalyx to some extent. The increased number of implantation sites in the 15 mg/kg anastrozole group suggests that this dose superovulates and favors implantation. Anastrozole is probably dose-/species-specific and additionally the surface uterine morphology suggests that anastrozole is implantation friendly.
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Affiliation(s)
- Anthony Mwakikunga
- School of Anatomical Sciences, University of the Witwatersrand, 7 York Road, Parktown 2193, Johannesburg, South Africa.
| | - Margot J Hosie
- School of Anatomical Sciences, University of the Witwatersrand, 7 York Road, Parktown 2193, Johannesburg, South Africa.,Newcastle University Medicine Malaysia Campus, Nusajaya, Johor, Malaysia
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Yapura J, Badea I, Zamberlam G, Price C, Mapletoft R, Pierson R, Singh J, Adams G. Formulation and testing of a non-steroidal aromatase inhibitor intravaginal device for the control of ovarian function in cattle. Anim Reprod Sci 2015; 156:91-102. [DOI: 10.1016/j.anireprosci.2015.03.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 02/17/2015] [Accepted: 03/10/2015] [Indexed: 12/11/2022]
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Mair KM, Wright AF, Duggan N, Rowlands DJ, Hussey MJ, Roberts S, Fullerton J, Nilsen M, Loughlin L, Thomas M, MacLean MR. Sex-dependent influence of endogenous estrogen in pulmonary hypertension. Am J Respir Crit Care Med 2014; 190:456-67. [PMID: 24956156 DOI: 10.1164/rccm.201403-0483oc] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
RATIONALE The incidence of pulmonary arterial hypertension is greater in women, suggesting estrogens may play a role in the disease pathogenesis. Experimentally, in males, exogenously administered estrogen can protect against pulmonary hypertension (PH). However, in models that display female susceptibility, estrogens may play a causative role. OBJECTIVES To clarify the influence of endogenous estrogen and sex in PH and assess the therapeutic potential of a clinically available aromatase inhibitor. METHODS We interrogated the effect of reduced endogenous estrogen in males and females using the aromatase inhibitor, anastrozole, in two models of PH: the hypoxic mouse and Sugen 5416/hypoxic rat. We also determined the effects of sex on pulmonary expression of aromatase in these models and in lungs from patients with pulmonary arterial hypertension. MEASUREMENTS AND MAIN RESULTS Anastrozole attenuated PH in both models studied, but only in females. To verify this effect was caused by reduced estrogenic activity we confirmed that in hypoxic mice inhibition of estrogen receptor α also has a therapeutic effect specifically in females. Female rodent lung displays increased aromatase and decreased bone morphogenetic protein receptor 2 and Id1 expression compared with male. Anastrozole treatment reversed the impaired bone morphogenetic protein receptor 2 pathway in females. Increased aromatase expression was also detected in female human pulmonary artery smooth muscle cells compared with male. CONCLUSIONS The unique phenotype of female pulmonary arteries facilitates the therapeutic effects of anastrozole in experimental PH confirming a role for endogenous estrogen in the disease pathogenesis in females and suggests aromatase inhibitors may have therapeutic potential.
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Affiliation(s)
- Kirsty M Mair
- 1 Institute of Cardiovascular and Medical Sciences, College of Medical and Veterinary Science, University of Glasgow, Glasgow, United Kingdom; and
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Akçay HT, Bayrak R. Computational studies on the anastrozole and letrozole, effective chemotherapy drugs against breast cancer. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 122:142-152. [PMID: 24309175 DOI: 10.1016/j.saa.2013.11.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 11/05/2013] [Accepted: 11/06/2013] [Indexed: 06/02/2023]
Abstract
In this paper, computational studies were carried out on anastrozole and letrozole, chemotherapy drugs used against breast cancer. Optimization and frequency calculations were performed at B3LYP/6-31G (d) basis set and vibrational frequencies were assignment. Single point calculations were performed at DFT method with a hybrid functional B3LYP/6-311G (d, p) basis set. Theoretical NMR data were obtained at DFT method with a hybrid functional B3LYP/6-311G++ (2d, p) with GIAO (Gauge-Independent Atomic Orbital). IEF-PCM method was used as solvation model. NBO calculations were performed by the same basis set and calculation method with single point calculation. Global and localized reactivity parameters; fukui indices (f) chemical hardness (η), softness (S), chemical potential (μ), electronegativity (χ) and electrophilicity index (ω) were calculated. All computational parameters were compared with the experimental results obtained from the literature.
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Affiliation(s)
- Hakki Türker Akçay
- Department of Chemistry, Faculty of Art and Science, Recep Tayyip Erdoğan University, 53100 Rize, Turkey.
| | - Riza Bayrak
- Department of Chemistry, Faculty of Art and Science, Sinop University, 57000 Sinop, Turkey
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13
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Chen S, Michels D, Culpepper E. Nonsurgical management of hyperadrenocorticism in ferrets. Vet Clin North Am Exot Anim Pract 2014; 17:35-49. [PMID: 24274921 DOI: 10.1016/j.cvex.2013.09.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Several medical therapeutic options are available for the management of the clinical signs of adrenal disease in ferrets. Many of these medical modalities seem to be well tolerated and are a suitable alternative to adrenalectomy, especially for ferrets that are not surgical candidates. However, drugs that are currently available only manage the symptoms and do not provide a cure for the diseased adrenal gland, which may continue to enlarge. The medical management of urinary obstruction caused by prostatic enlargement and nonregenerative anemia caused by hyperestrogenism are also discussed in this article.
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Affiliation(s)
- Sue Chen
- Gulf Coast Avian & Exotics, Gulf Coast Veterinary Specialists, 1111 West Loop South, Suite 110, Houston, TX 77027, USA.
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14
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Yamaoka M, Hara T, Araki H, Kaku T, Hitaka T, Tasaka A, Kusaka M. Effect of an investigational CYP17A1 inhibitor, orteronel (TAK-700), on estrogen- and corticoid-synthesis pathways in hypophysectomized female rats and on the serum estradiol levels in female cynomolgus monkeys. J Steroid Biochem Mol Biol 2013; 138:298-306. [PMID: 23856460 DOI: 10.1016/j.jsbmb.2013.07.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 06/28/2013] [Accepted: 07/02/2013] [Indexed: 11/21/2022]
Abstract
Orteronel (TAK-700) is an investigational, non-steroidal inhibitor of CYP17A1 with preferential inhibition of 17,20-lyase in NCI-H295 cells. Estrogen is synthesized from androgen by aromatase activity, and the effect of orteronel on estrogen synthesis was therefore evaluated. First, it was confirmed that orteronel does not directly inhibit aromatase activity. Second, the specific decline of serum estradiol and androgen levels in hypophysectomized female rats by orteronel in comparison with aromatase inhibitor anastrozole was evaluated; orteronel at doses ≥3mg/kg significantly suppressed serum estradiol, testosterone, androstenedione and 17-hydroxyprogesterone levels, and increased progesterone levels in the estrogen-synthesis pathway. Orteronel, at a dose of 300mg/kg, suppressed serum estradiol concentrations to a similar degree as 0.1mg/kg anastrozole. In contrast, in the corticoid-synthesis pathway, serum aldosterone, corticosterone, and progesterone levels did not change significantly following administration of 300mg/kg of orteronel. Third, the effect of multiple oral administration of orteronel on serum estradiol levels in regularly cycling female cynomolgus monkeys was evaluated. Orteronel at 15mg/kg/day (7.5mg/kg/treatment, twice daily [bid]) continued to suppress the estradiol surge prior to the start of luteal phase for 1.5-times the average duration of three consecutive, pre-treatment menstrual cycles, while serum progesterone was maintained at levels almost equal to those in the luteal phase although a certain portion of this increased level of progesterone could be of adrenal-origin. This suppressive effect on estradiol surge was thought to be reversible since serum estradiol levels started to rise immediately after the discontinuation of orteronel. Estradiol surge was not abrogated by treatment with anastrozole 0.2mg/kg/day (0.1mg/kg/treatment, bid). In summary, orteronel can suppress serum estradiol concentrations in hypophysectomized female rats and monkeys through selective inhibition of CYP17A1 activity, suggesting that orteronel might be effective for hormone-dependent breast cancers and estrogen-dependent diseases.
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Affiliation(s)
- Masuo Yamaoka
- Oncology Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa and Osaka, Japan.
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15
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Favia AD, Nicolotti O, Stefanachi A, Leonetti F, Carotti A. Computational methods for the design of potent aromatase inhibitors. Expert Opin Drug Discov 2013; 8:395-409. [DOI: 10.1517/17460441.2013.768983] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Angelo Danilo Favia
- Dipartimento di Farmacia, Università degli Studi di Bari “Aldo Moro”,
via Orabona 4, I-70125 Bari, Italy ;
- Lilly China R&D Center,
Building 8, 338 Jia Li Lue Road Zhangjiang Hi-Tech Park Pudong, 201203, Shanghai, China
| | - Orazio Nicolotti
- Dipartimento di Farmacia, Università degli Studi di Bari “Aldo Moro”,
via Orabona 4, I-70125 Bari, Italy ;
| | - Angela Stefanachi
- Dipartimento di Farmacia, Università degli Studi di Bari “Aldo Moro”,
via Orabona 4, I-70125 Bari, Italy ;
| | - Francesco Leonetti
- Dipartimento di Farmacia, Università degli Studi di Bari “Aldo Moro”,
via Orabona 4, I-70125 Bari, Italy ;
| | - Angelo Carotti
- Dipartimento di Farmacia, Università degli Studi di Bari “Aldo Moro”,
via Orabona 4, I-70125 Bari, Italy ;
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16
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Howell A. Anastrozole: a new gold standard of hormonal treatment for breast cancer? ACTA ACUST UNITED AC 2012; 1:309-22. [PMID: 19803873 DOI: 10.2217/17455057.1.3.309] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Tamoxifen has long been the standard endocrine therapy for postmenopausal women with hormone-sensitive breast cancer. However, data now suggest that the third-generation aromatase inhibitors have emerged as superior alternatives for advanced disease. In early disease evaluation of initial adjuvant therapy, data from the Arimidex((R)), Tamoxifen, Alone and in Combination trial has shown that anastrozole is more effective than tamoxifen with a better risk-benefit profile. This trial provides the most mature data of any aromatase inhibitor study and suggests that anastrozole should be considered the preferred initial adjuvant therapy for postmenopausal women with hormone-responsive early breast cancer. The emergence of aromatase inhibitors as an alternative to tamoxifen for the treatment of breast cancer is challenging the management of the disease and influencing the change of regulatory guidelines.
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Affiliation(s)
- Anthony Howell
- CRUK Department of Medical Oncology, Christie Hospital NHS Trust, Wilmslow Road, Withington, Manchester, M20 4BX, UK.
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17
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Manigrasso MB, Sawyer RT, Marbury DC, Flynn ER, Maric C. Inhibition of estradiol synthesis attenuates renal injury in male streptozotocin-induced diabetic rats. Am J Physiol Renal Physiol 2011; 301:F634-40. [PMID: 21653631 DOI: 10.1152/ajprenal.00718.2010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We previously showed that the male streptozotocin (STZ)-induced diabetic rat exhibits decreased circulating testosterone and increased estradiol levels. While supplementation with dihydrotestosterone is partially renoprotective, the aim of the present study was to examine whether inhibition of estradiol synthesis, by blocking the aromatization of testosterone to estradiol using an aromatase inhibitor, can also prevent diabetes-associated renal injury. The study was performed on male Sprague-Dawley nondiabetic, STZ-induced diabetic, and STZ-induced diabetic rats treated with 0.15 mg/kg of anastrozole, an aromatase inhibitor (Da) for 12 wk. Treatment with anastrozole reduced diabetes-associated increases in plasma estradiol by 39% and increased plasma testosterone levels by 187%. Anastrozole treatment also attenuated urine albumin excretion by 42%, glomerulosclerosis by 30%, tubulointerstitial fibrosis by 32%, along with a decrease in the density of renal cortical CD68-positive cells by 50%, and protein expression of transforming growth factor-β by 20%, collagen type IV by 29%, tumor necrosis factor-α by 28%, and interleukin-6 by 25%. Anastrozole also increased podocin protein expression by 18%. We conclude that blocking estradiol synthesis in male STZ-induced diabetic rats is renoprotective.
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Affiliation(s)
- Michaele B Manigrasso
- Department of Physiology and Biophysics, Univ. of Mississippi Medical Center, Jackson, 39216, USA
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18
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Mirsky ML, Sivaraman L, Houle C, Potter DM, Chapin RE, Cappon GD. Histologic and cytologic detection of endocrine and reproductive tract effects of exemestane in female rats treated for up to twenty-eight days. Toxicol Pathol 2011; 39:589-605. [PMID: 21540174 DOI: 10.1177/0192623311402220] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The objective of this study was to determine the shortest period of time necessary to detect histologic evidence of estrous cycle disruption in Sprague-Dawley rats treated for up to 28 days with the aromatase inhibitor exemestane at 1,000 mg/kg. Rats were evaluated on day 5, 8, 15, or 29. Vaginal mucification, uterine and cervical epithelial atrophy, uterine luminal epithelial vacuolation, decreased uterine granulocytes, and hypertrophy/hyperplasia of mammary ducts and alveoli were noted by day 5 and persisted throughout the study. From day 8 to day 29, absence of recent basophilic corpora lutea, increased atresia of antral follicles, interstitial cell hyperplasia, and increased luteinized follicles were present in the ovaries of treated rats. Vaginal smears detected persistent diestrus, confirming estrous cycle disruption between days 5 and 8. Ovary and uterine weights were largely unaffected. Serum hormone levels were not useful due to the study design employed. Other effects of exemestane included decreased adrenal weights and decreased cell size in both the adrenal zona fasciculata and the pituitary pars distalis. While early histologic changes were evident on day 5, only after 8 days of treatment were findings considered sufficient to clearly identify exemestane-induced estrous cycle disruption using microscopy alone.
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Affiliation(s)
- Michael L Mirsky
- Pfizer Global Research and Development, Groton, Connecticut 06340, USA.
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19
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Santmyire BR, Venkat V, Beinder E, Baylis C. Impact of the estrus cycle and reduction in estrogen levels with aromatase inhibition, on renal function and nitric oxide activity in female rats. Steroids 2010; 75:1011-5. [PMID: 20619284 PMCID: PMC2926238 DOI: 10.1016/j.steroids.2010.06.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 06/24/2010] [Accepted: 06/25/2010] [Indexed: 11/20/2022]
Abstract
Estradiol increases mRNA and/or protein expression of the nitric oxide synthase (NOS) isoforms in a variety of tissues including kidney. In this study we determined the relationship between cyclical variations in estradiol levels and renal function and total NO production in the virgin female rat. In addition, we used an aromatase inhibitor (Anastrozole), to inhibit synthesis of estradiol from testosterone. Estradiol levels were higher in proestrus vs. diestrus, and were markedly suppressed by 7 days treatment with aromatase inhibitor. There was no difference in total NO production (from urinary and plasma nitrate+nitrite=NO(X)) between proestrus and diestrus but aromatase inhibition resulted in increases in total NO production. The renal cortical NOS activity and protein abundance also increased in aromatase-inhibited female rats. There were no differences in blood pressure (BP) in any group but the renal vascular resistance (RVR) was low in proestrus, increased in diestrus and did not change further after aromatase inhibition. In summary, the cyclical changes in renal function correlate with estradiol but not NO levels. Pharmacologic castration with aromatase inhibition leads to a marked increase in total and renal NOS. This contrasts to earlier work where surgical castration causes decreased NOS.
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Affiliation(s)
| | - Vasuki Venkat
- Department of Physiology, West Virginia University, Morgantown, WV
| | - Ernst Beinder
- Department of Obstetrics, University Hospital, Zurich, Switzerland
| | - Chris Baylis
- Department of Physiology and Functional Genomics and Department of Medicine, University of Florida, Gainesville, Fl
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20
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Gomes GRO, Yasuhara F, Siu ER, Fernandes SAF, Avellar MCW, Lazari MFM, Porto CS. In vivo treatments with fulvestrant and anastrozole differentially affect gene expression in the rat efferent ductules. Biol Reprod 2010; 84:52-61. [PMID: 20826728 DOI: 10.1095/biolreprod.110.085340] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Estrogen plays a key role in maintaining the morphology and function of the efferent ductules. We previously demonstrated that the antiestrogen fulvestrant markedly affected gene expression in the rat efferent ductules. The mechanism of fulvestrant action to modulate gene expression may involve not only the blockade of ESR1 and ESR2 estrogen receptors, but also the activation of ESR1 and ESR2 when the receptors are tethered to AP-1 or SP1 transcription factors, or the activation of the G protein-coupled estrogen receptor 1. We therefore compared the effects of two strategies to interfere with estrogen action in the rat efferent ductules: treatment with fulvestrant or with the aromatase inhibitor anastrozole. Whereas fulvestrant markedly increased Mmp7 and Spp1, and reduced Nptx1 mRNA levels, no changes were observed with anastrozole. Fulvestrant caused changes in epithelial morphology that were not seen with anastrozole. Fulvestrant shifted MMP7 immunolocalization in the epithelial cells from the supranuclear to the apical region; this effect was less pronounced with anastrozole. In vitro studies of (35)S-methionine incorporation showed that protein release was increased, whereas tissue protein content in the efferent ductules of fulvestrant-treated rats was decreased. Although fulvestrant markedly affected gene expression, no changes were observed on AP-1 and SP1 DNA-binding activity. The blockade of ESRs seems to be the major reason explaining the differences between both treatments. At least some of the effects of fulvestrant appear to result from compensatory mechanisms activated by the dramatic changes caused by ESR1 blockade.
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Affiliation(s)
- Gisele Renata Oliveira Gomes
- Section of Experimental Endocrinology, Department of Pharmacology, Universidade Federal de São Paulo, Instituto Nacional de Farmacologia e Biologia Molecular, Vila Clementino, São Paulo, Brazil
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21
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Sexual dimorphism in cortical bone size and strength but not density is determined by independent and time-specific actions of sex steroids and IGF-1: evidence from pubertal mouse models. J Bone Miner Res 2010; 25:617-26. [PMID: 19888832 DOI: 10.1359/jbmr.090828] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Although it is well established that males acquire more bone mass than females, the underlying mechanism and timing of this sex difference remain controversial. The aim of this study was to assess the relative contribution of sex steroid versus growth hormone-insulin-like growth factor 1 (GH-IGF-1) action to pubertal bone mass acquisition longitudinally in pubertal mice. Radial bone expansion peaked during early puberty (3 to 5 weeks of age) in male and female mice, with significantly more expansion in males than in females (+40%). Concomitantly, in 5 week old male versus female mice, periosteal and endocortical bone formation was higher (+70%) and lower (-47%), respectively, along with higher serum IGF-1 levels during early puberty in male mice. In female mice, ovariectomy increased radial bone expansion during early puberty as well as the endocortical perimeter. In male mice, orchidectomy reduced radial bone expansion only during late puberty (5 to 8 weeks of age), whereas combined androgen and estrogen deficiency modestly decreased radial bone expansion during early puberty, accompanied by lower IGF-1 levels. GHRKO mice with very low IGF-1 levels, on the other hand, showed limited radial bone expansion and no skeletal dimorphism. From these data we conclude that skeletal sexual dimorphism is established during early puberty and depends primarily on GH-IGF-1 action. In males, androgens and estrogens have stimulatory effects on bone size during late and early puberty, respectively. In females, estrogens limit bone size during early puberty. These longitudinal findings in mice provide strong evidence that skeletal dimorphism is determined by independent and time-specific effects of sex steroids and IGF-1.
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Abstract
Male breast cancer is an uncommon condition. It often occurs in settings in which there is an imbalance between androgens and oestrogens. Genetics plays an important role, as many cases are associated with mutations in BRCA2 or other genes. Male breast cancer occurs at an older age than female breast cancer and is frequently diagnosed at a later stage. Tumors are predominantly oestrogen and progesterone positive. Prognosis is approximately equivalent to that of breast cancer in females when matched for age, stage and hormonal receptors. The recommended treatment for male breast cancer is similar to that for breast cancer in postmenopausal females. However, the presence of androgens in males has a strong effect on the hormonal milieu and the ability of male patients to respond to hormonal agents. When pharmacologic treatment is required, tamoxifen is effective for first-line therapy. Other hormonal approaches such as orchiectomy, aromatase inhibitors and androgen ablation may be useful in later lines of therapy.
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Affiliation(s)
- Teresa G Hayes
- Hematology Oncology Section, Department of Veterans' Affairs Medical Center, Baylor College of Medicine, Houston, TX 77030, USA.
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23
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Satoh K, Nonaka R, Ishikawa F, Ogata A, Nagai F. In Vitro Screening Assay for Detecting Aromatase Activity Using Rat Ovarian Microsomes and Estrone ELISA. Biol Pharm Bull 2008; 31:357-62. [DOI: 10.1248/bpb.31.357] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Kanako Satoh
- Department of Environmental Health and Toxicology, Tokyo Metropolitan Institute of Public Health
| | - Rhouichi Nonaka
- Department of Environmental Health and Toxicology, Tokyo Metropolitan Institute of Public Health
| | - Fusako Ishikawa
- Department of Food Safety, Tokyo Metropolitan Institute of Public Health
| | - Akio Ogata
- Department of Environmental Health and Toxicology, Tokyo Metropolitan Institute of Public Health
| | - Fumiko Nagai
- Department of Environmental Health and Toxicology, Tokyo Metropolitan Institute of Public Health
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24
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Aromatase inhibitors: past, present and future in breast cancer therapy. Med Oncol 2007; 25:113-24. [PMID: 17973095 DOI: 10.1007/s12032-007-9019-x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Accepted: 10/09/2007] [Indexed: 01/22/2023]
Abstract
Estrogen has been implicated in promoting breast cancer in a majority of women. Endocrine therapy controlling estrogen production has been the guiding principle in treating breast cancer for more than a century. A greater understanding of this disease at a molecular level has led to the development of molecules that inhibit estrogen production by inhibiting the aromatase enzyme, that is the primary source of estrogen in postmenopausal women. This review examines the evolution of aromatase inhibitor (AI) based therapies over the past three decades. The third generation aromatase inhibitors (anastrozole, letrozole and exemestane), which have been found to be extremely specific and effective in an adjuvant/neoadjuvant/extended adjuvant setting are discussed from a biochemical and clinical perspective. A comprehensive discussion of the past, present, and future of aromatase inhibitors is conducted in this review.
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25
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Graham PH. Anastrozole for malignant and benign conditions: present applications and future therapeutic integrations. Expert Opin Pharmacother 2007; 8:2347-57. [DOI: 10.1517/14656566.8.14.2347] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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26
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Goldstein I. A clinical paradigm for the combined management of androgen insufficiency and erectile dysfunction. Endocrinol Metab Clin North Am 2007; 36:435-52. [PMID: 17543728 DOI: 10.1016/j.ecl.2007.02.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Androgen insufficiency and erectile dysfunction are highly prevalent medical disorders in aging men who have associated multiple risk factors. Good clinical practice requires the use of appropriate strategies for patient- and goal-directed diagnosis and treatment. This article focuses on a rational, evidence based clinical management paradigm that combines diagnosis and treatment of men who have androgen insufficiency and erectile dysfunction.
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Affiliation(s)
- Irwin Goldstein
- Sexual Medicine, Alvarado Hospital, 5555 Reservoir Drive, Suite 203, San Diego, CA 92120, USA.
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27
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Traish AM, Goldstein I, Kim NN. Testosterone and erectile function: from basic research to a new clinical paradigm for managing men with androgen insufficiency and erectile dysfunction. Eur Urol 2007; 52:54-70. [PMID: 17329016 PMCID: PMC2562639 DOI: 10.1016/j.eururo.2007.02.034] [Citation(s) in RCA: 168] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2006] [Accepted: 02/09/2007] [Indexed: 01/15/2023]
Abstract
OBJECTIVES Androgens are essential for the development and growth of the penis, and they regulate erectile physiology by multiple mechanisms. Our goal is to provide a concise overview of the basic research and how this knowledge can be translated into a new clinical paradigm for patient management. In addition, this new paradigm may serve as a basis for stimulating constructive debate regarding the use of testosterone in men, and to promote new, innovative basic and clinical research to further understand the underlying mechanisms of androgen action in restoring erectile physiology. METHODS A literature review was performed utilizing the US National Library of Medicine's PubMed database. RESULTS On the basis of evidence derived from laboratory animal studies and clinical data, we postulate that androgen insufficiency disrupts cellular-signaling pathways and produces pathologic alterations in penile tissues, leading to erectile dysfunction. In this review, we discuss androgen-dependent cellular, molecular, and physiologic mechanisms modulating erectile function in the animal model, and the implication of this knowledge in testosterone use in the clinical setting to treat erectile dysfunction. The new clinical paradigm incorporates many of the consensed points of view discussed in traditional consensed algorithms exclusively designed for men with androgen insufficiency. There are, however, novel and innovative differences with this new clinical paradigm. This paradigm represents a fresh effort to provide mandatory and optional management strategies for men with both androgen insufficiency and erectile dysfunction. CONCLUSIONS The new clinical paradigm is evidence-based and represents one of the first attempts to address a logical management plan for men with concomitant hormonal and sexual health concerns.
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Affiliation(s)
- Abdulmaged M. Traish
- Department of Biochemistry, Boston University School of Medicine, Milton, MA, USA
- Department of Urology, Boston University School of Medicine, Milton, MA, USA
- Corresponding author. Abdulmaged M. Traish, PhD, Center for Advanced Biomedical Research, Boston University, School of Medicine, 700 Albany Street W607, Boston, MA 02118 USA. Tel. +1-617-638-4578. E-mail address: (A.M. Traish)
| | | | - Noel N. Kim
- Department of Urology, Boston University School of Medicine, Milton, MA, USA
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28
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Fatum M, Gyo Y, Diana P, Laufer N, Simon A. Is estradiol mandatory for an adequate follicular and embryo development? A mouse model using aromatase inhibitor (anastrozole). J Assist Reprod Genet 2006; 23:407-12. [PMID: 17146736 PMCID: PMC3455099 DOI: 10.1007/s10815-006-9089-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Accepted: 11/07/2006] [Indexed: 10/23/2022] Open
Abstract
BACKGROUND Although high levels of estradiol are found in the follicular fluid, little is known about its necessity for adequate follicular growth, oocyte maturation and embryo development. Arimidex (anastrozole) is a potent aromatase inhibitor capable to induce an in-vivo milieu deprived of estradiol. This study uses a mouse model applying Arimidex to create an in-vivo system lacking of estradiol, in order to explore whether this gonadal steroid hormone is mandatory for folliculogenesis followed by normal fertilization and embryo development. METHODS Experiment 1: Immature C57 Black female mice, aged 3-4 weeks were superovulated by 5 IU PMSG given intraperitoneally. A study group (9 mice) was concomitantly injected with 0.1 mg of Arimidex intraperitoneally given the morning day before PMSG, the morning day of PMSG injection and the following two days. The control group (8 mice) was similarly injected with normal saline. Estradiol (E2) and progesterone (P) serum levels were tested 48 hours after PMSG and the ovaries of each mouse blindly examined by a pathologist to evaluate follicular development. Experiment 2: 48 h after PMSG superovulation, hCG (7.5 IU) was injected intraperitoneally, followed by mating. The study group was treated with Arimidex 0.1 mg intraperitoneally daily from a day prior to PMSG injection to the day of sacrifice. The control group was treated similarly by normal saline. Forty-two hours after mating blood was withdrawn for E2 and P levels followed by tubal dissection. Embryos of 2-4 cells were cultured in-vitro and the development to the morula, blastocyst and hatching blastocyst stages were examined 24, 42, and 48 h later. RESULTS Experiment 1: A significant reduction of E2 levels was achieved in the Arimidex group in comparison to control group (126.3+/-104.8 and 1910+/-960 pmol/L, respectively; p < 0.0001). Nevertheless, the two groups did not differ by the mean number of follicles (27+/-9.5 and 30.4+/-13.0) or the distribution for antral (65% and 68.4%) and pre-antral (35% and 31.6%) follicles, respectively. Experiment 2: The reduction of estradiol during follicular phase did not hamper follicular development, in-vivo fertilization and in-vitro embryo development. Similar rates of embryo development to the morula stage (90.6% and 86%), blastocyst stage (86% and 89%) and hatching blastocyst (81% and 78%) were achieved in the Arimidex group and the control group, respectively. CONCLUSIONS Adequate folliculogenesis is independent of estrogen but is conditioned on gonadotropin stimulation. Moreover, depletion of estradiol in the vicinity of the oocyte did not impair its developmental potential, including its fertilization and development into morulae, blastocysts and hatching blastocysts.
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Affiliation(s)
- Muhammad Fatum
- Department of Obstetrics and Gynecology, Hadassah University Hospital, Ein Kerem, P.O. Box 12000, Jerusalem 91120, Israel.
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Movérare-Skrtic S, Venken K, Andersson N, Lindberg MK, Svensson J, Swanson C, Vanderschueren D, Oscarsson J, Gustafsson JA, Ohlsson C. Dihydrotestosterone treatment results in obesity and altered lipid metabolism in orchidectomized mice. Obesity (Silver Spring) 2006; 14:662-72. [PMID: 16741268 DOI: 10.1038/oby.2006.75] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVE To determine the role of androgen receptor (AR) activation for adipose tissue metabolism. Sex steroids are important regulators of adipose tissue metabolism in men. Androgens may regulate the adipose tissue metabolism in men either directly by stimulation of the AR or indirectly by aromatization of androgens into estrogens and, thereafter, by stimulation of the estrogen receptors. Previous studies have shown that estrogen receptor alpha stimulation results in reduced fat mass in men. RESEARCH METHODS AND PROCEDURES Orchidectomized mice were treated with the non-aromatizable androgen 5alpha-dihydrotestosterone (DHT), 17beta-estradiol, or vehicle. Vo(2), Vco(2), resting metabolic rate, locomotor activity, and food consumption were measured. Furthermore, changes in hepatic gene expression were analyzed. RESULTS DHT treatment resulted in obesity, associated with reduced energy expenditure and fat oxidation. In contrast, DHT did not affect food consumption or locomotor activity. Furthermore, DHT treatment resulted in increased high-density lipoprotein-cholesterol and triglyceride levels associated with markedly decreased 7alpha-hydroxylase gene expression, indicating decreased bile acid production. DISCUSSION We showed that AR activation results in obesity and altered lipid metabolism in orchidectomized mice. One may speculate that AR antagonists might be useful in the treatment of obesity in men.
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Affiliation(s)
- Sofia Movérare-Skrtic
- Center for Bone Research at the Sahlgrenska Academy (CBS), Department of Internal Medicine, Göteborg, Sweden
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Venken K, De Gendt K, Boonen S, Ophoff J, Bouillon R, Swinnen JV, Verhoeven G, Vanderschueren D. Relative impact of androgen and estrogen receptor activation in the effects of androgens on trabecular and cortical bone in growing male mice: a study in the androgen receptor knockout mouse model. J Bone Miner Res 2006; 21:576-85. [PMID: 16598378 DOI: 10.1359/jbmr.060103] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
UNLABELLED The relative importance of AR and ER activation has been studied in pubertal male AR knockout and WT mice after orchidectomy and androgen replacement therapy, either with or without an aromatase inhibitor. AR activation dominates normal trabecular bone development and cortical bone modeling in male mice. Moreover, optimal periosteal bone expansion is only observed in the presence of both AR and ER activation. INTRODUCTION Androgen receptor (AR)-mediated androgen action has traditionally been considered a key determinant of male skeletal growth. Increasing evidence, however, suggests that estrogens are also essential for normal male bone growth. Therefore, the relative importance of AR-mediated and estrogen receptor (ER)-mediated androgen action after aromatization remains to be clarified. MATERIALS AND METHODS Trabecular and cortical bone was studied in intact or orchidectomized pubertal AR knockout (ARKO) and male wildtype (WT) mice, with or without replacement therapy (3-8 weeks of age). Nonaromatizable (dihydrotestosterone [DHT]) and aromatizable (testosterone [T]) androgens and T plus an aromatase inhibitor (anastrazole) were administered to orchidectomized ARKO and WT mice. Trabecular and cortical bone modeling were evaluated by static and dynamic histomorphometry, respectively. RESULTS AR inactivation or orchidectomy induced a similar degree of trabecular bone loss (-68% and -71%, respectively). Both DHT and T prevented orchidectomy-induced bone loss in WT mice but not in ARKO mice. Administration of an aromatase inhibitor did not affect T action on trabecular bone. AR inactivation and orchidectomy had similar negative effects on cortical thickness (-13% and -8%, respectively) and periosteal bone formation (-50% and -26%, respectively). In orchidectomized WT mice, both DHT and T were found to stimulate periosteal bone formation and, as a result, to increase cortical thickness. In contrast, the periosteum of ARKO mice remained unresponsive to either DHT or T. Interestingly, administration of an aromatase inhibitor partly reduced T action on periosteal bone formation in orchidectomized WT mice (-34% versus orchidectomized WT mice on T), but not in ARKO mice. This effect was associated with a significant decrease in serum IGF-I (-21% versus orchidectomized WT mice on T). CONCLUSIONS These findings suggest a major role for AR activation in normal development of trabecular bone and periosteal bone growth in male mice. Moreover, optimal stimulation of periosteal growth is only obtained in the presence of both AR and ER activation.
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Affiliation(s)
- Katrien Venken
- Laboratory for Experimental Medicine and Endocrinology, Katholieke Universiteit Leuven, Leuven, Belgium
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Nahleh ZA. Hormonal therapy for male breast cancer: A different approach for a different disease. Cancer Treat Rev 2006; 32:101-5. [PMID: 16472925 DOI: 10.1016/j.ctrv.2005.12.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Accepted: 12/20/2005] [Indexed: 11/28/2022]
Abstract
Male breast cancer (MBC) is on the rise in the United States [Surveillance, Epidemiology, and End Results (SEER) Program () SEER Stat Database: Incidence-SEER 9 Regs Public-Use; November 2004 submission (1973-2002), National Cancer Institute, DCPPS, Surveillance Research Program, Cancer Statistics Branch, released April 2005, based on the November 2004 submission]; however mortality due to MBC has not changed unlike in its female counterpart [American Cancer Society: Cancer facts and figures 2005. Atlanta (GA): American Cancer Society; 2005]. The rarity of MBC has precluded major progress in the understanding and treatment of this disease. Treatment has often been extrapolated from female breast cancer (FBC) despite distinct clinicopathologic features between the two entities, especially with regards to the role of male hormones and estrogens in this disease. Also, it is uncertain if hormone receptor positive tumors carry the same prognostic implication in MBC as in the female disease. Hormonal therapy has been the mainstay of treatment in MBC with tamoxifen the front-line drug. The role of the newer generation aromatase inhibitors has not been well defined but they are being used in clinical practice for the treatment of MBC, based on accepted data for women with the disease. This commentary focuses on the major hormonal differences between male and female breast cancer that would suggest the need to explore different treatment strategies if significant advances are to be made in the understanding and treatment of this distinct disease.
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Affiliation(s)
- Zeina A Nahleh
- Department of Internal Medicine, Division of Hematology-Oncology, The Barrett Cancer Center, University of Cincinnati, 234 Goodman Avenue, ML 0501, Cincinnati, OH 45267, USA.
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Trösken ER, Fischer K, Völkel W, Lutz WK. Inhibition of human CYP19 by azoles used as antifungal agents and aromatase inhibitors, using a new LC–MS/MS method for the analysis of estradiol product formation. Toxicology 2006; 219:33-40. [PMID: 16330141 DOI: 10.1016/j.tox.2005.10.020] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Accepted: 10/30/2005] [Indexed: 11/22/2022]
Abstract
Azoles are used as fungicides in agriculture or antifungal drugs in medicine. Their therapeutic activity is based on the inhibition of fungal lanosterol-14alpha-demethylase (CYP51). Azoles are also used for the treatment of estrogen-dependent diseases, e.g. in breast cancer therapy. Inhibition of CYP19 (aromatase) is the working principle for tumor therapy, but is an unwanted side effect of azoles used as fungicides or antifungal drugs. The inhibition of recombinant human CYP19 by 21 azoles in use for the three different purposes was investigated using the natural substrate testosterone. Estradiol product formation was measured by a newly developed and fully validated analytical method based on liquid chromatography-tandem mass spectrometry utilizing photospray ionization (APPI). Potency of enzyme inhibition was expressed in terms of IC50 concentrations. The two cytostatic drugs fadrozole and letrozole were the most potent inhibitors. However, azoles used as fungicides, e.g. prochloraz, or as antifungal drugs, e.g. bifonazole, were almost as potent inhibitors of aromatase as the drugs used in tumor therapy. Comparison of plasma concentrations that may be reached in antifungal therapy do not allow for large safety factors for bifonazole and miconazole. The IC50 values were compared to data obtained with other substrates, such as the pseudo-substrate dibenzylfluorescein (DBF). A high correlation was found, indicating that the fluorescence assay with DBF can well be used for potency ranking and screening of chemicals for aromatase inhibition. The data for antifungal drugs show that side effects on steroid hormone synthesis in humans due to inhibition of aromatase should be considered.
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Affiliation(s)
- Eva R Trösken
- Department of Toxicology, University of Würzburg, 9 Versbacher St., 97078 Würzburg, Germany
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Barrett GM, Bardi M, Guillén AKZ, Mori A, Shimizu K. Regulation of sexual behaviour in male macaques by sex steroid modulation of the serotonergic system. Exp Physiol 2006; 91:445-56. [PMID: 16364983 DOI: 10.1113/expphysiol.2005.032193] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The view that androgen action is the primary impetus underlying male-typical behaviour has been irrevocably altered by the profound perturbations in social and sexual behaviour observed in recent models of oestrogen insufficiency in male mice. Evidence is also accumulating for an involvement of oestrogens in the modulation of neural systems that are thought to play important roles in male reproductive functioning. Specifically, the serotonergic system is implicated in diverse autonomic functions, most or all of which are sensitive to oestradiol as well. Although their interaction domains have yet to be examined in male primates, roles have been established for both oestrogen and serotonin in the regulation of male sexual behaviour. We used a blinded, sham-treated and self-controlled, randomized, multitreatment cross-over design to test the hypothesis that male sexual behaviour is regulated by oestrogen modulation of the serotonergic system in intact male Japanese macaques. Regression analysis revealed that oestradiol and whole blood tryptophan, but not testosterone or 5alpha-dihydrotestosterone, had additive, independent effects on male potentia over a range of hormone concentrations, whereas androgens were confirmed to be the primary determinants of sexual motivation. We suggest that modulation of the serotonergic system by 'female hormones' may be fundamental to the regulation of male mating success in higher primates. This might also explain, at least in part, why significant correlations between steroid hormones and male copulatory behaviour have traditionally proven so elusive in this order, thereby warranting a re-evaluation of the current notion that male sexual behaviour has been emancipated from activational hormonal control in higher primates.
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Affiliation(s)
- Gordon M Barrett
- Kyoto University Primate Research Institute, Inuyama, Aichi, Japan
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Cardone A, Comitato R, Bellini L, Angelini F. Effects of the aromatase inhibitor fadrozole on plasma sex steroid secretion, spermatogenesis and epididymis morphology in the lizard, Podarcis sicula. Mol Reprod Dev 2002; 63:63-70. [PMID: 12211062 DOI: 10.1002/mrd.10151] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Recently, increasing importance has been attached to the role of estrogens and their receptors in male reproduction, since they have been found to be abundant in the male reproductive tract. In the lizard, Podarcis sicula, a seasonal breeder, estrogens seem to be involved in the regulation of testicular activity. Particularly, it has been hypothesized that the block of spermatogenesis and the complete regression of the epididymis and other secondary sexual characters (SSCs) in autumn might be due to high estrogen levels. To investigate the role of estrogens in the reproductive process of male lizards, we utilized Fadrozole ((AI) [4-(5,6,7,8-tetrahydroimidazole [1,5-a] pyridin-5-yl)-benzonitrile monohydrochloride] (CGS 16949A)), a nonsteroidal inhibitor of aromatase, the enzyme involved in the aromatization of androgens to estrogens, evaluating its effects on plasma sex-hormone release, spermatogenesis and epididymis morphology. For this purpose, adult male lizards, captured during the autumnal recrudescence, were intraperitoneally injected with 0.5 microg and 5 microg/g/body weight of AI for 15 and 30 days. In the animals treated with the higher AI dose, estrogen levels decreased if compared to the control groups, whereas androgen levels increased. Furthermore, histologic sections of testes and epididymes showed that the 30-day treatment with AI-induced spermatogenesis resumption with release of sperms into the large lumen of the seminiferous tubules, and the epididymes appeared more developed with moderately secreting columnar canal cells. Therefore, it is proposed that failure of spermatogenesis in autumn might be due to high estrogen levels.
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Affiliation(s)
- Anna Cardone
- Dipartimento di Biologia Evolutiva e Comparata, University of Naples Federico II Napoli, Italy.
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Abstract
Anastrozole (Arimidex, AstraZeneca) is a third-generation aromatase inhibitor which rapidly reduces oestradiol concentrations to below detectable levels. It is both potent and selective for the aromatase enzyme, with near-maximal suppression of serum oestrogens occurring at the clinical dose of 1 mg/day in postmenopausal women with advanced breast cancer. Anastrozole has also been shown to be a potent suppressor of intratumoural oestrogens, with responses comparable to those in serum. The results of two large, identically designed, randomised trials in postmenopausal women with advanced breast cancer who had progressed on tamoxifen showed that oral anastrozole 1 mg/day produced a statistically significant survival advantage over megestrol acetate 40 mg q.i.d. The median duration of survival was 26.7 months for anastrozole versus 22.5 months for megestrol acetate. Anastrozole was as well-tolerated as megestrol acetate, while weight gain was significantly increased in the megestrol acetate group compared with the anastrozole group. In another Phase III clinical trial involving 1021 postmenopausal women with advanced breast cancer, anastrozole showed a statistically significant advantage over tamoxifen in median time to progression in a combined analysis of 611 patients who were known to be oestrogen receptor- or progesterone receptor-positive. Anastrozole was as well-tolerated as tamoxifen, with a low rate of withdrawals (2%) due to drug-related adverse events. In addition, anastrozole was associated with fewer thromboembolic events and episodes of vaginal bleeding than tamoxifen. For women with hormone receptor-positive tumours who progress on tamoxifen, anastrozole is superior to megestrol acetate. In addition, anastrozole is a reasonable alternative to tamoxifen for first-line endocrine therapy of advanced breast cancer. Recent data confirm an emerging role for anastrozole as adjuvant therapy for primary breast cancer in postmenopausal patients. Anastrozole is also being investigated in the neoadjuvant setting.
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Affiliation(s)
- Jean-Marc Nabholtz
- Cancer Therapy Development Programme and Jonsson Comprehensive Cancer Center, University of California, Los Angeles 90095-7077, USA.
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Abstract
Aromatase inhibitors and inactivators are increasingly important to the therapy of advanced breast cancer in postmenopausal women. These compounds are also currently being evaluated in the adjuvant setting and may have potential in breast cancer prevention. In addition to the recent clinical results, experimental research with development of aromatase 'knockout' mice as well as certain clinical observations in individuals lacking this enzyme have deepened our understanding of estrogens outside of the field of reproduction. Such information should help us to further develop this type of therapy in breast cancer and, in particular, extend our understanding of the lack of complete cross-resistance between aromatase inhibitors and inactivators. Clinically, third-generation aromatase inhibitors and inactivators have shown superiority compared with conventional treatment in advanced postmenopausal breast cancer with respect to second-line (tamoxifen failures) as well as first-line therapy. The fact that tamoxifen is noncurative in metastatic disease but improves long-term survival in the adjuvant setting suggests that even modest improvements in therapy of advanced disease may be translated into survival benefits in patients with early disease. In addition, these novel compounds with lack of complete cross-resistance extend the scope of using sequential treatment options to maximise the duration of optimal endocrine therapy in metastatic breast cancer disease.
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Affiliation(s)
- Per E Lønning
- Section of Oncology, Department of Medicine, Haukeland University Hospital, Bergen, Norway.
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Ashby J, Owens W, Deghenghi R, Odum J. Concept evaluation: an assay for receptor-mediated and biochemical antiestrogens using pubertal rats. Regul Toxicol Pharmacol 2002; 35:393-7. [PMID: 12202054 DOI: 10.1006/rtph.2002.1557] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
At present, assessment of chemicals for receptor-mediated antiestrogenic activity involves inhibition of uterine growth stimulated by coadministration of a reference estrogen in either ovariectomized or immature rodents. In the present paper, we describe an alternative assay for both receptor-mediated and biochemical antiestrogens. The assay involves treatment of immature rats from postnatal (pnd) 25 or 26 for either 7 or 14 days and monitors two benchmarks of puberty, the mean day of vaginal opening and the weight of the uterus, that require estrogen activity. The receptor-mediated antiestrogens ZM 189,154 and Faslodex (ICI 182,780), the aromatase inhibitor Arimidex (Anastrozole), and the GnRH inhibitor Antarelix were each effective in preventing uterine growth and in delaying vaginal opening for the course of the experiments. The 5alpha-reductase inhibitor Finasteride was inactive in the assay indicating assay specificity for antiestrogens. Delays in uterine growth were clearly evident in the 7-day experiments, but assessment of vaginal opening required the 14-day protocol. No significant changes in body weight were observed in any of the experiments. It is concluded that the assay holds promise as a simple method of detecting antiestrogens and that it is worthy of further study.
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Affiliation(s)
- J Ashby
- Syngenta Central Toxicology Laboratory, Alderley Park, Macclesfield, Cheshire, SK10 4TJ, United Kingdom
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Abstract
Inhibition of aromatase activity in vitro is one of the Tier 1 screening assays proposed by the Endocrine Disrupter Screening and Testing Advisory Committee (EDSTAC) for the detection of potential endocrine disrupters. In this report a rat ovarian aromatase inhibition assay has been evaluated using the reference aromatase inhibitors anastrozole, fadrozole, letrozole and CGS 18320B. Rat ovary microsomes were used as the enzyme source, as endocrine disruption studies are most commonly carried out in this species. Aromatase activity was inhibited in vitro by anastrozole, fadrozole, letrozole and CGS 18320B with IC(50)s of 25, 7, 7 and 5 nM, respectively. This assay, therefore, appears to have good sensitivity to aromatase inhibitors and may be useful as a general screening assay and in mechanistic studies.
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Affiliation(s)
- J Odum
- Syngenta Central Toxicology Laboratory, Alderley Park, Macclesfield, Cheshire SK10 4TJ, UK
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Geisler J, Haynes B, Anker G, Dowsett M, Lønning PE. Influence of letrozole and anastrozole on total body aromatization and plasma estrogen levels in postmenopausal breast cancer patients evaluated in a randomized, cross-over study. J Clin Oncol 2002; 20:751-7. [PMID: 11821457 DOI: 10.1200/jco.2002.20.3.751] [Citation(s) in RCA: 269] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PURPOSE To compare the effects of the two novel, potent, nonsteroidal aromatase inhibitors anastrozole and letrozole on total-body aromatization and plasma estrogen levels. PATIENTS AND METHODS Twelve postmenopausal women with estrogen receptor-positive, metastatic breast cancer were treated with anastrozole 1 mg orally (PO) and letrozole 2.5 mg PO once daily, each given for a time interval of 6 weeks in a randomized sequence. Total-body aromatization was determined before treatment and at the end of each treatment period using a dual-label isotopic technique involving isolation of the metabolites with high-performance liquid chromatography. Plasma levels of estrone (E(1)), estradiol (E(2)), and estrone sulfate (E(1)S) were determined in samples obtained before each injection using highly sensitive radioimmunoassays. RESULTS Pretreatment aromatase levels ranged from 1.68% to 4.27%. On-treatment levels of aromatase were detectable in 11 of 12 patients during treatment with anastrozole (mean percentage inhibition in the whole group, 97.3%) but in none of the 12 patients during treatment with letrozole (> 99.1% suppression in all patients; Wilcoxon, P =.0022, comparing the two drug regimens). Treatment with anastrozole suppressed plasma levels of E(1), E(2), and E(1)S by a mean of 81.0%, 84.9%, and 93.5%, respectively, whereas treatment with letrozole caused a corresponding decrease of 84.3%, 87.8% and 98.0%, respectively. The suppression of E(1) and E(1)S was found to be significantly better during treatment with letrozole compared with anastrozole (P =.019 and.0037, respectively). CONCLUSION This study revealed letrozole (2.5 mg once daily) to be a more potent suppressor of total-body aromatization and plasma estrogen levels compared with anastrozole (1 mg once daily) in postmenopausal women with metastatic breast cancer.
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Affiliation(s)
- Jürgen Geisler
- Department of Oncology, Haukeland University Hospital, Bergen, Norway
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Abstract
PURPOSE Testosterone-to-estradiol ratio levels in infertile men improve during treatment with the aromatase inhibitor, testolactone, and resulting changes in semen parameters. We evaluated the effect of anastrozole, a more selective aromatase inhibitor, on the hormonal and semen profiles of infertile men with abnormal baseline testosterone-to-estradiol ratios. MATERIALS AND METHODS A total of 140 subfertile men with abnormal testosterone-to-estradiol ratios were treated with 100 to 200 mg. testolactone daily or 1 mg. anastrozole daily. Changes in testosterone, estradiol, testosterone-to-estradiol ratios and semen parameters were evaluated during therapy. The effect of obesity, diagnosis of the Klinefelter syndrome, and presence of varicocele and/or history of varicocele repair on treatment results was studied. RESULTS Men treated with testolactone had an increase in testosterone-to-estradiol ratios during therapy (mean plus or minus standard error of the mean 5.3 +/- 0.2 versus 12.4 +/- 1.1, p <0.001). This change was confirmed in subgroups of men with the Klinefelter syndrome, a history of varicocele repair and those with varicocele. A total of 12 oligospermic men had semen analysis before and during testolactone treatment with an increase in sperm concentration (5.5 versus 11.2 million sperm per ml., p <0.01), motility (14.7% versus 21.0%, p <0.05), morphology (6.5% versus 12.8%, p = 0.05), and motility index (606.3 versus 1685.2 million motile sperm per ejaculate, respectively, p <0.05) appreciated. During anastrozole treatment, similar changes in the testosterone-to-estradiol ratios were seen (7.2 +/- 0.3 versus 18.1 +/- 1.0, respectively, p <0.001). This improvement of hormonal parameters was noted for all subgroups except those patients with the Klinefelter syndrome. A total of 25 oligospermic men with semen analysis before and during anastrozole treatment had an increase in semen volume (2.9 versus 3.5 ml., p <0.05), sperm concentration (5.5 versus 15.6 million sperm per ml., p <0.001) and motility index (832.8 versus 2930.8 million motile sperm per ejaculate, respectively, p <0.005). These changes were similar to those observed in men treated with testolactone. No significant difference in serum testosterone levels during treatment with testolactone and anastrozole was observed. However, the anastrozole treatment group did have a statistically better improvement of serum estradiol concentration and testosterone-to-estradiol ratios (p <0.001). CONCLUSIONS Men who are infertile with a low serum testosterone-to-estradiol ratio can be treated with an aromatase inhibitor. With treatment, an increase in testosterone-to-estradiol ratio occurred in association with increased semen parameters. Anastrozole and testolactone have similar effects on hormonal profiles and semen analysis. Anastrazole appears to be at least as effective as testolactone for treating men with abnormal testosterone-to-estradiol ratios, except for the subset with the Klinefelter syndrome, who appeared to be more effectively treated with testolactone.
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Affiliation(s)
- Jay D Raman
- Department of Urology, James Buchanan Brady Urology Foundation, Center for Male Reproductive Medicine and Microsurgery, New York Presbyterian Hospital, Weill Medical College of Cornell University, New York, New York, USA
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Abstract
The new generation of selective aromatase inhibitors (anastrozole, letrozole and exemestane) offer a significant efficacy and safety advantage over both older agents in this class (aminoglutethimide) and the progestins (megestrol acetate (MA)), as second-line treatment for postmenopausal women with advanced hormone-dependent breast cancer who have failed on tamoxifen therapy. Exemestane, a steroidal aromatase inhibitor, has been shown to have activity after failure with the non-steroidal aromatase inhibitors, anastrozole and letrozole, and could be used as third-line treatment. Although the newer aromatase inhibitors belong to the same class and appear, from indirect comparisons, to have similar efficacy compared with the older therapies, they have different pharmacokinetic and pharmacodynamic profiles, suggesting the potential for clinical differences. Compared with exemestane and letrozole, anastrozole shows greater selectivity for aromatase, as it lacks any evidence of an effect on adrenal steroidogenesis and has no androgenic effects. Therefore, it is clear that these agents should not be considered to be similar in all respects. In summary, the introduction of the aromatase inhibitors represents a significant step forward in the treatment of advanced breast cancer in postmenopausal women. Studies in the adjuvant setting will ultimately determine whether the differences in pharmacokinetics and phamacodynamics will be of clinical relevance.
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Affiliation(s)
- A U Buzdar
- Department of Breast Medical Oncology, M.D. Anderson Cancer Center, M.D. University of Texas, Box 424, 1515 Holcombe Blvd, Houston, TX 77030, USA.
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Abstract
The basic premise of this investigation was that local hormonal control of stockpiling of the base excision repair polymerase (poly) beta within oocytes of preovulatory follicles occurs as a function of cytoplasmic maturation. There was an increase in immunoreactive poly beta in sectioned oocytes of preovulatory ovine follicles during a 12-36-hour interval following the onset of prostaglandin (PG) F2alpha-induced (Day 14 of the estrous cycle) luteal regression; this response was not observed in subordinate (nonovulatory) follicles. Accumulation of poly beta in oocytes at 36 hr after PGF2alpha was negated by treatment of ewes at 12 hr with the aromatase inhibitor Arimidex or an ovulatory dose of GnRH (which, via surge gonadotropin stimulation, acutely downregulates the proestrous rise in follicular estrogen biosynthesis). Estradiol-17beta stimulated poly beta expression (transcriptional control) in oocytes of explanted (12 hr after PGF2alpha) follicles (24-hour incubation). We suggest that a critical period of estrogen amplification in the preovulatory follicle underscores the capacity of its oocyte to efficiently repair DNA and therefore reconcile spontaneous infidelities in genomic integrity that inevitably occur during preimplantation embryogenesis.
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Affiliation(s)
- W J Murdoch
- Department of Animal Science, University of Wyoming, Laramie, Wyoming
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Odum J, Tinwell H, Van Miller J, Joiner R, Ashby J. The uterotrophic activity of nonylphenol in the rat is not mediated by aromatase enzyme induction. Toxicol Lett 2001; 118:165-9. [PMID: 11137323 DOI: 10.1016/s0378-4274(00)00293-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
p-Nonylphenol (NP) is weakly estrogenic to rodents and to some species of fish. All evidence to date has indicated that the estrogenic effects of NP are due to the interaction of NP with the estrogen receptor. Recent findings of increased plasma estradiol in fish exposed to NP have, however, led to the proposal of an alternative mechanism for NP-induced estrogenicity in this species, possibly via induction of aromatase enzymes. In the present studies, this hypothesis was investigated in rats using the aromatase inhibitor anastrozole. The results indicated that the uterotrophic action of NP, as with estradiol used as a positive control, is mediated directly by its interaction with uterine ER, rather than an indirect effect via aromatase enzyme induction. Circulating levels of estradiol were unchanged after NP treatment and the aromatase inhibitor anastrozole failed to inhibit NP-induced uterine growth. These results are consistent with previous published data on NP in rodents.
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Affiliation(s)
- J Odum
- Syngenta Central Toxicology Laboratory, Alderley Park, Macclesfield, SK10 4TJ, Cheshire, UK
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Nomura Y, Koyama H, Ohashi Y, Watanabe H. Clinical Dosage Determination of a New Aromatase Inhibitor, Anastrozole, in Postmenopausal Japanese Women with Advanced Breast Cancer. Clin Drug Investig 2000. [DOI: 10.2165/00044011-200020050-00007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Ashby J, Tinwell H, Odum J, Kimber I, Brooks AN, Pate I, Boyle CC. Diet and the aetiology of temporal advances in human and rodent sexual development. J Appl Toxicol 2000; 20:343-7. [PMID: 11139164 DOI: 10.1002/1099-1263(200009/10)20:5<343::aid-jat719>3.0.co;2-o] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- J Ashby
- Zeneca Central Toxicology Laboratory, Macclesfield, Cheshire, UK
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Karjalainen A, Kalapudas A, Södervall M, Pelkonen O, Lammintausta R. Synthesis of new potent and selective aromatase inhibitors based on long-chained diarylalkylimidazole and diarylalkyltriazole molecule skeletons. Eur J Pharm Sci 2000; 11:109-31. [PMID: 10915960 DOI: 10.1016/s0928-0987(00)00074-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A series of long-chained diarylalkylimidazoles and diarylalkyltriazoles were synthesized and evaluated for the inhibitory potency for aromatase (estrogen synthetase) activity in human placental microsomes. The relative specificity of inhibition was evaluated by measuring the inhibition of cholesterol side-chain cleavage enzyme (desmolase) in human placental mitochondria and the inhibition of 7-ethoxycoumarin O-deethylase (a typical drug-metabolizing enzyme activity) in rat liver microsomes. The structural requirements including substituent effects for the strongest potency and for the highest specificity were delineated. alpha,omega-Diarylalkyltriazoles and imidazoles were the most interesting molecules, in which the geometric and optical isomerism displayed remarkable selectivity for aromatase inhibition.
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Affiliation(s)
- A Karjalainen
- Department of Synthetic Chemistry, Orion Corporation, Orion Pharma, R&D, P.O. Box 65, Espoo, Finland.
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Sonnet P, Dallemagne P, Guillon J, Enguehard C, Stiebing S, Tanguy J, Bureau R, Rault S, Auvray P, Moslemi S, Sourdaine P, Séralini GE. New aromatase inhibitors. Synthesis and biological activity of aryl-substituted pyrrolizine and indolizine derivatives. Bioorg Med Chem 2000; 8:945-55. [PMID: 10882007 DOI: 10.1016/s0968-0896(00)00024-9] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report herein the design and the synthesis of some aryl-substituted pyrrolizine and indolizine derivatives, on the basis of a hypothetical pharmacophore structure designed to fit the catalytic site of the human cytochrome P450 aromatase. The in vitro biological evaluation of these compounds allowed us to point out two new potent non-steroidal aromatase inhibitors, MR 20494 and MR 20492, with IC50 values in the range of 0.1 microM.
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Affiliation(s)
- P Sonnet
- Centre d'Etudes et de Recherche sur le Médicament de Normandie, Laboratoire de Pharmacochimie, UFR des Sciences Pharmaceutiques, Caen, France
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Negri-Cesi P, Colciago A, Poletti A, Motta M. 5alpha-reductase isozymes and aromatase are differentially expressed and active in the androgen-independent human prostate cancer cell lines DU145 and PC3. Prostate 1999; 41:224-32. [PMID: 10544295 DOI: 10.1002/(sici)1097-0045(19991201)41:4<224::aid-pros2>3.0.co;2-q] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND The presence and possible role of androgen-metabolizing enzymes in androgen-independent prostate carcinoma (CaP) are still unclear. The aim of the present study was: 1) to evaluate the pattern of androgen metabolism (relative production of 5alpha-reduced vs. 17-keto androgens); and 2) to analyze whether one or both the two known 5alpha-reductase isoforms (5alpha-R1 and 5alpha-R2) and the aromatase (Aro) are expressed and active in this pathology. METHODS Two different cell lines (DU145 and PC3) were used as a model of androgen-independent human CaP. In these cells, the expression of the two 5alpha-Rs and of Aro were evaluated by reverse transcription-polymerase chain reaction (RT-PCR) and Southern blot, using specific sets of oligoprimers and of [(32)P]-labeled oligoprobes; the enzymatic activities of 5alpha-R and of Aro were evaluated by radioenzymatic methods. The pH optimum for the activity of the two 5alpha-Rs was assessed in cell homogenates at different pH (from 3.5-8), using substrate concentrations similar either to 5alpha-R1 or to 5alpha-R2 Kms. RESULTS The two CaP cell lines DU145 and PC3, although unresponsive to androgens, possess the enzymatic machinery involved in the metabolism of this class of hormonal steroids: 5alpha-Rs, which allow their transformation into 5alpha-reduced steroids (5alpha-dihydrotestosterone, DHT, and 5alpha-androstandione, 5alpha-A), and 17beta-hydroxysteroid-oxidoreductase (17beta-HSD), which interconverts testosterone (T) and androstenedione (ADIONE); however, the two cell lines show differences in the rate of formation of these metabolites. Furthermore, two cell lines expressed the type 1 isoform of 5alpha-R, but only DU145 cells also possess 5alpha-R2. Aro is expressed and active in DU145 as well as in PC3 cells. CONCLUSIONS The present findings suggest that T might still be indirectly active in androgen-unresponsive CaP through its local conversion into estrogens by the action of Aro; the biological role played by the two 5alpha-Rs in androgen-independent CaP deserves further investigation.
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Affiliation(s)
- P Negri-Cesi
- Center for Endocrinological Oncology, Department of Endocrinology, University of Milan, Milan, Italy.
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Vorobiof DA, Kleeberg UR, Perez-Carrion R, Dodwell DJ, Robertson JF, Calvo L, Dowsett M, Clack G. A randomized, open, parallel-group trial to compare the endocrine effects of oral anastrozole (Arimidex) with intramuscular formestane in postmenopausal women with advanced breast cancer. Ann Oncol 1999; 10:1219-25. [PMID: 10586340 DOI: 10.1023/a:1008308609325] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND This study provides a direct randomized comparison of a new-generation, non-steroidal aromatase inhibitor, anastrozole (Arimidex), with a steroidal aromatase inhibitor (formestane) with respect to oestrogen (oestradiol, oestrone, and oestrone sulphate) suppression and tolerability. PATIENTS AND METHODS Sixty postmenopausal women with advanced breast cancer were randomized to receive either anastrozole 1 mg once daily orally (n = 29), or formestane 250 mg once every two weeks by intramuscular injection (n = 31). Treatment was continued until progression of disease or withdrawal from the study. The primary endpoints of this study were oestradiol suppression and tolerability. The secondary endpoints included oestrone and oestrone sulphate suppression. All laboratory analyses were conducted 'blind' of the randomized drug treatment. RESULTS Anastrozole produced a greater and more consistent suppression of oestradiol levels compared with formestane. Based on two- and four-week measurements, the mean fall from baseline (pre-dose) in oestradiol level was 79% and 58% in the anastrozole and formestane groups, respectively (P = 0.0001). After four weeks of treatment, oestrone and oestrone sulphate levels were also suppressed to a greater extent by anastrozole compared with formestane (oestrone: 85% versus 67%, respectively, P = 0.0043; oestrone sulphate: 92% versus 67%, respectively, P = 0.0007). No statistical differences were seen between the two drugs in the incidence of adverse events. CONCLUSIONS Anastrozole provides a more consistent and significantly more effective suppression of oestradiol compared with formestane. Similar results were observed for oestrone and oestrone sulphate. The clinical significance of these differences in total oestrogen suppression remains to be established.
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Lund SA, Murdoch J, Van Kirk EA, Murdoch WJ. Mitogenic and antioxidant mechanisms of estradiol action in preovulatory ovine follicles: relevance to luteal function. Biol Reprod 1999; 61:388-92. [PMID: 10411516 DOI: 10.1095/biolreprod61.2.388] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The objectives of this investigation were to determine the intrafollicular mechanisms and physiological consequences of estradiol actions in preovulatory ovine follicles. Acute suppression of estradiol production in proestrous ewes by an aromatase inhibitor (Arimidex) was associated with follicular lipid peroxidation, testosterone accumulation, and a granulosa cell deficiency (decreased proliferation/increased apoptosis). Estradiol-17beta stimulated granulosa proliferating cell nuclear antigen (PCNA) and protected cells from oxidative (H(2)O(2)) stress-induced apoptosis in vitro; the PCNA, but not the antiapoptotic response, was negated by the transcriptional inhibitor actinomycin D. Thus, it appears that genomic/mitotic and cytoprotective (oxygen-scavenging) modes of estradiol action operate in preovulatory follicles. Luteal (large steroidogenic cell) function was diminished following ovulation induction of estradiol-deficient follicles. It is suggested that inadequate exposure of the preovulatory follicle to estradiol caused the granulosa lutein insufficiency.
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Affiliation(s)
- S A Lund
- Department of Animal Science, University of Wyoming, Laramie, Wyoming 82071, USA
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