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Dembitsky VM. Steroids Bearing Heteroatom as Potential Drugs for Medicine. Biomedicines 2023; 11:2698. [PMID: 37893072 PMCID: PMC10604304 DOI: 10.3390/biomedicines11102698] [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: 09/04/2023] [Revised: 09/27/2023] [Accepted: 09/28/2023] [Indexed: 10/29/2023] Open
Abstract
Heteroatom steroids, a diverse class of organic compounds, have attracted significant attention in the field of medicinal chemistry and drug discovery. The biological profiles of heteroatom steroids are of considerable interest to chemists, biologists, pharmacologists, and the pharmaceutical industry. These compounds have shown promise as potential therapeutic agents in the treatment of various diseases, such as cancer, infectious diseases, cardiovascular disorders, and neurodegenerative conditions. Moreover, the incorporation of heteroatoms has led to the development of targeted drug delivery systems, prodrugs, and other innovative pharmaceutical approaches. Heteroatom steroids represent a fascinating area of research, bridging the fields of organic chemistry, medicinal chemistry, and pharmacology. The exploration of their chemical diversity and biological activities holds promise for the discovery of novel drug candidates and the development of more effective and targeted treatments.
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Affiliation(s)
- Valery M Dembitsky
- Centre for Applied Research, Innovation and Entrepreneurship, Lethbridge College, 3000 College Drive South, Lethbridge, AB T1K 1L6, Canada
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2
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Ghosh D. Structures and Functions of Human Placental Aromatase and Steroid Sulfatase, Two Key Enzymes in Estrogen Biosynthesis. Steroids 2023; 196:109249. [PMID: 37207843 DOI: 10.1016/j.steroids.2023.109249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/12/2023] [Accepted: 05/14/2023] [Indexed: 05/21/2023]
Abstract
Cytochrome P450 aromatase (AROM) and steroid sulfatase (STS) are the two key enzymes for the biosynthesis of estrogens in human, and maintenance of the critical balance between androgens and estrogens. Human AROM, an integral membrane protein of the endoplasmic reticulum, is a member of the cytochrome P450 superfamily. It is the only enzyme to catalyze the conversion of androgens with non-aromatic A-rings to estrogens characterized by the aromatic A-ring. Human STS, also an integral membrane protein of the endoplasmic reticulum, is a Ca2+-dependent enzyme that catalyzes the hydrolysis of sulfate esters of estrone and dehydroepiandrosterone to the unconjugated steroids, the precursors of the most potent forms of estrogens and androgens, namely, 17β-estradiol, 16α,17β-estriol, testosterone and dihydrotestosterone. Expression of these steroidogenic enzymes locally within organs and tissues of the endocrine, reproductive, and central nervous systems is the key for maintaining high levels of the reproductive steroids. The enzymes have been drug targets for the prevention and treatment of diseases associated with steroid hormone excesses, especially in breast, endometrial and prostate malignancies. Both enzymes have been the subjects of vigorous research for the past six decades. In this article, we review the important findings on their structure-function relationships, specifically, the work that began with unravelling of the closely guarded secrets, namely, the 3-D structures, active sites, mechanisms of action, origins of substrate specificity and the basis of membrane integration. Remarkably, these studies were conducted on the enzymes purified in their pristine forms from human placenta, the discarded and their most abundant source. The purification, assay, crystallization, and structure determination methodologies are described. Also reviewed are their functional quaternary organizations, post-translational modifications and the advancements made in the structure-guided inhibitor design efforts. Outstanding questions that still remain open are summarized in closing.
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Affiliation(s)
- Debashis Ghosh
- Department of Pharmacology, State University of New York Upstate Medical University, Syracuse, NY 13210.
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3
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Khan MZI, Uzair M, Nazli A, Chen JZ. An overview on Estrogen receptors signaling and its ligands in breast cancer. Eur J Med Chem 2022; 241:114658. [PMID: 35964426 DOI: 10.1016/j.ejmech.2022.114658] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 07/31/2022] [Accepted: 08/01/2022] [Indexed: 02/07/2023]
Abstract
Estrogen governs the regulations of various pathological and physiological actions throughout the body in both males and females. Generally, 17β-estradiol an endogenous estrogen is responsible for different health problems in pre and postmenopausal women. The major activities of endogenous estrogen are executed by nuclear estrogen receptors (ERs) ERα and ERβ while non-genomic cytoplasmic pathways also govern cell growth and apoptosis. Estrogen accomplished a fundamental role in the formation and progression of breast cancer. In this review, we have hyphenated different studies regarding ERs and a thorough and detailed study of estrogen receptors is presented. This review highlights different aspects of estrogens ranging from receptor types, their isoforms, structures, signaling pathways of ERα, ERβ and GPER along with their crystal structures, pathological roles of ER, ER ligands, and therapeutic strategies to overcome the resistance.
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Affiliation(s)
| | - Muhammad Uzair
- School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, 450001, China
| | - Adila Nazli
- Department of Pharmacy, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan
| | - Jian-Zhong Chen
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
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Cairns J, Ingle JN, Kalari KR, Goetz MP, Weinshilboum RM, Gao H, Li H, Bari MG, Wang L. Anastrozole Regulates Fatty Acid Synthase in Breast Cancer. Mol Cancer Ther 2022; 21:206-216. [PMID: 34667110 PMCID: PMC8742770 DOI: 10.1158/1535-7163.mct-21-0509] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/27/2021] [Accepted: 10/13/2021] [Indexed: 12/14/2022]
Abstract
Our previous matched case-control study of postmenopausal women with resected early-stage breast cancer revealed that only anastrozole, but not exemestane or letrozole, showed a significant association between the 6-month estrogen concentrations and risk of breast cancer. Anastrozole, but not exemestane or letrozole, is a ligand for estrogen receptor α. The mechanisms of endocrine resistance are heterogenous and with the new mechanism of anastrozole, we have found that treatment of anastrozole maintains fatty acid synthase (FASN) protein level by limiting the ubiquitin-mediated FASN degradation, leading to increased breast cancer cell growth. Mechanistically, anastrozole decreases the guided entry of tail-anchored proteins factor 4 (GET4) expression, resulting in decreased BCL2-associated athanogene cochaperone 6 (BAG6) complex activity, which in turn, prevents RNF126-mediated degradation of FASN. Increased FASN protein level can induce a negative feedback loop mediated by the MAPK pathway. High levels of FASN are associated with poor outcome only in patients with anastrozole-treated breast cancer, but not in patients treated with exemestane or letrozole. Repressing FASN causes regression of breast cancer cell growth. The anastrozole-FASN signaling pathway is eminently targetable in endocrine-resistant breast cancer.
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Affiliation(s)
- Junmei Cairns
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - James N. Ingle
- Division of Medical Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Krishna R. Kalari
- Department of Health Sciences Research, Mayo Clinic, Rochester, MN, 55905, USA
| | - Matthew P. Goetz
- Division of Medical Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Richard M. Weinshilboum
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - Huanyao Gao
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - Hu Li
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - Mehrab Ghanat Bari
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - Liewei Wang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA,Corresponding author: Liewei Wang, Gonda 19-460, 200 1 Street SW, Rochester MN USA 55905. Phone: +1 507 284-5264; Fax: +1 507-284-4455;
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5
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Multi-Therapeutic Potential of Naringenin (4',5,7-Trihydroxyflavonone): Experimental Evidence and Mechanisms. PLANTS 2020; 9:plants9121784. [PMID: 33339267 PMCID: PMC7766900 DOI: 10.3390/plants9121784] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 11/26/2020] [Accepted: 11/26/2020] [Indexed: 12/12/2022]
Abstract
Extensive research has been carried out during the last few decades, providing a detailed account of thousands of discovered phytochemicals and their biological activities that have the potential to be exploited for a wide variety of medicinal purposes. These phytochemicals, which are pharmacologically important for clinical use, primarily consist of polyphenols, followed by terpenoids and alkaloids. There are numerous published reports indicating the primary role of phytochemicals proven to possess therapeutic potential against several diseases. However, not all phytochemicals possess significant medicinal properties, and only some of them exhibit viable biological effects. Naringenin, a flavanone found in citrus fruits, is known to improve immunity, repair DNA damage, and scavenge free radicals. Despite the very low bioavailability of naringenin, it is known to exhibit various promising biological properties of medicinal importance, including anti-inflammatory and antioxidant activities. This review focuses on the various aspects related to naringenin, particularly its physicochemical, pharmacokinetic, and pharmacodynamic properties. Furthermore, various pharmacological activities of naringenin, such as anticancer, antidiabetic, hepatoprotective, neuroprotective, cardioprotective, nephroprotective, and gastroprotective effects, have been discussed along with their mechanisms of action.
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Cairns J, Ingle JN, Kalari KR, Shepherd LE, Kubo M, Goetz MP, Weinshilboum RM, Wang L. The lncRNA MIR2052HG regulates ERα levels and aromatase inhibitor resistance through LMTK3 by recruiting EGR1. Breast Cancer Res 2019; 21:47. [PMID: 30944027 PMCID: PMC6448248 DOI: 10.1186/s13058-019-1130-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 03/25/2019] [Indexed: 01/10/2023] Open
Abstract
Background Our previous genome-wide association study using the MA.27 aromatase inhibitors adjuvant trial identified SNPs in the long noncoding RNA MIR2052HG associated with breast cancer-free interval. MIR2052HG maintained ERα both by promoting AKT/FOXO3-mediated ESR1 transcription and by limiting ubiquitin-mediated ERα degradation. Our goal was to further elucidate MIR2052HG’s mechanism of action. Methods RNA-binding protein immunoprecipitation assays were performed to demonstrate that the transcription factor, early growth response protein 1 (EGR1), worked together with MIR2052HG to regulate that lemur tyrosine kinase-3 (LMTK3) transcription in MCF7/AC1 and CAMA-1 cells. The location of EGR1 on the LMTK3 gene locus was mapped using chromatin immunoprecipitation assays. The co-localization of MIR2052HG RNA and the LMTK3 gene locus was determined using RNA-DNA dual fluorescent in situ hybridization. Single-nucleotide polymorphisms (SNP) effects were evaluated using a panel of human lymphoblastoid cell lines. Results MIR2052HG depletion in breast cancer cells results in a decrease in LMTK3 expression and cell growth. Mechanistically, MIR2052HG interacts with EGR1 and facilitates its recruitment to the LMTK3 promoter. LMTK3 sustains ERα levels by reducing protein kinase C (PKC) activity, resulting in increased ESR1 transcription mediated through AKT/FOXO3 and reduced ERα degradation mediated by the PKC/MEK/ERK/RSK1 pathway. MIR2052HG regulated LMTK3 in a SNP- and aromatase inhibitor-dependent fashion: the variant SNP increased EGR1 binding to LMTK3 promoter in response to androstenedione, relative to wild-type genotype, a pattern that can be reversed by aromatase inhibitor treatment. Finally, LMTK3 overexpression abolished the effect of MIR2052HG on PKC activity and ERα levels. Conclusions Our findings support a model in which the MIR2052HG regulates LMTK3 via EGR1, and LMTK3 regulates ERα stability via the PKC/MEK/ERK/RSK1 axis. These results reveal a direct role of MIR2052HG in LMTK3 regulation and raise the possibilities of targeting MIR2052HG or LMTK3 in ERα-positive breast cancer. Electronic supplementary material The online version of this article (10.1186/s13058-019-1130-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Junmei Cairns
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - James N Ingle
- Division of Medical Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Krishna R Kalari
- Department of Health Sciences Research, Mayo Clinic, Rochester, MN, 55905, USA
| | - Lois E Shepherd
- NCIC Clinical Trials Group, Kingston, Ontario, K7L 3N6, Canada
| | - Michiaki Kubo
- RIKEN Center for Integrative Medical Science, Yokohama City, 230-0045, Japan
| | - Matthew P Goetz
- Division of Medical Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Richard M Weinshilboum
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - Liewei Wang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA.
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Slocum M, Garcia SF, McKoy JM. Cancer Drug Toxicity: Moving from Patient to Survivor. Cancer Treat Res 2018; 171:107-118. [PMID: 30552660 DOI: 10.1007/978-3-319-43896-2_8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Millions of individuals worldwide are living with cancer and have remained disease-free for more than 5 years. These individuals are considered to be cancer survivors. The advent of new targeted therapies and personalized treatment modalities have contributed to this increased survivorship. Additionally, earlier diagnosis and detection of cancer, greater access to preventive screenings, and greater focus on cancer pharmaceutical safety have all been contributed to increasing longevity. Of note, all cancer types have benefited in the survivorship arena. The advent of expansive survivorship care planning mandated by national governmental agencies and the emergence of newer classes of drug therapies for cancer are expected to buttress and support cancer survivorship in the coming decades.
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Affiliation(s)
- Megan Slocum
- Cancer Survivorship Institute, Robert H. Lurie Comprehensive Cancer Center Northwestern University, Chicago, IL, USA
| | - Sophie F Garcia
- Cancer Survivorship Institute, Robert H. Lurie Comprehensive Cancer Center Northwestern University, Chicago, IL, USA
| | - June M McKoy
- Cancer Survivorship Institute, Robert H. Lurie Comprehensive Cancer Center Northwestern University, Chicago, IL, USA.
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Patil VM, Masand N. Anticancer Potential of Flavonoids: Chemistry, Biological Activities, and Future Perspectives. STUDIES IN NATURAL PRODUCTS CHEMISTRY 2018. [DOI: 10.1016/b978-0-444-64179-3.00012-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Lui AJ, Geanes ES, Ogony J, Behbod F, Marquess J, Valdez K, Jewell W, Tawfik O, Lewis-Wambi J. IFITM1 suppression blocks proliferation and invasion of aromatase inhibitor-resistant breast cancer in vivo by JAK/STAT-mediated induction of p21. Cancer Lett 2017; 399:29-43. [PMID: 28411130 DOI: 10.1016/j.canlet.2017.04.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 03/23/2017] [Accepted: 04/04/2017] [Indexed: 12/19/2022]
Abstract
Interferon induced transmembrane protein 1 (IFITM1) belongs to a family of interferon stimulated genes (ISGs) that is associated with tumor progression and DNA damage resistance; however, its role in endocrine resistance is not known. Here, we correlate IFITM1 expression with clinical stage and poor response to endocrine therapy in a tissue microarray consisting of 94 estrogen receptor (ER)-positive breast tumors. IFITM1 overexpression is confirmed in the AI-resistant MCF-7:5C cell line and not found in AI-sensitive MCF-7 cells. In this study, the orthotopic (mammary fat pad) and mouse mammary intraductal (MIND) models of breast cancer are used to assess tumor growth and invasion in vivo. Lentivirus-mediated shRNA knockdown of IFITM1 in AI-resistant MCF-7:5C cells diminished tumor growth and invasion and induced cell death, whereas overexpression of IFITM1 in wild-type MCF-7 cells promoted estrogen-independent growth and enhanced their aggressive phenotype. Mechanistic studies indicated that loss of IFITM1 in MCF-7:5C cells markedly increased p21 transcription, expression and nuclear localization which was mediated by JAK/STAT activation. These findings suggest IFITM1 overexpression contributes to breast cancer progression and that targeting IFITM1 may be therapeutically beneficial to patients with endocrine-resistant disease.
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Affiliation(s)
- Asona J Lui
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, USA; The University of Kansas Cancer Center, Kansas City, KS 66160, USA.
| | - Eric S Geanes
- Department of Cancer Biology, University of Kansas Medical Center, USA; The University of Kansas Cancer Center, Kansas City, KS 66160, USA.
| | - Joshua Ogony
- Department of Cancer Biology, University of Kansas Medical Center, USA; The University of Kansas Cancer Center, Kansas City, KS 66160, USA.
| | - Fariba Behbod
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, USA; The University of Kansas Cancer Center, Kansas City, KS 66160, USA.
| | - Jordan Marquess
- University of Kansas Medical Center School of Medicine, USA.
| | - Kelli Valdez
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, USA; The University of Kansas Cancer Center, Kansas City, KS 66160, USA.
| | - William Jewell
- The University of Kansas Cancer Center, Kansas City, KS 66160, USA.
| | - Ossama Tawfik
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, USA.
| | - Joan Lewis-Wambi
- Department of Cancer Biology, University of Kansas Medical Center, USA; The University of Kansas Cancer Center, Kansas City, KS 66160, USA.
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Chou CW, Chiang TI, Chang IC, Huang CH, Cheng YW. Expression levels of estrogen receptor α mRNA in peripheral blood cells are an independent biomarker for postmenopausal osteoporosis. BBA CLINICAL 2016; 5:124-9. [PMID: 27051599 PMCID: PMC4816160 DOI: 10.1016/j.bbacli.2016.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 02/23/2016] [Accepted: 03/04/2016] [Indexed: 11/30/2022]
Abstract
BACKGROUND The up- and down-regulation of the osteoclastogenesis response depends on the estrogen/estrogen receptor (ER) signaling pathway. Previous reports have shown that the promoter hypermethylation and gene polymorphism of ERα are risks for menopausal osteoporosis. No previous study has evaluated the expression levels of ERα mRNA in menopausal osteoporosis using human subjects. We hypothesized that ERα mRNA expression may show less resistance to postmenopausal osteoporosis. METHODS In this study, we enrolled 107 women older than 45 years without menstruation and classified them into control, osteopenia, and osteoporosis groups depending on their T-scores. The ERα mRNA levels in peripheral blood cells (PBCs) were analyzed via quantitative real-time reverse-transcription polymerase chain reaction (QRT-PCR), and estrogen in the serum was detected via ELISA. RESULTS ERα mRNA levels in PBCs had a negative correlation with age and a positive correlation with estrogen and BAP in the osteopenia and osteoporosis groups, but not in the control group. Additionally, multivariate analysis showed that older age (> 55 years), and low ERα mRNA levels in PBLs (≦ 250.39 copies/μg DNA) were associated with an approximately 9.188-, and 31.25-fold risk of osteoporosis. CONCLUSION We conclude that ERα mRNA levels in PBLs could be used as an independent risk factor for postmenopausal osteoporosis. GENERAL SIGNIFICANCE Our findings suggested that ERα mRNA levels in PBLs may be more important than age and serum estrogen levels.
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Affiliation(s)
- Chi-Wen Chou
- Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan; Department of Orthopedic Surgery, National Taiwan University Hospital Yun-Lin Branch, Taiwan
| | - Tsay-I Chiang
- Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan; Department of Orthopedic Surgery, National Taiwan University Hospital Yun-Lin Branch, Taiwan; Department of Nursing, College of Medicine & Nursing, Hung Kuang University, Taichung, Taiwan; Graduate Institute of Cancer Biology and Drug Discovery, College of Medical Technology, Taipei Medical University, Taichung, Taiwan
| | - I-Chang Chang
- Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan; Department of Orthopedic Surgery, National Taiwan University Hospital Yun-Lin Branch, Taiwan
| | - Chung-Hung Huang
- Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Ya-Wen Cheng
- Graduate Institute of Cancer Biology and Drug Discovery, College of Medical Technology, Taipei Medical University, Taichung, Taiwan
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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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12
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Abstract
Biosynthesis of estrogens from androgens is catalyzed by cytochrome P450 aromatase. Aromatase inhibition by the triazole compounds letrozole (LTZ) and anastrozole is a prevalent therapy for estrogen-dependent postmenopausal breast cancer. Azoles are widely used as agricultural fungicides and antimycotic drugs that target 14α-demethylase. Some were previously shown to inhibit aromatase, thereby raising the possibility of endocrine disruptive effects. However, mechanistic analysis of their inhibition has never been undertaken. We have evaluated the inhibitory effects of 3 common fungicides, bifonazole, imazalil, and flusilazole, in human aromatase purified from placenta and compared them with LTZ, the most potent inhibitor of aromatase. Bifonazole exhibits strong inhibitory effects with an IC50 of 270nM and Ki (Michaeles-Menten inhibition constant) of 68nM, compared with 10nM and 13nM, respectively, for LTZ. The IC50 and Ki are 1100nM and 278nM for imazilil and 3200nM and 547nM for flusilazole, respectively. Analyses of inhibition kinetics suggest that the modes of inhibition by azole fungicides are mixed or competitive, whereas LTZ inhibition could be noncompetitive or mixed. We interpret the inhibition mechanism in the context of the x-ray structure of aromatase-androstenedione complex. Structural data show that aromatase has 3 binding pockets in relation to the heme. The substrate-binding cavity at the heme-distal site closely compliments the structures of the natural substrate, androstenedione, and steroidal aromatase inhibitors. Because the structures of LTZ and the azole fungicides are entirely dissimilar to the androstenedione backbone, the azoles possibly inhibit by binding to a structurally rearranged active site, the 2 other catalytically important sites, or both, in agreement with the kinetics data.
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Affiliation(s)
- Chinaza Egbuta
- Department of Pharmacology, State University of New York Upstate Medical University, Syracuse, New York 13210
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13
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Liu M, Goss PE, Ingle JN, Kubo M, Furukawa Y, Batzler A, Jenkins GD, Carlson EE, Nakamura Y, Schaid DJ, Chapman JAW, Shepherd LE, Ellis MJ, Khosla S, Wang L, Weinshilboum RM. Aromatase inhibitor-associated bone fractures: a case-cohort GWAS and functional genomics. Mol Endocrinol 2014; 28:1740-51. [PMID: 25148458 DOI: 10.1210/me.2014-1147] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Bone fractures are a major consequence of osteoporosis. There is a direct relationship between serum estrogen concentrations and osteoporosis risk. Aromatase inhibitors (AIs) greatly decrease serum estrogen levels in postmenopausal women, and increased incidence of fractures is a side effect of AI therapy. We performed a discovery case-cohort genome-wide association study (GWAS) using samples from 1071 patients, 231 cases and 840 controls, enrolled in the MA.27 breast cancer AI trial to identify genetic factors involved in AI-related fractures, followed by functional genomic validation. Association analyses identified 20 GWAS single nucleotide polymorphism (SNP) signals with P < 5E-06. After removal of signals in gene deserts and those composed entirely of imputed SNPs, we applied a functional validation "decision cascade" that resulted in validation of the CTSZ-SLMO2-ATP5E, TRAM2-TMEM14A, and MAP4K4 genes. These genes all displayed estradiol (E2)-dependent induction in human fetal osteoblasts transfected with estrogen receptor-α, and their knockdown altered the expression of known osteoporosis-related genes. These same genes also displayed SNP-dependent variation in E2 induction that paralleled the SNP-dependent induction of known osteoporosis genes, such as osteoprotegerin. In summary, our case-cohort GWAS identified SNPs in or near CTSZ-SLMO2-ATP5E, TRAM2-TMEM14A, and MAP4K4 that were associated with risk for bone fracture in estrogen receptor-positive breast cancer patients treated with AIs. These genes displayed E2-dependent induction, their knockdown altered the expression of genes related to osteoporosis, and they displayed SNP genotype-dependent variation in E2 induction. These observations may lead to the identification of novel mechanisms associated with fracture risk in postmenopausal women treated with AIs.
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Affiliation(s)
- Mohan Liu
- Division of Clinical Pharmacology (M.L., L.W., R.M.W.), Department of Molecular Pharmacology and Experimental Therapeutics; Departments of Oncology (J.N.I.) and Health Sciences Research (A.B., G.D.J., E.E.C., D.J.S.); and Division of Endocrinology (S.K.), Mayo Clinic, Rochester, Minnesota 55905; Massachusetts General Hospital (P.E.G.), Harvard University, Boston, Massachusetts 02114; Rikagaku Kenkyūsho Center for Integrative Medical Science (M.K., Y.F.), Yokohama, Japan 230-0045; School of Medicine (Y.N.), Chicago University, Chicago, Illinois 60637; National Cancer Institute of Canada Clinical Trials Group (J.-A.W.C., L.E.S.), Kingston, Ontario, Canada K7L 3N6; and Division of Oncology (M.J.E.), Department of Medicine, Washington University School of Medicine, St Louis, Missouri 63110
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Abstract
Estrogen exhibits a broad spectrum of physiological functions ranging from regulation of the menstrual cycle and reproduction to modulation of bone density, brain function, and cholesterol mobilization. Despite the beneficial actions of endogenous estrogen, sustained exposure to exogenous estrogen is a well-established risk factor for various cancers. We summarize our current understanding of the molecular mechanisms of estrogen signaling in normal and cancer cells and discuss the major challenges to existing antiestrogen therapies.
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Affiliation(s)
- Jing Liang
- Tianjin Key Laboratory of Medical Epigenetics, Department of Biochemistry and Molecular Biology, Tianjin Medical University, Tianjin 300070, China.
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15
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Ghosh D, Lo J, Morton D, Valette D, Xi J, Griswold J, Hubbell S, Egbuta C, Jiang W, An J, Davies HML. Novel aromatase inhibitors by structure-guided design. J Med Chem 2012; 55:8464-76. [PMID: 22951074 DOI: 10.1021/jm300930n] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Human cytochrome P450 aromatase catalyzes with high specificity the synthesis of estrogens from androgens. Aromatase inhibitors (AIs) such as exemestane, 6-methylideneandrosta-1,4-diene-3,17-dione, are preeminent drugs for the treatment of estrogen-dependent breast cancer. The crystal structure of human placental aromatase has shown an androgen-specific active site. By utilization of the structural data, novel C6-substituted androsta-1,4-diene-3,17-dione inhibitors have been designed. Several of the C6-substituted 2-alkynyloxy compounds inhibit purified placental aromatase with IC(50) values in the nanomolar range. Antiproliferation studies in a MCF-7 breast cancer cell line demonstrate that some of these compounds have EC(50) values better than 1 nM, exceeding that for exemestane. X-ray structures of aromatase complexes of two potent compounds reveal that, per their design, the novel side groups protrude into the opening to the access channel unoccupied in the enzyme-substrate/exemestane complexes. The observed structure-activity relationship is borne out by the X-ray data. Structure-guided design permits utilization of the aromatase-specific interactions for the development of next generation AIs.
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Affiliation(s)
- Debashis Ghosh
- Department of Pharmacology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA.
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Chahar MK, Sharma N, Dobhal MP, Joshi YC. Flavonoids: A versatile source of anticancer drugs. Pharmacogn Rev 2011; 5:1-12. [PMID: 22096313 PMCID: PMC3210013 DOI: 10.4103/0973-7847.79093] [Citation(s) in RCA: 332] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Indexed: 12/15/2022] Open
Abstract
An exponential increase in the number of studies investigating how different components of the diet interact at the molecular and cellular level to determine the fate of a cell has been witnessed. In search for anticancer drugs compelling data from laboratories, epidemiologic investigations, and human clinical trials showed that flavonoids have important effects on cancer chemoprevention and chemotherapy. In many molecular mechanisms of action for prevention against cancer, flavonoids play a major role by interacting between different types of genes and enzymes. Many mechanisms of action have been identified, including carcinogen inactivation, antiproliferation, cell cycle arrest, induction of apoptosis, inhibition of angiogenesis, antioxidation, and reversal of multidrug resistance or a combination of these mechanisms. This review focuses on the anticancer activity of flavonoids as well as their molecular mechanisms, including the treatment of mammary and prostate cancer. This review also highlights some advanced derivatives of flavonoids, which play an important role against cancer.
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Affiliation(s)
- Maheep K. Chahar
- Department of Chemistry, University of Rajasthan, Jaipur-302004, Rajasthan, India
| | - Neelu Sharma
- Department of Chemistry, University of Rajasthan, Jaipur-302004, Rajasthan, India
| | - Mahabeer P. Dobhal
- Department of Chemistry, University of Rajasthan, Jaipur-302004, Rajasthan, India
| | - Yogesh C. Joshi
- Department of Chemistry, University of Rajasthan, Jaipur-302004, Rajasthan, India
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17
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Potashman MH, Duggan ME. Covalent Modifiers: An Orthogonal Approach to Drug Design. J Med Chem 2009; 52:1231-46. [DOI: 10.1021/jm8008597] [Citation(s) in RCA: 265] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Michele H. Potashman
- Department of Medicinal Chemistry, Amgen Inc., One Kendall Square, Building 1000, Cambridge, Massachusetts 02139
| | - Mark E. Duggan
- Department of Medicinal Chemistry, Amgen Inc., One Kendall Square, Building 1000, Cambridge, Massachusetts 02139
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Masri S, Phung S, Wang X, Wu X, Yuan YC, Wagman L, Chen S. Genome-wide analysis of aromatase inhibitor-resistant, tamoxifen-resistant, and long-term estrogen-deprived cells reveals a role for estrogen receptor. Cancer Res 2008; 68:4910-8. [PMID: 18559539 DOI: 10.1158/0008-5472.can-08-0303] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Acquired resistance to either tamoxifen or aromatase inhibitors (AI) develops after prolonged treatment in a majority of hormone-responsive breast cancers. In an attempt to further elucidate mechanisms of acquired resistance to AIs, MCF-7aro cells resistant to letrozole (T+LET R), anastrozole (T+ANA R), and exemestane (T+EXE R), as well as long-term estrogen deprived (LTEDaro) and tamoxifen-resistant (T+TAM R) lines were generated. This is the first complete panel of endocrine therapy-resistant cell lines, which were generated as multiple independent biological replicates for unbiased genome-wide analysis using affymetrix microarrays. Although similarities are apparent, microarray results clearly show gene signatures unique to AI-resistance were inherently different from LTEDaro and T+TAM R gene expression profiles. Based on hierarchical clustering, unique estrogen-responsive gene signatures vary depending on cell line, with some genes up-regulated in all lines versus other genes up-regulated only in the AI-resistant lines. Characterization of these resistant lines showed that LTEDaro, T+LET R, and T+ANA R cells contained a constitutively active estrogen receptor (ER)alpha that does not require estrogen for activation. This ligand-independent activation of ER was not observed in the parental cells, as well as T+EXE R and T+TAM R cells. Further characterization of these resistant lines was performed using cell cycle analysis, immunofluorescence experiments to visualize ER subcellular localization, as well as cross-resistance studies to determine second-line inhibitor response. Using this well-defined model system, our studies provide important information regarding differences in resistance mechanisms to AIs, TAM, and LTEDaro, which are critical in overcoming resistance when treating hormone-responsive breast cancers.
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Affiliation(s)
- Selma Masri
- Department of Surgical Research, Division of Information Sciences, Beckman Research Institute of the City of Hope, Duarte, California, USA
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19
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Mankoff DA, Link JM, Linden HM, Sundararajan L, Krohn KA. Tumor receptor imaging. J Nucl Med 2008; 49 Suppl 2:149S-63S. [PMID: 18523071 DOI: 10.2967/jnumed.107.045963] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Tumor receptors play an important role in carcinogenesis and tumor growth and have been some of the earliest targets for tumor-specific therapy, for example, the estrogen receptor in breast cancer. Knowledge of receptor expression is key for therapy directed at tumor receptors and traditionally has been obtained by assay of biopsy material. Tumor receptor imaging offers complementary information that includes evaluation of the entire tumor burden and characterization of the heterogeneity of tumor receptor expression. The nature of the ligand-receptor interaction poses a challenge for imaging--notably, the requirement for a low molecular concentration of the imaging probe to avoid saturating the receptor and increasing the background because of nonspecific uptake. For this reason, much of the work to date in tumor receptor imaging has been done with radionuclide probes. In this overview of tumor receptor imaging, aspects of receptor biochemistry and biology that underlie tumor receptor imaging are reviewed, with the estrogen-estrogen receptor system in breast cancer as an illustrative example. Examples of progress in radionuclide receptor imaging for 3 receptor systems--steroid receptors, somatostatin receptors, and growth factor receptors-are highlighted, and recent investigations of receptor imaging with other molecular imaging modalities are reviewed.
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Affiliation(s)
- David A Mankoff
- Division of Nuclear Medicine, University of Washington, Seattle, Washington, USA.
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20
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Characterization of the weak estrogen receptor alpha agonistic activity of exemestane. Breast Cancer Res Treat 2008; 116:461-70. [PMID: 18677558 DOI: 10.1007/s10549-008-0151-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Accepted: 07/23/2008] [Indexed: 10/21/2022]
Abstract
Third generation aromatase inhibitors (AI) have shown good clinical efficacy in comparison to the anti-estrogen tamoxifen. The steroidal AI, exemestane (EXE) has previously been shown to act as an androgen, but this report demonstrates the estrogen-like activity of EXE. Based on genome-wide microarray analysis, high correlation was seen between EXE-Only (EXE O, hormone-free) and hormone-containing AI-resistant lines. In addition, the top regulated genes in the EXE O lines were mostly estrogen-responsive genes. This estrogen-like activity of EXE was further validated using estrogen receptor (ER) activity assays, where in comparison to 17beta-estradiol (E2), EXE was able to induce ER activity, though at a higher concentration. Also, this EXE-mediated ER activity was blocked by the ER antagonist ICI as well as the ERalpha-specific antagonist methyl-piperidino-pyrazole (MPP). Similarly, EXE was able to induce proliferation of breast cancer cell lines, MCF-7 and MCF-7aro, as well as activate transcription of known estrogen-responsive genes, i.e., PGR, pS2 and AREG. These results suggest that EXE does have weak estrogen-like activity.
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Fink BN, Steck SE, Wolff MS, Britton JA, Kabat GC, Gaudet MM, Abrahamson PE, Bell P, Schroeder JC, Teitelbaum SL, Neugut AI, Gammon MD. Dietary flavonoid intake and breast cancer survival among women on Long Island. Cancer Epidemiol Biomarkers Prev 2008; 16:2285-92. [PMID: 18006917 DOI: 10.1158/1055-9965.epi-07-0245] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Laboratory research and a growing number of epidemiologic studies have provided evidence for a reduced risk of breast cancer associated with dietary intake of certain classes of flavonoids. However, the effects of flavonoids on survival are not known. In a population-based cohort of breast cancer patients, we investigated whether dietary flavonoid intake before diagnosis is associated with subsequent survival. METHODS Women ages 25 to 98 years who were newly diagnosed with a first primary invasive breast cancer between August 1, 1996, and July 31, 1997, and participated in a population-based, case-control study (n=1,210) were followed for vital status through December 31, 2002. At the case-control interview conducted shortly after diagnosis, respondents completed a FFQ that assessed dietary intake in the previous 12 months. All-cause mortality (n=173 deaths) and breast cancer-specific mortality (n=113 deaths) were determined through the National Death Index. RESULTS Reduced hazard ratios [age- and energy-adjusted hazard ratio (95% confidence interval)] for all-cause mortality were observed among premenopausal and postmenopausal women for the highest quintile of intake, compared with the lowest, for flavones [0.63 (0.41-0.96)], isoflavones [0.52 (0.33-0.82)], and anthocyanidins [0.64 (0.42-0.98)]. No significant trends in risk were observed. Results were similar for breast cancer-specific mortality only. CONCLUSION Mortality may be reduced in association with high levels of dietary flavones and isoflavones among postmenopausal U.S. breast cancer patients. Larger studies are needed to confirm our findings.
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Affiliation(s)
- Brian N Fink
- Department of Epidemiology, School of Public Health, University of North Carolina, Chapel Hill, North Carolina, USA.
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22
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Yoneya T, Taniguchi K, Tsunenari T, Saito H, Kanbe Y, Morikawa K, Yamada-Okabe H. Identification of a novel, orally bioavailable estrogen receptor downregulator. Anticancer Drugs 2006; 16:751-6. [PMID: 16027525 DOI: 10.1097/01.cad.0000171515.27439.de] [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: 11/25/2022]
Abstract
Tamoxifen has been widely used for the treatment of estrogen receptor (ER)-positive breast cancer, but its partial agonist activity is considered to limit the efficacy, and cause tumor flare and endometrial cancer. Fulvestrant, on the other hand, binds and degrades ER, thereby acting as a pure anti-estrogen without partial agonist activity. However, due to its low oral bioavailability, fulvestrant has to be intramuscularly administered to patients, which limits the convenience of the drug, and causes pain and inflammation at the site of injection. In search of a patient- friendly pure anti-estrogen, we screened and identified an ER antagonist, CH4893237, which bound to ER with an IC50 value of 1.4 muM and, by oral administration, inhibited estrogen-stimulated uterine growth in ovariectomized mice. CH4893237 reduced the amount of ER at the protein level and impaired the nuclear accumulation of ER, indicating an orally active pure anti-estrogen. Furthermore, CH4893237 inhibited the estrogen-stimulated proliferation of MCF-7, ZR-75-1 and BT-474 cells, and caused a marked growth inhibition of the MCF-7 xenograft in vivo. Thus, CH4893237 will provide an additional option for second-line hormone treatment of breast cancer.
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MESH Headings
- Administration, Oral
- Animals
- Antineoplastic Agents/pharmacology
- Breast Neoplasms/metabolism
- Breast Neoplasms/pathology
- Cell Line, Tumor
- Cell Proliferation/drug effects
- Chlorocebus aethiops
- Down-Regulation
- Estradiol/analogs & derivatives
- Estradiol/pharmacology
- Estrogen Antagonists/pharmacology
- Female
- Humans
- Mice
- Mice, Inbred ICR
- Mice, Nude
- Neoplasm Transplantation
- Neoplasms, Experimental/drug therapy
- Neoplasms, Experimental/pathology
- Neoplasms, Hormone-Dependent/metabolism
- Neoplasms, Hormone-Dependent/pathology
- Ovariectomy
- Receptors, Estrogen/antagonists & inhibitors
- Receptors, Estrogen/metabolism
- Transplantation, Heterologous
- Uterus/anatomy & histology
- Uterus/drug effects
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Affiliation(s)
- Takaaki Yoneya
- Pharmaceutical Research Department III, Chugai Pharmaceutical, Kanagawa and Shizuoka, Japan
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24
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Su B, Hackett JC, Díaz-Cruz ES, Kim YW, Brueggemeier RW. Lead optimization of 7-benzyloxy 2-(4′-pyridylmethyl)thio isoflavone aromatase inhibitors. Bioorg Med Chem 2005; 13:6571-7. [PMID: 16125392 DOI: 10.1016/j.bmc.2005.07.038] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2005] [Revised: 07/12/2005] [Accepted: 07/13/2005] [Indexed: 10/25/2022]
Abstract
Aromatase, the enzyme responsible for estrogen biosynthesis, is a particularly attractive target in the treatment of hormone-dependent breast cancer. The synthesis and biological evaluation of a series of 2-(4'-pyridylmethyl)thio, 7-alkyl- or aryl-substituted isoflavones as potential aromatase inhibitors are described. The isoflavone derivatives demonstrate IC(50) values from 79 to 553 nM and compete with the endogenous substrate, androstenedione. Data supporting the ability of these analogs to suppress aromatase enzyme activity in the SK-BR-3 breast cancer cell line are also presented.
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Affiliation(s)
- Bin Su
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, 43210, USA
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25
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Abstract
Enzymes offer unique opportunities for drug design that are not available to cell surface receptors, nuclear hormone receptors, ion channels, transporters, and DNA. Here, we review the variety of inhibition mechanisms for enzyme-targeted drugs, and establish an enzyme target database for drugs currently marketed in the United States. From an analysis of the FDA Orange Book, there are 317 marketed drugs that work by inhibiting an enzyme. These drugs inhibit 71 enzymes, including 48 human, 13 bacterial, five viral, four fungal, and one protozoal enzyme. Among the 317 drugs, 65% either undergo reactive chemistry in the active site of the target enzyme or contain a structural motif related to the substrate. Among the 71 enzyme targets, 25 are irreversibly inhibited by drugs, and 19 of the 25 irreversibly inhibited enzymes are covalently modified by the drug. In two additional cases, the drug forms a covalent complex with the substrate, and in three more cases, the drug traps a covalent enzyme-substrate intermediate. Four of the 71 enzymes are inhibited by transition-state analogues. Moreover, advanced methods for determining transition-state structure now offer the opportunity for direct drug design without resorting to expensive random testing campaigns. A full appreciation of enzyme mechanisms sets enzymes apart as a specialized class of targets for highly directed drug design.
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26
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Hackett JC, Kim YW, Su B, Brueggemeier RW. Synthesis and characterization of azole isoflavone inhibitors of aromatase. Bioorg Med Chem 2005; 13:4063-70. [PMID: 15911319 DOI: 10.1016/j.bmc.2005.03.050] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2005] [Revised: 03/26/2005] [Accepted: 03/28/2005] [Indexed: 10/25/2022]
Abstract
The synthesis and biological evaluation of a series of 2-azole and 2-thioazole isoflavones as potential aromatase inhibitors are described. Differences in inhibitory activity of triazole and imidazole inhibitors are rationalized with density functional theory to expose a key difference in the electronic structure of these molecules. In addition, difference binding spectra of inhibitors to immunoaffinity-purified aromatase produces classical Type II spectra consistent with coordination of the nitrogen lone pair electrons to the aromatase P450 heme.
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Affiliation(s)
- John C Hackett
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, 500 W. 12th Avenue, Columbus, OH 43210, USA
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27
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Matsui K, Nishii S, Oka M. P450 aromatase inhibition assay using a competitive ELISA. J Pharm Biomed Anal 2005; 38:307-12. [PMID: 15925223 DOI: 10.1016/j.jpba.2005.01.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2003] [Revised: 01/11/2005] [Accepted: 01/11/2005] [Indexed: 10/25/2022]
Abstract
P450 aromatase (P450arom) is a well known target by anti-cancer drugs and toxic chemicals and efficient and convenient analytical tools are desired for. We established a convenient assay for P450arom inhibition based on an enzyme-linked immunosorbent assay (ELISA). The first step of the assay consists of a P450arom reaction, which converts a testosterone to a 17beta-estradiol using a recombinant human P450arom and a NADPH regenerating system. The second step of the assay consists of an ELISA system using a highly specific and sensitive anti-estradiol monoclonal antibody in conjunction with estradiol-3-CMO-horseradish peroxidase (E2-3-CMO-HRP). This system has advantages over other P450arom assays because it does not use radioactive ligands and because it is not subject to interference from self-fluorescing test compounds. We could successfully estimate some types of P450arom inhibitors reported before. This assay should be very useful for high throughput screening of drug candidates and endocrine disrupting chemicals via P450arom.
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Affiliation(s)
- Kazuhiro Matsui
- Tsuruga Institute of Biotechnology, Toyobo Co. Ltd., 10-24 Toyo-Cho, Tsuruga-shi, Fukui 914-0047, Japan.
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Murata H, Khattar NH, Gu L, Li GM. Roles of mismatch repair proteins hMSH2 and hMLH1 in the development of sporadic breast cancer. Cancer Lett 2004; 223:143-50. [PMID: 15890247 DOI: 10.1016/j.canlet.2004.09.039] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2004] [Accepted: 09/07/2004] [Indexed: 02/07/2023]
Abstract
Defects in mismatch repair (MMR) genes, particularly the hMSH2 and hMLH1 genes, are associated with a variety of cancers including sporadic breast cancer. However, whether or not patient clinical background, e.g. age, progesterone receptor (PR), estrogen receptor (ER), tumor progression and stage, chemotherapy history, and menopausal status, influences MMR status is not understood. To address these issues, 83 archival breast cancer specimens were examined for expression of hMSH2 and hMLH1 by immunohistochemistry and the relationship between MMR protein expression and patient clinical background was analyzed. We detected lack of or reduced expression of hMSH2 and hMLH1 in 23 (27.7%) and 26 cases (31.3%), respectively, and hypermethylation of the hMLH1 promoter accounted for the majority of the cases with reduced expression of hMLH1. Statistical analysis revealed that (i) reduced expression of hMLH1 and hMSH2 seemed to confer advantage for the progression of breast tumors to more advanced stages; (ii) attenuated expression of hMLH1 correlated with history of chemotherapy, but not with age, menopause, or the status of PR and ER; (iii) hypermethylation of the hMLH1 promoter was linked with clinical stage and lymphatic metastasis. These analyses indicate that defective expression of MMR genes is closely associated with the development of sporadic breast cancer.
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Affiliation(s)
- Hiroaki Murata
- Department of Pathology and Laboratory Medicine, University of Kentucky Medical Center, Suite MS117, 800 Rose Street, Lexington, KY 40536, USA
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30
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Seimbille Y, Bénard F, Rousseau J, Pepin E, Aliaga A, Tessier G, van Lier JE. Impact on estrogen receptor binding and target tissue uptake of [18F]fluorine substitution at the 16α-position of fulvestrant (faslodex; ICI 182,780). Nucl Med Biol 2004; 31:691-8. [PMID: 15246359 DOI: 10.1016/j.nucmedbio.2004.02.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2003] [Revised: 11/05/2003] [Accepted: 02/06/2004] [Indexed: 10/26/2022]
Abstract
Fulvestrant (Faslodex; ICI 182,780) is a pure estrogen receptor (ER) antagonist recently approved for the treatment of hormone-sensitive breast cancer in post-menopausal women with disease progression following antiestrogen therapy. Fulvestrant strongly binds to the ER and its mode of action consists of inhibition of ER dimerization leading to a down regulation of ER protein cellular levels. With the aim to develop a probe for positron emission tomography (PET) imaging capable of predicting the potential therapeutic efficacy of selective ER modulators (SERM), we prepared three new 16alpha-[18F]fluoro-fulvestrant derivatives. These new radiopharmaceuticals were evaluated for their binding affinity to the human ERalpha and for their target tissue uptake in immature female rats. Substitution of one of the side-chain F-atoms of fulvestrant for 18F would have led to a product of low specific activity; instead we selected the 16alpha-position for 18F-labeling, which at least in the case of estradiol (ES) is well tolerated by the ER. Radiochemical synthesis proceeds by stereoselective introduction of the [18F]fluoride at the 16-18F-position of fulvestrant via opening of an intermediate O-cyclic sulfate followed by hydrolysis of the protecting methoxymethyl (MOM) ether and sulfate groups. Three analogs with different oxidation states of the side chain sulfur, i.e. sulfide, sulfone or sulfoxide (fulvestrant) were prepared. Introduction of the 16(18)F-fluorine led to a dramatic decrease of the apparent binding affinity for ER, as reported by Wakeling et al. (Cancer Res. 1991;51:3867-73). Likewise, in vivo ER-mediated uterus uptake values in immature female rats were disappointing. Overall, our findings suggest that these new PET radiopharmaceuticals are not suitable as tracers to predict ER(+) breast cancer response to hormonal therapy with selective ER modulators.
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Affiliation(s)
- Yann Seimbille
- Sherbrooke PET Center, Department of Nuclear Medicine and Radiobiology, Faculty of Medicine, Université de Sherbrooke, Sherbrooke, Québec, Canada J1H 5N4
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Kim YW, Hackett JC, Brueggemeier RW. Synthesis and Aromatase Inhibitory Activity of Novel Pyridine-Containing Isoflavones. J Med Chem 2004; 47:4032-40. [PMID: 15267241 DOI: 10.1021/jm0306024] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aromatase, a cytochrome P450 hemoprotein that is responsible for estrogen biosynthesis by conversion of androgens into estrogens, has been an attractive target in the treatment of hormone-dependent breast cancer. As a result, a number of synthetic steroidal or nonsteroidal aromatase inhibitors have been successfully developed. In addition, there are several classes of natural products that exert potent activities in aromatase inhibition, with the flavonoids being most prominent. Previous studies have exploited flavone and flavanone scaffolds for the development of new aromatase inhibitors. In this paper, we describe the design, synthesis, and biological evaluation of a novel series of 2-(4'-pyridylmethyl)thioisoflavones as the first example of synthetic isoflavone-based aromatase inhibitors.
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Affiliation(s)
- Young-Woo Kim
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, 500 West 12th Avenue, Columbus, Ohio 43210, USA
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Abstract
Osteopenia and osteoporosis are prevalent in women. Epidemiologic studies show that the risk of breast cancer is greater in postmenopausal women with higher bone mineral density (BMD). Standard treatments for breast cancer such as adjuvant chemotherapy or hormonal therapy can increase bone loss, and hence may increase the risk of osteoporosis. Premenopausal women treated with standard adjuvant chemotherapy frequently develop permanent ovarian failure, or early menopause. Ovarian failure is associated with accelerated bone loss, and bisphosphonates may mitigate this bone loss in women treated with adjuvant chemotherapy. Tamoxifen preserves BMD in postmenopausal women; however, in premenopausal women tamoxifen may increase bone loss. Anastrazole, an aromatase inhibitor, is approved for adjuvant treatment of postmenopausal women with early-stage, estrogen receptor-positive breast cancer. With a follow-up duration of less than 5 years, anastrazole-treated women experience increased fractures relative to those treated with tamoxifen. The management of osteopenia and osteoporosis in women with breast cancer generally does not differ from women without breast cancer. Adequate dietary calcium and vitamin D intake, encouraging weight-bearing exercise, and counseling about the relationship between smoking and alcohol and bone loss are all prudent recommendations for overall health and may lessen bone loss and the risk of subsequent osteoporosis. BMD should be measured in women with chemotherapy-induced ovarian failure, and in those on aromatase inhibitors. Bisphosphonates reduce the bone loss associated with chemotherapy-induced ovarian failure, and clinical trials evaluating third-generation bisphosphonates in women with chemotherapy-induced ovarian failure are underway. As many women with breast cancer will be long-term survivors, increasing recognition of maintaining skeletal health is important.
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Affiliation(s)
- Bhuvaneswari Ramaswamy
- Department of Medicine, Ohio State University Medical Center and Comprehensive Cancer Center, Columbus 43210, USA
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33
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Reich O, Regauer S. Aromatase expression in low-grade endometrial stromal sarcomas: an immunohistochemical study. Mod Pathol 2003. [DOI: 10.1038/modpathol.3800031] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Piccart M, Parker LM, Pritchard KI. Oestrogen receptor downregulation: an opportunity for extending the window of endocrine therapy in advanced breast cancer. Ann Oncol 2003; 14:1017-25. [PMID: 12853342 DOI: 10.1093/annonc/mdg290] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Advanced breast cancer is largely incurable and current treatment modalities are aimed towards restricting tumour growth, prolonging survival, palliating symptoms and maintaining quality of life (QoL). The development of breast cancer is strongly influenced by endogenous oestrogens (and other growth factors), leading to a strong focus on the development of antioestrogenic compounds for the treatment of hormone-sensitive advanced disease. DESIGN This is a review of current endocrine therapies available for postmenopausal women with advanced breast cancer, examining the likely impact of newer agents on treatment strategies. RESULTS In postmenopausal women, current treatment options include tamoxifen, aromatase inhibitors (AIs) and megestrol acetate. Fulvestrant ('Faslodex') is a new, well-tolerated, oestrogen receptor antagonist that has no known agonist effect and is at least as effective as the AI anastrozole for the treatment of postmenopausal patients with metastatic or advanced breast cancer who have progressed on prior endocrine therapy. Fulvestrant maintains QoL throughout successful treatment. CONCLUSIONS Fulvestrant represents a new treatment option for postmenopausal women with advanced disease. New agents that appear to lack cross-resistance with existing treatments may be used to extend the time period during which endocrine therapy may be employed before the need for cytotoxic chemotherapy.
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Affiliation(s)
- M Piccart
- Chemotherapy Unit, Internal Medicine and Oncology, Jules Bordet Institute, Brussels, Belgium.
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Abstract
Flavonoids are polyphenolic compounds that are ubiquitously in plants. They have been shown to possess a variety of biological activities at nontoxic concentrations in organisms. The role of dietary flavonoids in cancer prevention is widely discussed. Compelling data from laboratory studies, epidemiological investigations, and human clinical trials indicate that flavonoids have important effects on cancer chemoprevention and chemotherapy. Many mechanisms of action have been identified, including carcinogen inactivation, antiproliferation, cell cycle arrest, induction of apoptosis and differentiation, inhibition of angiogenesis, antioxidation and reversal of multidrug resistance or a combination of these mechanisms. Based on these results, flavonoids may be promising anticancer agents.
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Affiliation(s)
- Wenying Ren
- Department of Hematology, 2nd Hospital of Shanxi Medical University, Taiyuan, Shanxi 030001, P. R. China
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Aapro MS, Forbes JF. Three Years' Follow-up from the ATAC Trial is Sufficient to Change Clinical Practice: A Debate. Breast Cancer Res Treat 2003; 80 Suppl 1:S3-11; discussion S13-8. [PMID: 14535530 DOI: 10.1023/a:1025455130476] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Tamoxifen is currently the adjuvant treatment of choice for postmenopausal women with hormone-sensitive breast cancer. However, in the treatment of postmenopausal women with advanced disease, the third-generation aromatase inhibitor anastrozole ('Arimidex') has been shown to be at least as effective as tamoxifen, and to be more effective than tamoxifen in patients with estrogen receptor-positive disease. Furthermore, anastrozole is well tolerated and is associated with fewer adverse reactions (such as thromboembolic events, vaginal bleeding, and endometrial cancer) compared with tamoxifen. A change in clinical practice has now emerged for the first-line treatment of postmenopausal advanced disease in patients, with tamoxifen becoming the second- or third-line choice for many clinicians. These data have raised questions about the optimal adjuvant treatment for postmenopausal women with early breast cancer. The 'Arimidex', Tamoxifen, Alone or in Combination (ATAC) trial has compared the efficacy and safety of tamoxifen and anastrozole in the adjuvant treatment of postmenopausal women with early breast cancer. At 3 years' follow-up in the overall population, anastrozole demonstrated a significant benefit compared with tamoxifen for disease-free survival (DFS) (89.4% vs. 87.4%; p = 0.013), time to recurrence (hazard ratio = 0.79; p = 0.008), and contralateral breast cancers (odds ratio = 0.42; 95% confidence interval: 0.22-0.79; p = 0.007). Anastrozole produced improvements in quality of life similar to tamoxifen and was better tolerated for a number of predefined adverse events. Of course, a large body of evidence is available regarding the safety profile of tamoxifen and some feel that more data are needed from the ATAC trial to demonstrate that the early advantages of anastrozole over tamoxifen can be maintained in the longer term. However, a follow-up analysis at 47 months has confirmed that the tolerability profile and the absolute benefit of anastrozole were maintained over the extended follow-up period, demonstrating that the benefits of anastrozole are likely to be maintained over the long term. This review assesses these and other data from the ATAC trial and presents the arguments for and against whether 3 years' follow-up is sufficient to inform a change in clinical practice for the adjuvant treatment of postmenopausal women with early breast cancer.
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