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Selvaraj MK, Kaur J. Computational method for aromatase-related proteins using machine learning approach. PLoS One 2023; 18:e0283567. [PMID: 36989252 PMCID: PMC10057777 DOI: 10.1371/journal.pone.0283567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 03/12/2023] [Indexed: 03/30/2023] Open
Abstract
Human aromatase enzyme is a microsomal cytochrome P450 and catalyzes aromatization of androgens into estrogens during steroidogenesis. For breast cancer therapy, third-generation aromatase inhibitors (AIs) have proven to be effective; however patients acquire resistance to current AIs. Thus there is a need to predict aromatase-related proteins to develop efficacious AIs. A machine learning method was established to identify aromatase-related proteins using a five-fold cross validation technique. In this study, different SVM approach-based models were built using the following approaches like amino acid, dipeptide composition, hybrid and evolutionary profiles in the form of position-specific scoring matrix (PSSM); with maximum accuracy of 87.42%, 84.05%, 85.12%, and 92.02% respectively. Based on the primary sequence, the developed method is highly accurate to predict the aromatase-related proteins. Prediction scores graphs were developed using the known dataset to check the performance of the method. Based on the approach described above, a webserver for predicting aromatase-related proteins from primary sequence data was developed and implemented at https://bioinfo.imtech.res.in/servers/muthu/aromatase/home.html. We hope that the developed method will be useful for aromatase protein related research.
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Affiliation(s)
| | - Jasmeet Kaur
- Department of Biophysics, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
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2
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Ardevines S, Marqués-López E, Herrera RP. Heterocycles in Breast Cancer Treatment: The Use of Pyrazole Derivatives. Curr Med Chem 2023; 30:1145-1174. [PMID: 36043746 DOI: 10.2174/0929867329666220829091830] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 04/21/2022] [Accepted: 05/05/2022] [Indexed: 11/22/2022]
Abstract
Among the aromatic heterocycle rings, pyrazole -a five-membered ring with two adjacent nitrogen atoms in its structure has been postulated as a potent candidate in the pharmacological context. This moiety is an interesting therapeutic target covering a broad spectrum of biological activities due to its presence in many natural substances. Hence, the potential of the pyrazole derivatives as antitumor agents has been explored in many investigations, showing promising results in some cases. In this sense, breast cancer, which is already the leading cause of cancer mortality in women in some countries, has been the topic selected for this review, which covers a range of different research from the earliest studies published in 2003 to the most recent ones in 2021.
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Affiliation(s)
- Sandra Ardevines
- Laboratorio de Organocatálisis Asimétrica, Departamento de Química Orgánica. Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza. C/Pedro Cerbuna 12, E-50009 Zaragoza, Spain
| | - Eugenia Marqués-López
- Laboratorio de Organocatálisis Asimétrica, Departamento de Química Orgánica. Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza. C/Pedro Cerbuna 12, E-50009 Zaragoza, Spain
| | - Raquel P Herrera
- Laboratorio de Organocatálisis Asimétrica, Departamento de Química Orgánica. Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza. C/Pedro Cerbuna 12, E-50009 Zaragoza, Spain
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3
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Effects of phytoestrogens on reproductive organ health. Arch Pharm Res 2022; 45:849-864. [DOI: 10.1007/s12272-022-01417-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Accepted: 11/14/2022] [Indexed: 11/29/2022]
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4
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Adhikari N, Baidya SK, Jha T. Effective anti-aromatase therapy to battle against estrogen-mediated breast cancer: Comparative SAR/QSAR assessment on steroidal aromatase inhibitors. Eur J Med Chem 2020; 208:112845. [DOI: 10.1016/j.ejmech.2020.112845] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 09/09/2020] [Accepted: 09/10/2020] [Indexed: 02/08/2023]
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5
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Banjare L, Verma SK, Jain AK, Thareja S. Design and pharmacophoric identification of flavonoid scaffold‐based aromatase inhibitors. J Heterocycl Chem 2020. [DOI: 10.1002/jhet.4068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Laxmi Banjare
- School of Pharmaceutical SciencesGuru Ghasidas Central University Bilaspur Chhattisgarh India
| | - Sant Kumar Verma
- School of Pharmaceutical SciencesGuru Ghasidas Central University Bilaspur Chhattisgarh India
| | - Akhlesh Kumar Jain
- School of Pharmaceutical SciencesGuru Ghasidas Central University Bilaspur Chhattisgarh India
| | - Suresh Thareja
- Department of Pharmaceutical Sciences and Natural ProductsCentral University of Punjab Bathinda Punjab India
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6
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Dawood HM, Ibrahim RS, Shawky E, Hammoda HM, Metwally AM. Integrated in silico-in vitro strategy for screening of some traditional Egyptian plants for human aromatase inhibitors. JOURNAL OF ETHNOPHARMACOLOGY 2018; 224:359-372. [PMID: 29909120 DOI: 10.1016/j.jep.2018.06.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 06/01/2018] [Accepted: 06/11/2018] [Indexed: 06/08/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Aromatase enzyme (CYP19) is widely known as a critical target protein for treating hormone-dependent breast cancer. Natural products from traditional medicinal plants continue to be an active source of aromatase inhibitors. Meanwhile, high cost of experimental work and low hit rate associated with HTS have stimulated the implementation of in-silico virtual screening to resolve these pitfalls, where coupling of both classical wet lab procedure and VS may offer a more deepened access to bioactive compounds with less work and time waste. AIM OF THE STUDY In this work, a sequential structure-based and ligand-based virtual screening strategy was utilized for investigating an in-house database of 1720 phytochemical constituents of 29 medicinal plants and natural products used in traditional Egyptian medicine to search for compounds with the potential to be used as inhibitors of the human aromatase enzyme. MATERIALS AND METHODS The suggested strategy included using Glide docking with its feature 'extra precision (XP)' for carrying out structure-based virtual screening (SBVS) where the resulting hits were further promoted to ligand-based virtual screening (LBVS) through the development of two pharmacophore and QSAR models; one for steroidal and the other for non-steroidal aromatase inhibitors. RESULTS The combined results revealed that Artemisia annua, Zingiber officinale, Cicer arietinum, Annona muricata and Vitex agnus castus were the top scoring plants in terms of in-silico activity scores, respectively. The hydro-alcoholic extracts and different solvent fractions of the top scoring plants were subsequently tested experimentally for their aromatase inhibitory activity, by the aid of in-vitro fluorometric assay. The rank ordering of the activities for the plants agreed with the ordering predicted on the basis of SBVS and LBVS workflow implemented. CONCLUSION The suggested strategy provides a reliable means of prospecting in-silico screening of natural products databases in the search for new dug leads as aromatase inhibitors. The hits so obtained can then be subjected to further phytochemical studies, to isolate and identify suitable compounds for further in-vitro testing.
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Affiliation(s)
- Hend M Dawood
- Department of Pharmacognosy, Faculty of Pharmacy, Alexandria University, Egypt
| | - Reham S Ibrahim
- Department of Pharmacognosy, Faculty of Pharmacy, Alexandria University, Egypt
| | - Eman Shawky
- Department of Pharmacognosy, Faculty of Pharmacy, Alexandria University, Egypt.
| | - Hala M Hammoda
- Department of Pharmacognosy, Faculty of Pharmacy, Alexandria University, Egypt
| | - Aly M Metwally
- Department of Pharmacognosy, Faculty of Pharmacy, Alexandria University, Egypt
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7
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Abstract
As a result of an increasing aging population, the number of individuals taking multiple medications simultaneously has grown considerably. For these individuals, taking multiple medications has increased the risk of undesirable drug–drug interactions (DDIs), which can cause serious and debilitating adverse drug reactions (ADRs). A comprehensive understanding of DDIs is needed to combat these deleterious outcomes. This review provides a synopsis of the pharmacokinetic (PK) and pharmacodynamic (PD) mechanisms that underlie DDIs. PK-mediated DDIs affect all aspects of drug disposition: absorption, distribution, metabolism and excretion (ADME). In this review, the cells that play a major role in ADME and have been investigated for DDIs are discussed. Key examples of drug metabolizing enzymes and drug transporters that are involved in DDIs and found in these cells are described. The effect of inhibiting or inducing these proteins through DDIs on the PK parameters is also reviewed. Despite most DDI studies being focused on the PK effects, DDIs through PD can also lead to significant and harmful effects. Therefore, this review outlines specific examples and describes the additive, synergistic and antagonistic mechanisms of PD-mediated DDIs. The effects DDIs on the maximum PD response (Emax) and the drug dose or concentration (EDEC50) that lead to 50% of Emax are also examined. Significant gaps in our understanding of DDIs remain, so innovative and emerging approaches are critical for overcoming them.
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Affiliation(s)
- Arthur G Roberts
- Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA, USA,
| | - Morgan E Gibbs
- Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA, USA,
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8
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Martin GDA, Narvaez J, Bulmer R, Durrant MC. Biotransformation and molecular docking studies of aromatase inhibitors. Steroids 2016; 113:95-102. [PMID: 27421190 DOI: 10.1016/j.steroids.2016.07.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Revised: 06/16/2016] [Accepted: 07/09/2016] [Indexed: 11/16/2022]
Abstract
Bioconversion of the aromatase inhibitor formestane (4-hydroxyandrost-4-ene-3,17-dione) (1) by the fungus Rhizopus oryzae ATCC 11145 resulted in a new minor metabolite 3,5α-dihydroxyandrost-2-ene-4,17-dione (2) and the known 4β,5α-dihydroxyandrostane-4,17-dione (3) as the major product. The structural elucidation and bioactivities of these metabolites are reported herein. Molecular modeling studies of the interactions between these metabolites and the aromatase protein indicated that acidic (D309), basic (R115), polar (T310), aromatic (F134, F221, and W224), and non-polar (I133, I305, A306, V369, V370, L372, V373, M374, and L477) amino acid residues contribute important interactions with the steroidal substrates. These combined experimental and theoretical studies provide fresh insights for the further development of more potent aromatase inhibitors.
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Affiliation(s)
- Glenroy D A Martin
- Department of Life and Physical Sciences, Fisk University, 1000 17th Ave N, Nashville, TN 37208, United States.
| | - Javier Narvaez
- Chemistry, Biochemistry and Physics Department, The University of Tampa, 401 West Kennedy Blvd., Tampa, FL 33606, United States
| | - Rachel Bulmer
- Department of Applied Sciences, Northumbria University, Newcastle upon Tyne NE1 8ST, United Kingdom
| | - Marcus C Durrant
- Department of Applied Sciences, Northumbria University, Newcastle upon Tyne NE1 8ST, United Kingdom.
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9
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Viciano I, Martí S. Theoretical Study of the Mechanism of Exemestane Hydroxylation Catalyzed by Human Aromatase Enzyme. J Phys Chem B 2016; 120:3331-43. [PMID: 26972150 DOI: 10.1021/acs.jpcb.6b01014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Human aromatase (CYP19A1) aromatizes the androgens to form estrogens via a three-step oxidative process. The estrogens are necessary in humans, mainly in women, because of the role they play in sexual and reproductive development. However, these also are involved in the development and growth of hormone-dependent breast cancer. Therefore, inhibition of the enzyme aromatase, by means of drugs known as aromatase inhibitors, is the frontline therapy for these types of cancers. Exemestane is a suicidal third-generation inhibitor of aromatase, currently used in breast cancer treatment. In this study, the hydroxylation of exemestane catalyzed by aromatase has been studied by means of hybrid QM/MM methods. The Free Energy Perturbation calculations provided a free energy of activation for the hydrogen abstraction step (rate-limiting step) of 17 kcal/mol. The results reveal that the hydroxylation of exemestane is not the inhibition stage, suggesting a possible competitive mechanism between the inhibitor and the natural substrate androstenedione in the first catalytic subcycle of the enzyme. Furthermore, the analysis of the interaction energy for the substrate and the cofactor in the active site shows that the role of the enzymatic environment during this reaction consists of a transition state stabilization by means of electrostatic effects.
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Affiliation(s)
- Ignacio Viciano
- Departament de Química Física i Analítica, Universitat Jaume I , 12071 Castelló, Spain
| | - Sergio Martí
- Departament de Química Física i Analítica, Universitat Jaume I , 12071 Castelló, Spain
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10
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Yadav MR, Barmade MA, Tamboli RS, Murumkar PR. Developing steroidal aromatase inhibitors-an effective armament to win the battle against breast cancer. Eur J Med Chem 2015; 105:1-38. [DOI: 10.1016/j.ejmech.2015.09.038] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 09/29/2015] [Accepted: 09/30/2015] [Indexed: 01/05/2023]
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11
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Viciano I, González-Navarrete P, Andrés J, Martí S. Joint Use of Bonding Evolution Theory and QM/MM Hybrid Method for Understanding the Hydrogen Abstraction Mechanism via Cytochrome P450 Aromatase. J Chem Theory Comput 2015; 11:1470-80. [DOI: 10.1021/ct501030q] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Ignacio Viciano
- Departament
de Química
Física i Analítica, Universitat Jaume I, 12071, Castellón, Spain
| | | | - Juan Andrés
- Departament
de Química
Física i Analítica, Universitat Jaume I, 12071, Castellón, Spain
| | - Sergio Martí
- Departament
de Química
Física i Analítica, Universitat Jaume I, 12071, Castellón, Spain
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12
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Di Nardo G, Gilardi G. Human aromatase: perspectives in biochemistry and biotechnology. Biotechnol Appl Biochem 2014; 60:92-101. [PMID: 23586996 DOI: 10.1002/bab.1088] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 12/25/2012] [Indexed: 11/07/2022]
Abstract
Aromatase (CYP19) is involved in steroidogenesis, catalyzing the conversion of androgens into estrogens through a unique reaction that causes the aromatization of the A ring of the steroid. The enzyme is widely distributed and well conserved among species as it plays a crucial role in physiological processes such as control of reproduction and neuroprotection. It has also been a subject of intense research both at the biotechnological level in drug development due to its involvement in estrogen-dependent tumors and at a fundamental biochemical level because there are numerous questions regarding its reaction mechanism. This review will report the great progress made in this area.
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Affiliation(s)
- Giovanna Di Nardo
- Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
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13
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Lo J, Di Nardo G, Griswold J, Egbuta C, Jiang W, Gilardi G, Ghosh D. Structural basis for the functional roles of critical residues in human cytochrome p450 aromatase. Biochemistry 2013; 52:5821-9. [PMID: 23899247 DOI: 10.1021/bi400669h] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cytochrome P450 aromatase (CYP19A1) is the only enzyme known to catalyze the biosynthesis of estrogens from androgens. The crystal structure of human placental aromatase (pArom) has paved the way toward understanding the structure-function relationships of this remarkable enzyme. Using an amino terminus-truncated recombinant human aromatase (rArom) construct, we investigate the roles of key amino acids in the active site, at the intermolecular interface, inside the access channel, and at the lipid-protein boundary for their roles in enzyme function and higher-order organization. Replacing the active site residue D309 with an N yields an inactive enzyme, consistent with its proposed involvement in aromatization. Mutation of R192 at the lipid interface, pivotal to the proton relay network in the access channel, results in the loss of enzyme activity. In addition to the distal catalytic residues, we show that mutation of K440 and Y361 of the heme-proximal region critically interferes with substrate binding, enzyme activity, and heme stability. The D-E loop deletion mutant Del7 that disrupts the intermolecular interaction significantly reduces enzyme activity. However, the less drastic Del4 and point mutants E181A and E181K do not. Furthermore, native gel electrophoresis, size-exclusion chromatography, and analytical ultracentrifugation are used to show that mutations in the intermolecular interface alter the quaternary organization of the enzyme in solution. As a validation for interpretation of the mutational results in the context of the innate molecule, we determine the crystal structure of rArom to show that the active site, tertiary, and quaternary structures are identical to those of pArom.
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Affiliation(s)
- Jessica Lo
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, New York 13210, United States
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14
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Młynarczuk J, Wróbel MH, Kotwica J. Adverse influence of coumestrol on secretory function of bovine luteal cells in the first trimester of pregnancy. ENVIRONMENTAL TOXICOLOGY 2013; 28:411-418. [PMID: 21656645 DOI: 10.1002/tox.20735] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 04/22/2011] [Accepted: 04/30/2011] [Indexed: 05/30/2023]
Abstract
Coumestrol is one of a few biologically active substances present in leguminous plants, which are widely used as fodder for ruminants. Depending on the doses, coumestrol acts on the reproductive processes as an estrogen-like factor or antiestrogen to evoke a decrease in ovulation frequency, elongation of estrous cycle duration. The aim of the current investigations was to study the influence of coumestrol on secretory function of luteal cells obtained from first trimester of pregnant cows. Luteal cells (2.5 × 10(5) /mL) from 3rd to 5th, 6th to 8th, and 9th to 12th week of pregnancy were preincubated for 24 h and incubated with coumestrol (1 × 10(-6) M) for successive 48 h and the medium concentrations of progesterone (P4), oxytocin (OT), prostaglandin (PG) E2 and F2α were determined. Moreover, the expression of mRNA for neurophysin-I/oxytocin (NP-I/OT; precursor of OT) and peptidyl-glycine-α-amidating mono-oxygenase (PGA, an enzyme responsible for post-translational OT synthesis) was determined after 8 h of treatment. Coumestrol did not affect P4 secretion but increased the secretion of OT from the cells collected at all stages of gestation studied. Hence, the ratio of P4 to OT was markedly decreased. Simultaneously, coumestrol increased the expression of NP-I/OT mRNA during 9th to 12th weeks of pregnancy, and mRNA for PGA during 3rd to 5th and 9th to 12th weeks of gestation. Furthermore, coumestrol decreased PGE2 secretion from luteal cells in all studied stages of pregnancy, while it affected PGF2α metabolite (PGFM) concentration only from week 3 to 5 of pregnancy. Obtained results suggest that coumestrol impairs secretory function of the corpus luteum (CL) and this way it can affect the maintenance of pregnancy in the cow.
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Affiliation(s)
- J Młynarczuk
- Institute of Animal Reproduction and Food Research Polish Academy of Sciences, Olsztyn, Poland
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15
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The chemistry of small-molecule fluorogenic probes. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 113:1-34. [PMID: 23244787 DOI: 10.1016/b978-0-12-386932-6.00001-6] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Chemical fluorophores find wide use in biology to detect and visualize different phenomena. A key advantage of small-molecule dyes is the ability to construct compounds where fluorescence is activated by chemical or biochemical processes. Fluorogenic molecules, in which fluorescence is activated by enzymatic activity, light, or environmental changes, enable advanced bioassays and sophisticated imaging experiments. Here, we detail the collection of fluorophores and highlight both general strategies and unique approaches that are employed to control fluorescence using chemistry.
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16
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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: 137] [Impact Index Per Article: 11.4] [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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17
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Optimization of the aromatase inhibitory activities of pyridylthiazole analogues of resveratrol. Bioorg Med Chem 2012; 20:2427-34. [DOI: 10.1016/j.bmc.2012.01.047] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2011] [Revised: 01/18/2012] [Accepted: 01/26/2012] [Indexed: 01/03/2023]
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18
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Oberlander JG, Porter DM, Penatti CAA, Henderson LP. Anabolic androgenic steroid abuse: multiple mechanisms of regulation of GABAergic synapses in neuroendocrine control regions of the rodent forebrain. J Neuroendocrinol 2012; 24:202-14. [PMID: 21554430 PMCID: PMC3168686 DOI: 10.1111/j.1365-2826.2011.02151.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Anabolic androgenic steroids (AAS) are synthetic derivatives of testosterone originally developed for clinical purposes but are now predominantly taken at suprapharmacological levels as drugs of abuse. To date, almost 100 different AAS compounds that vary in metabolic fate and physiological effects have been designed and synthesised. Although they are administered for their ability to enhance muscle mass and performance, untoward side effects of AAS use include changes in reproductive and sexual behaviours. Specifically, AAS, depending on the type of compound administered, can delay or advance pubertal onset, lead to irregular oestrous cyclicity, diminish male and female sexual behaviours, and accelerate reproductive senescence. Numerous brains regions and neurotransmitter signalling systems are involved in the generation of these behaviours, and are potential targets for both chronic and acute actions of the AAS. However, critical to all of these behaviours is neurotransmission mediated by GABA(A) receptors within a nexus of interconnected forebrain regions that includes the medial preoptic area, the anteroventral periventricular nucleus and the arcuate nucleus of the hypothalamus. We review how exposure to AAS alters GABAergic transmission and neural activity within these forebrain regions, taking advantage of in vitro systems and both wild-type and genetically altered mouse strains, aiming to better understand how these synthetic steroids affect the neural systems that underlie the regulation of reproduction and the expression of sexual behaviours.
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Affiliation(s)
- Joseph G. Oberlander
- Department of Physiology and Neurobiology, Dartmouth Medical School, Hanover, NH 03755 USA
| | - Donna M. Porter
- Department of Physiology and Neurobiology, Dartmouth Medical School, Hanover, NH 03755 USA
| | - Carlos A. A. Penatti
- Departamento de Ciências Médicas, Universidade Nove de Julho - UNINOVE, São Paulo, SP 01504-000 Brasil
| | - Leslie P. Henderson
- Department of Physiology and Neurobiology, Dartmouth Medical School, Hanover, NH 03755 USA
- To Whom Correspondence Should be Addressed:
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19
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Hong Y, Chen S. Aromatase, estrone sulfatase, and 17β-hydroxysteroid dehydrogenase: structure-function studies and inhibitor development. Mol Cell Endocrinol 2011; 340:120-6. [PMID: 20888390 PMCID: PMC3035767 DOI: 10.1016/j.mce.2010.09.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Revised: 09/15/2010] [Accepted: 09/18/2010] [Indexed: 11/23/2022]
Abstract
Aromatase, estrone sulfatase, and 17β-hydroxysteroid dehydrogenase type 1 are involved in the key steps of 17β-estradiol biosynthesis. Structure-function studies of aromatase, estrone sulfatase and 17β-hydroxysteroid dehydrogenase type 1 are important to evaluate the molecular basis of the interaction between these enzymes and their inhibitors. Selective and potent inhibitors of the three enzymes have been developed as antiproliferative agents in hormone-dependent breast carcinoma. New treatment strategies for hormone-dependent breast cancer are discussed.
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Affiliation(s)
- Yanyan Hong
- Division of Tumor Cell Biology, Beckman Research Institute of the City of Hope, 1450 E. Duarte Road, Duarte, CA 91010, United States
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20
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Galeazzi R, Massaccesi L. Insight into the binding interactions of CYP450 aromatase inhibitors with their target enzyme: a combined molecular docking and molecular dynamics study. J Mol Model 2011; 18:1153-66. [DOI: 10.1007/s00894-011-1144-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 05/31/2011] [Indexed: 10/18/2022]
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Chronic exposure to anabolic androgenic steroids alters activity and synaptic function in neuroendocrine control regions of the female mouse. Neuropharmacology 2011; 61:653-64. [PMID: 21645530 DOI: 10.1016/j.neuropharm.2011.05.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Revised: 05/09/2011] [Accepted: 05/11/2011] [Indexed: 11/21/2022]
Abstract
Disruption of reproductive function is a hallmark of abuse of anabolic androgenic steroids (AAS) in female subjects. To understand the central actions of AAS, patch clamp recordings were made in estrous, diestrous and AAS-treated mice from gonadotropin releasing hormone (GnRH) neurons, neurons in the medial preoptic area (mPOA) and neurons in the anteroventroperiventricular nucleus (AVPV); regions known to provide GABAergic and kisspeptin inputs to the GnRH cells. Action potential (AP) frequency was significantly higher in GnRH neurons of estrous mice than in AAS-treated or diestrous animals. No significant differences in AAS-treated, estrous or diestrous mice were evident in the amplitude or kinetics of spontaneous postsynaptic currents (sPSCs), miniature PSCs or tonic currents mediated by GABA(A) receptors or in GABA(A) receptor subunit expression in GnRH neurons. In contrast, the frequency of GABA(A) receptor-mediated sPSCs in GnRH neurons showed an inverse correlation with AP frequency across the three hormonal states. Surprisingly, AP activity in the medial preoptic area (mPOA), a likely source of GABAergic afferents to GnRH cells, did not vary in concert with the sPSCs in the GnRH neurons. Furthermore, pharmacological blockade of GABA(A) receptors did not alter the pattern in which there was lower AP frequency in GnRH neurons of AAS-treated and diestrous versus estrous mice. These data suggest that AAS do not impose their effects either directly on GnRH neurons or on putative GABAergic afferents in the mPOA. AP activity recorded from neurons in kisspeptin-rich regions of the AVPV and the expression of kisspeptin mRNA and peptide did vary coordinately with AP activity in GnRH neurons. Our data demonstrate that AAS treatment imposes a "diestrous-like" pattern of activity in GnRH neurons and suggest that this effect may arise from suppression of presynaptic kisspeptin-mediated excitatory drive arising from the AVPV. The actions of AAS on neuroendocrine regulatory circuits may contribute the disruption of reproductive function observed in steroid abuse.
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Abstract
Aromatase is an enzyme that plays a critical role in the development of estrogen receptor positive breast cancer. As aromatase catalyzes the aromatization of androstenedione to estrone, a naturally occurring estrogen, it is a promising drug target for therapeutic management. The undesirable effects found in aromatase inhibitors (AIs) that are in clinical use necessitate the discovery of novel AIs with higher selectivity, less toxicity and improving potency. In this study, we elucidate the binding mode of all three generations of AI drugs to the crystal structure of aromatase by means of molecular docking. It was demonstrated that the docking protocol could reliably reproduce the interaction of aromatase with its substrate with an RMSD of 1.350 Å. The docking study revealed that polar (D309, T310, S478 and M374), aromatic (F134, F221 and W224) and non-polar (A306, A307, V370, L372 and L477) residues were important for interacting with the AIs. The insights gained from the study herein have great potential for the design of novel AIs.
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Safety and efficacy of low-dose esterified estrogens and methyltestosterone, alone or combined, for the treatment of hot flashes in menopausal women: a randomized, double-blind, placebo-controlled study. Fertil Steril 2011; 95:366-8. [DOI: 10.1016/j.fertnstert.2010.08.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 07/11/2010] [Accepted: 08/06/2010] [Indexed: 11/19/2022]
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Salminen KA, Leppänen J, Venäläinen JI, Pasanen M, Auriola S, Juvonen RO, Raunio H. Simple, direct, and informative method for the assessment of CYP2C19 enzyme inactivation kinetics. Drug Metab Dispos 2010; 39:412-8. [PMID: 21148250 DOI: 10.1124/dmd.110.036376] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Many clinically relevant drug interactions involving cytochrome P450 inhibition are mediated by mechanism-based inactivation (MBI). Time-dependent inhibition is one of the major features distinguishing between reversible inhibition and MBI. It thus provides a useful screening approach for early drug interaction risk assessment. Accordingly, we developed an easy and informative fluorometric method for the assessment of CYP2C19 enzyme inactivation kinetics. Dibenzylfluorescein (DBF) is widely used as a profluorescent probe substrate for P450 activity and inhibition assays, but its use has been considered to be limited to traditional endpoint assays. We monitored CYP2C19-catalyzed metabolism of DBF using synthesized fluorescein benzyl ester and fluorescein benzyl ether along with commercially available fluorescein as intermediate standards. Furthermore, we demonstrated the use of DBF in a kinetic assay as a progress curve analysis for straightforward determination of whether a compound is a time-dependent inactivator of CYP2C19. The recombinant human CYP2C19 inactivation kinetics of isoniazid, ticlopidine, and tranylcypromine were evaluated, and their key kinetic parameters were measured from the same experiment. The known mechanism-based inactivators, isoniazid and ticlopidine, exhibited clear time-dependent inactivation with K(I) and k(inact) values of 250.5 ± 34 μM and 0.137 ± 0.006 min(-1) and 1.96 ± 0.5 μM and 0.135 ± 0.009 min(-1), respectively. Tranylcypromine did not display any time-dependent inhibition, which is consistent with its reported mechanism of competitive inhibition. In summary, DBF is suitable for use in the progress curve analysis approach and can be used as an initial screen to identify compounds that require more detailed investigations in drug interaction optimization.
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Affiliation(s)
- Kaisa A Salminen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, P.O. Box 1627, 70211 Kuopio, Finland.
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Roy PP, Roy K. Molecular docking and QSAR studies of aromatase inhibitor androstenedione derivatives. J Pharm Pharmacol 2010; 62:1717-28. [DOI: 10.1111/j.2042-7158.2010.01154.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Abstract
Objectives
Aromatase (CYP19) inhibitors have emerged as promising candidates for the treatment of estrogen-dependent breast cancer. In this study, a series of androstenedione derivatives with CYP19 inhibitory activity was subjected to a molecular docking study followed by quantitative structure–activity relationship (QSAR) analyses in search of ideal physicochemical characteristics of potential aromatase inhibitors.
Methods
The QSAR studies were carried out using both two-dimensional (topological, and structural) and three-dimesional (spatial) descriptors. We also used thermodynamic parameters along with 2D and 3D descriptors. Genetic function approximation (GFA) and genetic partial least squares (G/PLS) were used as chemometric tools for QSAR modelling.
Key findings
The docking study indicated that the important interacting amino acids in the active site were Met374, Arg115, Ile133, Ala306, Thr310, Asp309, Val370, Leu477 and Ser478. The 17-keto oxygen of the ligands is responsible for the formation of a hydrogen bond with Met374 and the remaining parts of the molecules are stabilized by the hydrophobic interactions with the non-polar amino acids. The C2 and C19 positions in the ligands are important for maintaining the appropriate orientation of the molecules in the active site. The results of docking experiments and QSAR studies supported each other.
Conclusions
The developed QSAR models indicated the importance of some Jurs parameters, structural parameters, topological branching index and E-state indices of different fragments. All the developed QSAR models were statistically significant according to the internal and external validation parameters.
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Affiliation(s)
- Partha Pratim Roy
- Drug Theoretics and Cheminformatics Laboratory, Division of Medicinal and Pharmaceutical Chemistry, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India
| | - Kunal Roy
- Drug Theoretics and Cheminformatics Laboratory, Division of Medicinal and Pharmaceutical Chemistry, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India
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Molecular docking and QSAR study on steroidal compounds as aromatase inhibitors. Eur J Med Chem 2010; 45:5612-20. [PMID: 20926163 DOI: 10.1016/j.ejmech.2010.09.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 08/06/2010] [Accepted: 09/06/2010] [Indexed: 11/21/2022]
Abstract
In order to develop more potent, selective and less toxic steroidal aromatase (AR) inhibitors, molecular docking, 2D and 3D hybrid quantitative structure-activity relationship (QSAR) study have been conducted using topological, molecular shape, spatial, structural and thermodynamic descriptors on 32 steroidal compounds. The molecular docking study shows that one or more hydrogen bonds with MET374 are one of the essential requirements for the optimum binding of ligands. The QSAR model obtained indicates that the aromatase inhibitory activity can be enhanced by increasing SIC, SC_3_C, Jurs_WNSA_1, Jurs_WPSA_1 and decreasing CDOCKER interaction energy (ECD), IAC_Total and Shadow_XZfrac. The predicted results shows that this model has a comparatively good predictive power which can be used in prediction of activity of new steroidal aromatase inhibitors.
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27
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Farag AM, Mayhoub AS, Eldebss TMA, Amr AGE, Ali KAK, Abdel-Hafez NA, Abdulla MM. Synthesis and Structure-Activity Relationship Studies of Pyrazole-based Heterocycles as Antitumor Agents. Arch Pharm (Weinheim) 2010; 343:384-96. [DOI: 10.1002/ardp.200900176] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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28
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Roy PP, Roy K. Docking and 3D-QSAR studies of diverse classes of human aromatase (CYP19) inhibitors. J Mol Model 2010; 16:1597-616. [DOI: 10.1007/s00894-010-0667-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Accepted: 01/18/2010] [Indexed: 11/30/2022]
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29
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Ghosh D, Griswold J, Erman M, Pangborn W. X-ray structure of human aromatase reveals an androgen-specific active site. J Steroid Biochem Mol Biol 2010; 118:197-202. [PMID: 19808095 PMCID: PMC2826573 DOI: 10.1016/j.jsbmb.2009.09.012] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Revised: 09/13/2009] [Accepted: 09/24/2009] [Indexed: 11/30/2022]
Abstract
Aromatase is a unique cytochrome P450 that catalyzes the removal of the 19-methyl group and aromatization of the A-ring of androgens for the synthesis of estrogens. All human estrogens are synthesized via this enzymatic aromatization pathway. Aromatase inhibitors thus constitute a frontline therapy for estrogen-dependent breast cancer. Despite decades of intense investigation, this enzyme of the endoplasmic reticulum membrane has eluded all structure determination efforts. We have determined the crystal structure of the highly active aromatase purified from human placenta, in complex with its natural substrate androstenedione. The structure shows the binding mode of androstenedione in the catalytically active oxidized high-spin ferric state of the enzyme. Hydrogen bond-forming interactions and tight packing hydrophobic side chains that complement the puckering of the steroid backbone provide the molecular basis for the exclusive androgenic specificity of aromatase. Locations of catalytic residues and water molecules shed new light on the mechanism of the aromatization step. The structure also suggests a membrane integration model indicative of the passage of steroids through the lipid bilayer.
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Affiliation(s)
- Debashis Ghosh
- Hauptman-Woodward Medical Research Institute, Buffalo, NY 14203, USA.
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30
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Hong Y, Li H, Yuan YC, Chen S. Sequence-function correlation of aromatase and its interaction with reductase. J Steroid Biochem Mol Biol 2010; 118:203-6. [PMID: 19944754 PMCID: PMC2836254 DOI: 10.1016/j.jsbmb.2009.11.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Revised: 11/19/2009] [Accepted: 11/19/2009] [Indexed: 11/26/2022]
Abstract
Aromatase is an enzyme required for the conversion of androgens to estrogens. Estrogens are female sex hormones involved in the development and growth of breast tumors. It has been of significant interest to investigate the structure-function relationship of aromatase since its inhibitors have shown great promise in fighting breast cancer. Aromatase belongs to the cytochrome P450 family, and forms an electron-transfer complex with its partner, NADPH-cytochrome P450 reductase (CPR), during the aromatization reaction. Aromatase is found to be widely expressed in vertebrates with unique substrates androstenedione and testosterone, but with various catalytic capacities reflecting species differences in K(m), Vmax, etc. This report will summarize current progress in sequence-function correlation analysis of the aromatase protein family and molecular characterization of the interaction between aromatase and CPR. These studies may lead to a novel field for the development of new inhibitors which interfere with the interaction between aromatase and CPR in order to inhibit the aromatization reaction.
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Affiliation(s)
- Yanyan Hong
- Division of Tumor Cell Biology, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
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31
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Chronic exposure to anabolic androgenic steroids alters neuronal function in the mammalian forebrain via androgen receptor- and estrogen receptor-mediated mechanisms. J Neurosci 2009; 29:12484-96. [PMID: 19812324 DOI: 10.1523/jneurosci.3108-09.2009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Anabolic androgenic steroids (AAS) can promote detrimental effects on social behaviors for which GABA type A (GABA(A)) receptor-mediated circuits in the forebrain play a critical role. While all AAS bind to androgen receptors (AR), they may also be aromatized to estrogens and thus potentially impart effects via estrogen receptors (ER). Chronic exposure of wild-type male mice to a combination of chemically distinct AAS increased action potential (AP) frequency, selective GABA(A) receptor subunit mRNAs, and GABAergic synaptic current decay in the medial preoptic area (mPOA). Experiments performed with pharmacological agents and in AR-deficient Tfm mutant mice suggest that the AAS-dependent enhancement of GABAergic transmission in wild-type mice is AR-mediated. In AR-deficient mice, the AAS elicited dramatically different effects, decreasing AP frequency, spontaneous IPSC amplitude and frequency and the expression of selective GABA(A) receptor subunit mRNAs. Surprisingly, in the absence of AR signaling, the data indicate that the AAS do not act as ER agonists, but rather suggest a novel in vivo action in which the AAS inhibit aromatase and impair endogenous ER signaling. These results show that the AAS have the capacity to alter neuronal function in the forebrain via multiple steroid signaling mechanisms and suggest that effects of these steroids in the brain will depend not only on the balance of AR- versus ER-mediated regulation for different target genes, but also on the ability of these drugs to alter steroid metabolism and thus the endogenous steroid milieu.
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Moon HJ, Seok JH, Kim SS, Rhee GS, Lee RD, Yang JY, Chae SY, Kim SH, Kim JY, Chung JY, Kim JM, Chung SY. Lactational coumestrol exposure increases ovarian apoptosis in adult rats. Arch Toxicol 2009; 83:601-8. [PMID: 19165469 PMCID: PMC2695544 DOI: 10.1007/s00204-008-0400-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Accepted: 12/15/2008] [Indexed: 10/24/2022]
Abstract
This study is the first to examine the increased apoptosis in the adult rat ovary after lactational exposure to coumestrol (COU), a potent phytoestrogen. Lactating dams were gavaged at doses of 0.01, 0.1, 1, and 10 mg/kg COU during the lactation period and the reproductive effects of female pups were investigated in young adults. Rats were sacrificed at postnatal days (PND) 81-84. Ovarian weights were reduced significantly at 0.1 and 1.0 mg/kg COU. The reduction in the ovarian weight occurred in parallel with an increase in the apoptosis at PND 135-140. A marked dose-dependent increase in the expressions of active caspase-3 and -7 was observed in ovarian granulosa cells. Immunostaining for active caspase-3 and the TUNEL staining of apoptotic cells were also increased in ovaries exposed to COU in a dose-dependent manner. These results suggest new sights into the effect of lactational exposure to COU on the female reproductive health.
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Affiliation(s)
- Hyun-Ju Moon
- Reproductive and Developmental Toxicology Division, National Institute of Toxicological Research, Korea Food and Drug Administration, 194 Tongil-ro, Eunpyung-gu, Seoul 122-704, South Korea.
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Abstract
Aromatase is an estrogen synthetase. Estrogens are female sex hormones involved in the development and growth of breast tumors. Elucidation of the structure-function relationship of aromatase has been of significant interest since its inhibitors have shown great promise in fighting breast cancer. Aromatase belongs to the cytochrome P450 family and forms an electron-transfer complex with its partner, NADPH-cytochrome P450 reductase. Because of the membrane-bound character and heme-binding instability, no crystal structure of aromatase has been reported so far. Much remains to be investigated, including the 3-dimensional structure of aromatase, interaction between aromatase and reductase, catalytic mechanism of estrogen synthesis by aromatase, and the binding mechanism of aromatase inhibitors. This review presents current knowledge about structural and functional characteristics of aromatase to address unsolved mysteries about this enzyme.
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Affiliation(s)
- Yanyan Hong
- Department of Surgical Research, Beckman Research Institute of City of Hope, Duarte, California 91010, USA
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Karkola S, Wähälä K. The binding of lignans, flavonoids and coumestrol to CYP450 aromatase: a molecular modelling study. Mol Cell Endocrinol 2009; 301:235-44. [PMID: 19000737 DOI: 10.1016/j.mce.2008.10.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2008] [Revised: 10/06/2008] [Accepted: 10/08/2008] [Indexed: 10/21/2022]
Abstract
Androgens are transformed into aromatic estrogens by CYP450 aromatase in a three-step reaction consuming three equivalents of oxygen and three equivalents of NADPH. Estrogens are substrates for nuclear estrogen receptors (ERs) and play a key role in estrogen-dependent tumour cell formation and proliferation. Natural phytoestrogens are proved to be competitive inhibitors of aromatase enzyme at IC(50) values in micromolar levels. In order to understand the mechanisms involved in the binding of various phytoestrogens, we used our model of CYP450 aromatase to study the binding of phytoestrogens using molecular dynamics simulations with a bound phytoestrogen. The simulation trajectory was analysed to find the essential interactions which take place upon binding and a representative structure of the trajectory was minimized for docking studies. Sets of phytoestrogens, such as lignans, flavonoids/isoflavonoids and coumestrol, were docked into the aromatase active site and the binding modes were studied.
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Affiliation(s)
- Sampo Karkola
- Laboratory of Organic Chemistry, Department of Chemistry, Faculty of Science, University of Helsinki, P. O. Box 55, FIN-00014 Helsinki, Finland
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35
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Ghosh D, Griswold J, Erman M, Pangborn W. Structural basis for androgen specificity and oestrogen synthesis in human aromatase. Nature 2009; 457:219-23. [PMID: 19129847 DOI: 10.1038/nature07614] [Citation(s) in RCA: 378] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2008] [Accepted: 11/06/2008] [Indexed: 11/09/2022]
Abstract
Aromatase cytochrome P450 is the only enzyme in vertebrates known to catalyse the biosynthesis of all oestrogens from androgens. Aromatase inhibitors therefore constitute a frontline therapy for oestrogen-dependent breast cancer. In a three-step process, each step requiring 1 mol of O(2), 1 mol of NADPH, and coupling with its redox partner cytochrome P450 reductase, aromatase converts androstenedione, testosterone and 16alpha-hydroxytestosterone to oestrone, 17beta-oestradiol and 17beta,16alpha-oestriol, respectively. The first two steps are C19-methyl hydroxylation steps, and the third involves the aromatization of the steroid A-ring, unique to aromatase. Whereas most P450s are not highly substrate selective, it is the hallmark androgenic specificity that sets aromatase apart. The structure of this enzyme of the endoplasmic reticulum membrane has remained unknown for decades, hindering elucidation of the biochemical mechanism. Here we present the crystal structure of human placental aromatase, the only natural mammalian, full-length P450 and P450 in hormone biosynthetic pathways to be crystallized so far. Unlike the active sites of many microsomal P450s that metabolize drugs and xenobiotics, aromatase has an androgen-specific cleft that binds the androstenedione molecule snugly. Hydrophobic and polar residues exquisitely complement the steroid backbone. The locations of catalytically important residues shed light on the reaction mechanism. The relative juxtaposition of the hydrophobic amino-terminal region and the opening to the catalytic cleft shows why membrane anchoring is necessary for the lipophilic substrates to gain access to the active site. The molecular basis for the enzyme's androgenic specificity and unique catalytic mechanism can be used for developing next-generation aromatase inhibitors.
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Affiliation(s)
- Debashis Ghosh
- Structural Biology, Hauptman-Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, New York 14203, USA.
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Lack of complete cross-resistance between different aromatase inhibitors; a real finding in search for an explanation? Eur J Cancer 2008; 45:527-35. [PMID: 19062270 DOI: 10.1016/j.ejca.2008.10.019] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 09/23/2008] [Accepted: 10/16/2008] [Indexed: 11/21/2022]
Abstract
While third-generation aromatase inhibitors (anastrozole, letrozole and exemestane) are successfully implemented as adjuvant and first-line therapy for hormone-sensitive breast cancer in postmenopausal women, important questions remain to be addressed. An issue of particular interest is the question about lack of complete cross-resistance between steroidal and non-steroidal compounds. Although the studies reporting this phenomenon in general contain a small number of patients, the findings across the different reports seem consistent. While several potential mechanisms have been suggested, so far we lack scientific proof what mechanisms may be responsible for this finding. Finally, we do not know whether lack of cross-resistance actually signals an improved efficacy for certain compounds or may be due to alternative mechanisms of action. Neither do we know whether some tumours are more sensitive to particular drugs. This paper summarizes clinical findings up to now with respect to lack of cross-resistance and discuss potential mechanisms involved.
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Lønning PE, Geisler J. Experience with Exemestane in the Treatment of Early and Advanced Breast Cancer. Expert Opin Drug Metab Toxicol 2008; 4:987-97. [DOI: 10.1517/17425255.4.7.987] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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