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Meshram RJ, Bagul KT, Pawnikar SP, Barage SH, Kolte BS, Gacche RN. Known compounds and new lessons: structural and electronic basis of flavonoid-based bioactivities. J Biomol Struct Dyn 2019; 38:1168-1184. [DOI: 10.1080/07391102.2019.1597770] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Rohan J. Meshram
- Bioinformatics Centre, Savitribai Phule Pune University, Pune, Maharashtra, India
| | - Kamini T. Bagul
- Bioinformatics Centre, Savitribai Phule Pune University, Pune, Maharashtra, India
| | - Shristi P. Pawnikar
- Bioinformatics Centre, Savitribai Phule Pune University, Pune, Maharashtra, India
| | - Sagar H. Barage
- Amity Institute of Biotechnology, Amity University, Panvel, Maharashtra, India
| | - Baban S. Kolte
- Bioinformatics Centre, Savitribai Phule Pune University, Pune, Maharashtra, India
- Department of Biotechnology, Savitribai Phule Pune University, Pune, Maharashtra, India
| | - Rajesh N. Gacche
- Department of Biotechnology, Savitribai Phule Pune University, Pune, Maharashtra, India
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Shamsudin Y, Gutiérrez-de-Terán H, Åqvist J. Molecular Mechanisms in the Selectivity of Nonsteroidal Anti-Inflammatory Drugs. Biochemistry 2018; 57:1236-1248. [PMID: 29345921 DOI: 10.1021/acs.biochem.7b01019] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit cyclooxygenase (COX) 1 and 2 with varying degrees of selectivity. A group of COX-2 selective inhibitors-coxibs-binds in a time-dependent manner through a three-step mechanism, utilizing a side pocket in the binding site. Coxibs have been extensively probed to identify the structural features regulating the slow tight-binding mechanism responsible for COX-2 selectivity. In this study, we further probe a structurally and kinetically diverse data set of COX inhibitors in COX-2 by molecular dynamics and free energy simulations. We find that the features regulating the high affinities associated with time-dependency in COX depend on the inhibitor kinetics. In particular, most time-dependent inhibitors share a common structural binding mechanism, involving an induced-fit rotation of the side-chain of Leu531 in the main binding pocket. The high affinities of two-step slow tight-binding inhibitors and some slow reversible inhibitors can thus be explained by the increased space in the main binding pocket after this rotation. Coxibs that belong to a separate class of slow tight-binding inhibitors benefit more from the displacement of the neighboring side-chain of Arg513, exclusive to the COX-2 side-pocket. This displacement further stabilizes the aforementioned rotation of Leu531 and can explain the selectivity of coxibs for COX-2.
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Affiliation(s)
- Yasmin Shamsudin
- Department of Cell and Molecular Biology, Box 596, Uppsala University, BMC , SE-751 24 Uppsala, Sweden
| | - Hugo Gutiérrez-de-Terán
- Department of Cell and Molecular Biology, Box 596, Uppsala University, BMC , SE-751 24 Uppsala, Sweden
| | - Johan Åqvist
- Department of Cell and Molecular Biology, Box 596, Uppsala University, BMC , SE-751 24 Uppsala, Sweden
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3
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Biological activity evaluation and molecular docking study of chromone derivatives as cyclooxygenase-2 inhibitors. Med Chem Res 2017. [DOI: 10.1007/s00044-017-1786-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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4
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Synthesis and in silico investigation of thiazoles bearing pyrazoles derivatives as anti-inflammatory agents. Comput Biol Chem 2016; 61:86-96. [PMID: 26844536 DOI: 10.1016/j.compbiolchem.2016.01.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 12/15/2015] [Accepted: 01/21/2016] [Indexed: 11/23/2022]
Abstract
Searching novel, safe and effective anti-inflammatory agents has remained an evolving research enquiry in the mainstream of inflammatory disorders. In the present investigation series of thiazoles bearing pyrazole as a possible pharmacophore were synthesized and assessed for their anti inflammatory activity using in vitro and in vivo methods. In order to decipher the possible anti-inflammatory mechanism of action of the synthesized compounds, cyclooxygenase I and II (COX-I and COX-II) inhibition assays were also carried out. The results obtained clearly focus the significance of compounds 5d, 5h and 5i as selective COX-II inhibitors. Moreover, compound 5h was also identified as a lead molecule for inhibition of the carrageenin induced rat paw edema in animal model studies. Molecular docking results revealed significant interactions of the test compounds with the active site of COX-II, which perhaps can be explored for design and development of novel COX-II selective anti-inflammatory agents.
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Tseng TS, Chuang SM, Hsiao NW, Chen YW, Lee YC, Lin CC, Huang C, Tsai KC. Discovery of a potent cyclooxygenase-2 inhibitor, S4, through docking-based pharmacophore screening, in vivo and in vitro estimations. MOLECULAR BIOSYSTEMS 2016; 12:2541-51. [DOI: 10.1039/c6mb00229c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cyclooxygenase (COX; EC: 1.14.99.1), the key enzyme in prostaglandin production in the human body, is a major pharmacological target for developing anti-inflammatory agents.
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Affiliation(s)
- Tien-Sheng Tseng
- National Research Institute of Chinese Medicine
- Ministry of Health and Welfare
- Taipei
- Taiwan
- Institute of Biomedical Sciences
| | - Show-Mei Chuang
- Institute of Biomedical Sciences
- National Chung Hsing University
- Taichung
- Taiwan
| | - Nai-Wan Hsiao
- Institute of Biotechnology
- National Changhua University of Education
- Changhua
- Taiwan
| | | | - Yu-Ching Lee
- The Center of Translational Medicine
- Taipei Medical University
- Taipei
- Taiwan
- The Ph.D. Program for Medical Biotechnology
| | - Chi-Chen Lin
- Institute of Biomedical Sciences
- National Chung Hsing University
- Taichung
- Taiwan
| | - Cheng Huang
- National Research Institute of Chinese Medicine
- Ministry of Health and Welfare
- Taipei
- Taiwan
| | - Keng-Chang Tsai
- National Research Institute of Chinese Medicine
- Ministry of Health and Welfare
- Taipei
- Taiwan
- The Ph.D. Program for Medical Biotechnology
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6
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Suthar SK, Sharma M. Recent Developments in Chimeric NSAIDs as Safer Anti-Inflammatory Agents. Med Res Rev 2014; 35:341-407. [DOI: 10.1002/med.21331] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Sharad Kumar Suthar
- Department of Pharmacy; Jaypee University of Information Technology; Waknaghat 173234 India
| | - Manu Sharma
- Department of Pharmacy; Jaypee University of Information Technology; Waknaghat 173234 India
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7
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Cyclooxygenase metabolism mediates vasorelaxation to 2-arachidonoylglycerol (2-AG) in human mesenteric arteries. Pharmacol Res 2014; 81:74-82. [PMID: 24548820 PMCID: PMC3992009 DOI: 10.1016/j.phrs.2014.02.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 01/19/2014] [Accepted: 02/03/2014] [Indexed: 01/04/2023]
Abstract
Objective The vasorelaxant effect of 2-arachidonoylglycerol (2-AG) has been well characterised in animals. 2-AG is present in human vascular cells and is up-regulated in cardiovascular pathophysiology. However, the acute vascular actions of 2-AG have not been explored in humans. Approach Mesenteric arteries were obtained from patients receiving colorectal surgery and mounted on a myograph. Arteries were contracted and 2-AG concentration–response curves were carried out. Mechanisms of action were characterised pharmacologically. Post hoc analysis was carried out to assess the effects of cardiovascular disease/risk factors on 2-AG responses. Results 2-AG caused vasorelaxation of human mesenteric arteries, independent of cannabinoid receptor or transient receptor potential vanilloid-1 activation, the endothelium, nitric oxide or metabolism via monoacyglycerol lipase or fatty acid amide hydrolase. 2-AG-induced vasorelaxation was reduced in the presence of indomethacin and flurbiprofen, suggesting a role for cyclooxygenase metabolism 2-AG. Responses to 2-AG were also reduced in the presence of Cay10441, L-161982 and potentiated in the presence of AH6809, suggesting that metabolism of 2-AG produces both vasorelaxant and vasoconstrictor prostanoids. Finally, 2-AG-induced vasorelaxation was dependent on potassium efflux and the presence of extracellular calcium. Conclusions We have shown for the first time that 2-AG causes vasorelaxation of human mesenteric arteries. Vasorelaxation is dependent on COX metabolism, activation of prostanoid receptors (EP4 & IP) and ion channel modulation. 2-AG responses are blunted in patients with cardiovascular risk factors.
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8
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Blobaum AL, Uddin MJ, Felts AS, Crews BC, Rouzer CA, Marnett LJ. The 2'-Trifluoromethyl Analogue of Indomethacin Is a Potent and Selective COX-2 Inhibitor. ACS Med Chem Lett 2013; 4:486-490. [PMID: 23687559 PMCID: PMC3654564 DOI: 10.1021/ml400066a] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Accepted: 03/24/2013] [Indexed: 11/29/2022] Open
Abstract
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Indomethacin is a potent, time-dependent,
nonselective inhibitor
of the cyclooxygenase enzymes (COX-1 and COX-2). Deletion of the 2′-methyl
group of indomethacin produces a weak, reversible COX inhibitor, leading
us to explore functionality at that position. Here, we report that
substitution of the 2′-methyl group of indomethacin with trifluoromethyl
produces CF3–indomethacin, a tight-binding inhibitor
with kinetic properties similar to those of indomethacin and unexpected
COX-2 selectivity (IC50 mCOX-2 = 267 nM; IC50 oCOX-1 > 100 μM). Studies with site-directed mutants reveal
that COX-2 selectivity results from insertion of the CF3 group into a small hydrophobic pocket formed by Ala-527, Val-349,
Ser-530, and Leu-531 and projection of the methoxy group toward a
side pocket bordered by Val-523. CF3–indomethacin
inhibited COX-2 activity in human head and neck squamous cell carcinoma
cells and exhibited in vivo anti-inflammatory activity in the carrageenan-induced
rat paw edema model with similar potency to that of indomethacin.
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Affiliation(s)
- Anna L. Blobaum
- The A. B.
Hancock Jr. Memorial Laboratory for Cancer
Research, Departments of Biochemistry, Chemistry, and Pharmacology,
Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology,
and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United
States
| | - Md. Jashim Uddin
- The A. B.
Hancock Jr. Memorial Laboratory for Cancer
Research, Departments of Biochemistry, Chemistry, and Pharmacology,
Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology,
and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United
States
| | - Andrew S. Felts
- The A. B.
Hancock Jr. Memorial Laboratory for Cancer
Research, Departments of Biochemistry, Chemistry, and Pharmacology,
Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology,
and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United
States
| | - Brenda C. Crews
- The A. B.
Hancock Jr. Memorial Laboratory for Cancer
Research, Departments of Biochemistry, Chemistry, and Pharmacology,
Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology,
and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United
States
| | - Carol A. Rouzer
- The A. B.
Hancock Jr. Memorial Laboratory for Cancer
Research, Departments of Biochemistry, Chemistry, and Pharmacology,
Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology,
and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United
States
| | - Lawrence J. Marnett
- The A. B.
Hancock Jr. Memorial Laboratory for Cancer
Research, Departments of Biochemistry, Chemistry, and Pharmacology,
Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology,
and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United
States
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9
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Ribeiro DA, Paiotti APR, Medalha CC. Dual role of cyclooxygenase-2 during tissue repair induced by low level laser therapy: an intriguing issue. J COSMET LASER THER 2012; 14:184-8. [PMID: 22506724 DOI: 10.3109/14764172.2012.685479] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Tissue repair is an excellent example of pathophysiological model for studying the role of cyclooxygenase-2 (COX-2) on eukaryotic cells. It has been established that two COX isoforms are expressed in human tissues: constitutive or induced. COX-1 activity is constitutive, present in nearly all cell types at a constant level; COX-2 activity is normally absent from cells, and when induced, the protein levels increase and decrease in a matter of hours after a single stimulus. Thus, the purpose of this review was to describe the role of COX-2 during tissue repair induced by low level laser therapy (LLLT) in humans and experimental models. COX-2 expression has been implicated in the onset or the exacerbation of inflammation during tissue repair induced by LLLT in a number of studies, Many studies are conducted to investigate the role of COX-2 during tissue repair induced by LLLT using different experimental protocols and dosages. Therefore, this is an area that warrants investigation, since the estimation of COX-2 expression from using such important techniques in therapeutics with respect to tissue repair will be added to those already established in the literature as a way to improve health status and prevention of side effects.
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Affiliation(s)
- Daniel A Ribeiro
- Department of Biosciences, Federal University of São Paulo UNIFESP, Santos, SP, Brazil.
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11
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Vecchio AJ, Malkowski MG. The structure of NS-398 bound to cyclooxygenase-2. J Struct Biol 2011; 176:254-8. [PMID: 21843643 DOI: 10.1016/j.jsb.2011.07.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 07/26/2011] [Accepted: 07/27/2011] [Indexed: 11/29/2022]
Abstract
The cyclooxygenases (COX-1 and COX-2) are membrane-associated, heme-containing homodimers that generate prostaglandin H(2) from arachidonic acid (AA) in the committed step of prostaglandin biogenesis and are the targets for nonsteroidal anti-inflammatory drugs (NSAIDs). N-(2-cyclohexyloxy-4-nitrophenyl) methanesulfonamide (NS-398) was the first in a series of isoform-selective drugs designed to preferentially inhibit COX-2, with the aim of ameliorating many of the toxic gastrointestinal side effects caused by conventional NSAID inhibition. We determined the X-ray crystal structure of murine COX-2 in complex with NS-398 utilizing synchrotron radiation to 3.0A resolution. NS-398 binds in the cyclooxygenase channel in a conformation that is different than that observed for other COX-2-selective inhibitors, such as celecoxib, with no discernible penetration into the side pocket formed in COX-2 by the isoform-specific substitutions of I434V, H513R, and I523V. Instead, the methanesulfonamide moiety of NS-398 interacts with the side chain of Arg-120 at the opening of the cyclooxygenase channel, similar to that observed for acidic, nonselective NSAIDs such as indomethacin and flurbiprofen. Our structure validates inhibitor studies that identified Arg-120 as a molecular determinant for time-dependent inhibition of COX-2 by NS-398.
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Affiliation(s)
- Alex J Vecchio
- Hauptman-Woodward Medical Research Institute, The State University of New York at Buffalo, 700 Ellicott Street, Buffalo, NY 14203, USA
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12
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Xu Y, Phipps S, Turner MJ, Simmons DL. The N-terminus of COX-1 and its effect on cyclooxygenase-1 catalytic activity. J Genet Genomics 2010; 37:117-23. [PMID: 20227045 DOI: 10.1016/s1673-8527(09)60030-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2009] [Revised: 11/13/2009] [Accepted: 11/20/2009] [Indexed: 10/19/2022]
Abstract
Cyclooxygenases are encoded by COX-1 and COX-2. They share over sixty percent sequence identity in human and are similar to each other in their crystallographic structures. One major difference in the primary structure of these two isozymes is the presence of eight amino acids in the amino-terminal region of COX-1 that are not present in COX-2. The function of this amino acid sequence is unknown. In this study, a human COX-1 mutant (Delta7aa) with this sequence removed was studied in parallel with COX-1. Signal peptide cleavage, N-linked glycosylation, protein expression, distribution and dimerization were not affected by the mutation. The mutant was enzymatically active and showed the same sensitivity toward aspirin. The KM for the enzyme remained the same as COX-1. However, the V(max) of the COX-1 mutant decreased by 3.3-fold. We conclude that the COX-1 specific amino-terminal sequence has a subtle but detectable effect on COX-1 catalysis.
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Affiliation(s)
- Yibing Xu
- Chemistry and Biochemistry Department, Brigham Young University, Provo, UT 84601, USA.
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13
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Liu W, Poole EM, Ulrich CM, Kulmacz RJ. Polymorphic human prostaglandin H synthase-2 proteins and their interactions with cyclooxygenase substrates and inhibitors. THE PHARMACOGENOMICS JOURNAL 2010; 11:337-47. [PMID: 20548327 DOI: 10.1038/tpj.2010.49] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The cyclooxygenase (COX) activity of prostaglandin H synthase-2 (PGHS-2) is implicated in colorectal cancer and is targeted by nonsteroidal anti-inflammatory drugs (NSAIDs) and dietary n-3 fatty acids. We used purified, recombinant proteins to evaluate the functional impacts of the R228H, E488G, V511A and G587R PGHS-2 polymorphisms on COX activity, fatty acid selectivity and NSAID actions. Compared to wild-type PGHS-2, COX activity with arachidonate was ∼20% lower in 488G and ∼20% higher in 511A. All variants showed time-dependent inhibition by the COX-2-specific inhibitor (coxib) nimesulide, but 488G and 511A had 30-60% higher residual COX activity; 511A also showed up to 70% higher residual activity with other time-dependent inhibitors. In addition, 488G and 511A differed significantly from wild type in Vmax values with the two fatty acids: 488G showed ∼20% less and 511A showed ∼20% more discrimination against eicosapentaenoic acid. The Vmax value for eicosapentaenoate was not affected in 228H or 587R, nor were the Km values or the COX activation efficiency (with arachidonate) significantly altered in any variant. Thus, the E488G and V511A PGHS-2 polymorphisms may predict who will most likely benefit from interventions with some NSAIDs or n-3 fatty acids.
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Affiliation(s)
- W Liu
- Department of Internal Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
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14
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Wu G, Tsai AL, Kulmacz RJ. Cyclooxygenase competitive inhibitors alter tyrosyl radical dynamics in prostaglandin H synthase-2. Biochemistry 2010; 48:11902-11. [PMID: 19894761 DOI: 10.1021/bi901600f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Reaction of prostaglandin H synthase (PGHS) isoforms 1 or 2 with peroxide forms a radical at Tyr385 that is required for cyclooxygenase catalysis and another radical at Tyr504, whose function is unknown. Both tyrosyl radicals are transient and rapidly dissipated by reductants, suggesting that cyclooxygenase catalysis might be vulnerable to suppression by intracellular antioxidants. Our initial hypothesis was that the two radicals are in equilibrium and that their proportions and stability are altered upon binding of fatty acid substrate. As a test, we examined the effects of three competitive inhibitors (nimesulide, flurbiprofen, and diclofenac) on the proportions and stability of the two radicals in PGHS-2 pretreated with peroxide. Adding nimesulide after ethyl peroxide led to some narrowing of the tyrosyl radical signal detected by EPR spectroscopy, consistent with a small increase in the proportion of the Tyr504 radical. Neither flurbiprofen nor diclofenac changed the EPR line width when added after peroxide. In contrast, the effects of cyclooxygenase inhibitors on the stability of the preformed tyrosyl radicals were dramatic. The half-life of total tyrosyl radical was 4.1 min in the control, >10 h with added nimesulide, 48 min with flurbiprofen, and 0.8 min with diclofenac. Stabilization of the tyrosyl radicals was evident even at substoichiometric levels of nimesulide. Thus, the inhibitors had potent, structure-dependent, effects on the stability of both tyrosyl radicals. This dramatic modulation of tyrosyl radical stability by cyclooxygenase site ligands suggests a mechanism for regulating the reactivity of PGHS tyrosyl radicals with cellular antioxidants.
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Affiliation(s)
- Gang Wu
- Department of Internal Medicine, University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
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15
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Singh B, Vincent L, Berry JA, Multani AS, Lucci A. Cyclooxygenase-2 expression induces genomic instability in MCF10A breast epithelial cells. J Surg Res 2007; 140:220-6. [PMID: 17418864 DOI: 10.1016/j.jss.2007.01.039] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Revised: 01/08/2007] [Accepted: 01/31/2007] [Indexed: 01/08/2023]
Abstract
BACKGROUND Cyclooxygenase-2 (COX-2) is induced in many breast cancers and COX-2 expression correlates with a worse outcome in the clinic. We hypothesized that the induction of genomic instability is a major mechanism through which COX-2 contributes to breast cancer progression. METHODS We transfected a normal immortalized breast epithelial cell line of Basal B subtype, MCF10A, with the pSG5-COX-2 vector and established the stably transfected cell line MCF10A/COX-2. We analyzed the genomic instability phenotype by chromosomal analysis of metaphase-arrested MCF10A and MCF10A/COX-2 cells after Giemsa staining. Groups were compared using chi(2) tests. To investigate the DNA damage checkpoint signaling, we analyzed the phosphorylation status of CHK1 protein with a phospho-specific antibody. RESULTS Cytogenetic analysis of early passage transfected cells showed that COX-2 expression increased genomic instability compared with the MCF10A cells transfected with a luciferase vector alone. COX-2 overexpression was associated with a significant increase in chromosomal aberrations (fusions, breaks, and tetraploidy). There was a statistically significant increase in the number of polyploid cells in the COX-2 transfected cells versus the control (P=0.004). We also found that an inhibitory CHK1 phosphorylation at Ser-280 was dramatically increased upon COX-2 overexpression in MCF10A cells, thus explaining the mechanism of inactivation of an important cell cycle checkpoint. Further analysis of the MCF10A/COX-2 cells showed that these cells have acquired a premalignant phenotype characterized by a morphological transformation, a resistance to anoikis, a reduced requirement of epidermal growth factor for growth in culture, but their inability to establish tumors in a nude mouse model of malignancy. CONCLUSION We found that COX-2 expression in MCF10A breast epithelial cells confers a premalignant phenotype that includes enhanced genomic instability and altered cell-cycle regulation.
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Affiliation(s)
- Balraj Singh
- Department of Surgical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA
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16
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Singh B, Berry JA, Shoher A, Ayers GD, Wei C, Lucci A. COX-2 involvement in breast cancer metastasis to bone. Oncogene 2007; 26:3789-96. [PMID: 17213821 DOI: 10.1038/sj.onc.1210154] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cyclooxygenase-2 (COX-2) is expressed in 40% of human invasive breast cancers. Bone is the predominant site of metastasis in case of breast cancer. We investigated the role of COX-2 in a suitable mouse model of breast cancer metastasis to bone using the whole-body luciferase imaging of cancer cells. We provide several lines of evidence that COX-2 produced in breast cancer cells is important for bone metastasis in this model including (1) COX-2 transfection enhanced the bone metastasis of MDA-435S cells and (2) breast cancer cells isolated and cultured from the bone metastases produced significantly more prostaglandin E(2) (an important mediator of COX-2) than the parental injected cell populations of breast cancer cells. Next, we found that a COX-2 inhibitor, MF-tricyclic, inhibited bone metastasis caused by a bone-seeking clone both in prevention regimen (in which case mice started receiving MF-tricyclic 1 week before the injection of cancer cells) and in treatment regimen (in which case mice received MF-tricyclic after the development of bone metastasis). These studies indicate that COX-2 produced in breast cancer cells may be vital to the development of osteolytic bone metastases in patients with breast cancer, and that COX-2 inhibitors may be useful in halting this process.
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Affiliation(s)
- B Singh
- Department of Surgical Oncology and Advanced Research Center for Microscopic Disease, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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Hewett SJ, Bell SC, Hewett JA. Contributions of cyclooxygenase-2 to neuroplasticity and neuropathology of the central nervous system. Pharmacol Ther 2006; 112:335-57. [PMID: 16750270 DOI: 10.1016/j.pharmthera.2005.04.011] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2005] [Accepted: 04/19/2005] [Indexed: 01/08/2023]
Abstract
Cyclooxygenase (COX) enzymes, or prostaglandin-endoperoxide synthases (PTGS), are heme-containing bis-oxygenases that catalyze the first committed reaction in metabolism of arachidonic acid (AA) to the potent lipid mediators, prostanoids and thromboxanes. Two isozymes of COX enzymes (COX-1 and COX-2) have been identified to date. This review will focus specifically on the neurobiological and neuropathological consequences of AA metabolism via the COX-2 pathway and discuss the potential therapeutic benefit of COX-2 inhibition in the setting of neurological disease. However, given the controversy surrounding the use of COX-2 selective inhibitors with respect to cardiovascular health, it will be important to move beyond COX to identify which down-stream effectors are responsible for the deleterious and/or potentially protective effects of COX-2 activation in the setting of neurological disease. Important advances toward this goal are highlighted herein. Identification of unique effectors in AA metabolism could direct the development of new therapeutics holding significant promise for the prevention and treatment of neurological disorders.
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Affiliation(s)
- Sandra J Hewett
- Department of Neuroscience MC3401, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA.
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Rouzer C, Tranguch S, Wang H, Zhang H, Dey S, Marnett L. Zymosan-induced glycerylprostaglandin and prostaglandin synthesis in resident peritoneal macrophages: roles of cyclo-oxygenase-1 and -2. Biochem J 2006; 399:91-9. [PMID: 16787386 PMCID: PMC1570173 DOI: 10.1042/bj20060615] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
COX [cyclo-oxygenase; PG (prostaglandin) G/H synthase] oxygenates AA (arachidonic acid) and 2-AG (2-arachidonylglycerol) to endoperoxides that are converted into PGs and PG-Gs (glycerylprostaglandins) respectively. In vitro, 2-AG is a selective substrate for COX-2, but in zymosan-stimulated peritoneal macrophages, PG-G synthesis is not sensitive to selective COX-2 inhibition. This suggests that COX-1 oxygenates 2-AG, so studies were carried out to identify enzymes involved in zymosan-dependent PG-G and PG synthesis. When macrophages from COX-1-/- or COX-2-/- mice were treated with zymosan, 20-25% and 10-15% of the PG and PG-G synthesis observed in wild-type cells respectively was COX-2 dependent. When exogenous AA and 2-AG were supplied to COX-2-/- macrophages, PG and PG-G synthesis was reduced as compared with wild-type cells. In contrast, when exogenous substrates were provided to COX-1-/- macrophages, PG-G but not PG synthesis was reduced. Product synthesis also was evaluated in macrophages from cPLA(2alpha) (cytosolic phospholipase A2alpha)-/- mice, in which zymosan-induced PG synthesis was markedly reduced, and PG-G synthesis was increased approx. 2-fold. These studies confirm that peritoneal macrophages synthesize PG-Gs in response to zymosan, but that this process is primarily COX-1-dependent, as is the synthesis of PGs. They also indicate that the 2-AG and AA used for PG-G and PG synthesis respectively are derived from independent pathways.
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Affiliation(s)
- Carol A. Rouzer
- *Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
- ‡Vanderbilt Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
- §Vanderbilt Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
- ∥Center for Pharmacology and Drug Toxicology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
- ¶Center in Molecular Toxicology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
| | - Susanne Tranguch
- §Vanderbilt Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
- **Departments of Cell and Developmental Biology, Pediatrics, and Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
- ††Division of Reproductive and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
| | - Haibin Wang
- §Vanderbilt Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
- **Departments of Cell and Developmental Biology, Pediatrics, and Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
- ††Division of Reproductive and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
| | - Hao Zhang
- §Vanderbilt Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
- **Departments of Cell and Developmental Biology, Pediatrics, and Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
- ††Division of Reproductive and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
| | - Sudhansu K. Dey
- §Vanderbilt Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
- **Departments of Cell and Developmental Biology, Pediatrics, and Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
- ††Division of Reproductive and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
| | - Lawrence J. Marnett
- †Departments of Chemistry and Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
- ‡Vanderbilt Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
- §Vanderbilt Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
- ∥Center for Pharmacology and Drug Toxicology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
- ¶Center in Molecular Toxicology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, U.S.A
- To whom correspondence should be addressed, at Department of Biochemistry, Vanderbilt University School of Medicine (email )
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Singh B, Berry JA, Vincent LE, Lucci A. Involvement of IL-8 in COX-2-Mediated Bone Metastases from Breast Cancer. J Surg Res 2006; 134:44-51. [PMID: 16678856 DOI: 10.1016/j.jss.2006.03.018] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2006] [Revised: 02/28/2006] [Accepted: 03/10/2006] [Indexed: 11/22/2022]
Abstract
BACKGROUND Cyclooxygenase-2 (COX-2) overexpression by a primary tumor correlates with poor prognosis in breast cancer, including early spread to bone. Interleukin-8 (IL-8) stimulates osteoclastogenesis and resorption of bone, and elevated IL-8 levels predict early metastatic spread of breast cancer. The purpose of this study was to test our hypothesis that tumors that overexpress COX-2 induce IL-8 production. MATERIALS AND METHODS We cotransfected MCF-10A (nonmalignant breast epithelial) cells, as well as MDA-231 (highly metastatic human breast cancer) cell lines with a pSG5-COX-2 vector and pEF1a-Luc-IRES-Neo vector (luciferase reporter). COX-2 overexpression was confirmed by Western blot and PGE2 (a product of the COX-2 pathway) immunoassay. IL-8 production was measured by immunoassay. In vivo testing used a nude mouse model to measure COX-2 and IL-8 production from breast cancer cells that had metastasized to bone (bone-seeking clones (BSCs)). Long bone metastases were localized and quantified by luciferase imaging (Xenogen IVIS system) and X-ray. BSCs were isolated and cultured and then tested for the production of PGE2 and IL-8. RESULTS COX-2 overexpression caused a 4- to 5-fold increase in IL-8 production in both MCF-10A and MDA-231 cells in vitro. In vivo, we observed that the MDA-231-BSC (metastatic cells isolated from bone metastases) produced significantly greater levels of both PGE2 and IL-8 compared to the parental MDA-231 cells (P < 0.01). In contrast to the results obtained with these estrogen receptor-negative cell lines, COX-2 expression failed to induce IL-8 in the MCF-7 estrogen receptor-positive breast cancer cell line. Treatment with the COX-2 inhibitor NS-398 at a low 1-mu[scap]M dose reduced the production of IL-8 in COX-2-transfected MDA-231 cells by 30%, thus confirming the involvement of COX-2 in IL-8 induction. CONCLUSION COX-2 expression induced formation of PGE2 and IL-8 in breast cancer cells. Since PGE2 and IL-8 stimulate osteoclasts to resorb bone, COX-2 inhibition is a potential target for treatment to prevent bone metastases.
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Affiliation(s)
- Balraj Singh
- Department of Surgical Oncology, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA
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20
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Fowler PW, Coveney PV. A computational protocol for the integration of the monotopic protein prostaglandin H2 synthase into a phospholipid bilayer. Biophys J 2006; 91:401-10. [PMID: 16632499 PMCID: PMC1483072 DOI: 10.1529/biophysj.105.077784] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Prostaglandin H2 synthase (PGHS) synthesizes PGH2, a prostaglandin precursor, from arachidonic acid and was the first monotopic enzyme to have its structure experimentally determined. Both isozymes of PGHS are inhibited by nonsteroidal antiinflammatory drugs, an important class of drugs that are the primary means of relieving pain and inflammation. Selectively inhibiting the second isozyme, PGHS-2, minimizes the gastrointestinal side-effects. This had been achieved by the new PGHS-2 selective NSAIDs (i.e., COX-2 inhibitors) but it has been recently suggested that they suffer from additional side-effects. The design of these drugs only made use of static structures from x-ray crystallographic experiments. Investigating the dynamics of both PGHS-1 and PGHS-2 using classical molecular dynamics is expected to generate new insight into the differences in behavior between the isozymes, and therefore may allow improved PGHS-2 selective inhibitors to be designed. We describe a molecular dynamics protocol that integrates PGHS monomers into phospholipid bilayers, thereby producing in silico atomistic models of the PGHS system. Our protocol exploits the vacuum created beneath the protein when several lipids are removed from the top leaflet of the bilayer. The protein integrates into the bilayer during the first 5 ns in a repeatable process. The integrated PGHS monomer is stable and forms multiple hydrogen bonds between the phosphate groups of the lipids and conserved basic residues (Arg, Lys) on the protein. These interactions stabilize the system and are similar to interactions observed for transmembrane proteins.
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Affiliation(s)
- Philip W Fowler
- Centre for Computational Science, Department of Chemistry, University College London, London, United Kingdom
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21
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Singh B, Berry JA, Shoher A, Lucci A. COX-2 Induces IL-11 Production in Human Breast Cancer Cells. J Surg Res 2006; 131:267-75. [PMID: 16457848 DOI: 10.1016/j.jss.2005.11.582] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2005] [Revised: 10/17/2005] [Accepted: 11/09/2005] [Indexed: 11/28/2022]
Abstract
BACKGROUND Cyclooxygenase-2 (COX-2) is overexpressed in 40% of human invasive breast cancers. Interleukin-11 (IL-11), a potent mediator of osteoclastogenesis, is involved in breast cancer metastasis to bone. Since breast cancers that overexpress COX-2 are associated with a higher rate of metastasis to bone, we hypothesized that COX-2 expression in tumor cells would induce IL-11. MATERIALS AND METHODS We transfected MCF-7 (poorly metastatic) and MDA-231 (highly metastatic) human breast cancer cell lines with COX-2 expression vectors. COX-2 overexpression was confirmed by Western blot and PGE(2) immunoassay, and IL-11 production was measured by immunoassay. We also used a nude mouse model to study COX-2 and IL-11 production from breast cancer cells that metastasized to bone. The bone-seeking clones (BSC) were isolated and cultured from the long bone metastases. RESULTS COX-2 transfection caused an approximately 5- to 6-fold increase in IL-11 production in both MCF-7 and MDA-231 cells. MDA-435S-COX2-BSC (cells isolated from bone metastasis) produced elevated levels of IL-11 and PGE2 (an important mediator of COX-2) as compared to the parental MDA-435S-COX2 cells. Furthermore, a treatment with low 1- to 2-microm concentration NS-398 or Celecoxib significantly reduced the production of IL-11 in COX-2-transfected MDA-231 cells, thus confirming the involvement of COX-2 in IL-11 induction. CONCLUSION COX-2-mediated production of IL-11 in breast cancer cells may be vital to the development of osteolytic bone metastases in patients with breast cancer, and a COX-2 inhibitor may be useful in inhibiting this process.
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Affiliation(s)
- Balraj Singh
- Department of Surgical Oncology, University of Texas, M.D. Anderson Cancer Center, Houston, Texas 77030, USA
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22
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Rogge CE, Ho B, Liu W, Kulmacz RJ, Tsai AL. Role of Tyr348 in Tyr385 radical dynamics and cyclooxygenase inhibitor interactions in prostaglandin H synthase-2. Biochemistry 2006; 45:523-32. [PMID: 16401081 PMCID: PMC2851202 DOI: 10.1021/bi051235w] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Both prostaglandin H synthase (PGHS) isoforms utilize a radical at Tyr385 to abstract a hydrogen atom from arachidonic acid, initializing prostaglandin synthesis. A Tyr348-Tyr385 hydrogen bond appears to be conserved in both isoforms; this hydrogen bonding has the potential to modulate the positioning and reactivity of the Tyr385 side chain. The EPR signal from the Tyr385 radical undergoes a time-dependent transition from a wide doublet to a wide singlet species in both isoforms. In PGHS-2, this transition results from radical migration from Tyr385 to Tyr504. Localization of the radical to Tyr385 in the recombinant human PGHS-2 Y504F mutant was exploited in examining the effects of blocking Tyr385 hydrogen bonding by introduction of a further Y348F mutation. Cyclooxygenase and peroxidase activities were found to be maintained in the Y348F/Y504F mutant, but the Tyr385 radical was formed more slowly and had greater rotational freedom, as evidenced by observation of a transition from an initial wide doublet species to a narrow singlet species, a transition not seen in the parent Y504F mutant. The effect of disrupting Tyr385 hydrogen bonding on the cyclooxygenase active site structure was probed by examination of cyclooxygenase inhibitor kinetics. Aspirin treatment eliminated all oxygenase activity in the Y348F/Y504F double mutant, with no indication of the lipoxygenase activity observed in aspirin-treated wild-type PGHS-2. Introduction of the Y348F mutation also strengthened the time-dependent inhibitory action of nimesulide. These results suggest that removal of Tyr348-Tyr385 hydrogen bonding in PGHS-2 allows greater conformational flexibility in the cyclooxygenase active site, resulting in altered interactions with inhibitors and altered Tyr385 radical behavior.
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Affiliation(s)
| | | | | | - Richard J. Kulmacz
- To whom correspondence should be addressed: Department of Internal Medicine, University of Texas Health Science Center, MSB 5.284, 6431 Fannin St., Houston, TX 77225. . Phone: (713) 500-6772. Fax: (713) 500-6810
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Mollace V, Muscoli C, Masini E, Cuzzocrea S, Salvemini D. Modulation of prostaglandin biosynthesis by nitric oxide and nitric oxide donors. Pharmacol Rev 2005; 57:217-52. [PMID: 15914468 DOI: 10.1124/pr.57.2.1] [Citation(s) in RCA: 249] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The biosynthesis and release of nitric oxide (NO) and prostaglandins (PGs) share a number of similarities. Two major forms of nitric-oxide synthase (NOS) and cyclooxygenase (COX) enzymes have been identified to date. Under normal circumstances, the constitutive isoforms of these enzymes (constitutive NOS and COX-1) are found in virtually all organs. Their presence accounts for the regulation of several important physiological effects (e.g. antiplatelet activity, vasodilation, and cytoprotection). On the other hand, in inflammatory setting, the inducible isoforms of these enzymes (inducible NOS and COX-2) are detected in a variety of cells, resulting in the production of large amounts of proinflammatory and cytotoxic NO and PGs. The release of NO and PGs by the inducible isoforms of NOS and COX has been associated with the pathological roles of these mediators in disease states as evidenced by the use of selective inhibitors. An important link between the NOS and COX pathways was made in 1993 by Salvemini and coworkers when they demonstrated that the enhanced release of PGs, which follows inflammatory mechanisms, was nearly entirely driven by NO. Such studies raised the possibility that COX enzymes represent important endogenous "receptor" targets for modulating the multifaceted roles of NO. Since then, numerous papers have been published extending the observation across various cellular systems and animal models of disease. Furthermore, other studies have highlighted the importance of such interaction in physiology as well as in the mechanism of action of drugs such as organic nitrates. More importantly, mechanistic studies of how NO switches on/off the PG/COX pathway have been undertaken and additional pathways through which NO modulates prostaglandin production unraveled. On the other hand, NO donors conjugated with COX inhibitors have recently found new interest in the understanding of NO/COX reciprocal interaction and potential clinical use. The purpose of this article is to cover the advances which have occurred over the years, and in particular, to summarize experimental data that outline how the discovery that NO modulates prostaglandin production has impacted and extended our understanding of these two systems in physiopathological events.
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Affiliation(s)
- Vincenzo Mollace
- Faculty of Pharmacy, University of Catanzaro Magna Graecia, Roccelletta di Borgia, Catanazaro, Italy
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24
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Rouzer CA, Marnett LJ. Glycerylprostaglandin synthesis by resident peritoneal macrophages in response to a zymosan stimulus. J Biol Chem 2005; 280:26690-700. [PMID: 15917246 DOI: 10.1074/jbc.m501021200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclooxygenase (COX)-2 oxygenates arachidonic acid (AA) and 2-arachidonylglycerol (2-AG) to endoperoxides, which are subsequently transformed to prostaglandins (PGs) and glycerylprostaglandins (PG-Gs). PG-G formation has not been demonstrated in intact cells treated with a physiological agonist. Resident peritoneal macrophages, which express COX-1, were pretreated with lipopolysaccharide to induce COX-2. Addition of zymosan caused release of 2-AG and production of the glyceryl esters of PGE2 and PGI2 over 60 min. The total quantity of PG-Gs (16 +/- 6 pmol/10(7) cells) was much lower than that of the corresponding PGs produced from AA (21,000 +/- 7,000 pmol/10(7) cells). The differences in PG-G and PG production were partially explained by differences in the amounts of 2-AG and AA released in response to zymosan. The selective COX-2 inhibitor, SC236, reduced PG-G and PG production by 49 and 17%, respectively, indicating a significant role for COX-1 in PG-G and especially PG synthesis. Time course studies indicated that COX-2-dependent oxygenation rapidly declined 20 min after zymosan addition. When exogenous 2-AG was added to macrophages, a substantial portion was hydrolyzed to AA and converted to PGs; 1 microm 2-AG yielded 820 +/- 200 pmol of PGs/10(7) cells and 78 +/- 41 pmol of PG-Gs/10(7) cells. SC236 reduced PG-G and PG production from exogenous 2-AG by 88 and 76%, respectively, indicating a more significant role for COX-2 in the utilization of exogenous substrate. In conclusion, lipopolysaccharide-pretreated macrophages produce PG-Gs from endogenous 2-AG during zymosan phagocytosis, but PG-G formation is limited by substrate hydrolysis and inactivation of COX-2.
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Affiliation(s)
- Carol A Rouzer
- Department of Biochemistry, the Vanderbilt Institute of Chemical Biology, the Center in Molecular Toxicology, Nashville, TN 37232-0146, USA
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25
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Takayama K, Yuhki KI, Ono K, Fujino T, Hara A, Yamada T, Kuriyama S, Karibe H, Okada Y, Takahata O, Taniguchi T, Iijima T, Iwasaki H, Narumiya S, Ushikubi F. Thromboxane A2 and prostaglandin F2alpha mediate inflammatory tachycardia. Nat Med 2005; 11:562-6. [PMID: 15834430 DOI: 10.1038/nm1231] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Accepted: 03/09/2005] [Indexed: 11/09/2022]
Abstract
Systemic inflammation induces various adaptive responses including tachycardia. Although inflammation-associated tachycardia has been thought to result from increased sympathetic discharge caused by inflammatory signals of the immune system, definitive proof has been lacking. Prostanoids, including prostaglandin (PG) D(2), PGE(2), PGF(2alpha), PGI(2) and thromboxane (TX) A(2), exert their actions through specific receptors: DP, EP (EP(1), EP(2), EP(3), EP(4)), FP, IP and TP, respectively. Here we have examined the roles of prostanoids in inflammatory tachycardia using mice that lack each of these receptors individually. The TXA(2) analog I-BOP and PGF(2alpha) each increased the beating rate of the isolated atrium of wild-type mice in vitro through interaction with TP and FP receptors, respectively. The cytokine-induced increase in beating rate was markedly inhibited in atria from mice lacking either TP or FP receptors. The tachycardia induced in wild-type mice by injection of lipopolysaccharide (LPS) was greatly attenuated in TP-deficient or FP-deficient mice and was completely absent in mice lacking both TP and FP. The beta-blocker propranolol did not block the LPS-induced increase in heart rate in wild-type animals. Our results show that inflammatory tachycardia is caused by a direct action on the heart of TXA(2) and PGF(2alpha) formed under systemic inflammatory conditions.
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Affiliation(s)
- Koji Takayama
- Department of Pharmacology, Asahikawa Medical College, Midorigaoka-Higashi 2-1-1-1, Asahikawa 078-8510, Japan
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26
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Ruan KH, Deng H, Wu J, So SP. The N-terminal membrane anchor domain of the membrane-bound prostacyclin synthase involved in the substrate presentation of the coupling reaction with cyclooxygenase. Arch Biochem Biophys 2005; 435:372-81. [PMID: 15708381 DOI: 10.1016/j.abb.2004.12.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2004] [Indexed: 11/29/2022]
Abstract
To mimic the native conditions, the cyclooxygenase (COX)/prostaglandin I(2) synthase (PGIS) coupling reaction system was used to determine the coordination of PGIS with COX for the biosynthesis of prostacyclin (PGI(2)) using arachidonic acid (AA) as a substrate in a membrane-bound environment. The membrane-bound PGIS exhibited a faster isomerization of PGH(2) produced by COX to PGI(2) than the detergent-solubilized PGIS. To determine whether the N-terminal domain of PGIS responds to the facilitation of PGH(2) movement (presentation) from COX to the active site of PGIS, the first 20 residues of PGIS (Delta20-PGIS) were deleted and expressed in COS-7 cells. Delta20-PGIS retained membrane-bound properties and exhibited a slower substrate presentation property. Furthermore, a chimeric molecule (PGIS/TXAS(8-27)) with the replacement of the first 20 residues of PGIS by the corresponding membrane anchor region (residues 8-27) of thromboxane A(2) synthase was created to evaluate the mechanism influencing the biosynthesis of PGI(2) in coordination with COX. The chimera revealed a multiple fold delay in the PGH(2) presentation in low range concentrations of AA (0.3-3muM) at 30s reactions. However, the delay could be recovered by a longer incubation time in high range concentrations of AA (>10muM), but not in low range concentrations of AA. These results demonstrated that the N-terminal domain of PGIS plays a role in the facilitation of the substrate presentation to the PGIS active site in low concentrations of AA, which may be a physiological condition. The TXAS N-terminal domain could not replace the function of the corresponding domain of PGIS, indicating that the facilitation of the substrate presentation is specific.
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Affiliation(s)
- Ke-He Ruan
- Department of Internal Medicine, The University of Texas Health Science Center, Houston, TX 77030, USA.
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27
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Rouzer CA, Jacobs AT, Nirodi CS, Kingsley PJ, Morrow JD, Marnett LJ. RAW264.7 cells lack prostaglandin-dependent autoregulation of tumor necrosis factor-alpha secretion. J Lipid Res 2005; 46:1027-37. [PMID: 15722559 DOI: 10.1194/jlr.m500006-jlr200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Studies of the response of RAW264.7 cells (RAW) to lipopolysaccharide (LPS) were carried out to determine why these cells do not demonstrate the prostaglandin (PG)-dependent autocrine regulation of tumor necrosis factor-alpha (TNF-alpha) secretion observed in primary resident peritoneal macrophages (RPMs). The major cyclooxygenase (COX) product of LPS-stimulated RAW was PGD2, with lesser amounts of PGE2. LPS-treated RAW produced PGs more slowly and reached their maximal PG synthetic rate later than did LPS-treated RPMs, as a result of lower constitutive COX-1 expression and a slower rate of COX-2 induction. Cytosolic phospholipase A2 and levels of free arachidonic acid were similar in RAW and RPMs. In contrast to RPMs, LPS-treated RAW produced high quantities of TNF-alpha, which were not altered in the presence of COX inhibitors. This failure of endogenous PGs to suppress TNF-alpha secretion was explained by the absence of the prostaglandin D2 receptor and the low levels of PGE2 produced during the first 2 h of the LPS response. These studies demonstrate that autocrine regulation of TNF-alpha secretion in response to LPS is greatly facilitated by a COX-1-mediated rapid accumulation of PGs as well by a correspondence between the PGs produced and the receptors expressed by the cells.
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Affiliation(s)
- Carol A Rouzer
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA.
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Park H, Lee S. Free energy perturbation approach to the critical assessment of selective cyclooxygenase-2 inhibitors. J Comput Aided Mol Des 2005; 19:17-31. [PMID: 16059664 DOI: 10.1007/s10822-005-0098-5] [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: 10/07/2004] [Accepted: 12/29/2004] [Indexed: 11/24/2022]
Abstract
The discovery of selective cyclooxygenase-2 (COX-2) inhibitors represents a major achievement of the efforts over the past few decades to develop therapeutic treatments for inflammation. To gain insights into designing new COX-2-selective inhibitors, we address the energetic and structural basis for the selective inhibition of COX isozymes by means of a combined computational protocol involving docking experiment, force field design for the heme prothetic group, and free energy perturbation (FEP) simulation. We consider both COX-2- and COX-1-selective inhibitors taking the V523I mutant of COX-2 to be a relevant structural model for COX-1 as confirmed by a variety of experimental and theoretical evidences. For all COX-2-selective inhibitors under consideration, we find that free energies of binding become less favorable as the receptor changes from COX-2 to COX-1, due to the weakening and/or loss of hydrogen bond and hydrophobic interactions that stabilize the inhibitors in the COX-2 active site. On the other hand, COX-1-selective oxicam inhibitors gain extra stabilization energy with the change of residue 523 from valine to isoleucine because of the formations of new hydrogen bonds in the enzyme-inhibitor complexes. The utility of the combined computational approach, as a valuable tool for in silico screening of COX-2-selective inhibitors, is further exemplified by identifying the physicochemical origins of the enantiospecific selective inhibition of COX-2 by alpha-substituted indomethacin ethanolamide inhibitors.
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Affiliation(s)
- Hwangseo Park
- School of Chemistry and Molecular Engineering, and Center for Molecular Catalysis, Seoul National University, Seoul 151-747, South Korea.
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Cao WM, Murao K, Imachi H, Yu X, Dobashi H, Yoshida K, Muraoka T, Kotsuna N, Nagao S, Wong NCW, Ishida T. Insulin-like growth factor-i regulation of hepatic scavenger receptor class BI. Endocrinology 2004; 145:5540-7. [PMID: 15345670 DOI: 10.1210/en.2004-0330] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
High-density lipoprotein mediates a normal physiological process called reverse cholesterol transport. This process enables the transfer of cholesterol from peripheral tissues to the liver for further metabolism and eventual secretion in the form of bile. The scavenger receptor of the B class (SR-BI), human homolog of SR-BI, and CD36 and LIMPII analogous-1 (CLA-1) are different names for the same receptor that facilitates hepatocellular uptake of cholesterol from high-density lipoprotein. The pivotal role of this receptor in enterohepatic circulation of cholesterol and bile salts underlies our interest to study the regulation of hepatic SR-BI gene in response to the actions of IGF-I. The results of our studies showed that endogenous expression of SR-BI/CLA-1 was suppressed by exposure to GH or IGF-I in cultured HepG2 cells. This observation extended to a whole animal model of rats continuously infused with IGF-I. IGF-I decreased transcriptional activity of the SR-BI promoter. However, the inhibitory effect of IGF-I on SR-BI/CLA-1 promoter activity was abrogated by wortmannin, a specific inhibitor of phosphoinositide 3-kinase (PI3-K). Exposure of HepG2 cells to IGF-I elicited a rapid phosphorylation of Akt. We also demonstrated that the constitutively active form of both p110, a subunit of PI3-K, and Akt inhibited activity of the human SR-BI/CLA-1 promoter. Furthermore, the dominant-negative mutant of Akt abolished the ability of IGF-I to suppress activity of the SR-BI/CLA-1 promoter. In conclusion, PI3-K/Akt pathways participate in IGF-I-suppression of SR-BI/CLA-1 expression, which suggests that the activation of Akt plays an important role in cholesterol metabolism in liver.
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Affiliation(s)
- Wen M Cao
- First Department of Internal Medicine, Faculty of Medicine, Kagawa University, Kagawa, Japan
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Jo EJ, Lee HY, Lee YN, Kim JI, Kang HK, Park DW, Baek SH, Kwak JY, Bae YS. Group IB Secretory Phospholipase A2 Stimulates CXC Chemokine Ligand 8 Production via ERK and NF-κB in Human Neutrophils. THE JOURNAL OF IMMUNOLOGY 2004; 173:6433-9. [PMID: 15528384 DOI: 10.4049/jimmunol.173.10.6433] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Although the level of group IB secretory phospholipase A(2) (sPLA(2)-IB) has been reported to be up-regulated during inflammatory response, the role of sPLA(2)-IB on the regulation of inflammation and immune responses has not been fully elucidated. In this study, we found that sPLA(2)-IB stimulates the expression and secretion of CXCL8 without affecting other proinflammatory cytokines, such as IL-1beta or TNF alpha in human neutrophils. The induction of CXCL8 secretion by sPLA(2)-IB occurs at both the transcription and translational levels and correlates with activation of NF-kappaB. Moreover, the NF-kappaB inhibitors pyrrolidinedithiocarbamate, dexamethasone, or sulfasalazine were found to prevent CXCL8 production by sPLA(2)-IB in human neutrophils. In addition, the signaling events induced by sPLA(2)-IB included activation of the MAPK ERK and an increase in intracellular Ca(2+), which are both required for CXCL8 production. The exogenous addition of sPLA(2)-IB did not induce arachidonic acid release from human neutrophils, and the inactivation of sPLA(2)-IB by EGTA did not affect CXCL8 production by sPLA(2)-IB in human neutrophils. Taken together, we suggest that sPLA(2)-IB plays a role in the modulation of inflammatory and immune responses via the sPLA(2) receptor, by inducing CXCL8 in human neutrophils.
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Affiliation(s)
- Eun Jin Jo
- Medical Research Center for Cancer Molecular Therapy and Dong-A University, Busan 602-714, Korea
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31
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Rouzer CA, Kingsley PJ, Wang H, Zhang H, Morrow JD, Dey SK, Marnett LJ. Cyclooxygenase-1-dependent prostaglandin synthesis modulates tumor necrosis factor-alpha secretion in lipopolysaccharide-challenged murine resident peritoneal macrophages. J Biol Chem 2004; 279:34256-68. [PMID: 15181007 DOI: 10.1074/jbc.m402594200] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Comprehensive studies of prostaglandin (PG) synthesis in murine resident peritoneal macrophages (RPM) responding to bacterial lipopolysaccharide (LPS) revealed that the primary PGs produced by RPM were prostacyclin and PGE(2). Detectable increases in net PG formation occurred within the first hour, and maximal PG formation had occurred by 6-10 h after LPS addition. Free arachidonic acid levels rose and peaked at 1-2 h after LPS addition and then returned to baseline. Cyclooxygenase-2 (COX-2) and microsomal PGE synthase levels markedly increased upon exposure of RPM to LPS, with the most rapid increases in protein expression occurring 2-6 h after addition of the stimulus. RPM constitutively expressed high levels of COX-1. Studies using isoform-selective inhibitors and RPM from mice bearing targeted deletions of ptgs-1 and ptgs-2 demonstrated that COX-1 contributes significantly to PG synthesis in RPM, especially during the initial 1-2 h after LPS addition. Selective inhibition of either COX isoform resulted in increased secretion of tumor necrosis factor-alpha (TNF-alpha); however, this effect was much greater with the COX-1 than with the COX-2 inhibitor. These results demonstrate autocrine regulation of TNF-alpha secretion by endogenous PGs synthesized primarily by COX-1 in RPM and suggest that COX-1 may play a significant role in the regulation of the early response to endotoxemia.
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Affiliation(s)
- Carol A Rouzer
- Departments of Biochemistry and Chemistry, Vanderbilt Institute for Chemical Biology, Vanderbilt University School of medicine, Nashville, TN 37232-0146.
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32
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Aronov AM, Bemis GW. A minimalist approach to fragment-based ligand design using common rings and linkers: Application to kinase inhibitors. Proteins 2004; 57:36-50. [PMID: 15326593 DOI: 10.1002/prot.20173] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We present a novel method for stepwise scaffold assembly that integrates fragment-by-fragment ligand design approaches with high-throughput virtual library screening (COREGEN). As an extension of our earlier studies of common features present in drug molecules, we investigate the hypothesis that most pharmaceutically interesting ligands can be expressed in terms of the ring-linker frameworks that comprise them. Analysis of 119 published kinase inhibitors from at least 18 different targets illustrates that a basis set of 4 rings and 8 linkers is sufficient to describe approximately 90% of ring and linker occurrences, respectively. A similar result was derived from a larger set of approximately 40,000 kinase inhibitors from curated patents. A method for ring-linker-based assembly of scaffold libraries that uses experimental information to guide the placement of anchor fragments is validated using a set of reported kinase inhibitors of Bcr-Abl, Cdk2, and Src. In every case, the predominant structural motif of reported ligand cores is reproduced and variations are suggested. To underscore generality of this approach, a novel scaffold for a cyclooxygenase-2 (COX-2) selective ligand is proposed.
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Affiliation(s)
- Alex M Aronov
- Vertex Pharmaceuticals Inc., Cambridge, Massachusetts 02139-4242, USA.
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33
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Rowlinson SW, Kiefer JR, Prusakiewicz JJ, Pawlitz JL, Kozak KR, Kalgutkar AS, Stallings WC, Kurumbail RG, Marnett LJ. A novel mechanism of cyclooxygenase-2 inhibition involving interactions with Ser-530 and Tyr-385. J Biol Chem 2003; 278:45763-9. [PMID: 12925531 DOI: 10.1074/jbc.m305481200] [Citation(s) in RCA: 224] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A variety of drugs inhibit the conversion of arachidonic acid to prostaglandin G2 by the cyclooxygenase (COX) activity of prostaglandin endoperoxide synthases. Several modes of inhibitor binding in the COX active site have been described including ion pairing of carboxylic acid containing inhibitors with Arg-120 of COX-1 and COX-2 and insertion of arylsulfonamides and sulfones into the COX-2 side pocket. Recent crystallographic evidence suggests that Tyr-385 and Ser-530 chelate polar or negatively charged groups in arachidonic acid and aspirin. We tested the generality of this binding mode by analyzing the action of a series of COX inhibitors against site-directed mutants of COX-2 bearing changes in Arg-120, Tyr-355, Tyr-348, and Ser-530. Interestingly, diclofenac inhibition was unaffected by the mutation of Arg-120 to alanine but was dramatically attenuated by the S530A mutation. Determination of the crystal structure of a complex of diclofenac with murine COX-2 demonstrates that diclofenac binds to COX-2 in an inverted conformation with its carboxylate group hydrogen-bonded to Tyr-385 and Ser-530. This finding represents the first experimental demonstration that the carboxylate group of an acidic non-steroidal anti-inflammatory drug can bind to a COX enzyme in an orientation that precludes the formation of a salt bridge with Arg-120. Mutagenesis experiments suggest Ser-530 is also important in time-dependent inhibition by nimesulide and piroxicam.
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Affiliation(s)
- Scott W Rowlinson
- Department of Biochemistry, Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, USA
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34
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Garavito RM, Mulichak AM. The structure of mammalian cyclooxygenases. ANNUAL REVIEW OF BIOPHYSICS AND BIOMOLECULAR STRUCTURE 2003; 32:183-206. [PMID: 12574066 DOI: 10.1146/annurev.biophys.32.110601.141906] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cyclooxygenases-1 and -2 (COX-1 and COX-2, also known as prostaglandin H2 synthases-1 and -2) catalyze the committed step in prostaglandin synthesis. COX-1 and -2 are of particular interest because they are the major targets of nonsteroidal antiinflammatory drugs (NSAIDs) including aspirin, ibuprofen, and the new COX-2-selective inhibitors. Inhibition of the COXs with NSAIDs acutely reduces inflammation, pain, and fever, and long-term use of these drugs reduces the incidence of fatal thrombotic events, as well as the development of colon cancer and Alzheimer's disease. In this review, we examine how the structures of COXs relate mechanistically to cyclooxygenase and peroxidase catalysis and how alternative fatty acid substrates bind within the COX active site. We further examine how NSAIDs interact with COXs and how differences in the structure of COX-2 result in enhanced selectivity toward COX-2 inhibitors.
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Affiliation(s)
- R Michael Garavito
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824-1319, USA.
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35
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Kulmacz RJ, van der Donk WA, Tsai AL. Comparison of the properties of prostaglandin H synthase-1 and -2. Prog Lipid Res 2003; 42:377-404. [PMID: 12814642 DOI: 10.1016/s0163-7827(03)00023-7] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Biosynthesis of prostanoid lipid signaling agents from arachidonic acid begins with prostaglandin H synthase (PGHS), a hemoprotein in the myeloperoxidase family. Vertebrates from humans to fish have two principal isoforms of PGHS, termed PGHS-1 and-2. These two isoforms are structurally quite similar, but they have very different pathophysiological roles and are regulated very differently at the level of catalysis. The focus of this review is on the structural and biochemical distinctions between PGHS-1 and-2, and how these differences relate to the functional divergence between the two isoforms.
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Affiliation(s)
- Richard J Kulmacz
- Department of Internal Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
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36
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Rouzer CA, Marnett LJ. Mechanism of free radical oxygenation of polyunsaturated fatty acids by cyclooxygenases. Chem Rev 2003; 103:2239-304. [PMID: 12797830 DOI: 10.1021/cr000068x] [Citation(s) in RCA: 184] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Carol A Rouzer
- A. B. Hancock Jr. Memorial Laboratory for Cancer Research, Department of Biochemistry, Vanderbilt Institute of Chemical Biology, Vanderbilt Ingram Comprehensive Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, USA
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37
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Imachi H, Murao K, Cao W, Tada S, Taminato T, Wong NCW, Takahara J, Ishida T. Expression of human scavenger receptor B1 on and in human platelets. Arterioscler Thromb Vasc Biol 2003; 23:898-904. [PMID: 12649086 DOI: 10.1161/01.atv.0000067429.46333.7b] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The abundance of HDL particles correlates inversely with the incidence of coronary heart disease. The human scavenger receptor B1 (hSR-B1/CLA-1) is a receptor for HDL. Expression of hSR-B1/CLA-1 mRNA and protein in human platelets was determined using reverse transcriptase-polymerase chain reaction and Western blot, respectively. Presence of the protein on the surface of platelets was shown using flow cytometry. METHODS AND RESULTS Immunochemical staining for hSR-B1/CLA-1 showed that it was expressed in megakaryocytes, the platelet precursors of human bone marrow. These findings prompted us to ask whether hSR-B1/CLA-1 was differentially expressed on platelets obtained from patients with atherosclerotic disease compared with those in control subjects. Our findings showed that abundance of hSR-B1/CLA-1 was significantly reduced on the surface of platelets from patients with atherosclerotic disease. The reduced levels of hSR-B1/CLA-1 were associated with increased cholesterol ester content in platelets from patients with atherosclerotic disease compared with control subjects. A negative correlation existed between hSR-B1/CLA-1 expression and platelet aggregation. In summary, our studies show that the HDL receptor hSR-B1/CLA-1 is expressed in platelets and their precursor, the megakaryocyte. The levels of hSR-B1/CLA-1 expression correlate inversely with cholesterol ester content and platelet aggregation. CONCLUSIONS These findings suggest that determining the level of hSR-B1/CLA-1 expression on the platelets may be a useful clinical marker for atherosclerotic diseases.
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Affiliation(s)
- Hitomi Imachi
- First Department of Internal Medicine, Central Laboratory, Kagawa Medical University, 1750-1, Miki-cho, Kita-gun, Kagawa, 761-0793, Japan
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38
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Hood WF, Gierse JK, Isakson PC, Kiefer JR, Kurumbail RG, Seibert K, Monahan JB. Characterization of celecoxib and valdecoxib binding to cyclooxygenase. Mol Pharmacol 2003; 63:870-7. [PMID: 12644588 DOI: 10.1124/mol.63.4.870] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Two compounds (celecoxib and valdecoxib) from the diarylheterocycle class of cyclooxygenase inhibitors were radiolabeled and used to characterize their binding to cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), several single-point variants of COX-2 (Val523Ile, Tyr355Ala, Arg120Ala, Arg120Gln, Arg120Asn) and one triple-point variant of COX-2 [Val523Ile, Arg513His, Val434Ile (IHI)]. We demonstrate highly specific and saturable binding of these inhibitors to COX-2. Under the same assay conditions, little or no specific binding to COX-1 could be detected. The affinity of [(3)H]celecoxib for COX-2 (K(D) = 2.3 nM) was similar to the affinity of [(3)H]valdecoxib (K(D) = 3.2 nM). The binding to COX-2 seems to be both rapid and slowly reversible with association rates of 5.8 x 10(6)/M/min and 4.5 x 10(6)/M/min and dissociation rates of 14 x 10(-3)/min (t(1/2) = 50 min) and 7.0 x 10(-3)/min (t(1/2) = 98 min) for [(3)H]celecoxib and [(3)H]valdecoxib, respectively. These association rates increased (4- to 11-fold) when the charged arginine residue located at the entrance to the main hydrophobic channel was mutated to smaller uncharged amino acids (Arg120Ala, Arg120Gln, and Arg120Asn). Mutation of residues located within the active site of COX-2 that define a 'side pocket' (Tyr355Ala, Val523Ile, IHI) of the main channel had a greater effect on the dissociation rate than the association rate. These mutations, which modified the shape of and access to the 'side pocket', affected the binding affinity of [(3)H]valdecoxib more than that of [(3)H]celecoxib. These binding studies provide direct insight into the properties and binding constants of celecoxib and valdecoxib to COX-2.
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Affiliation(s)
- William F Hood
- Pharmacia Research and Development, St. Louis, Missouri, USA.
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39
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Garg R, Kurup A, Mekapati SB, Hansch C. Cyclooxygenase (COX) inhibitors: a comparative QSAR study. Chem Rev 2003; 103:703-32. [PMID: 12630850 DOI: 10.1021/cr020464a] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Rajni Garg
- Chemistry Department, Clarkson University, Potsdam, NY 13699, USA
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40
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Pouplana R, Lozano JJ, Pérez C, Ruiz J. Structure-based QSAR study on differential inhibition of human prostaglandin endoperoxide H synthase-2 (COX-2) by nonsteroidal anti-inflammatory drugs. J Comput Aided Mol Des 2002; 16:683-709. [PMID: 12650588 DOI: 10.1023/a:1022488507391] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The prostaglandin-endoperoxide H synthase-1 (PGHS- 1) and prostaglandin-endoperoxide H synthase-2 (PGHS-2) are the targets of nonsteroidal anti-inflammatory drugs (NSAIDs). It appears that the high degree of selectivity for inhibition of PGHS-2 shown by certain compounds is the result of two mechanisms (time-dependent, time-independent inhibition), by which they interact with each isoform. Molecular models of the complexes formed by indomethacin, sulindac, fenamates, 2-phenylpropionic acids and selective cyclooxygenase-2 (COX-2) inhibitors with the cyclooxygenase active site of human PGHS-2 have been built, paying particular attention to water molecules that participate in the hydrogen-bonding network at the polar active site entrance. The stability of the complexes has been assessed by molecular dynamics simulations and interaction energy decomposition analysis, and their biological significance has been discussed in light of available X-ray crystallographic and kinetic results. The selective PGHS-2 inhibitors exploit the extra space of a side-pocket in the active site of PGHS-2 that is not found in PGHS-1. The results suggest that active site hydration together with residues Tyr355, Glu524, Arg120 and Arg513 are crucial to understand the time-dependent inhibition mechanism. A marked relationship between the isoform selectivity and tightly interactions with residues into the side pocket bordered by Val523 is also found.
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Affiliation(s)
- R Pouplana
- Department de Fisicoquímica, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII, s/n, 08028 Barcelona, Spain.
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41
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Abstract
Recent studies of the mechanism and selectivity of inhibition of cyclooxygenase enzymes are reviewed. The structural determinants of inhibition by the non-selective inhibitor, aspirin, and COX-2-selective diarylheterocycles are considered. Kinetic investigations indicate that the time-dependence of binding and inhibition of COX-1 and COX-2 by diarylheterocycles is more complex than originally postulated. The selectivity of inhibition is not determined by differences in the rates of association of the inhibitors with the two enzymes but rather by differences in the rates of dissociation. New strategies for the development of COX-2-selective inhibitors are highlighted.
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Affiliation(s)
- Lawrence J Marnett
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37215, USA.
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42
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Garavito RM, Malkowski MG, DeWitt DL. The structures of prostaglandin endoperoxide H synthases-1 and -2. Prostaglandins Other Lipid Mediat 2002; 68-69:129-52. [PMID: 12432914 DOI: 10.1016/s0090-6980(02)00026-6] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Despite the marked differences in their physiological roles, the structures and catalytic functions of the prostaglandin H2 endoperoxide synthases-1 and -2 (PGHS-1 and -2) are almost completely identical. These integral membrane proteins catalyze the conversion of arachidonic acid to PGG2 and finally to PGH2. The crystal structures of PGHS-1 and -2 provide new insights into the catalytic mechanism for fatty acid oxygenation. Moreover, a clearer picture emerges to explain how a handful of amino acid substitutions can give rise to subtle differences in ligand binding between the two isoforms. These "small" alterations of isozyme structure are sufficient to allow the design of new, isoform-selective drugs.
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Affiliation(s)
- R Michael Garavito
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing 48824, USA.
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43
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Grosser T, Yusuff S, Cheskis E, Pack MA, FitzGerald GA. Developmental expression of functional cyclooxygenases in zebrafish. Proc Natl Acad Sci U S A 2002; 99:8418-23. [PMID: 12011329 PMCID: PMC123082 DOI: 10.1073/pnas.112217799] [Citation(s) in RCA: 157] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2001] [Accepted: 04/10/2002] [Indexed: 11/18/2022] Open
Abstract
Study of the cyclooxygenases (COXs) has been limited by the role of COX-2 in murine reproduction and renal organogenesis. We sought to characterize COX expression and function in zebrafish (z). Full-length cDNAs of zCOX-1 and zCOX-2 were cloned and assigned to conserved regions of chromosomes 5 and 2, respectively. The deduced proteins are 67% homologous with their human orthologs. Prostaglandin (PG) E(2) is the predominant zCOX product detected by mass spectrometry. Pharmacological inhibitors demonstrate selectivity when directed against heterologously expressed zCOX isoforms. Zebrafish thrombocyte aggregation ex vivo and hemostasis in vivo are sensitive to inhibition of zCOX-1, but not zCOX-2. Both zCOXs were widely expressed during development, and knockdown of zCOX-1 causes growth arrest during early embryogenesis. zCOX-1 is widely evident in the embryonic vasculature, whereas zCOX-2 exhibits a more restricted pattern of expression. Both zCOX isoforms are genetically and functionally homologous to their mammalian orthologs. The zebrafish affords a tractable model system for the study of COX biology and development.
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Affiliation(s)
- Tilo Grosser
- Center for Experimental Therapeutics, University of Pennsylvania School of Medicine, 153 Johnson Pavilion, 3620 Hamilton Walk, Philadelphia, PA 19104, USA
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44
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Kozak KR, Prusakiewicz JJ, Rowlinson SW, Marnett LJ. Enantiospecific, selective cyclooxygenase-2 inhibitors. Bioorg Med Chem Lett 2002; 12:1315-8. [PMID: 11965379 DOI: 10.1016/s0960-894x(02)00133-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Cyclooxygenase inhibition studies with novel indomethacin alkanolamides demonstrate the potential for dramatic differences in inhibitor properties conferred by subtle structural modifications. The transformation of non-selective alpha-(S)-substituted indomethacin ethanolamides to potent, COX-2 selective inhibitors by simple stereocenter inversion highlights this property.
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Affiliation(s)
- Kevin R Kozak
- Department of Biochemistry, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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45
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Abstract
Disease prevention is one area that both public and governmental agencies strongly support owing to its potential for an improved lifestyle and a reduction in health care costs. In this review, we focus on the clinical development of one target for cancer prevention, the COX-2 enzyme. This provides an excellent example of how basic research in biochemistry and pharmacology can lead to translational studies and eventually to approval of a drug by the FDA for use as a chemopreventive agent in humans. It is hoped that, as the genome sequence is understood more clearly, other targets will emerge that will provide even more effective drugs for future cancer prevention.
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Affiliation(s)
- Lawrence J Marnett
- A.B. Hancock Jr. Memorial Laboratory for Cancer Research, Center in Molecular Toxicology, Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA.
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46
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Shimamura T, Hsu TC, Colburn NH, Bejcek BE. Activation of NF-kappaB is required for PDGF-B chain to transform NIH3T3 cells. Exp Cell Res 2002; 274:157-67. [PMID: 11855867 DOI: 10.1006/excr.2001.5449] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Elucidating the secondary signaling molecules that are necessary for platelet-derived growth factor (PDGF) to stimulate tumor development will be crucial to the understanding and treatment of a variety of cancers. Several lines of evidence have indicated that the transcription factor NF-kappaB plays a central role in transformation induced by Ha-ras and Bcr-abl, but nothing is known concerning its role in transformation by PDGF. Here we demonstrate that transcription from a promoter containing NF-kappaB binding sequences as well as the DNA binding activity of NF-kappaB were increased in PDGF-B-chain-transformed mouse fibroblast cells. Focus formation of PDGF-B-chain-transformed mouse fibroblasts was suppressed by treatment with acetylsalicylic acid (ASA) and salicylic acid, which are known inhibitors of NF-kappaB activation, but other nonsteroidal anti-inflammatory drugs that do not have an effect on NF-kappaB activity did not affect focus formation in these cells. Furthermore, expression of a dominant negative mutant of IkappaBalpha, pMEIkappaBalpha67CJ, and a dominant negative mutant of p65, p65DeltaC, resulted in decreased focus formation and NF-kappaB activity. Therefore, the transcription factor NF-kappaB plays a vital role in PDGF-B chain transformation of mouse fibroblast cells, and the NF-kappaB activity is sensitive to treatment with ASA.
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Affiliation(s)
- Takeshi Shimamura
- Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008, USA
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47
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Llorens O, Perez JJ, Palomer A, Mauleon D. Differential binding mode of diverse cyclooxygenase inhibitors. J Mol Graph Model 2002; 20:359-71. [PMID: 11885959 DOI: 10.1016/s1093-3263(01)00135-8] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Non-steroidal anti-inflammatory drugs (NSAIDs) are competitive inhibitors of cyclooxygenase (COX), the enzyme that mediates biosynthesis of prostaglandins and thromboxanes from arachidonic acid. There are at least two different isoforms of the enzyme known as COX-1 and -2. Site directed mutagenesis studies suggest that non-selective COX inhibitors of diverse chemical families exhibit differential binding modes to the two isozymes. These results cannot clearly be explained from the sole analysis of the crystal structures of COX available from X-ray diffraction studies. With the aim to elucidate the structural features governing the differential inhibitory binding behavior of these inhibitors, molecular modeling studies were undertaken to generate atomic models compatible with the experimental data available. Accordingly, docking of different COX inhibitors, including selective and non-selective ligands: rofecoxib, ketoprofen, suprofen, carprofen, zomepirac, indomethacin, diclofenac and meclofenamic acid were undertaken using the AMBER program. The results of the present study provide new insights into a better understanding of the differential binding mode of diverse families of COX inhibitors, and are expected to contribute to the design of new selective compounds.
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Affiliation(s)
- Oriol Llorens
- Department of d'Enginyeria Química, UPC, ETSEIB, Barcelona, Spain
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48
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Kothekar V, Sahi S. Design of peptides and peptidomimetics as COX-2 selective inhibitors. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s0166-1280(01)00659-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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49
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Pouplana R, Lozano JJ, Ruiz J. Molecular modelling of the differential interaction between several non-steroidal anti-inflammatory drugs and human prostaglandin endoperoxide H synthase-2 (h-PGHS-2). J Mol Graph Model 2002; 20:329-43. [PMID: 11858641 DOI: 10.1016/s1093-3263(01)00133-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The prostaglandin endoperoxide H synthase-1 (PGHS-1) and prostaglandin endoperoxide H synthase-2 (PGHS-2) are the targets of non-steroidal anti-inflammatory drugs (NSAIDs). The high degree of selectivity for inhibition of PGHS-2 shown by certain compounds appears to stem from two mechanisms (time-dependent, time-independent inhibition) by which they interact with each isoform. Molecular models of the complexes between indomethacin, fenamates, 2-phenylpropionic acids and the selective cyclooxygenase-2 (COX-2) inhibitors, with the cyclooxygenase active site of human PGHS-2 have been built by combining homology modelling, conformational searching and automated docking techniques. The stability of the resulting complexes has been assessed by molecular dynamics simulations combined with extended linear response calculations. The results allow us to identify regions of biological significance consistent with both X-ray crystallographic and kinetic results. The selective PGHS-2 inhibitors exploit the extra space of a side-pocket in the active site of PGHS-2 that is not found in PGHS-1. The results obtained point out a marked relationship between the experimental affinity and the electrostatic interaction energy alone for a series of NSAIDs. Analysis of the structural and the energetic data provides evidence supporting that network of hydrogen bonds between Tyr355, Glu524, Arg120 and Arg513 might be involved in mediating the binding of the time-dependent inhibitors of PGHS-2.
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Affiliation(s)
- R Pouplana
- Departament de Fisicoquímica, Facultat de Farmàcia, Universitat de Barcelona, Spain.
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Kozak KR, Prusakiewicz JJ, Rowlinson SW, Schneider C, Marnett LJ. Amino acid determinants in cyclooxygenase-2 oxygenation of the endocannabinoid 2-arachidonylglycerol. J Biol Chem 2001; 276:30072-7. [PMID: 11402053 DOI: 10.1074/jbc.m104467200] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The endocannabinoid, 2-arachidonylglycerol (2-AG), is an endogenous ligand for the central (CB1) and peripheral (CB2) cannabinoid receptors and has been shown to be efficiently and selectively oxygenated by cyclooxygenase (COX)-2. We have investigated 2-AG/COX-2 interactions through site-directed mutagenesis. An evaluation of more than 20 site-directed mutants of murine COX-2 has allowed for the development of a model of 2-AG binding within the COX-2 active site. Most strikingly, these studies have identified Arg-513 as a critical determinant in the ability of COX-2 to efficiently generate prostaglandin H(2) glycerol ester, explaining, in part, the observed isoform selectivity for this substrate. Mutational analysis of Leu-531, an amino acid located directly across from Arg-513 in the COX-2 active site, suggests that 2-AG is shifted in the active site away from this hydrophobic residue and toward Arg-513 relative to arachidonic acid. Despite this difference, aspirin-treated COX-2 oxygenates 2-AG to afford 15-hydroxyeicosatetraenoic acid glycerol ester in a reaction analogous to the C-15 oxygenation of arachidonic acid observed with acetylated COX-2. Finally, the differences in substrate binding do not alter the stereospecificity of the cyclooxygenase reaction; 2-AG-derived and arachidonic acid-derived products share identical stereochemistry.
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Affiliation(s)
- K R Kozak
- Departments of Biochemistry and Chemistry, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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