1
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Oliw EH. Thirty years with three-dimensional structures of lipoxygenases. Arch Biochem Biophys 2024; 752:109874. [PMID: 38145834 DOI: 10.1016/j.abb.2023.109874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 12/17/2023] [Accepted: 12/17/2023] [Indexed: 12/27/2023]
Abstract
The X-ray crystal structures of soybean lipoxygenase (LOX) and rabbit 15-LOX were reported in the 1990s. Subsequent 3D structures demonstrated a conserved U-like shape of the substrate cavities as reviewed here. The 8-LOX:arachidonic acid (AA) complex showed AA bound to the substrate cavity carboxylate-out with C10 at 3.4 Å from the iron metal center. A recent cryo-electron microscopy (EM) analysis of the 12-LOX:AA complex illustrated AA in the same position as in the 8-LOX:AA complex. The 15- and 12-LOX complexes with isoenzyme-specific inhibitors/substrate mimics confirmed the U-fold. 5-LOX oxidizes AA to leukotriene A4, the first step in biosynthesis of mediators of asthma. The X-ray structure showed that the entrance to the substrate cavity was closed to AA by Phe and Tyr residues of a partly unfolded α2-helix. Recent X-ray analysis revealed that soaking with inhibitors shifted the short α2-helix to a long and continuous, which opened the substrate cavity. The α2-helix also adopted two conformations in 15-LOX. 12-LOX dimers consisted of one closed and one open subunit with an elongated α2-helix. 13C-ENDOR-MD computations of the 9-MnLOX:linoleate complex showed carboxylate-out position with C11 placed 3.4 ± 0.1 Å from the catalytic water. 3D structures have provided a solid ground for future research.
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Affiliation(s)
- Ernst H Oliw
- Department of Pharmaceutical Biosciences, Uppsala University, Box 591, SE 751 24, Uppsala, Sweden.
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2
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Zerangnasrabad S, Jabbari A, Khavari Moghadam E, Sadeghian H, Seyedi SM. Design, synthesis, and structure-activity relationship study of O-prenylated 3-acetylcoumarins as potent inhibitors of soybean 15-lipoxygenase. Drug Dev Res 2021; 82:826-834. [PMID: 33416204 DOI: 10.1002/ddr.21787] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 02/01/2023]
Abstract
In this work, the design, synthesis, and structure-activity relationships of a novel array of geranyloxy and farnesyloxy 3-acetylcoumarins were reported as potent soybean 15-lipoxygenase inhibitors. Among the prepared coumarins, 7-farnesyloxy-3-acetylcoumarin (12b) was found to be the most potent inhibitor by IC50 = 0.68 μM while O-geranyl substituents at positions 5 and 6 of 3-acetylcoumarin (10a and 11a) were not inhibitors. Using docking studies, the binding affinity and the preferred pose of synthetic compounds were considered. It was found that lipoxygenase inhibitory activity and prenyl length chain were directly related. The hydrophobic cavity of the enzyme was more effectively occupied by the farnesyl moiety of the potent inhibitor 12b rather than other derivatives. Also, with this pose of farnesyl chain in 7-farnesyloxy-3-acetylcoumarins, the acetyl group could be directed to the hydrophilic pocket in the active site.
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Affiliation(s)
- Sara Zerangnasrabad
- Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Atena Jabbari
- Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Elahe Khavari Moghadam
- Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Hamid Sadeghian
- Department of Laboratory Sciences, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Seyed Mohammad Seyedi
- Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
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3
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Ivanov I, Cruz A, Zhuravlev A, Di Venere A, Nicolai E, Stehling S, Lluch JM, González-Lafont À, Kuhn H. Conformational Heterogeneity and Cooperative Effects of Mammalian ALOX15. Int J Mol Sci 2021; 22:ijms22063285. [PMID: 33807076 PMCID: PMC8004969 DOI: 10.3390/ijms22063285] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/16/2021] [Accepted: 03/19/2021] [Indexed: 12/19/2022] Open
Abstract
Arachidonic acid lipoxygenases (ALOXs) have been suggested to function as monomeric enzymes, but more recent data on rabbit ALOX15 indicated that there is a dynamic monomer-dimer equilibrium in aqueous solution. In the presence of an active site ligand (the ALOX15 inhibitor RS7) rabbit ALOX15 was crystalized as heterodimer and the X-ray coordinates of the two monomers within the dimer exhibit subtle structural differences. Using native polyacrylamide electrophoresis, we here observed that highly purified and predominantly monomeric rabbit ALOX15 and human ALOX15B are present in two conformers with distinct electrophoretic mobilities. In silico docking studies, molecular dynamics simulations, site directed mutagenesis experiments and kinetic measurements suggested that in aqueous solutions the two enzymes exhibit motional flexibility, which may impact the enzymatic properties.
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Affiliation(s)
- Igor Ivanov
- Lomonosov Institute of Fine Chemical Technologies, MIREA—Russian Technological University, Vernadskogo pr. 86, 119571 Moscow, Russia; (I.I.); (A.Z.)
| | - Alejandro Cruz
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain; (A.C.); (J.M.L.); (À.G.-L.)
| | - Alexander Zhuravlev
- Lomonosov Institute of Fine Chemical Technologies, MIREA—Russian Technological University, Vernadskogo pr. 86, 119571 Moscow, Russia; (I.I.); (A.Z.)
| | - Almerinda Di Venere
- Department of Experimental Medicine, University of Tor Vergata, Via Montpellier 1, 00133 Rome, Italy; (A.D.V.); (E.N.)
| | - Eleonora Nicolai
- Department of Experimental Medicine, University of Tor Vergata, Via Montpellier 1, 00133 Rome, Italy; (A.D.V.); (E.N.)
| | - Sabine Stehling
- Institute of Biochemistry, Charite—University Medicine Berlin, Corporate member of Free University Berlin, Humboldt University Berlin and Berlin Institute of Health, Charitéplatz 1, D-10117 Berlin, Germany;
| | - José M. Lluch
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain; (A.C.); (J.M.L.); (À.G.-L.)
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
| | - Àngels González-Lafont
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain; (A.C.); (J.M.L.); (À.G.-L.)
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
| | - Hartmut Kuhn
- Institute of Biochemistry, Charite—University Medicine Berlin, Corporate member of Free University Berlin, Humboldt University Berlin and Berlin Institute of Health, Charitéplatz 1, D-10117 Berlin, Germany;
- Correspondence: ; Tel.: +49-30-450-528040
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Clemente SM, Martínez-Costa OH, Monsalve M, Samhan-Arias AK. Targeting Lipid Peroxidation for Cancer Treatment. Molecules 2020; 25:E5144. [PMID: 33167334 PMCID: PMC7663840 DOI: 10.3390/molecules25215144] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/31/2020] [Accepted: 11/03/2020] [Indexed: 02/07/2023] Open
Abstract
Cancer is one of the highest prevalent diseases in humans. The chances of surviving cancer and its prognosis are very dependent on the affected tissue, body location, and stage at which the disease is diagnosed. Researchers and pharmaceutical companies worldwide are pursuing many attempts to look for compounds to treat this malignancy. Most of the current strategies to fight cancer implicate the use of compounds acting on DNA damage checkpoints, non-receptor tyrosine kinases activities, regulators of the hedgehog signaling pathways, and metabolic adaptations placed in cancer. In the last decade, the finding of a lipid peroxidation increase linked to 15-lipoxygenases isoform 1 (15-LOX-1) activity stimulation has been found in specific successful treatments against cancer. This discovery contrasts with the production of other lipid oxidation signatures generated by stimulation of other lipoxygenases such as 5-LOX and 12-LOX, and cyclooxygenase (COX-2) activities, which have been suggested as cancer biomarkers and which inhibitors present anti-tumoral and antiproliferative activities. These findings support the previously proposed role of lipid hydroperoxides and their metabolites as cancer cell mediators. Depletion or promotion of lipid peroxidation is generally related to a specific production source associated with a cancer stage or tissue in which cancer originates. This review highlights the potential therapeutical use of chemical derivatives to stimulate or block specific cellular routes to generate lipid hydroperoxides to treat this disease.
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Affiliation(s)
- Sofia M. Clemente
- Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal;
| | - Oscar H. Martínez-Costa
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid (UAM), c/Arturo Duperier 4, 28029 Madrid, Spain;
- Instituto de Investigaciones Biomédicas ‘Alberto Sols’ (CSIC-UAM), c/Arturo Duperier 4, 28029 Madrid, Spain;
| | - Maria Monsalve
- Instituto de Investigaciones Biomédicas ‘Alberto Sols’ (CSIC-UAM), c/Arturo Duperier 4, 28029 Madrid, Spain;
| | - Alejandro K. Samhan-Arias
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid (UAM), c/Arturo Duperier 4, 28029 Madrid, Spain;
- Instituto de Investigaciones Biomédicas ‘Alberto Sols’ (CSIC-UAM), c/Arturo Duperier 4, 28029 Madrid, Spain;
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Szopa A, Dziurka M, Warzecha A, Kubica P, Klimek-Szczykutowicz M, Ekiert H. Targeted Lignan Profiling and Anti-Inflammatory Properties of Schisandra rubriflora and Schisandra chinensis Extracts. Molecules 2018; 23:E3103. [PMID: 30486445 PMCID: PMC6321394 DOI: 10.3390/molecules23123103] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 11/21/2018] [Accepted: 11/22/2018] [Indexed: 12/29/2022] Open
Abstract
Schisandra rubriflora is a dioecious plant of increasing importance due to its lignan composition, and therefore, possible therapeutic properties. The aim of the work was lignan profiling of fruits, leaves and shoots of female (F) and male (M) plants using UHPLC-MS/MS. Additionally, the anti-inflammatory activity of plant extracts and individual lignans was tested in vitro for the inhibition of 15-lipooxygenase (15-LOX), phospholipases A2 (sPLA₂), cyclooxygenase 1 and 2 (COX-1; COX-2) enzyme activities. The extracts of fruits, leaves and shoots of the pharmacopoeial species, S. chinensis, were tested for comparison. Twenty-four lignans were monitored. Lignan contents in S. rubriflora fruit extracts amounted to 1055.65 mg/100 g DW and the dominant compounds included schisanhenol, aneloylgomisin H, schisantherin B, schisandrin A, gomisin O, angeloylgomisin O and gomisin G. The content of lignan in leaf extracts was 853.33 (F) and 1106.80 (M) mg/100 g DW. Shoot extracts were poorer in lignans-559.97 (F) and 384.80 (M) mg/100 g DW. Schisantherin B, schisantherin A, 6-O-benzoylgomisin O and angeloylgomisin H were the dominant compounds in leaf and shoot extracts. The total content of detected lignans in S. chinensis fruit, leaf and shoot extracts was: 1686.95, 433.59 and 313.83 mg/100 g DW, respectively. Gomisin N, schisandrin A, schisandrin, gomisin D, schisantherin B, gomisin A, angeloylgomisin H and gomisin J were the dominant lignans in S. chinensis fruit extracts were. The results of anti-inflammatory assays revealed higher activity of S. rubriflora extracts. Individual lignans showed significant inhibitory activity against 15-LOX, COX-1 and COX-2 enzymes.
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Affiliation(s)
- Agnieszka Szopa
- Chair and Department of Pharmaceutical Botany, Medical College, ul. Medyczna 9, 30-688 Kraków, Poland.
| | - Michał Dziurka
- Polish Academy of Sciences, The Franciszek Górski Institute of Plant Physiology, ul. Niezapominajek 21, 30-239 Kraków, Poland.
| | - Angelika Warzecha
- Chair and Department of Pharmaceutical Botany, Medical College, ul. Medyczna 9, 30-688 Kraków, Poland.
| | - Paweł Kubica
- Chair and Department of Pharmaceutical Botany, Medical College, ul. Medyczna 9, 30-688 Kraków, Poland.
| | | | - Halina Ekiert
- Chair and Department of Pharmaceutical Botany, Medical College, ul. Medyczna 9, 30-688 Kraków, Poland.
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6
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Abstract
We present a novel elastic network model, lmcENM, to determine protein motion even for localized functional motions that involve substantial changes in the protein's contact topology. Existing elastic network models assume that the contact topology remains unchanged throughout the motion and are thus most appropriate to simulate highly collective function-related movements. lmcENM uses machine learning to differentiate breaking from maintained contacts. We show that lmcENM accurately captures functional transitions unexplained by the classical ENM and three reference ENM variants, while preserving the simplicity of classical ENM. We demonstrate the effectiveness of our approach on a large set of proteins covering different motion types. Our results suggest that accurately predicting a "deformation-invariant" contact topology offers a promising route to increase the general applicability of ENMs. We also find that to correctly predict this contact topology a combination of several features seems to be relevant which may vary slightly depending on the protein. Additionally, we present case studies of two biologically interesting systems, Ferric Citrate membrane transporter FecA and Arachidonate 15-Lipoxygenase.
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Affiliation(s)
- Ines Putz
- Robotics and Biology Laboratory, Department of Computer Science and Electrical Engineering, Technische Universität Berlin, Berlin, Berlin, Germany
| | - Oliver Brock
- Robotics and Biology Laboratory, Department of Computer Science and Electrical Engineering, Technische Universität Berlin, Berlin, Berlin, Germany
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7
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Saeed A, Khan SU, Mahesar PA, Channar PA, Shabir G, Iqbal J. Substituted (E)-2-(2-benzylidenehydrazinyl)-4-methylthiazole-5-carboxylates as dual inhibitors of 15-lipoxygenase & carbonic anhydrase II: synthesis, biochemical evaluation and docking studies. Biochem Biophys Res Commun 2016; 482:176-181. [PMID: 27836541 DOI: 10.1016/j.bbrc.2016.11.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 11/06/2016] [Indexed: 12/31/2022]
Abstract
15-Lipoxygenase (15-LOX) plays a major role in many inflammatory lung diseases including chronic obstructive pulmonary disease (COPD), asthma and chronic bronchitis. Over-expression of 15-LOX is related with some specific carcinomas including pancreatic, gastric and brain tumor. Similarly among different isozymes of carbonic anhydrase (CA), CA II is expressed in pancreatic, gastric carcinomas as well as in brain tumors. Therefore, novel potent inhibitors of both 15-LOX and CA II are required to explore the role of these enzymes further and to enable the drug discovery efforts. For this purpose, a series of benzyledinyl-hydrazinyl substituted thiazole derivatives were designed, synthesized and characterized by FTIR, 1H, &13C NMR spectroscopy. The derivatives were then evaluated for their potential to inhibit 15-LOX and bovine carbonic anhydrase II (bCA II). Most of these compounds showed excellent inhibitory potential for 15-LOX with an IC50 of 0.12 ± 0.002 to 0.69 ± 0.5 μM and showed moderate inhibition potency for bCA II with compound 5h (IC50 = 1.26 ± 0.24 μM) being the most active. The most potent compound 5a that emerged as a dual inhibitor of both enzymes, exhibiting 24 times greater selectivity for 15-LOX over bCA II. Compound 5a exhibited dual potent inhibitory activity against both 15-LOX and bCA II enzymes having IC50 values of 0.12 ± 0.002 and 2.93 ± 0.22 μM, respectively. Molecular docking studies of potent as well as dual inhibitors were also carried out to provide an insight into the binding site interactions.
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Affiliation(s)
- Aamer Saeed
- Department of Chemistry, Quaid-i-Azam University, 45320, Islamabad, Pakistan.
| | - Shafi Ullah Khan
- Centre for Advanced Drug Research, COMSATS Institute of Information Technology, Abbottabad, 22060, Pakistan
| | - Parvez Ali Mahesar
- Department of Chemistry, Quaid-i-Azam University, 45320, Islamabad, Pakistan
| | - Pervaiz Ali Channar
- Department of Chemistry, Quaid-i-Azam University, 45320, Islamabad, Pakistan
| | - Ghulam Shabir
- Department of Chemistry, Quaid-i-Azam University, 45320, Islamabad, Pakistan
| | - Jamshed Iqbal
- Centre for Advanced Drug Research, COMSATS Institute of Information Technology, Abbottabad, 22060, Pakistan.
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Suardíaz R, Jambrina PG, Masgrau L, González-Lafont À, Rosta E, Lluch JM. Understanding the Mechanism of the Hydrogen Abstraction from Arachidonic Acid Catalyzed by the Human Enzyme 15-Lipoxygenase-2. A Quantum Mechanics/Molecular Mechanics Free Energy Simulation. J Chem Theory Comput 2016; 12:2079-90. [PMID: 26918937 DOI: 10.1021/acs.jctc.5b01236] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Lipoxygenases (LOXs) are a family of enzymes involved in the biosynthesis of several lipid mediators. In the case of human 15-LOX, the 15-LOX-1 and 15-LOX-2 isoforms show slightly different reaction regiospecificity and substrate specificity, indicating that substrate binding and recognition may be different, a fact that could be related to their different biological role. Here, we have used long molecular dynamics simulations, QM(DFT)/MM potential energy and free energy calculations (using the newly developed DHAM method), to investigate the binding mode of the arachidonic acid (AA) substrate into 15-LOX-2 and the rate-limiting hydrogen-abstraction reaction 15-LOX-2 catalyzes. Our results strongly indicate that hydrogen abstraction from C13 in 15-LOX-2 is only consistent with the "tail-first" orientation of AA, with its carboxylate group interacting with Arg429, and that only the pro-S H13 hydrogen will be abstracted (being the pro-R H13 and H10 too far from the acceptor oxygen atom). At the B3LYP/6-31G(d) level the potential and free energy barriers for the pro-S H13 abstraction of AA by 15-LOX-2 are 18.0 and 18.6 kcal/mol, respectively. To analyze the kinetics of the hydrogen abstraction process, we determined a Markov model corresponding to the unbiased simulations along the state-discretized reaction coordinate. The calculated rates based on the second largest eigenvalue of the Markov matrices agree well with experimental measurements, and also provide the means to directly determine the pre-exponential factor for the reaction by comparing with the free energy barrier height. Our calculated pre-exponential factor is close to the value of kBT/h. On the other hand, our results suggest that the spin inversion of the complete system (including the O2 molecule) that is required to happen at some point along the full process to lead to the final hydroperoxide product, is likely to take place during the hydrogen transfer, which is a proton coupled electron transfer. Overall, a different binding mode from the one accepted for 15-LOX-1 is proposed, which provides a molecular basis for 15-LOX-2 exclusive 15-HPETE production in front of the double (although highly 15-) 12/15 regiospecificity of 15-LOX-1. Understanding how these different isoenzymes achieve their regiospecificity is expected to help in specific inhibitor design.
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Affiliation(s)
- Reynier Suardíaz
- Department of Chemistry, King's College London , London SE1 1DB, United Kingdom
| | - Pablo G Jambrina
- Department of Chemistry, King's College London , London SE1 1DB, United Kingdom
| | - Laura Masgrau
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona , 08193 Bellaterra, Barcelona Spain
| | - Àngels González-Lafont
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona , 08193 Bellaterra, Barcelona Spain
- Departament de Química, Universitat Autònoma de Barcelona , 08193 Bellaterra, Barcelona Spain
| | - Edina Rosta
- Department of Chemistry, King's College London , London SE1 1DB, United Kingdom
| | - José M Lluch
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona , 08193 Bellaterra, Barcelona Spain
- Departament de Química, Universitat Autònoma de Barcelona , 08193 Bellaterra, Barcelona Spain
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Kotla S, Singh NK, Traylor JG, Orr AW, Rao GN. ROS-dependent Syk and Pyk2-mediated STAT1 activation is required for 15(S)-hydroxyeicosatetraenoic acid-induced CD36 expression and foam cell formation. Free Radic Biol Med 2014; 76:147-62. [PMID: 25152235 PMCID: PMC4253592 DOI: 10.1016/j.freeradbiomed.2014.08.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 08/07/2014] [Accepted: 08/11/2014] [Indexed: 02/02/2023]
Abstract
15(S)-Hydroxyeicosatetraenoic acid (15(S)-HETE), the major 15-lipoxygenase 1/2 (15-LO1/2) metabolite of arachidonic acid (AA), induces CD36 expression through xanthine oxidase and NADPH oxidase-dependent ROS production and Syk and Pyk2-dependent STAT1 activation. In line with these observations, 15(S)-HETE also induced foam cell formation involving ROS, Syk, Pyk2, and STAT1-mediated CD36 expression. In addition, peritoneal macrophages from Western diet-fed ApoE(-/-) mice exhibited elevated levels of xanthine oxidase and NADPH oxidase activities, ROS production, Syk, Pyk2, and STAT1 phosphorylation, and CD36 expression compared to those from ApoE(-/-):12/15-LO(-/-) mice and these events correlated with increased lipid deposits, macrophage content, and lesion progression in the aortic roots. Human atherosclerotic arteries also showed increased 15-LO1 expression, STAT1 phosphorylation, and CD36 levels as compared to normal arteries. Together, these findings suggest that 12/15-LO metabolites of AA, particularly 12/15(S)-HETE, might play a crucial role in atherogenesis by enhancing foam cell formation.
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Affiliation(s)
- Sivareddy Kotla
- Department of Physiology, University of Tennessee Health Science Center, 894 Union Avenue, Memphis, TN 38163, USA
| | - Nikhlesh K Singh
- Department of Physiology, University of Tennessee Health Science Center, 894 Union Avenue, Memphis, TN 38163, USA
| | - James G Traylor
- Department of Pathology, Louisiana State University Health Science Center, 1501 King׳s Hwy, Shreveport, LA 71130, USA
| | - A Wayne Orr
- Department of Pathology, Louisiana State University Health Science Center, 1501 King׳s Hwy, Shreveport, LA 71130, USA
| | - Gadiparthi N Rao
- Department of Physiology, University of Tennessee Health Science Center, 894 Union Avenue, Memphis, TN 38163, USA.
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Tomy MJ, Dileep KV, Prasanth S, Preethidan DS, Sabu A, Sadasivan C, Haridas M. Cuminaldehyde as a lipoxygenase inhibitor: in vitro and in silico validation. Appl Biochem Biotechnol 2014; 174:388-97. [PMID: 25080377 DOI: 10.1007/s12010-014-1066-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Accepted: 07/21/2014] [Indexed: 11/27/2022]
Abstract
The search for lipoxygenase (LOX) inhibitors has been carried out for decades due to its importance in inflammatory diseases. In the present study, it was observed that the methanolic extract of Cuminum cyminum L. inhibited LOX activity. Activity-guided screening of the C. cyminum crude extracts helped the identification and isolation of cuminaldehyde as a 15-LOX inhibitor. The enzyme kinetics analysis suggested cuminaldehyde to be a competitive inhibitor and the IC 50 value derived from LB plots is 1,370 μM. Binding constants of cuminaldehyde on LOX was deduced by isothermal titration calorimetry. The combined thermodynamics and molecular modeling analyses suggested cuminaldehyde as a competitive LOX inhibitor. It is proposed from the present study that the coordinate bond between the Fe(2+) atom in the active site of the enzyme and the cuminaldehyde may be responsible for the enzyme inhibition. The study suggests that cuminaldehyde may be acting as an anti-inflammatory compound and may be therefore included in the category of leads for developing dual COX-LOX inhibitors as non-steroidal anti-inflammatory drugs (NSAIDs).
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Affiliation(s)
- M J Tomy
- Inter University Centre for Bioscience and Department of Biotechnology and Microbiology, Kannur University, Thalassery Campus, Palayad, 670661, India
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Beavers W, Serwa R, Shimozu Y, Tallman KA, Vaught M, Dalvie ED, Marnett LJ, Porter NA. ω-Alkynyl lipid surrogates for polyunsaturated fatty acids: free radical and enzymatic oxidations. J Am Chem Soc 2014; 136:11529-39. [PMID: 25034362 PMCID: PMC4140476 DOI: 10.1021/ja506038v] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Indexed: 12/22/2022]
Abstract
Lipid and lipid metabolite profiling are important parameters in understanding the pathogenesis of many diseases. Alkynylated polyunsaturated fatty acids are potentially useful probes for tracking the fate of fatty acid metabolites. The nonenzymatic and enzymatic oxidations of ω-alkynyl linoleic acid and ω-alkynyl arachidonic acid were compared to that of linoleic and arachidonic acid. There was no detectable difference in the primary products of nonenzymatic oxidation, which comprised cis,trans-hydroxy fatty acids. Similar hydroxy fatty acid products were formed when ω-alkynyl linoleic acid and ω-alkynyl arachidonic acid were reacted with lipoxygenase enzymes that introduce oxygen at different positions in the carbon chains. The rates of oxidation of ω-alkynylated fatty acids were reduced compared to those of the natural fatty acids. Cyclooxygenase-1 and -2 did not oxidize alkynyl linoleic but efficiently oxidized alkynyl arachidonic acid. The products were identified as alkynyl 11-hydroxy-eicosatetraenoic acid, alkynyl 11-hydroxy-8,9-epoxy-eicosatrienoic acid, and alkynyl prostaglandins. This deviation from the metabolic profile of arachidonic acid may limit the utility of alkynyl arachidonic acid in the tracking of cyclooxygenase-based lipid oxidation. The formation of alkynyl 11-hydroxy-8,9-epoxy-eicosatrienoic acid compared to alkynyl prostaglandins suggests that the ω-alkyne group causes a conformational change in the fatty acid bound to the enzyme, which reduces the efficiency of cyclization of dioxalanyl intermediates to endoperoxide intermediates. Overall, ω-alkynyl linoleic acid and ω-alkynyl arachidonic acid appear to be metabolically competent surrogates for tracking the fate of polyunsaturated fatty acids when looking at models involving autoxidation and oxidation by lipoxygenases.
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Affiliation(s)
- William
N. Beavers
- A.B. Hancock Memorial Laboratory for
Cancer Research, Departments of Chemistry, Biochemistry, and Pharmacology, Vanderbilt Institute for Chemical Biology, Vanderbilt
Center in Molecular Toxicology, Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Remigiusz Serwa
- A.B. Hancock Memorial Laboratory for
Cancer Research, Departments of Chemistry, Biochemistry, and Pharmacology, Vanderbilt Institute for Chemical Biology, Vanderbilt
Center in Molecular Toxicology, Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Yuki Shimozu
- A.B. Hancock Memorial Laboratory for
Cancer Research, Departments of Chemistry, Biochemistry, and Pharmacology, Vanderbilt Institute for Chemical Biology, Vanderbilt
Center in Molecular Toxicology, Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Keri A. Tallman
- A.B. Hancock Memorial Laboratory for
Cancer Research, Departments of Chemistry, Biochemistry, and Pharmacology, Vanderbilt Institute for Chemical Biology, Vanderbilt
Center in Molecular Toxicology, Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Melissa Vaught
- A.B. Hancock Memorial Laboratory for
Cancer Research, Departments of Chemistry, Biochemistry, and Pharmacology, Vanderbilt Institute for Chemical Biology, Vanderbilt
Center in Molecular Toxicology, Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Esha D. Dalvie
- A.B. Hancock Memorial Laboratory for
Cancer Research, Departments of Chemistry, Biochemistry, and Pharmacology, Vanderbilt Institute for Chemical Biology, Vanderbilt
Center in Molecular Toxicology, Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Lawrence J. Marnett
- A.B. Hancock Memorial Laboratory for
Cancer Research, Departments of Chemistry, Biochemistry, and Pharmacology, Vanderbilt Institute for Chemical Biology, Vanderbilt
Center in Molecular Toxicology, Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Ned A. Porter
- A.B. Hancock Memorial Laboratory for
Cancer Research, Departments of Chemistry, Biochemistry, and Pharmacology, Vanderbilt Institute for Chemical Biology, Vanderbilt
Center in Molecular Toxicology, Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, United States
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12
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Jameson JB, Kantz A, Schultz L, Kalyanaraman C, Jacobson MP, Maloney DJ, Jadhav A, Simeonov A, Holman TR. A high throughput screen identifies potent and selective inhibitors to human epithelial 15-lipoxygenase-2. PLoS One 2014; 9:e104094. [PMID: 25111178 PMCID: PMC4128814 DOI: 10.1371/journal.pone.0104094] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 07/08/2014] [Indexed: 12/26/2022] Open
Abstract
Lipoxygenase (LOX) enzymes catalyze the hydroperoxidation of arachidonic acid and other polyunsaturated fatty acids to hydroxyeicosatetraenoic acids with varying positional specificity to yield important biological signaling molecules. Human epithelial 15lipoxygenase2 (15-LOX-2) is a highly specific LOX isozyme that is expressed in epithelial tissue and whose activity has been correlated with suppression of tumor growth in prostate and other epithelial derived cancers. Despite the potential utility of an inhibitor to probe the specific role of 15-LOX-2 in tumor progression, no such potent/specific 15LOX2 inhibitors have been reported to date. This study employs high throughput screening to identify two novel, specific 15LOX2 inhibitors. MLS000545091 is a mixed-type inhibitor of 15-LOX-2 with a Ki of 0.9+/−0.4 µM and has a 20-fold selectivity over 5-LOX, 12-LOX, 15-LOX-1, COX-1, and COX-2. MLS000536924 is a competitive inhibitor with a Ki of 2.5+/−0.5 µM and also possesses 20-fold selectivity toward 15-LOX-2 over the other oxygenases, listed above. Finally, neither compound possesses reductive activity towards the active-site ferrous ion.
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Affiliation(s)
- J. Brian Jameson
- Chemistry and Biochemistry Department, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Auric Kantz
- Chemistry and Biochemistry Department, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Lena Schultz
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Chakrapani Kalyanaraman
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of California San Francisco, San Francisco, California, United States of America
| | - Matthew P. Jacobson
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of California San Francisco, San Francisco, California, United States of America
| | - David J. Maloney
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ajit Jadhav
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Anton Simeonov
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: (AS); (TRH)
| | - Theodore R. Holman
- Chemistry and Biochemistry Department, University of California Santa Cruz, Santa Cruz, California, United States of America
- * E-mail: (AS); (TRH)
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13
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Wennman A, Karkehabadi S, Oliw EH. Kinetic investigation of the rate-limiting step of manganese- and iron-lipoxygenases. Arch Biochem Biophys 2014; 555-556:9-15. [PMID: 24857825 DOI: 10.1016/j.abb.2014.05.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 05/12/2014] [Accepted: 05/13/2014] [Indexed: 11/17/2022]
Abstract
Lipoxygenases (LOX) oxidize polyunsaturated fatty acids to hydroperoxides, which are generated by proton coupled electron transfer to the metal center with FeIIIOH- or MnIIIOH-. Hydrogen abstraction by FeIIIOH- of soybean LOX-1 (sLOX-1) is associated with a large deuterium kinetic isotope effect (D-KIE). Our goal was to compare the D-KIE and other kinetic parameters at different temperatures of sLOX-1 with 13R-LOX with catalytic manganese (13R-MnLOX). The reaction rate and the D-KIE of sLOX-1 with unlabeled and [11-2H2]18:2n-6 were almost temperature independent with an apparent D-KIE of ∼56 at 30°C, which is in agreement with previous studies. In contrast, the reaction rate of 13R-MnLOX increased 7-fold with temperature (8-50°C), and the apparent D-KIE decreased linearly from ∼38 at 8°C to ∼20 at 50°C. The kinetic lag phase of 13R-MnLOX was consistently extended at low temperatures. The Phe337Ile mutant of 13R-MnLOX, which catalyzes antarafacial hydrogen abstraction and oxygenation in analogy with sLOX-1, retained the large D-KIE and its temperature-dependent reaction rate. The kinetic differences between 13R-MnLOX and sLOX-1 may be due to protein dynamics, hydrogen donor-acceptor distances, and to the metal ligands, which may not equalize the 0.7V-gap between the redox potentials of the free metals.
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Affiliation(s)
- Anneli Wennman
- Division of Biochemical Pharmacology, Department of Pharmaceutical Biosciences, Uppsala University, Biomedical Center, SE-751 24 Uppsala, Sweden
| | - Saeid Karkehabadi
- Division of Biochemical Pharmacology, Department of Pharmaceutical Biosciences, Uppsala University, Biomedical Center, SE-751 24 Uppsala, Sweden
| | - Ernst H Oliw
- Division of Biochemical Pharmacology, Department of Pharmaceutical Biosciences, Uppsala University, Biomedical Center, SE-751 24 Uppsala, Sweden.
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14
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Bedreag CFG, Trifan A, Vasincu A, Miron SD, Aprotosoaie AC, Miron A. In vitro screening of Crataegus succulenta extracts for free radical scavenging and 15-lipoxygenase inhibitory activities. Rev Med Chir Soc Med Nat Iasi 2014; 118:544-550. [PMID: 25076729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
UNLABELLED Crataegus succulenta Schrad. ex Link is widely spread in North America. A literature survey revealed no studies on the chemical composition and biological effects of this species. AIM The aim of the present study was to investigate the phenolic content, free radical scavenging and 15-lipoxygenase inhibitory effects of Crataegus succulenta leaf and flower extracts. MATERIAL AND METHODS Total phenolic, flavonoid and proanthocyanidin contents were quantified by spectrophotometric methods. Both extracts were evaluated for their ability to scavenge DPPH, superoxide anion and hydroxyl radicals and to inhibit 15-lipoxygenase activity. RESULTS There were noticed no striking differences in the total phenolic, flavonoid and proanthocyanidin contents between leaf and flower extracts. Both extracts showed similar 15-lipoxygenase inhibitory effects. Flower extract scavenged more effectively DPPH and superoxide radicals while leave extract was more active against hydroxyl radical. In superoxide anion radical scavenging assay, both extracts were more active than (+)-catechin. In hydroxyl radical scavenging and 15-lipoxygenase inhibition assays, the extracts were only 4-5 times less active than (+)-catechin. CONCLUSIONS The high antioxidant potential of Crataegus succulenta extracts suggest a possible use as ingredients in functional foods for the prevention of oxidative stress-related diseases.
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Pham AT, Nguyen C, Malterud KE, Diallo D, Wangensteen H. Bioactive flavone-C-glycosides of the African medicinal plant Biophytum umbraculum. Molecules 2013; 18:10312-9. [PMID: 24064447 PMCID: PMC6270149 DOI: 10.3390/molecules180910312] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 08/08/2013] [Accepted: 08/14/2013] [Indexed: 11/16/2022] Open
Abstract
Three flavone-C-glycosides-cassiaoccidentalin A (1), isovitexin (2) and isoorientin (3)-were isolated from the ethyl acetate (EtOAc) soluble fraction of the methanol crude extract of the African medicinal plant Biophytum umbraculum, This is the first report of these compounds in this plant. All compounds were identified by spectroscopic analysis and comparison with published data. Isoorientin (3) and the EtOAc extract showed the greatest antioxidant activity in the DPPH assay as well as the strongest inhibition of xanthine oxidase (XO) and 15-lipoxygenase (15-LO). From these results, the extract of B. umbraculum might be a valuable source of flavone C-glycosides.
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Affiliation(s)
- Anh Thu Pham
- Section of Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, P.O. Box 1068 Blindern, N-0316 Oslo, Norway; E-Mails: (C.N.); (K.E.M.)
- Authors to whom correspondence should be addressed; E-Mails: (A.T.P.); (H.W.); Tel.: +47-22-856-569 (A.T.P.); Fax: +47-22-85-44-02 (A.T.P. & H.W.)
| | - Celine Nguyen
- Section of Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, P.O. Box 1068 Blindern, N-0316 Oslo, Norway; E-Mails: (C.N.); (K.E.M.)
| | - Karl Egil Malterud
- Section of Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, P.O. Box 1068 Blindern, N-0316 Oslo, Norway; E-Mails: (C.N.); (K.E.M.)
| | - Drissa Diallo
- Department of Traditional Medicine, Institut National de Recherche en Santé Publique, BP 1746, Bamako, Mali; E-Mail:
| | - Helle Wangensteen
- Section of Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, P.O. Box 1068 Blindern, N-0316 Oslo, Norway; E-Mails: (C.N.); (K.E.M.)
- Authors to whom correspondence should be addressed; E-Mails: (A.T.P.); (H.W.); Tel.: +47-22-856-569 (A.T.P.); Fax: +47-22-85-44-02 (A.T.P. & H.W.)
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16
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Dobson EP, Barrow CJ, Kralovec JA, Adcock JL. Controlled formation of mono- and dihydroxy-resolvins from EPA and DHA using soybean 15-lipoxygenase. J Lipid Res 2013; 54:1439-47. [PMID: 23471029 PMCID: PMC3622336 DOI: 10.1194/jlr.m036186] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 02/26/2013] [Indexed: 12/20/2022] Open
Abstract
Resolvins and protectins are important anti-inflammatory and pro-resolution compounds derived from the enzymatic oxidation of omega-3 fatty acids all-cis-5,8,11,14,17-eicosapentaenoic acid (EPA) and all-cis-4,7,10,13,16,19-docosahexaenoic acid (DHA). We have developed a simple, controlled method to synthesize an array of resolvin and protectin analogs from fatty acid starting materials using soybean 15-lipoxygenase. The conditions were optimized for the production of both mono- and dihydroxy derivatives, with enzyme concentration and pH found to have a significant effect on the reaction products. The methods were applied to five biologically important omega-3 and omega-6 fatty acid substrates. Mono- and dihydroxy compounds were successfully synthesized from all substrates and the products were characterized by normal phase (NP) HPLC, GC-MS, TOF-MS, UV-visible (UV-vis) spectroscopy, and NMR spectroscopy. The methods could be further applied to any polyunsaturated fatty acids containing the cis-1,4,7,10-undecatetraene moiety to produce a range of novel compounds with potential biological activity.
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Affiliation(s)
- Eleanor P. Dobson
- Centre for Chemistry and Biotechnology, Deakin University, Geelong, Victoria 3220, Australia; and
| | - Colin J. Barrow
- Centre for Chemistry and Biotechnology, Deakin University, Geelong, Victoria 3220, Australia; and
| | | | - Jacqui L. Adcock
- Centre for Chemistry and Biotechnology, Deakin University, Geelong, Victoria 3220, Australia; and
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17
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Iranshahi M, Jabbari A, Orafaie A, Mehri R, Zeraatkar S, Ahmadi T, Alimardani M, Sadeghian H. Synthesis and SAR studies of mono O-prenylated coumarins as potent 15-lipoxygenase inhibitors. Eur J Med Chem 2012; 57:134-42. [PMID: 23047230 DOI: 10.1016/j.ejmech.2012.09.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 07/23/2012] [Accepted: 09/04/2012] [Indexed: 01/18/2023]
Abstract
All of the mono isopentenyloxy, -geranyloxy and -farnesyloxy derivatives of coumarin were synthesized and their inhibitory potency against soybean 15-lipoxygenase (SLO) and human 15-lipoxygenase-1 (HLO-1) were determined. Amongst the synthetic analogs, 5-farnesyloxycoumarin showed the most potent inhibitory activity against SLO (IC(50) = 0.8 μM) while 6-farnesyloxycoumarin was the strongest HLO-1 inhibitor (IC(50) = 1.3 μM). The IC(50) variations of the farnesyl derivatives for HLO-1 (1.3 to ∼75 μM) were much higher than that observed for SLO (0.8-5.8 μM). SAR studies showed that hydrogen bonding, CH/π, anion-π and S-OC interactions with Fe(III)-OH, Leu408, Glu357 and Met419 were the distinct intermolecular interactions which can lead to important role of the coumarin substitution site in HLO-1 inhibitory potency, respectively.
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Affiliation(s)
- Mehrdad Iranshahi
- Biotechnology Research Center and School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
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18
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Moussalli MJ, Wu Y, Zuo X, Yang XL, Wistuba II, Raso MG, Morris JS, Bowser JL, Minna JD, Lotan R, Shureiqi I. Mechanistic contribution of ubiquitous 15-lipoxygenase-1 expression loss in cancer cells to terminal cell differentiation evasion. Cancer Prev Res (Phila) 2011; 4:1961-72. [PMID: 21881028 PMCID: PMC3232310 DOI: 10.1158/1940-6207.capr-10-0280] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Loss of terminal cell differentiation promotes tumorigenesis. 15-Lipoxygenase-1 (15-LOX-1) contributes to terminal cell differentiation in normal cells. The mechanistic significance of 15-LOX-1 expression loss in human cancers to terminal cell differentiation suppression is unknown. In a screen of 128 cancer cell lines representing more than 20 types of human cancer, we found that 15-LOX-1 mRNA expression levels were markedly lower than levels in terminally differentiated cells. Relative expression levels of 15-LOX-1 (relative to the level in terminally differentiated primary normal human-derived bronchial epithelial cells) were lower in 79% of the screened cancer cell lines than relative expression levels of p16 (INK4A), which promotes terminal cell differentiation and is considered one of the most commonly lost tumor suppressor genes in cancer cells. 15-LOX-1 was expressed during terminal differentiation in three-dimensional air-liquid interface cultures, and 15-LOX-1 expression and terminal differentiation occurred in immortalized nontransformed bronchial epithelial but not in lung cancer cell lines. 15-LOX-1 expression levels were lower in human tumors than in paired normal lung epithelia. Short hairpin RNA-mediated downregulation of 15-LOX-1 in Caco-2 cells blocked enterocyte-like differentiation, disrupted tight junction formation, and blocked E-cadherin and ZO-1 localization to the cell wall membrane. 15-LOX-1 episomal expression in Caco-2 and HT-29 colon cancer cells induced differentiation. Our findings indicate that 15-LOX-1 downregulation in cancer cells is an important mechanism for terminal cell differentiation dysregulation and support the potential therapeutic utility of 15-LOX-1 reexpression to inhibit tumorigenesis.
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Affiliation(s)
- Micheline J. Moussalli
- Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Yuanqing Wu
- Department of Clinical Cancer Prevention, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Xiangsheng Zuo
- Department of Clinical Cancer Prevention, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Xiu L. Yang
- Department of Clinical Cancer Prevention, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Ignacio Ivan Wistuba
- Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Maria G. Raso
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Jeffrey S. Morris
- Department of Biostatistics and Applied Mathematics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Jessica L. Bowser
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - John D. Minna
- Hamon Center for Therapeutic Oncology Research, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Reuben Lotan
- Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Imad Shureiqi
- Department of Clinical Cancer Prevention, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
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19
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Caballero J, Fernández M, Coll D. Quantitative structure-activity relationship of organosulphur compounds as soybean 15-lipoxygenase inhibitors using CoMFA and CoMSIA. Chem Biol Drug Des 2010; 76:511-7. [PMID: 21040497 DOI: 10.1111/j.1747-0285.2010.01039.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Three-dimensional quantitative structure-activity relationship studies were carried out on a series of 28 organosulphur compounds as 15-lipoxygenase inhibitors using comparative molecular field analysis and comparative molecular similarity indices analysis. Quantitative information on structure-activity relationships is provided for further rational development and direction of selective synthesis. All models were carried out over a training set including 22 compounds. The best comparative molecular field analysis model only included steric field and had a good Q² = 0.789. Comparative molecular similarity indices analysis overcame the comparative molecular field analysis results: the best comparative molecular similarity indices analysis model also only included steric field and had a Q² = 0.894. In addition, this model predicted adequately the compounds contained in the test set. Furthermore, plots of steric comparative molecular similarity indices analysis field allowed conclusions to be drawn for the choice of suitable inhibitors. In this sense, our model should prove useful in future 15-lipoxygenase inhibitor design studies.
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Affiliation(s)
- Julio Caballero
- Centro de Bioinformática y Simulación Molecular, Facultad de Ingeniería en Bioinformática, Universidad de Talca, 2 Norte 685, Casilla 721, Talca, Chile.
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20
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Johannesson M, Backman L, Claesson HE, Forsell PKA. Cloning, purification and characterization of non-human primate 12/15-lipoxygenases. Prostaglandins Leukot Essent Fatty Acids 2010; 82:121-9. [PMID: 20106647 DOI: 10.1016/j.plefa.2009.11.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2009] [Revised: 10/07/2009] [Accepted: 11/29/2009] [Indexed: 11/18/2022]
Abstract
The enzyme 15-lipoxygenase-1 (15-LO-1) possesses mainly 15-LO activity and has so far only been described in human cells and rabbit reticulocytes. The animal ortholog, except rabbit reticulocytes, is an enzyme with predominantly a 12-lipoxygenase activity, commonly referred to as 12/15-LO. We describe herein the characterization of the 12/15-LOs in Macaca mulatta (rhesus monkey) and in Pongo pygmaeus (orang-utan). The rhesus and the orang-utan enzymes have mainly 12-lipoxygenase and 15-lipoxygenase activity, respectively, and they display 94% and 98% identity to the human 15-LO-1 protein. The rhesus enzyme was functionally different from the human enzyme with respect to substrate utilization in that anandamide was used differently and that the rhesus enzymes positional specificity could be affected by the substrate concentration. Furthermore, genomic data indicate that chimpanzees express an enzyme with mainly 15-lipoxygenase activity whereas marmosets express an enzyme with mainly 12-LO activity. Taken together, the switch during evolution from a 12-lipoxygenating enzyme in lower primates to a 15-lipoxygenating enzyme in higher primates and man might be of importance for the biological function of this enzyme.
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Affiliation(s)
- M Johannesson
- Orexo AB, P.O. Box 303, 751 05 Uppsala, Stockholm, Sweden
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21
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Zhu P, Jian W, Blair IA. A 4-oxo-2(E)-nonenal-derived glutathione adduct from 15-lipoxygenase-1-mediated oxidation of cytosolic and esterified arachidonic acid. Free Radic Biol Med 2009; 47:953-61. [PMID: 19576981 PMCID: PMC2777738 DOI: 10.1016/j.freeradbiomed.2009.06.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2009] [Revised: 06/20/2009] [Accepted: 06/25/2009] [Indexed: 12/19/2022]
Abstract
15(S)-Hydroperoxy-[5Z,8Z,11Z,13E]-eicosatetraenoic acid (15(S)-HpETE) undergoes homolytic decomposition to bifunctional electrophiles such as 4-oxo-2(E)-nonenal. 4-Oxo-2(E)-nonenal reacts with glutathione to form a thiadiazabicyclo-4-oxo-2(E)-nonenal-glutathione adduct (TOG). Therefore, this endogenous glutathione adduct can serve as a specific biomarker of lipid hydroperoxide-mediated 4-oxo-2(E)-nonenal formation. A monocyte/macrophage cell line was generated to constitutively express human 15-lipoxygenase-1. In these cells, TOG was formed from 15(S)-HpETE-derived 4-oxo-2(E)-nonenal in a nonlinear dose-dependent manner upon arachidonic acid treatment. The lipoxygenase inhibitor cinnamyl-3,4-dihydroxy-alpha-cyanocinnamate abolished arachidonic acid-mediated TOG formation. The calcium ionophore A23187 was also used to induce the formation of 15(S)-HpETE from esterified arachidonic acid present in the membrane lipids. In the 15-lipoxygenase-1-expressing cells, the calcium ionophore A23187 significantly increased TOG levels compared with mock-transfected cells. This was due to the 15-lipoxygenase-mediated formation of 15(S)-HpETE in the forms of free fatty acid and esterified lipids, which was subsequently converted to 4-oxo-2(E)-nonenal. The increase in TOG formation was again abrogated by pretreatment with cinnamyl-3,4-dihydroxy-alpha-cyanocinnamate. Only 8.7% 15(S)-HETE (both the free fatty acid and its esterified form in the cell membrane) was formed after ionophore A23187 stimulation compared with that formed after the addition of arachidonic acid. In contrast, the TOG levels after treatment with ionophore A23187 or arachidonic acid were comparable. Thus, it is likely that esterified 15(S)-HpETE underwent homolytic decomposition to 4-oxo-2(E)-nonenal more efficiently than the free 15(S)-HpETE that was formed in the cytosol.
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Affiliation(s)
- Peijuan Zhu
- Centers for Cancer Pharmacology and Excellence in Environmental Toxicology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6160, USA
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22
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Sadeghian H, Attaran N, Jafari Z, Saberi MR, Seyedi SM, Eshghi H, Pordel M, Riazi MM. Design and synthesis of 4-methoxyphenylacetic acid esters as 15-lipoxygenase inhibitors and SAR comparative studies of them. Bioorg Med Chem 2009; 17:2327-35. [PMID: 19251422 DOI: 10.1016/j.bmc.2009.02.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2008] [Revised: 01/18/2009] [Accepted: 02/09/2009] [Indexed: 10/21/2022]
Abstract
A group of 4-methoxyphenylacetic acid esters were designed, synthesized and evaluated as potential inhibitors of soybean 15-lipoxygenase (SLO) on the basis of eugenol and esteragol structures. Compounds 7d-e showed the best IC(50) in SLO inhibition (IC(50)=3.8 and 1.9 microM, respectively). All compounds were docked in SLO active site and showed that carbonyl group of compounds is oriented toward the Fe(III)-OH moiety in the active site of enzyme and fixed by hydrogen bonding with hydroxyl group. It is assumed that lipophilic interaction of ligand-enzyme would be in charge of inhibiting the enzyme activity. The selectivity of the synthetic esters in inhibiting of 15-HLOb was also compared with 15-HLOa by molecular modeling and multiple alignment techniques.
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Affiliation(s)
- Hamid Sadeghian
- Department of Laboratory Sciences, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad 91389-13131, Iran.
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Lapenna D, Ciofani G, Pierdomenico SD, Neri M, Cuccurullo C, Giamberardino MA, Cuccurullo F. Inhibitory activity of salicylic acid on lipoxygenase-dependent lipid peroxidation. Biochim Biophys Acta 2009; 1790:25-30. [PMID: 18950686 DOI: 10.1016/j.bbagen.2008.09.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Revised: 09/03/2008] [Accepted: 09/22/2008] [Indexed: 11/30/2022]
Abstract
BACKGROUND Since iron is essential for lipoxygenase activity and salicylic acid (SA) can interact with the metal, possible lipoxygenase inhibition by SA was investigated. METHODS Kinetic spectrophotometric evaluation of enzymatic lipid peroxidation catalyzed by soybean lipoxygenase (SLO), rabbit reticulocyte 15-lipoxygenase (RR15-LOX), porcine leukocyte 12-lipoxygenase (PL12-LOX) and human recombinant 5-lipoxygenase (HR5-LOX) with and without SA. RESULTS SA inhibited linoleic, arachidonic and docosahexaenoic acid or human lipoprotein peroxidation catalyzed by SLO with IC50 of, respectively, 107, 153, 47 and 108 microM. Using the same substrates, SA inhibited RR15-LOX with IC50 of, respectively, 49, 63, 27 and 51 microM. Further, arachidonic acid peroxidation catalyzed by PL12-LOX and HR5-LOX was inhibited by SA with IC50 of 101 and 168 microM, respectively. Enzymatic inhibition was complete, reversible and non-competitive. Conceivably due to its lower hydrophobicity, aspirin was less effective, indicating acetylation-independent enzyme inhibition. SA and aspirin were ineffective peroxyl radical scavengers but readily reduced Fe3+, i.e. FeCl3, to Fe2+, suggesting their capacity to reduce Fe3+ at the enzyme active site. Indeed, similar to the catecholic redox inhibitor nordihydroguaiaretic acid, SA inhibited with the same efficiency both ferric and the native ferrous SLO form, indicating that these compounds reduce the active ferric enzyme leading to its inactivation. GENERAL SIGNIFICANCE SA can inhibit lipoxygenase-catalyzed lipid peroxidation at therapeutic concentrations, suggesting its possible inhibitory activity against enzymatic lipid peroxidation in the clinical setting.
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Affiliation(s)
- Domenico Lapenna
- Dipartimento di Medicina e Scienze dell'Invecchiamento, and Centro di Scienze dell'Invecchiamento-Fondazione Università G. d'Annunzio, Facoltà di Medicina e Chirurgia, 66100 Chieti, Italy.
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Bakavoli M, Sadeghian H, Tabatabaei Z, Rezaei E, Rahimizadeh M, Nikpour M. SAR comparative studies on pyrimido[4,5-b][1,4] benzothiazine derivatives as 15-lipoxygenase inhibitors, using ab initio calculations. J Mol Model 2008; 14:471-8. [PMID: 18425541 DOI: 10.1007/s00894-008-0298-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2007] [Accepted: 02/01/2008] [Indexed: 10/22/2022]
Abstract
The enzyme inhibitory activity of a new group of 2-substituted pyrimido[4,5-b][1,4]benzothiazines on soybean 15-lipoxygenase (15-LO) was evaluated and compared with those of their 4-methyl analogs using ab initio calculations. The results of these studies showed that the lack of 4-methyl substituent in the pyrimido[4,5-b][1,4] benzothiazine molecules greatly reduces their 15-LO inhibitory activities.
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Affiliation(s)
- Mehdi Bakavoli
- Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad 91775-1436, Iran.
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25
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Abstract
Lipoxygenases (LOXs) are a family of nonheme iron dioxygenases that catalyze the regioselective and stereospecific hydroperoxidation of polyunsaturated fatty acids, and are involved in a variety of inflammatory diseases and cancers. The crystal structure of rabbit 15S-LOX1 that was reported by Gillmor et al. in 1997 has played key roles for understanding the properties of mammalian LOXs. In this structure, three segments, including 12 residues in the superficial alpha2 helix, are absent and have usually been described as "disordered." By reinterpreting the original crystallographic data we were able to elucidate two different conformations of the molecule, both having well ordered alpha2 helices. Surprisingly, one molecule contained an inhibitor and the other did not, thereby adopting a closed and an open form, respectively. They differed in the conformation of the segments that were absent in the original structure, which is highlighted by a 12 A movement of alpha2. Consequently, they showed a difference in the size and shape of the substrate-binding cavity. The new model should provide new insight into the catalytic mechanism involving induced conformational change of the binding pocket. It may also be helpful for the structure-based design of LOX inhibitors.
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Affiliation(s)
- Jongkeun Choi
- Department of Chemistry, Seoul National University, Seoul, Korea
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26
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Saam J, Ivanov I, Walther M, Holzhütter HG, Kuhn H. Molecular dioxygen enters the active site of 12/15-lipoxygenase via dynamic oxygen access channels. Proc Natl Acad Sci U S A 2007; 104:13319-24. [PMID: 17675410 PMCID: PMC1948941 DOI: 10.1073/pnas.0702401104] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Cells contain numerous enzymes that use molecular oxygen for their reactions. Often, their active sites are buried deeply inside the protein, which raises the question whether there are specific access channels guiding oxygen to the site of catalysis. Choosing 12/15-lipoxygenase as a typical example for such oxygen-dependent enzymes, we determined the oxygen distribution within the protein and defined potential routes for oxygen access. For this purpose, we have applied an integrated strategy of structural modeling, molecular dynamics simulations, site-directed mutagenesis, and kinetic measurements. First, we computed the 3D free-energy distribution for oxygen, which led to identification of four oxygen channels in the protein. All channels connect the protein surface with a region of high oxygen affinity at the active site. This region is localized opposite to the nonheme iron providing a structural explanation for the reaction specificity of this lipoxygenase isoform. The catalytically most relevant path can be obstructed by L367F exchange, which leads to a strongly increased Michaelis constant for oxygen. The blocking mechanism is explained in detail by reordering the hydrogen-bonding network of water molecules. Our results provide strong evidence that the main route for oxygen access to the active site of the enzyme follows a channel formed by transiently interconnected cavities whereby the opening and closure are governed by side chain dynamics.
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Affiliation(s)
- Jan Saam
- Institute of Biochemistry, Charité-Universitätsmedizin Berlin, Monbijoustrasse 2, 10117 Berlin, Germany.
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27
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Messias AC, Harnisch C, Ostareck-Lederer A, Sattler M, Ostareck DH. The DICE-binding activity of KH domain 3 of hnRNP K is affected by c-Src-mediated tyrosine phosphorylation. J Mol Biol 2006; 361:470-81. [PMID: 16854432 DOI: 10.1016/j.jmb.2006.06.025] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2006] [Revised: 05/09/2006] [Accepted: 06/12/2006] [Indexed: 10/24/2022]
Abstract
hnRNP K and hnRNP E1/E2 are RNA-binding proteins comprised of three hnRNP K-homology (KH) domains. These proteins are involved in the translational control and stabilization of mRNAs in erythroid cells. hnRNP E1 and hnRNP K regulate the translation of reticulocyte 15-lipoxygenase (r15-LOX) mRNA. Both proteins bind specifically to the differentiation control element (DICE) in the 3' untranslated region (3'UTR) of the r15-LOX mRNA. It has been shown that hnRNP K is a substrate of the tyrosine kinase c-Src and that tyrosine phosphorylation by c-Src inhibits the binding of hnRNP K to the DICE. Here, we investigate which of the three KH domains of hnRNP E1 and hnRNP K mediate the DICE interaction. Using RNA-binding assays, we demonstrate DICE-binding of the KH domains 1 and 3 of hnRNP E1, and KH domain 3 of hnRNP K. Furthermore, with RNA-binding assays, NMR experiments and in vitro translation studies, we show that tyrosine 458 in KH domain 3 of hnRNP K is important for the DICE interaction and we provide evidence that it is a target of c-Src.
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Affiliation(s)
- Ana C Messias
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstr. 1, 69117 Heidelberg, Germany
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28
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Rao PNP, Chen QH, Knaus EE. Synthesis and structure-activity relationship studies of 1,3-diarylprop-2-yn-1-ones: dual inhibitors of cyclooxygenases and lipoxygenases. J Med Chem 2006; 49:1668-83. [PMID: 16509583 DOI: 10.1021/jm0510474] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A group of 1,3-diarylprop-2-yn-1-ones (13, 17, 23, 26 and 27) possessing a C-3 p-SO2Me COX-2 pharmacophore were designed, synthesized and evaluated as potential dual inhibitors of cyclooxygenase-1/2 (COX-1/2) and 5/15-lipoxygenases (5/15-LOX) that exhibit vivo antiinflammatory and analgesic activities. Among this class of compounds, 3-(4-methanesulfonylphenyl)-1-(4-fluorophenyl)prop-2-yn-1-one (13h) was identified as a potent and selective inhibitor of COX-2 (COX-2 IC50 = 0.1 microM; SI = 300), being 5-fold more potent than rofecoxib (COX-2 IC50 = 0.5 microM; SI > 200). In a rat carrageenan-induced paw edema assay 13h exhibited moderate antiinflammatory activity (26% inhibition of inflammation) at 3 h after administration of a 30 mg/kg oral dose. A related dual COX-1/2 and 5/15-LOX inhibitor 3-(4-methanesulfonylphenyl)-1-(4-cyanophenyl)prop-2-yn-1-one (13g, COX-1 IC50 = 31.5 microM; COX-2 IC50 = 1.0 microM; SI = 31.5; 5-LOX IC50 = 1.0 microM; 15-LOX IC50 = 3.2 microM) exhibited more potent antiinflammatory activity (ED50 = 90 mg/kg), being superior to the reference drug aspirin (ED50 = 129 mg/kg). Within this group of compounds 3-(4-methanesulfonylphenyl)-1-(4-isopropylphenyl)prop-2-yn-1-one (13e) emerged as having an optimal combination of in vitro COX-1/2 and 5/15-LOX inhibitory effects (COX-1 IC50 = 9.2 microM; COX-2 IC50 = 0.32 microM; SI = 28; 5-LOX IC50 = 0.32 microM; 15-LOX IC50 = 0.36 microM) in conjunction with a good antiinflammatory activity (ED50 = 35 mg/kg) compared to the reference drug celecoxib (ED50 = 10.8 mg/kg) when administered orally. A molecular modeling study where 13e was docked in the COX-2 binding site indicated the C-1 p-i-Pr group was positioned within a hydrophobic pocket (Phe205, Val344, Val349, Phe381 and Leu534), and that this positioning of the i-Pr group facilitated orientation of the C-3 p-SO2Me COX-2 pharmacophore such that it inserted into the COX-2 secondary pocket (His90, Arg513, Ile517 and Val523). A related docking study of 13e in the 15-LOX binding site indicates that the C-3 p-SO2Me COX-2 pharmacophore was positioned in a region closer to the catalytic iron site where it undergoes a hydrogen bonding interaction with His541 and His366, and that the C-1 p-i-Pr substituent is buried deep in a hydrophobic pocket (Ile414, Ile418, Met419 and Ile593) near the base of the 15-LOX binding site.
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Affiliation(s)
- P N Praveen Rao
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, T6G 2N8, Canada
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Kenyon V, Chorny I, Carvajal WJ, Holman TR, Jacobson MP. Novel human lipoxygenase inhibitors discovered using virtual screening with homology models. J Med Chem 2006; 49:1356-63. [PMID: 16480270 DOI: 10.1021/jm050639j] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the discovery of new, low micromolar, small molecule inhibitors of human platelet-type 12- and reticulocyte 15-lipoxygenase-1 (12-hLO and 15-hLO) using structure-based methods. Specifically, we created homology models of 12-hLO and 15-hLO, based on the structure of rabbit 15-lipoxygenase, for in silico screening of a large compound library followed by in vitro screening of 20 top scoring molecules. Eight of these compounds inhibited either 12- or 15-human lipoxygenase with lower than 100 microM affinity. Of these, we obtained IC50 values for the three best inhibitors, all of which displayed low micromolar inhibition. One compound showed specificity for 15-hLO versus 12-hLO; however, a selective inhibitor for 12-hLO was not identified. As a control we screened 20 randomly selected compounds, of which none showed low micromolar inhibition. The new low-micromolar inhibitors appear to be suitable as leads for further inhibitor development efforts against 12-hLO and 15-hLO, based on the fact their size and chemical properties are appropriate to classify them as drug-like compounds. The models of these protein-inhibitor complexes suggest strategies for future development of selective lipoxygenase inhibitors.
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Affiliation(s)
- Victor Kenyon
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143-2240, USA
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30
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Romanov S, Wiesner R, Myagkova G, Kuhn H, Ivanov I. Affinity Labeling of the Rabbit 12/15-Lipoxygenase Using Azido Derivatives of Arachidonic Acid. Biochemistry 2006; 45:3554-62. [PMID: 16533037 DOI: 10.1021/bi052152i] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lipoxygenases are lipid-peroxidizing enzymes, which have been implicated in the pathogenesis of important diseases. They consist of a single polypeptide chain, which is folded into a two-domain structure. The large catalytic domain contains the putative substrate-binding pocket and the catalytic non-heme iron. To identify structural elements of the rabbit 12/15-lipoxygenase that are involved in enzyme/substrate and/or enzyme/product interaction, we synthesized a set of radioactively labeled lipoxygenase substrates carrying a photoreactive azido group (17-azido-ETE, 18-azido-ETE, 19-azido-ETE) and used these compounds as affinity probes. After photoaffinity labeling, the enzyme was digested proteolytically and modified tryptic cleavage peptides were identified by a combination of radio-HPLC and mass spectral analysis. Following this strategy, we observed covalent linkage of a cleavage peptide that contained Ile593, which has previously been identified as the sequence determinant for the positional specificity. These data are consistent with the previous suggestion that this peptide lines the substrate-binding pocket. Surprisingly, we also observed strong labeling of cleavage peptides originating from the N-terminal beta-barrel domain, and our mass spectral data suggested covalent linkage of oxidized affinity probes. Taken together, these results confirm the previous conclusion that Ile593 and surrounding amino acids are constituents of the active site, but they also implicate the N-terminal beta-barrel in enzyme/substrate and/or enzyme/product interaction.
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Affiliation(s)
- Stepan Romanov
- Institute of Biochemistry, University Medicine Berlin-Charité, Monbijoustrasse 2, 10117 Berlin, Germany
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31
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Charlier C, Hénichart JP, Durant F, Wouters J. Structural insights into human 5-lipoxygenase inhibition: combined ligand-based and target-based approach. J Med Chem 2006; 49:186-95. [PMID: 16392803 DOI: 10.1021/jm050870x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The human 5-LOX enzyme and its interaction with competitive inhibitors were investigated by means of a combined ligand-based and target-based approach. First, a pharmacophore model was generated for 16 non redox 5-LOX inhibitors with Catalyst (HipHop module). It includes two hydrophobic groups, an aromatic ring, and two hydrogen bond acceptors. The 3D structure of human 5-LOX was then modeled based on the crystal structure of rabbit 15-LOX, and the binding modes of representative ligands were studied by molecular docking. Confrontation of the docking results with the pharmacophore model allowed the weighting of the pharmacophoric features and the integration of structural information. This led to the proposal of an interaction model inside the 5-LOX active site, consisting of four major and two secondary interaction points: on one hand, two hydrophobic groups, an aromatic ring, and a hydrogen bond acceptor, and, on the other hand, an acidic moiety and an additional hydrogen bond acceptor.
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Affiliation(s)
- Caroline Charlier
- Laboratory of Structural Biological Chemistry, University of Namur, FUNDP, 61, rue de Bruxelles, B-5000 Namur, Belgium
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32
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Abstract
Lipoxygenases (LOXs) form a heterogeneous family of lipid-peroxidizing enzymes, and several LOX-isoforms (12/15-LOX, 5-LOX) have been implicated in atherogenesis. However, the precise role of these enzymes is still a matter of discussion. 12/15-LOXs are capable of oxidizing lipoproteins (low-density lipoprotein (LDL), high-density lipoprotein (HDL)) to atherogenic forms, and functional inactivation of this enzyme in murine atherosclerosis models slows down lesion formation. In contrast, rabbits that overexpress this enzyme were protected from lesion formation when fed a lipid-rich diet. To contribute to this discussion, we recently investigated the impact of 12/15-LOX overexpression on in vitro foam cell formation. When 12/15-LOX-transfected J774 cells were incubated in culture with modified LDL, we found that intracellular lipid deposition was reduced in the transfected cells when compared with the corresponding control transfectants. This paper briefly summarizes the current status of knowledge on the biological activity of different LOX-isoforms in atherogenesis and will also provide novel experimental data characterizing the role of 12/15-LOX in cellular LDL modification and for in vitro foam cell formation.
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Affiliation(s)
- Hartmut Kühn
- Institute of Biochemistry, University Medicine Berlin, Berlin, Germany.
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Abstract
Hepoxilins constitute a group of 12S-hydroperoxyeicosatetraenoic acid (12S-HpETE)-derived epoxy-hydroxy fatty acids that have been detected in various cell types and tissues. Although hepoxilin A3 (HXA3) exhibits a myriad of biological activities, its biosynthetic mechanism was not investigated in detail. Here we review the isolation, cloning, and characterization of a leukocyte-type 12S-lipoxygenase (12S-LOX) from rat insulinoma cells RINm5F, which exhibits an intrinsic hepoxilin A3 synthase activity. Confirmation for this observation was achieved by coimmunoprecipitation of HXA3 synthase activity with an anti-leukocyte 12S-LOX antibody, preparation of recombinant rat 12S-LOX enzyme from RINm5F cells, and assay of HXA3 synthase activity therein. Site-directed mutagenesis studies performed on rat 12S-LOX showed that 12-lipoxygenating enzyme species exhibit a strong HXA3 synthase activity that is impaired when the positional specificity of arachidonic acid is altered in favor of 15-lipoxygenation. Inasmuch as cellular glutathione peroxidases (cGPx and PHGPx) and HXA3 synthase compete for the same substrate 12S-HpETE, it can be proposed that the overall activity of glutathione peroxidases, representing the overall peroxide tone, finely tunes the rate of HXA3 formation.
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Affiliation(s)
- Santosh Nigam
- Eicosanoid and Lipid Research Division, Centre of Experimental Gynecology and Breast Research, University Medical Centre Berlin, Charité-Campus Benjamin Franklin, D-12200 Berlin, Germany.
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Abstract
Studying the oxygenation kinetics of (19R/S,5Z,8Z,11Z,14Z)-19-hydroxyeicosa-5,8,11,14-tetraenoic acid (19-OH-AA) by rabbit 15-lipoxygenase-1 we observed a pronounced oxygen dependence of the reaction rate, which was not apparent with arachidonic acid as substrate. Moreover, we found that peroxide-dependent activation of the lipoxygenase depended strongly on the oxygen concentration. These data can be described with a kinetic model that extends previous schemes of the lipoxygenase reaction in three essential aspects: (a) the product of 19-OH-AA oxygenation is a less effective lipoxygenase activator than (13S,9Z,11E)-13-hydroperoxyoctadeca-9,11-dienoic acid; (b) molecular dioxygen serves not only as a lipoxygenase substrate, but also impacts peroxide-dependent enzyme activation; (c) there is a leakage of radical intermediates from the catalytic cycle, which leads to the formation of inactive ferrous lipoxygenase. This enzyme inactivation can be reversed by another round of peroxide-dependent activation. Taken together our data indicate that both peroxide activation and the oxygen affinity of lipoxygenases depend strongly on the chemistry of the lipid substrate. These findings are of biological relevance as variations of the reaction conditions may turn the lipoxygenase reaction into an efficient source of free radicals.
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Affiliation(s)
- Igor Ivanov
- Institute of Biochemistry Humboldt University Medical School Charité, Berlin, Germany
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Abstract
15-Lipoxygenases are lipid-peroxidizing enzymes which have been implicated in the pathogenesis of various diseases, such as inflammation, atherosclerosis, and osteoporosis. Although the crystal structures for several lipoxygenase isoforms have been solved, there is little information on the substrate alignment at the active site and its impact on the catalytic mechanism. Investigating the oxygenation of specifically designed hydroxy fatty acids, we observed a pronounced enantioselectivity of 15-lipoxygenases for substrates carrying the oxygen moiety in close proximity to the site of hydrogen abstraction [16(R/S)-HETE, 17(R/S)-HETE]. To investigate the mechanistic basis for this unexpected behavior, we applied a strategy involving targeted substrate modification, site-directed mutagenesis, and structural modeling of the enzyme-substrate complex. Taken together, our data suggest that an (S)-hydroxy group in 16-HETE may form a hydrogen bridge between the substrate molecule and Gln548, which contributes to proper alignment of the fatty acid derivative at the active site of the enzyme. This interaction, which was not observed with 16(R)-HETE, 18(R)-HETE, or 18(S)-HETE, appears to be a major reason for the high degree of enantioselectivity during lipoxygenation of 16-HETE.
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Affiliation(s)
- Igor Ivanov
- Institute of Biochemistry, University Clinics Charite, Humboldt University Berlin, Monbijoustrasse 2, 10117 Berlin, Germany
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Hammel M, Walther M, Prassl R, Kuhn H. Structural flexibility of the N-terminal beta-barrel domain of 15-lipoxygenase-1 probed by small angle X-ray scattering. Functional consequences for activity regulation and membrane binding. J Mol Biol 2004; 343:917-29. [PMID: 15476810 DOI: 10.1016/j.jmb.2004.08.076] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2004] [Revised: 08/12/2004] [Accepted: 08/25/2004] [Indexed: 10/26/2022]
Abstract
Mammalian lipoxygenases form a heterogeneous family of lipid peroxidizing enzymes, which have been implicated in synthesis of inflammatory mediators, in cell development and in the pathogenesis of various diseases (atherosclerosis, osteoporosis) with major health political importance. The crystal structures of two plant lipoxygenase isoforms have been solved and X-ray coordinates for an inhibitor complex of the rabbit 15-lipoxygenase-1 are also accessible. Here, we investigated the solution structure of the ligand-free rabbit 15-lipoxygenase-1 by small angle X-ray scattering. From the scattering profiles we modeled the solution structure of the enzyme using two independent ab initio approaches. Preliminary experiments indicated that at low protein concentrations (<1mg/ml) and at 10 degrees C the enzyme is present as hydrated monomer. Superposition of the high resolution crystal structure and our low resolution model of the solution structure revealed two major differences. (i) Although the two models are almost perfectly superimposed in the region of the catalytic domain the solution structure is stretched out in the region of the N-terminal beta-barrel domain and exhibits a bigger molecular volume. (ii) There is a central bending of the enzyme molecule in the solution structure, which does not show up in the crystal structure. Both structural peculiarities may be explained by a high degree of motional freedom of the N-terminal beta-barrel domain in aqueous solutions. This interdomain movement may be of functional importance for regulation of the catalytic activity and membrane binding.
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Affiliation(s)
- Michal Hammel
- Institute of Biophysics and X-Ray Structure Research of the Austrian Academy of Sciences, Schmiedlstr. 6, A-8042 Graz, Austria
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Segraves EN, Shah RR, Segraves NL, Johnson TA, Whitman S, Sui JK, Kenyon VA, Cichewicz RH, Crews P, Holman TR. Probing the activity differences of simple and complex brominated aryl compounds against 15-soybean, 15-human, and 12-human lipoxygenase. J Med Chem 2004; 47:4060-5. [PMID: 15267244 DOI: 10.1021/jm049872s] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lipoxygenases (LO) have been implicated in asthma, immune disorders, and various cancers. As a consequence of these broad biological implications, there is great interest in understanding the effects of naturally occurring and environmental contaminants against its activity. On the basis of our earlier studies indicating that polybrominated diphenol ethers are potent inhibitors to mammalian 15-LO, we expanded our structure-activity study to include marine-derived brominated phenol ethers (including a newly discovered tribrominated diphenyl ether), dioxins, and bastadins, as well as the synthetic brominated fire retardants, brominated bisphenol A (BBPA), and polybrominated diphenyl ethers (PBDEs). We report herein the effects of 21 simple and complex organobromine compounds against human platelet 12-LO, human reticulocyte 15-LO, and soybean 15-LO-1.
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Affiliation(s)
- Erika N Segraves
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA
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Abstract
Among mammalian lipoxygenases the 15-lipoxygenase-1 is somewhat special because of its capability of oxygenating complex lipid-protein assemblies (biomembranes, lipoproteins) and previous investigations have implicated calcium in enzyme/membrane interaction. We investigated the mechanism of calcium-dependent membrane association and obtained the following results. (i) Membrane binding of 15-lipoxygenase-1 involves electrostatic forces as well as hydrophobic interactions of solvent-exposed apolar amino acids (Tyr(15), Phe(70), Leu(71), Trp(181), and Leu(195)) with the hydrophobic core of membrane phospholipids. These sequence determinants of membrane association are clustered at the membrane contact plane of the enzyme that also involves the entrance to the substrate binding pocket. Site-directed mutagenesis of these determinants to negatively charged residues strongly impaired membrane binding. (ii) Calcium at micromolar concentrations (5-50 microM) is required for efficient membrane binding. For direct 15-lipoxygenase/calcium interaction a dissociation constant of 2-5 x 10(-4) m was determined (low affinity binding) and we failed to detect high affinity calcium-binding sites at the enzyme. Reversible low affinity calcium binding induces subtle structural alterations of the enzyme, which did not impact catalytic activity. (iii) Increasing calcium concentrations failed to reverse impairment of membrane binding induced by mutagenesis of the sequence determinants indicating the priority of hydrophobic interactions. Taken together these data suggest that 15-lipoxygenase-1 associates to biomembranes primarily via hydrophobic interactions between surface-exposed apolar amino acid side chains and membrane lipids. Calcium supports membrane binding probably by forming salt bridges between the negatively charged head groups of membrane phospholipids and acidic surface amino acids of the membrane contact plane and this interaction might contribute to overcome repulsive forces.
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Affiliation(s)
- Matthias Walther
- Institute of Biochemistry, University Clinics Charité, Humboldt University, Monbijoustrasse 2, 10117 Berlin, Germany
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39
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Abstract
15-Lipoxygenase (15-LO) has been implicated in oxidation of low-density lipoproteins (LDL) and this enzyme may be involved in the development of atherosclerosis. We have examined 1-substituted indolizines as possible inhibitors of 15-LO from soy beans and from rabbit reticulocytes. Most compounds studied were significantly more active as inhibitors of 15-LO from soy beans than quercetin. The indolizines were slightly less potent inhibitors of the mammalian enzyme, but we found good correlation between inhibitory activity against both 15-LO enzymes studied. Several of the compounds were only weak DPPH scavengers and they may therefore be regarded as so-called non antioxidant inhibitors of 15-LO.
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Affiliation(s)
- Lise-Lotte Gundersen
- Department of Chemistry, University of Oslo, PO Box 1033, Blindern, N-0315 Oslo, Norway.
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Abstract
Mammalian lipoxygenases have been implicated in several inflammatory disorders; however, the details of the kinetic mechanism are still not well understood. In this paper, human platelet 12-lipoxygenase (12-hLO) and human reticulocyte 15-lipoxygenase-1 (15-hLO) were tested with arachidonic acid (AA) and linoleic acid (LA), respectively, under a variety of changing experimental conditions, such as temperature, dissolved oxygen concentration, and viscosity. The data that are presented show that 12-hLO and 15-hLO have slower rates of product release (k(cat)) than soybean lipoxygenase-1 (sLO-1), but similar or better rates of substrate capture for the fatty acid (k(cat)/K(M)) or molecular oxygen [k(cat)/K(M(O)2)]. The primary, kinetic isotope effect (KIE) for 15-hLO with LA was determined to be temperature-independent and large ((D)k(cat) = 40 +/- 8), over the range of 10-35 degrees C, indicating that C-H bond cleavage is the sole rate-limiting step and proceeds through a tunneling mechanism. The (D)k(cat)/K(M) for 15-hLO, however, was temperature-dependent, consistent with our previous results [Lewis, E. R., Johansen, E., and Holman, T. R. (1999) J. Am. Chem. Soc. 121, 1395-1396], indicating multiple rate-limiting steps. This was confirmed by a temperature-dependent, k(cat)/K(M) solvent isotope effect (SIE), which indicated a hydrogen bond rearrangement step at low temperatures, similar to that of sLO-1 [Glickman, M. H., and Klinman, J. P. (1995) Biochemistry 34, 14077-14092]. The KIE could not be determined for 12-hLO due to its inability to efficiently catalyze LA, but the k(cat)/K(M) SIE was temperature-independent, indicating distinct rate-limiting steps from both 15-hLO and sLO-1.
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Affiliation(s)
- Erika N Segraves
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA
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42
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Wiesner R, Suzuki H, Walther M, Yamamoto S, Kuhn H. Suicidal inactivation of the rabbit 15-lipoxygenase by 15S-HpETE is paralleled by covalent modification of active site peptides. Free Radic Biol Med 2003; 34:304-15. [PMID: 12543246 DOI: 10.1016/s0891-5849(02)01244-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Lipoxygenases (LOXs) are multifunctional enzymes that catalyze the oxygenation of polyunsaturated fatty acids to hydroperoxy derivatives; they also convert hydroperoxy fatty acids to epoxy leukotrienes and other secondary products. LOXs undergo suicidal inactivation but the mechanism of this process is still unclear. We investigated the mechanism of suicidal inactivation of the rabbit 15-lipoxygenase by [1-(14)C]-(15S,5Z,8Z,11Z,13E)-15-hydroperoxyeicosa-5,8,11,13-tetraenoic acid (15-HpETE) and observed covalent modification of the enzyme protein. In contrast, nonlipoxygenase proteins (bovine serum albumin and human gamma-globulin) were not significantly modified. Under the conditions of complete enzyme inactivation we found that 1.3 +/- 0.2 moles (n = 10) of inactivator were bound per mole lipoxygenase, and this value did depend neither on the enzyme/inactivator ratio nor on the duration of the inactivation period. Covalent modification required active enzyme protein and proceeded to a similar extent under aerobic and anaerobic conditions. In contrast, [1-(14)C]-(15S,5Z,8Z,11Z,13E)-15-hydroxyeicosa-5,8,11,13-tetraenoic acid (15-HETE), which is no substrate for epoxy-leukotriene formation, did not inactivate the enzyme and protein labeling was minimal. Separation of proteolytic cleavage peptides (Lys-C endoproteinase digestion) by tricine SDS-PAGE and isoelectric focusing in connection with N-terminal amino acid sequencing revealed covalent modification of several active site peptides. These data suggest that 15-lipoxygenase-catalyzed conversion of (15S,5Z,8Z,11Z,13E)-15-hydroperoxyeicosa-5,8,11,13-tetraenoic acid to 14,15-epoxy-leukotriene leads to the formation of reactive intermediate(s), which are covalently linked to the active site. Therefore, this protein modification contributes to suicidal inactivation.
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Affiliation(s)
- Rainer Wiesner
- Institute of Biochemistry, University Clinics Charité, Humboldt University, Berlin, Germany
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43
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Abstract
Lipoxygenases (LOXs) constitute a heterogeneous family of lipid peroxidizing enzymes capable of oxygenating polyunsaturated fatty acids to their corresponding hydroperoxy derivatives. In mammals, LOXs are classified with respect to their positional specificity of arachidonic acid oxygenation into 5-, 8-, 12-, and 15-LOXs. Arachidonate 15-LOXs may be sub-classified into a reticulocyte-type (type-1) and an epidermis-type (type-2) enzyme. Since the leukocyte-type 12-LOXs are very similar to the reticulocyte-type 15-LOXs, these enzymes are designated 12/15-LOXs. Several LOX isoforms, in particular the reticulocyte-type 15-LOX and the human 5-LOX, are well characterized with respect to their structural and functional properties On the other hand, the biological role of most LOX-isozymes including the reticulocyte-type 15-LOC is far from clear. This review is intended to summarize the recent developments in 15-LOX research with particular emphasis to molecular enzymology and regulation of gene expression. In addition, the major hypotheses on the physiological and patho-physiological roles of 15-LOXs will be discussed briefly.
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Affiliation(s)
- Hartmut Kuhn
- Institute of Biochemistry, University Clinics Charité, Humboldt University, Berlin, Germany.
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44
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Walther M, Anton M, Wiedmann M, Fletterick R, Kuhn H. The N-terminal domain of the reticulocyte-type 15-lipoxygenase is not essential for enzymatic activity but contains determinants for membrane binding. J Biol Chem 2002; 277:27360-6. [PMID: 12004065 DOI: 10.1074/jbc.m203234200] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The rabbit reticulocyte-type 15-lipoxygenase is capable of oxygenating biomembranes and lipoproteins without the preceding action of ester lipid cleaving enzymes. This reaction requires an efficient membrane binding, and the N-terminal beta-barrel domain of the enzyme has been implicated in this process. To obtain detailed information on the structural requirements for membrane oxygenation, we expressed the rabbit wild-type 15-lipoxygenase, its beta-barrel deletion mutant (catalytic domain), and several lipoxygenase point mutations as His-tagged fusion proteins in Escherichia coli and tested their membrane binding characteristics. We found that: (i) the beta-barrel deletion mutant was catalytically active and its enzymatic properties (K(M), V(max), pH optimum, substrate specificity) were similar to those of the wild-type enzyme; (ii) when compared with the wild-type lipoxygenase, the membrane binding properties of the N-terminal truncation mutant were impaired but not abolished, suggesting a role of the catalytic domain in membrane binding; and (iii) Phe-70 and Leu-71 (constituents of the beta-barrel domain) but also Trp-181, which is located in the catalytic domain, were identified as sequence determinants for membrane binding. Mutation of these amino acids to more polar residues (F70H, L71K, W181E) impaired the membrane binding capacity of the recombinant enzyme. These data indicate that the C-terminal catalytic domain of the rabbit 15-lipoxygenase is enzymatically active and that the membrane binding properties of the enzyme are determined by a concerted action of the N-terminal beta-barrel and the C-terminal catalytic domain.
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Affiliation(s)
- Matthias Walther
- Institute of Biochemistry, University Clinics Charité, Humboldt University, Monbijoustrasse 2, D-10117 Berlin, Germany
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Tang S, Bhatia B, Maldonado CJ, Yang P, Newman RA, Liu J, Chandra D, Traag J, Klein RD, Fischer SM, Chopra D, Shen J, Zhau HE, Chung LWK, Tang DG. Evidence that arachidonate 15-lipoxygenase 2 is a negative cell cycle regulator in normal prostate epithelial cells. J Biol Chem 2002; 277:16189-201. [PMID: 11839751 DOI: 10.1074/jbc.m111936200] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
15-Lipoxygenase 2 (15-LOX2) is a recently cloned human lipoxygenase that shows tissue-restricted expression in prostate, lung, skin, and cornea. The protein level and enzymatic activity of 15-LOX2 have been shown to be down-regulated in prostate cancers compared with normal and benign prostate tissues. The biological function of 15-LOX2 and the role of loss of 15-LOX2 expression in prostate tumorigenesis, however, remain unknown. We report the cloning and functional characterization of 15-LOX2 and its three splice variants (termed 15-LOX2sv-a, 15-LOX2sv-b, and 15-LOX2sv-c) from primary prostate epithelial cells. Western blotting with multiple primary prostate cell strains and prostate cancer cell lines reveals that the expression of 15-LOX2 is lost in all prostate cancer cell lines, accompanied by decreased enzymatic activity revealed by liquid chromatography/tandem mass spectrometry analyses. Further experiments show that the loss of 15-LOX2 expression results from transcriptional repression caused by mechanism(s) other than promoter hypermethylation or histone deacetylation. Subsequent functional studies indicate the following: 1) the 15-LOX2 product, 15(S)-hydroxyeicosatetraenoic acid, inhibits prostate cancer cell cycle progression; 2) 15-LOX2 expression in primary prostate epithelial cells is inversely correlated with cell cycle; and 3) restoration of 15-LOX2 expression in prostate cancer cells partially inhibits cell cycle progression. Taken together, these results suggest that 15-LOX2 could be a suppressor of prostate cancer development, which functions by restricting cell cycle progression.
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Affiliation(s)
- Shaohua Tang
- Department of Carcinogenesis, the University of Texas MD Anderson Cancer Center, Science Park Research Division, Smithville, Texas 78957, USA
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46
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Abstract
Human and rabbit reticulocyte 15-lipoxygenase (15-lipoxygenase-1) and the leukocyte-type 12-lipoxygenases (12/15-lipoxygenases) of pig, beef, mouse and rat constitute a particular subfamily of mammalian lipoxygenases (reticulocyte-type lipoxygenases) with unique properties and functions. They catalyze enzymatic lipid peroxidation in complex biological structures via direct dioxygenation of phospholipids and cholesterol esters of biomembranes and plasma lipoproteins. Moreover, they are a source of free radicals initiating non-enzymatic lipid peroxidation and other oxidative processes. Expression and activity of reticulocyte-type lipoxygenases are highly regulated. Moreover, the susceptibility of intracellular membranes toward these lipoxygenases is controlled and may be increased together with lipoxygenase activity under conditions of oxidative stress. Thus, oxidative stress may favor a concerted package of lipoxygenase-mediated enzymatic and non-enzymatic lipid peroxidation and co-oxidative processes. Reaction of reticulocyte-type lipoxygenases with low-density lipoprotein renders the latter atherogenic and appears to be involved in the formation of atherosclerotic lesions.
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Affiliation(s)
- Tankred Schewe
- Institut für Physiologische Chemie I, Heinrich-Heine-Universität Düsseldorf, Germany
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47
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Schwarz K, Walther M, Anton M, Gerth C, Feussner I, Kuhn H. Structural basis for lipoxygenase specificity. Conversion of the human leukocyte 5-lipoxygenase to a 15-lipoxygenating enzyme species by site-directed mutagenesis. J Biol Chem 2001; 276:773-9. [PMID: 11027682 DOI: 10.1074/jbc.m005114200] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mammalian lipoxygenases constitute a heterogeneous family of lipid-peroxidizing enzymes, and the various isoforms are categorized with respect to their positional specificity of arachidonic acid oxygenation into 5-, 8-, 12-, and 15-lipoxygenases. Structural modeling suggested that the substrate binding pocket of the human 5-lipoxygenase is 20% bigger than that of the reticulocyte-type 15-lipoxygenase; thus, reduction of the active-site volume was suggested to convert a 5-lipoxygenase to a 15-lipoxygenating enzyme species. To test this "space-based" hypothesis of the positional specificity, the volume of the 5-lipoxygenase substrate binding pocket was reduced by introducing space-filling amino acids at critical positions, which have previously been identified as sequence determinants for the positional specificity of other lipoxygenase isoforms. We found that single point mutants of the recombinant human 5-lipoxygenase exhibited a similar specificity as the wild-type enzyme but double, triple, and quadruple mutations led to a gradual alteration of the positional specificity from 5S- via 8S- toward 15S-lipoxygenation. The quadruple mutant F359W/A424I/N425M/A603I exhibited a major 15S-lipoxygenase activity (85-95%), with (8S,5Z,9E,11Z,14Z)-8-hydroperoxyeicosa-5,9 ,11, 14-tetraenoic acid being a minor side product. These data indicate the principle possibility of interconverting 5- and 15-lipoxygenases by site-directed mutagenesis and appear to support the space-based hypothesis of positional specificity.
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Affiliation(s)
- K Schwarz
- Institute of Biochemistry, University Clinics Charité, Humboldt-University, Hessische Strasse 3-4, D-10115 Berlin, Germany
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48
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Abstract
15 lipoxygenase (15LO) is a lipid-oxidizing enzyme that is considered to contribute to the formation of oxidized lipids in atherosclerotic lesions. Monocyte-macrophages are the key cells that express 15LO in atherosclerotic lesions. In this review, we examine the evidence for 15LO involvement in atherogenesis and explore and evaluate the potential mechanisms whereby 15LO may contribute to the oxidation of LDL by monocyte-macrophages. We also describe several possible pro- versus anti-atherogenic functions that may be mediated by various products of 15LO lipid oxidation. Central pathways involved in regulating 15LO expression and activity that may serve as future targets for intervention and regulation of this enzyme are also reviewed.
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Affiliation(s)
- M K Cathcart
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
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49
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Jisaka M, Kim RB, Boeglin WE, Brash AR. Identification of amino acid determinants of the positional specificity of mouse 8S-lipoxygenase and human 15S-lipoxygenase-2. J Biol Chem 2000; 275:1287-93. [PMID: 10625675 DOI: 10.1074/jbc.275.2.1287] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phorbol ester-inducible mouse 8S-lipoxygenase (8-LOX) and its human homologue, 15S-lipoxygenase-2 (15-LOX-2), share 78% identity in amino acid sequences, yet there is no overlap in their positional specificities. In this study, we investigated the determinants of positional specificity using a random chimeragenesis approach in combination with site-directed mutagenesis. Exchange of the C-terminal one-third of the 8-LOX with the corresponding portion of 15-LOX-2 yielded a chimeric enzyme with exclusively 15S-lipoxygenase activity. The critical region was narrowed down to a cluster of five amino acids by expression of multiple cDNAs obtained by in situ chimeragenesis in Escherichia coli. Finally, a pair of amino acids, Tyr(603) and His(604), was identified as the positional determinant by site-directed mutagenesis. Mutation of both of these amino acids to the corresponding amino acids in 15-LOX-2 (Asp and Val, respectively) converted the positional specificity from 8S to 90% 15S without yielding any other by-products. Mutation of the corresponding residues in 15-LOX-2 to the 8-LOX sequence changed specificity to 50% oxygenation at C-8 for one amino acid substitution and 70% at C-8 for the double mutant. Based on the crystal structure of the reticulocyte 15-LOX, these two amino acids lie opposite the open coordination position of the catalytic iron in a likely site for substrate binding. The change from 8 to 15 specificity entails a switch in the head to tail binding of substrate. Enzymes that react with substrate "head first" (5-LOX and 8-LOX) have a bulky aromatic amino acid and a histidine in these positions, whereas lipoxygenases that accept substrates "tail first" (12-LOX and 15-LOX) have an aliphatic residue with a glutamine or aspartate. Thus, this positional determinant of the 8-LOX and 15-LOX-2 may have significance for other lipoxygenases.
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Affiliation(s)
- M Jisaka
- Division of Clinical Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-6602, USA.
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50
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Borngräber S, Browner M, Gillmor S, Gerth C, Anton M, Fletterick R, Kühn H. Shape and specificity in mammalian 15-lipoxygenase active site. The functional interplay of sequence determinants for the reaction specificity. J Biol Chem 1999; 274:37345-50. [PMID: 10601303 DOI: 10.1074/jbc.274.52.37345] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Previous mutagenesis studies along with molecular modeling using the x-ray coordinates of the rabbit 15-lipoxygenase have led to the suggestion that the size of the substrate binding pocket may play an essential role in determining the oxygenation specificity of 5-, 12-, and 15-lipoxygenases. Based on the x-ray crystal structure of rabbit 15-lipoxygenase, Ile(593) appeared to be important in defining size and shape of the substrate-binding site in 15-lipoxygenases. We found that substitution of Ile(593) with alanine shifted the positional specificity of this enzyme toward 12-lipoxygenation. To compare the importance of position 593 with previously defined determinants for the oxygenation specificity, we introduced small (alanine-scan) or large amino acids (phenylalanine-scan) at critical positions surrounding the putative fatty acid-binding site, so that the volume of the pocket was either increased or decreased. Enlargement or alteration in packing density within the substrate binding pocket in the rabbit 15-lipoxygenase increased the share of 12-lipoxygenase products, whereas a smaller active site favored 15-lipoxygenation. Simultaneous substitution of both large and small residues in the context of either a 15- or 12-lipoxygenase indicated that there is a functional interplay of the sequence determinants for lipoxygenation specificity. If the 15-lipoxygenase active site is enlarged excessively, however, no lipoxygenation was observed anymore. Together these results indicate the importance of the overall size and shape of the arachidonic acid binding pocket in defining the specificity of lipoxygenase reaction.
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Affiliation(s)
- S Borngräber
- Institute of Biochemistry, University Clinics (Charité), Humboldt University, Hessische Str. 3-4, 10115 Berlin, Germany
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