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Castillo GM, Yao Y, Guerra RE, Jiang H, Nishimoto-Ashfield A, Lyubimov AV, Alfaro JF, Striker KA, Buynov N, Schwabl P, Bolotin EM. Subcutaneous therapy for portal hypertension: PHIN-214, a partial vasopressin receptor 1A agonist. Biomed Pharmacother 2024; 171:116068. [PMID: 38176129 PMCID: PMC10953113 DOI: 10.1016/j.biopha.2023.116068] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 12/14/2023] [Accepted: 12/21/2023] [Indexed: 01/06/2024] Open
Abstract
Cirrhosis is a liver disease that leads to increased intrahepatic resistance, portal hypertension (PH), and splanchnic hyperemia resulting in ascites, variceal bleeding, and hepatorenal syndrome. Terlipressin, a prodrug that converts to a short half-life vasopressin receptor 1 A (V1a) full agonist [8-Lys]-Vasopressin (LVP), is an intravenous treatment for PH complications, but hyponatremia and ischemic side effects require close monitoring. We developed PHIN-214 which converts into PHIN-156, a more biologically stable V1a partial agonist. PHIN-214 enables once-daily subcutaneous administration without causing ischemia or tissue necrosis and has a 10-fold higher therapeutic index than terlipressin in healthy rats. As V1a partial agonists, PHIN-214 and PHIN-156 exhibited maximum activities of 28 % and 42 % of Arginine vasopressin (AVP), respectively. The potency of PHIN-156 and LVP relative to AVP is comparable for V1a (5.20 and 1.65 nM, respectively) and V1b (102 and 115 nM, respectively) receptors. However, the EC50 of PHIN-156 to the V2 receptor was 26-fold higher than that of LVP, indicating reduced potential for dilutional hyponatremia via V2 agonism compared to terlipressin/LVP. No significant off-target binding to 87 toxicologically relevant receptors were observed when evaluated in vitro at 10 µM concentration. In bile duct ligated rats with PH, subcutaneous PHIN-214 reduced portal pressure by 13.4 % ± 3.4 in 4 h. These collective findings suggest that PHIN-214 could be a novel pharmacological treatment for patients with PH, potentially administered outside of hospital settings, providing a safe and convenient alternative for managing PH and its complications.
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Affiliation(s)
| | - Yao Yao
- PharmaIN Corp., Bothell, Washington 98011, USA
| | | | - Han Jiang
- PharmaIN Corp., Bothell, Washington 98011, USA
| | | | - Alexander V Lyubimov
- University of Illinois, Toxicology Research Laboratory, Department of Pharmacology, Chicago 60612, USA
| | | | | | | | - Philipp Schwabl
- Medical University of Vienna, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Vienna, Austria
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2
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Klaene JJ, Ni W, Alfaro JF, Zhou ZS. Detection and quantitation of succinimide in intact protein via hydrazine trapping and chemical derivatization. J Pharm Sci 2014; 103:3033-42. [PMID: 25043726 DOI: 10.1002/jps.24074] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Revised: 06/01/2014] [Accepted: 06/04/2014] [Indexed: 12/19/2022]
Abstract
The formation of aspartyl succinimide is a common post-translational modification of protein pharmaceuticals under acidic conditions. We present a method to detect and quantitate succinimide in intact protein via hydrazine trapping and chemical derivatization. Succinimide, which is labile under typical analytical conditions, is first trapped with hydrazine to form stable hydrazide and can be directly analyzed by mass spectrometry. The resulting aspartyl hydrazide can be selectively derivatized by various tags, such as fluorescent rhodamine sulfonyl chloride that absorbs strongly in the visible region (570 nm). Our tagging strategy allows the labeled protein to be analyzed by orthogonal methods, including HPLC-UV-Vis, liquid chromatography mass spectrometry (LC-MS), and SDS-PAGE coupled with fluorescence imaging. A unique advantage of our method is that variants containing succinimide, after derivatization, can be readily resolved via either affinity enrichment or chromatographic separation. This allows further investigation of individual factors in a complex protein mixture that affect succinimide formation. Some additional advantages are imparted by fluorescence labeling including the facile detection of the intact protein without proteolytic digestion to peptides; and high sensitivity, for example, without optimization, 0.41% succinimide was readily detected. As such, our method should be useful for rapid screening, optimization of formulation conditions, and related processes relevant to protein pharmaceuticals.
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Affiliation(s)
- Joshua J Klaene
- Barnett Institute of Chemical and Biological Analysis, Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts, 02115
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3
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Hartmann T, Terao M, Garattini E, Teutloff C, Alfaro JF, Jones JP, Leimkühler S. The impact of single nucleotide polymorphisms on human aldehyde oxidase. Drug Metab Dispos 2012. [PMID: 22279051 PMCID: PMC4738704 DOI: 10.1124/dmd.111.043828+10.1124/dmd.112.043828err] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Aldehyde oxidase (AO) is a complex molybdo-flavoprotein that belongs to the xanthine oxidase family. AO is active as a homodimer, and each 150-kDa monomer binds two distinct [2Fe2S] clusters, FAD, and the molybdenum cofactor. AO has an important role in the metabolism of drugs based on its broad substrate specificity oxidizing aromatic aza-heterocycles, for example, N(1)-methylnicotinamide and N-methylphthalazinium, or aldehydes, such as benzaldehyde, retinal, and vanillin. Sequencing the 35 coding exons of the human AOX1 gene in a sample of 180 Italian individuals led to the identification of relatively frequent, synonymous, missense and nonsense single-nucleotide polymorphisms (SNPs). Human aldehyde oxidase (hAOX1) was purified after heterologous expression in Escherichia coli. The recombinant protein was obtained with a purity of 95% and a yield of 50 μg/l E. coli culture. Site-directed mutagenesis of the hAOX1 cDNA allowed the purification of protein variants bearing the amino acid changes R802C, R921H, N1135S, and H1297R, which correspond to some of the identified SNPs. The hAOX1 variants were purified and compared with the wild-type protein relative to activity, oligomerization state, and metal content. Our data show that the mutation of each amino acid residue has a variable impact on the ability of hAOX1 to metabolize selected substrates. Thus, the human population is characterized by the presence of functionally inactive hAOX1 allelic variants as well as variants encoding enzymes with different catalytic activities. Our results indicate that the presence of these allelic variants should be considered for the design of future drugs.
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Affiliation(s)
| | | | | | | | | | | | - Silke Leimkühler
- Address correspondence to: Dr. Silke Leimkü hler, Department of Molecular Enzymology, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany. E-mail:
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4
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Hartmann T, Terao M, Garattini E, Teutloff C, Alfaro JF, Jones JP, Leimkühler S. The Impact of Single Nucleotide Polymorphisms on Human Aldehyde Oxidase. Drug Metab Dispos 2012. [DOI: 10.1124/dmd.111.043828 10.1124/dmd.112.043828err] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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5
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Hartmann T, Terao M, Garattini E, Teutloff C, Alfaro JF, Jones JP, Leimkühler S. The impact of single nucleotide polymorphisms on human aldehyde oxidase. Drug Metab Dispos 2012; 40:856-64. [PMID: 22279051 DOI: 10.1124/dmd.111.043828] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Aldehyde oxidase (AO) is a complex molybdo-flavoprotein that belongs to the xanthine oxidase family. AO is active as a homodimer, and each 150-kDa monomer binds two distinct [2Fe2S] clusters, FAD, and the molybdenum cofactor. AO has an important role in the metabolism of drugs based on its broad substrate specificity oxidizing aromatic aza-heterocycles, for example, N(1)-methylnicotinamide and N-methylphthalazinium, or aldehydes, such as benzaldehyde, retinal, and vanillin. Sequencing the 35 coding exons of the human AOX1 gene in a sample of 180 Italian individuals led to the identification of relatively frequent, synonymous, missense and nonsense single-nucleotide polymorphisms (SNPs). Human aldehyde oxidase (hAOX1) was purified after heterologous expression in Escherichia coli. The recombinant protein was obtained with a purity of 95% and a yield of 50 μg/l E. coli culture. Site-directed mutagenesis of the hAOX1 cDNA allowed the purification of protein variants bearing the amino acid changes R802C, R921H, N1135S, and H1297R, which correspond to some of the identified SNPs. The hAOX1 variants were purified and compared with the wild-type protein relative to activity, oligomerization state, and metal content. Our data show that the mutation of each amino acid residue has a variable impact on the ability of hAOX1 to metabolize selected substrates. Thus, the human population is characterized by the presence of functionally inactive hAOX1 allelic variants as well as variants encoding enzymes with different catalytic activities. Our results indicate that the presence of these allelic variants should be considered for the design of future drugs.
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Affiliation(s)
- Tobias Hartmann
- Department of Molecular Enzymology, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany
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6
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Abstract
DFT calculations support a concerted mechanism for xanthine oxidase and aldehyde oxidase hydride displacement from the sp(2) carbon of 6-substituted 4-quinazolinones. The variations in transition state structure show that C-O bond formation is nearly complete in the transition state and the transition state changes are anti-Hammond with the C-H and C-O bond lengths being more product-like for the faster reactions. The C-O bond length in the transition state is around 90% formed. However, the C-H bond is only about 80% broken. This leads to a very tetrahedral transition state with an O-C-N angle of 109 degrees. Thus, while the mechanism is concerted, the antibonding orbital of the C-H bond that is broken is not directly attacked by the nucleophile and instead hydride displacement occurs after almost complete tetrahedral transition state formation. In support of this the C=N bond is lengthened in the transition state indicating that attack on the electrophilic carbon occurs by addition to the C=N bond with negative charge increasing on the nitrogen. Differences in experimental reaction rates are accurately reproduced by these calculations and tend to support this mechanism.
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Affiliation(s)
- Joshua F Alfaro
- Department of Chemistry, Washington State University, Pullman, Washington 99164, USA
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7
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Lee BWK, Sun HG, Zang T, Kim BJ, Alfaro JF, Zhou ZS. Enzyme-catalyzed transfer of a ketone group from an S-adenosylmethionine analogue: a tool for the functional analysis of methyltransferases. J Am Chem Soc 2010; 132:3642-3. [PMID: 20196537 DOI: 10.1021/ja908995p] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
S-adenosylmethionine (AdoMet or SAM)-dependent methyltransferases belong to a large and diverse family of group-transfer enzymes that perform vital biological functions on a host of substrates. Despite the progress in genomics, structural proteomics, and computational biology, functional annotation of methyltransferases remains a challenge. Herein, we report the synthesis and activity of a new AdoMet analogue functionalized with a ketone group. Using catechol O-methyltransferase (COMT, EC 2.1.1.6) and thiopurine S-methyltransferase (TPMT, EC 2.1.1.67) as model enzymes, this robust and readily accessible analogue displays kinetic parameters that are comparable to AdoMet and exhibits multiple turnovers with enzyme. More importantly, this AdoMet surrogate displays the same substrate specificity as the natural methyl donor. Incorporation of the ketone group allows for subsequent modification via bio-orthogonal labeling strategies and sensitive detection of the tagged ketone products. Hence, this AdoMet analogue expands the toolbox available to interrogate the biochemical functions of methyltransferases.
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Affiliation(s)
- Bobby W K Lee
- The Barnett Institute and Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, USA
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8
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Alfaro JF, Joswig-Jones CA, Ouyang W, Nichols J, Crouch GJ, Jones JP. Purification and mechanism of human aldehyde oxidase expressed in Escherichia coli. Drug Metab Dispos 2009; 37:2393-8. [PMID: 19741035 DOI: 10.1124/dmd.109.029520] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Human aldehyde oxidase 1 (AOX1) has been subcloned into a vector suitable for expression in Escherichia coli, and the protein has been expressed. The resulting protein is active, with sulfur being incorporated in the molybdopterin cofactor. Expression levels are modest, but 1 liter of cells supplies enough protein for both biochemical and kinetic characterization. Partial purification is achieved by nickel affinity chromatography through the addition of six histidines to the amino-terminal end of the protein. Kinetic analysis, including kinetic isotope effects and comparison with xanthine oxidase, reveal similar mechanisms, with some subtle differences. This expression system will allow for the interrogation of human aldehyde oxidase structure/function relationships by site-directed mutagenesis and provide protein for characterizing the role of AOX1 in drug metabolism.
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Affiliation(s)
- Joshua F Alfaro
- Department of Chemistry, Washington State University, Pullman, WA 99163, USA
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9
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Alfaro JF, Gillies LA, Sun HG, Dai S, Zang T, Klaene JJ, Kim BJ, Lowenson JD, Clarke SG, Karger BL, Zhou ZS. Chemo-enzymatic detection of protein isoaspartate using protein isoaspartate methyltransferase and hydrazine trapping. Anal Chem 2008; 80:3882-9. [PMID: 18419136 DOI: 10.1021/ac800251q] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Isoaspartate formation is a ubiquitous post-translation modification arising from spontaneous asparagine deamidation or aspartate isomerization. The formation of isoaspartate inserts a methylene group into the protein backbone, generating a "kink", and may drastically alter protein structure and function, thereby playing critical roles in a myriad of biological processes, human diseases, and protein pharmaceutical development. Herein, we report a chemo-enzymatic detection method for the isoaspartate protein, which in particular allows the affinity enrichment of isoaspartate-containing proteins. In the initial step, protein isoaspartate methyltransferase selectively converts isoaspartates into the corresponding methyl esters. Subsequently, the labile methyl ester is trapped by strong nucleophiles in aqueous solutions, such as hydrazines to form hydrazides. The stable hydrazide products can be analyzed by standard proteomic techniques, such as matrix-assisted laser desorption ionization and electrospray ionization mass spectrometry. Furthermore, the chemical trapping step allows us to introduce several tagging strategies for product identification and quantification, such as UV-vis and fluorescence detection through a dansyl derivative. Most significantly, the hydrazide product can be enriched by affinity chromatography using aldehyde resins, thus drastically reducing sample complexity. Our method hence represents the first technique for the affinity enrichment of isoaspartyl proteins and should be amendable to the systematic and comprehensive characterization of isoaspartate, particularly in complex systems.
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Affiliation(s)
- Joshua F Alfaro
- Department of Chemistry, Washington State University, Pullman, Washington 99164, USA
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10
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Wooderchak WL, Dorgan KM, Karschner EL, Wynn DP, Alfaro JF, Cui Y, Zhou ZS, Hevel JM. Continuous assay measures methyltransferase activity: Defining the substrate specificity of rat Protein Arginine Methyltransferase 1 (PRMT1). FASEB J 2006. [DOI: 10.1096/fasebj.20.5.lb50-c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Whitney Lyn Wooderchak
- Chemistry and Biochemistry DepartmentUtah State University0300 Old Main HillLoganUtah84322
| | - Kathy M. Dorgan
- Department of ChemistryWashington State University470 Fulmer HallPullmanWashington99164
| | - Erin L. Karschner
- Departments of Chemistry and BiologyLycoming College700 College PlaceWilliamsportPA17701
| | - DonRaphael P. Wynn
- Department of ChemistryWashington State University470 Fulmer HallPullmanWashington99164
| | - Joshua F. Alfaro
- Department of ChemistryWashington State University470 Fulmer HallPullmanWashington99164
| | - Yinqiu Cui
- Department of ChemistryWashington State University470 Fulmer HallPullmanWashington99164
| | - Zhaohui Sunny Zhou
- Department of ChemistryWashington State University470 Fulmer HallPullmanWashington99164
| | - Joan M. Hevel
- Chemistry and Biochemistry DepartmentUtah State University0300 Old Main HillLoganUtah84322
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11
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Dorgan KM, Wooderchak WL, Wynn DP, Karschner EL, Alfaro JF, Cui Y, Zhou ZS, Hevel JM. An enzyme-coupled continuous spectrophotometric assay for S-adenosylmethionine-dependent methyltransferases. Anal Biochem 2006; 350:249-55. [PMID: 16460659 DOI: 10.1016/j.ab.2006.01.004] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [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] [Received: 10/07/2005] [Revised: 12/30/2005] [Accepted: 01/04/2006] [Indexed: 10/25/2022]
Abstract
Modification of small molecules and proteins by methyltransferases affects a wide range of biological processes. Here, we report an enzyme-coupled continuous spectrophotometric assay to quantitatively characterize S-adenosyl-L-methionine (AdoMet/SAM)-dependent methyltransferase activity. In this assay, S-adenosyl-L-homocysteine (AdoHcy/SAH), the transmethylation product of AdoMet-dependent methyltransferases, is hydrolyzed to S-ribosylhomocysteine and adenine by recombinant S-adenosylhomocysteine/5'-methylthioadenosine nucleosidase (SAHN/MTAN, EC 3.2.2.9). Subsequently, adenine generated from AdoHcy is further hydrolyzed to hypoxanthine and ammonia by recombinant adenine deaminase (EC 3.5.4.2). This deamination is associated with a decrease in absorbance at 265 nm that can be monitored continuously. Coupling enzymes are recombinant and easily purified. The utility of this assay was shown using recombinant rat protein arginine N-methyltransferase 1 (PRMT1, EC 2.1.1.125), which catalyzes the mono- and dimethylation of guanidino nitrogens of arginine residues in select proteins. Using this assay, the kinetic parameters of PRMT1 with three synthetic peptides were determined. An advantage of this assay is the destruction of AdoHcy by AdoHcy nucleosidase, which alleviates AdoHcy product feedback inhibition of S-adenosylmethionine-dependent methyltransferases. Finally, this method may be used to assay other enzymes that produce AdoHcy, 5'-methylthioadenosine, or compounds that can be cleaved by AdoHcy nucleosidase.
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Affiliation(s)
- Kathleen M Dorgan
- Department of Chemistry, Washington State University, Pullman, WA 99164, USA
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12
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Abstract
[reaction: see text] Quorum sensing is a process by which bacteria sense cell density. This cell-cell communication process is mediated by autoinducers. A cross-species messenger, autoinducer-2 (AI-2) is produced from S-ribosyl-L-homocysteine by the LuxS enzyme. A proposed mechanism for LuxS is an aldose-ketose isomerization of S-ribosylhomocysteine followed by a beta-elimination. We report here the synthesis of two substrate analogues, S-anhydroribosyl-L-homocysteine and S-homoribosyl-L-cysteine, which prevent the initial and final step of the mechanism, respectively.
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Affiliation(s)
- Joshua F Alfaro
- Department of Chemistry, School of Molecular Biosciences, Center for Integrated Biotechnology, Graduate Program in Pharmacology and Toxicology, Washington State University, Pullman, Washington 99164-4630, USA
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13
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Chen J, Halls SC, Alfaro JF, Zhou Z, Hu M. Potential beneficial metabolic interactions between tamoxifen and isoflavones via cytochrome P450-mediated pathways in female rat liver microsomes. Pharm Res 2005; 21:2095-104. [PMID: 15587933 DOI: 10.1023/b:pham.0000048202.92930.61] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [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: 11/12/2022]
Abstract
PURPOSE This study aims to evaluate a cytochrome P450-based tamoxifen-isoflavone interaction and to determine the mechanisms responsible for inhibitory effects of isoflavones (e.g., genistein) on the formation of alpha-hydroxytamoxifen. METHODS Metabolism studies were performed in vitro using female rat liver microsomes. The effects of genistein and an isoflavone mixture on tamoxifen metabolism and the inhibition mechanism were determined using standard kinetic analysis, preincubation, and selective chemical inhibitors of P450. RESULTS Metabolism of tamoxifen was saturable with Km values of 4.9+/-0.6, 14.6+/-2.2, 25+/-5.9 microM and Vmax values of 34.7+/-1.4, 297.5+/-19.2, 1867+/-231 pmol min(-1) mg(-1) for a-hydroxylation, N-desmethylation, and N-oxidation, respectively. Genistein (25 microM) inhibited alpha-hydroxylation at 2.5 microM tamoxifen by 64% (p < 0.001) but did not affect the 4-hydroxylation, N-desmethylation, and N-oxidation. A combination of three (genistein, daidzein, and glycitein) to five isoflavones (plus biochanin A and formononetin) inhibited tamoxifen alpha-hydroxylation to a greater extent but did not decrease the formation of identified metabolites. The inhibition on alpha-hydroxylation by genistein was mixed-typed with a Ki, value of 10.6 microM. Studies using selective chemical inhibitors showed that tamoxifen alpha-hydroxylation was mainly mediated by rat CYP1A2 and CYP3A1/2 and that genistein 3'-hydroxylation was mainly mediated by rat CYP1A2, CYP2C6 and CYP2D1. CONCLUSIONS Genistein and its isoflavone analogs have the potential to decrease side effects of tamoxifen through metabolic interactions that inhibit the formation of a-hydroxytamoxifen via inhibition of CYP1A2.
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Affiliation(s)
- Jun Chen
- Department of Pharmaceutical Sciences, College of Pharmacy, Washington State University, Pullman, Washington 99164, USA
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Zhao G, Wan W, Mansouri S, Alfaro JF, Bassler BL, Cornell KA, Zhou ZS. Chemical synthesis of S-ribosyl-l-homocysteine and activity assay as a LuxS substrate. Bioorg Med Chem Lett 2003; 13:3897-900. [PMID: 14592470 DOI: 10.1016/j.bmcl.2003.09.015] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [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: 10/27/2022]
Abstract
Bacterial quorum sensing is mediated by autoinducers, small signaling molecules generated by bacteria. It has been proposed that the LuxS enzyme converts S-ribosyl-L-homocysteine to 4,5-dihydroxy-2,3-pentanedione, the precursor of autoinducer 2 (AI-2). We report here a chemical synthesis of S-ribosyl-L-homocysteine and its analogue using Mitsunobu coupling. Chemically synthesized ribosylhomocysteine has been confirmed as a substrate for LuxS in both an enzyme assay and a whole cell quorum sensing assay. The chemical entities of products from the LuxS reaction were also established. Several ribosylhomocysteine analogues have been tested as LuxS inhibitors.
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Affiliation(s)
- Gang Zhao
- Department of Chemistry and School of Molecular Biosciences, Washington State University, Pullman, WA 99164, USA
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