Bioactivation of Carboxylic Acid Compounds by UDP-Glucuronosyltransferases to DNA-Damaging Intermediates : Role of Glycoxidation and Oxidative Stress Genotoxicity

B.C. Sallustio, Y.C. Degraff, J.S. Weekley, Philip Burcham

    Research output: Contribution to journalArticle

    27 Citations (Scopus)

    Abstract

    Nonenzymatic modification of proteins by acyl glucuronides is well documented; however, little is known about their potential to damage DNA. We have previously reported that clofibric acid undergoes glucuronidation-dependent bioactivation to DNA-damaging species in cultured mouse hepatocytes. The aim of this study was to investigate the mechanisms underlying such DNA damage, and to screen chemically diverse carboxylic acid drugs for their DNA-damaging potential in glucuronidation proficient murine hepatocytes. Cells were incubated with each aglycone for 18 h, followed by assessment of compound cytotoxicity using the MTT assay and evaluation of DNA damage using the Comet assay. Relative cytotoxic potencies were ketoprofen > diclofenac, benoxaprofen, nafenopin. gemfibrozil, probenecid > bezafibrate > clofibric acid. At a noncytotoxic (0.1 mM) concentration, only benoxaprofen, nafenopin, clofibric acid, and probenecid significantly increased Comet moments (P < 0.05 KruskalWallis). Clofibric acid and probenecid exhibited the greatest DNA-damaging potency, producing significant DNA damage at 0.01 mM concentrations. The two drugs produced maximal increases in Comet moment of 4.51 x and 2.57 x control, respectively. The glucuronidation inhibitor borneol (1 mM) abolished the induction of DNA damage by 0.5 mM concentrations of clofibric acid and probenecid. In an in vitro cell-free system, clofibric acid glucuronide was 10 x more potent than glucuronic acid in causing DNA strand-nicking, although both compounds showed similar rates of autoxidation to generate hydroxyl radicals. In cultured hepatocytes, the glycation inhibitor, aminoguanidine, and the iron chelator, desferrioxamine mesylate, inhibited DNA damage by clofibric acid, whereas the free radical scavengers Trolox and butylated hydroxytoluene, and the superoxide dismutase mimetic bis-3,5-diisopropylsalicylate had no effect. In conclusion, clinically relevant concentrations of two structurally unrelated carboxylic acids, probenecid and clofibric acid, induced DNA damage in isolated hepatocytes via glucuronidation-dependent pathways. These findings suggest acyl glucuronides are able to access and damage nuclear DNA via iron-catalyzed glycation/glycoxidative processes.
    Original languageEnglish
    Pages (from-to)683-691
    JournalChemical Research in Toxicology
    Volume19
    Issue number5
    DOIs
    Publication statusPublished - 2006

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    Clofibric Acid
    Glucuronosyltransferase
    Oxidative stress
    Carboxylic Acids
    DNA Damage
    Probenecid
    Oxidative Stress
    DNA
    Hepatocytes
    Nafenopin
    Glucuronides
    Iron
    Bezafibrate
    Gemfibrozil
    Ketoprofen
    Butylated Hydroxytoluene
    Glucuronic Acid
    Free Radical Scavengers
    Mesylates
    Deferoxamine

    Cite this

    @article{68db4e824cf14d6a89d4250f11cf05b2,
    title = "Bioactivation of Carboxylic Acid Compounds by UDP-Glucuronosyltransferases to DNA-Damaging Intermediates : Role of Glycoxidation and Oxidative Stress Genotoxicity",
    abstract = "Nonenzymatic modification of proteins by acyl glucuronides is well documented; however, little is known about their potential to damage DNA. We have previously reported that clofibric acid undergoes glucuronidation-dependent bioactivation to DNA-damaging species in cultured mouse hepatocytes. The aim of this study was to investigate the mechanisms underlying such DNA damage, and to screen chemically diverse carboxylic acid drugs for their DNA-damaging potential in glucuronidation proficient murine hepatocytes. Cells were incubated with each aglycone for 18 h, followed by assessment of compound cytotoxicity using the MTT assay and evaluation of DNA damage using the Comet assay. Relative cytotoxic potencies were ketoprofen > diclofenac, benoxaprofen, nafenopin. gemfibrozil, probenecid > bezafibrate > clofibric acid. At a noncytotoxic (0.1 mM) concentration, only benoxaprofen, nafenopin, clofibric acid, and probenecid significantly increased Comet moments (P < 0.05 KruskalWallis). Clofibric acid and probenecid exhibited the greatest DNA-damaging potency, producing significant DNA damage at 0.01 mM concentrations. The two drugs produced maximal increases in Comet moment of 4.51 x and 2.57 x control, respectively. The glucuronidation inhibitor borneol (1 mM) abolished the induction of DNA damage by 0.5 mM concentrations of clofibric acid and probenecid. In an in vitro cell-free system, clofibric acid glucuronide was 10 x more potent than glucuronic acid in causing DNA strand-nicking, although both compounds showed similar rates of autoxidation to generate hydroxyl radicals. In cultured hepatocytes, the glycation inhibitor, aminoguanidine, and the iron chelator, desferrioxamine mesylate, inhibited DNA damage by clofibric acid, whereas the free radical scavengers Trolox and butylated hydroxytoluene, and the superoxide dismutase mimetic bis-3,5-diisopropylsalicylate had no effect. In conclusion, clinically relevant concentrations of two structurally unrelated carboxylic acids, probenecid and clofibric acid, induced DNA damage in isolated hepatocytes via glucuronidation-dependent pathways. These findings suggest acyl glucuronides are able to access and damage nuclear DNA via iron-catalyzed glycation/glycoxidative processes.",
    author = "B.C. Sallustio and Y.C. Degraff and J.S. Weekley and Philip Burcham",
    year = "2006",
    doi = "10.1021/tx060022k",
    language = "English",
    volume = "19",
    pages = "683--691",
    journal = "Chemical Research in Toxicology",
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    Bioactivation of Carboxylic Acid Compounds by UDP-Glucuronosyltransferases to DNA-Damaging Intermediates : Role of Glycoxidation and Oxidative Stress Genotoxicity. / Sallustio, B.C.; Degraff, Y.C.; Weekley, J.S.; Burcham, Philip.

    In: Chemical Research in Toxicology, Vol. 19, No. 5, 2006, p. 683-691.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Bioactivation of Carboxylic Acid Compounds by UDP-Glucuronosyltransferases to DNA-Damaging Intermediates : Role of Glycoxidation and Oxidative Stress Genotoxicity

    AU - Sallustio, B.C.

    AU - Degraff, Y.C.

    AU - Weekley, J.S.

    AU - Burcham, Philip

    PY - 2006

    Y1 - 2006

    N2 - Nonenzymatic modification of proteins by acyl glucuronides is well documented; however, little is known about their potential to damage DNA. We have previously reported that clofibric acid undergoes glucuronidation-dependent bioactivation to DNA-damaging species in cultured mouse hepatocytes. The aim of this study was to investigate the mechanisms underlying such DNA damage, and to screen chemically diverse carboxylic acid drugs for their DNA-damaging potential in glucuronidation proficient murine hepatocytes. Cells were incubated with each aglycone for 18 h, followed by assessment of compound cytotoxicity using the MTT assay and evaluation of DNA damage using the Comet assay. Relative cytotoxic potencies were ketoprofen > diclofenac, benoxaprofen, nafenopin. gemfibrozil, probenecid > bezafibrate > clofibric acid. At a noncytotoxic (0.1 mM) concentration, only benoxaprofen, nafenopin, clofibric acid, and probenecid significantly increased Comet moments (P < 0.05 KruskalWallis). Clofibric acid and probenecid exhibited the greatest DNA-damaging potency, producing significant DNA damage at 0.01 mM concentrations. The two drugs produced maximal increases in Comet moment of 4.51 x and 2.57 x control, respectively. The glucuronidation inhibitor borneol (1 mM) abolished the induction of DNA damage by 0.5 mM concentrations of clofibric acid and probenecid. In an in vitro cell-free system, clofibric acid glucuronide was 10 x more potent than glucuronic acid in causing DNA strand-nicking, although both compounds showed similar rates of autoxidation to generate hydroxyl radicals. In cultured hepatocytes, the glycation inhibitor, aminoguanidine, and the iron chelator, desferrioxamine mesylate, inhibited DNA damage by clofibric acid, whereas the free radical scavengers Trolox and butylated hydroxytoluene, and the superoxide dismutase mimetic bis-3,5-diisopropylsalicylate had no effect. In conclusion, clinically relevant concentrations of two structurally unrelated carboxylic acids, probenecid and clofibric acid, induced DNA damage in isolated hepatocytes via glucuronidation-dependent pathways. These findings suggest acyl glucuronides are able to access and damage nuclear DNA via iron-catalyzed glycation/glycoxidative processes.

    AB - Nonenzymatic modification of proteins by acyl glucuronides is well documented; however, little is known about their potential to damage DNA. We have previously reported that clofibric acid undergoes glucuronidation-dependent bioactivation to DNA-damaging species in cultured mouse hepatocytes. The aim of this study was to investigate the mechanisms underlying such DNA damage, and to screen chemically diverse carboxylic acid drugs for their DNA-damaging potential in glucuronidation proficient murine hepatocytes. Cells were incubated with each aglycone for 18 h, followed by assessment of compound cytotoxicity using the MTT assay and evaluation of DNA damage using the Comet assay. Relative cytotoxic potencies were ketoprofen > diclofenac, benoxaprofen, nafenopin. gemfibrozil, probenecid > bezafibrate > clofibric acid. At a noncytotoxic (0.1 mM) concentration, only benoxaprofen, nafenopin, clofibric acid, and probenecid significantly increased Comet moments (P < 0.05 KruskalWallis). Clofibric acid and probenecid exhibited the greatest DNA-damaging potency, producing significant DNA damage at 0.01 mM concentrations. The two drugs produced maximal increases in Comet moment of 4.51 x and 2.57 x control, respectively. The glucuronidation inhibitor borneol (1 mM) abolished the induction of DNA damage by 0.5 mM concentrations of clofibric acid and probenecid. In an in vitro cell-free system, clofibric acid glucuronide was 10 x more potent than glucuronic acid in causing DNA strand-nicking, although both compounds showed similar rates of autoxidation to generate hydroxyl radicals. In cultured hepatocytes, the glycation inhibitor, aminoguanidine, and the iron chelator, desferrioxamine mesylate, inhibited DNA damage by clofibric acid, whereas the free radical scavengers Trolox and butylated hydroxytoluene, and the superoxide dismutase mimetic bis-3,5-diisopropylsalicylate had no effect. In conclusion, clinically relevant concentrations of two structurally unrelated carboxylic acids, probenecid and clofibric acid, induced DNA damage in isolated hepatocytes via glucuronidation-dependent pathways. These findings suggest acyl glucuronides are able to access and damage nuclear DNA via iron-catalyzed glycation/glycoxidative processes.

    U2 - 10.1021/tx060022k

    DO - 10.1021/tx060022k

    M3 - Article

    VL - 19

    SP - 683

    EP - 691

    JO - Chemical Research in Toxicology

    JF - Chemical Research in Toxicology

    SN - 0893-228X

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