Journal Article

DKFZ-2017-04404

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png The influence of dicoumarol on the bioactivation of the carcinogen aristolochic acid I in rats.

Stiborová, M. ; Levová, K. ; Bárta, F. ; Šulc, M. ; Frei, E.DKFZ* ; Arlt, V. M. ; Schmeiser, H. (Last author)DKFZ*

2014
Oxford Univ. Press Oxford

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Please use a persistent id in citations: doi:10.1093/mutage/geu004

Abstract: Aristolochic acid I (AAI) is the major toxic component of the plant extract AA, which leads to the development of nephropathy and urothelial cancer in human. Individual susceptibility to AAI-induced disease might reflect variability in enzymes that metabolise AAI. In vitroquinone oxidoreductase (NQO1) is the most potent enzyme that activates AAI by catalyzing formation of AAI-DNA adducts, which are found in kidneys of patients exposed to AAI. Inhibition of renal NQO1 activity by dicoumarol has been shown in mice. Here, we studied the influence of dicoumarol on metabolic activation of AAI in Wistar rats in vivo. In contrast to previous in vitro findings, dicoumarol did not inhibit AAI-DNA adduct formation in rats. Compared with rats treated with AAI alone, 11- and 5.4-fold higher AAI-DNA adduct levels were detected in liver and kidney, respectively, of rats pretreated with dicoumarol prior to exposure to AAI. Cytosols and microsomes isolated from liver and kidney of these rats were analysed for activity and protein levels of enzymes known to be involved in AAI metabolism. The combination of dicoumarol with AAI induced NQO1 protein level and activity in both organs. This was paralleled by an increase in AAI-DNA adduct levels found in ex vivo incubations with cytosols from rats pretreated with dicoumarol compared to cytosols from untreated rats. Microsomal ex vivo incubations showed a lower AAI detoxication to its oxidative metabolite, 8-hydroxyaristolochic acid (AAIa), although cytochrome P450 (CYP) 1A was practically unchanged. Because of these unexpected results, we examined CYP2C activity in microsomes and found that treatment of rats with dicoumarol alone and in combination with AAI inhibited CYP2C6/11 in liver. Therefore, these results indicate that CYP2C enzymes might contribute to AAI detoxication.

Keyword(s): Aristolochic Acids ; Carcinogens ; Cytochromes ; DNA Adducts ; Mutagens ; Dicumarol ; aristolochic acid I ; Cyp1a2 protein, rat ; Cytochrome P-450 CYP1A1 ; Cytochrome P-450 CYP1A2 ; NAD(P)H Dehydrogenase (Quinone) ; NQO1 protein, rat

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Contributing Institute(s):

1. Präventive Onkologie (G110)
2. Genetische Veränderungen bei der Karzinogenese (C016)
3. Radiopharmazeutische Chemie (E030)

Research Program(s):

1. 315 - Imaging and radiooncology (POF3-315) (POF3-315)

Appears in the scientific report 2014

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Database coverage:
; Allianz-Lizenz / DFG ; BIOSIS Previews ; Current Contents - Life Sciences ; Ebsco Academic Search ; IF < 5 ; JCR ; NCBI Molecular Biology Database ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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