Posted: |
20 Dec 2004 05:10 |
Subject: |
Ochratoxin A: induction of (oxidative)
DNA damage, cytotoxic |
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http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TCN-4DB5BD9-1&_coverDate=01%2F31%2F2005&_alid=230959069&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=5175&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=8481ef9833d34a4fc06fd48abcd8f0b1
Toxicology
Volume 206, Issue 3 , 31 January 2005, Pages 413-425
doi:10.1016/j.tox.2004.08.004
Copyright © 2004 Elsevier Ireland Ltd All rights reserved.
Ochratoxin A: induction of (oxidative) DNA damage, cytotoxicity
and apoptosis in mammalian cell lines and primary cells
Hennicke G. Kampa, Gerhard Eisenbranda, Josef Schlatterb,
Kirsten Würtha and Christine Janzowskia, ,
aDepartment of Chemistry, Division of Food Chemistry and
Environmental Toxicology, University of Kaiserslautern, Erwin
Schroedinger Straße 52, D-67663 Kaiserslautern, Germany
bSwiss Federal Office of Public Health, Food Toxicology Section,
Stauffacherstrasse 101, CH-8004 Zürich, Switzerland
Received 24 May 2004; revised 2 August 2004; accepted 2 August
2004. Available online 15 September 2004.
Abstract
Ochratoxin A (OTA) is a nephrotoxic/-carcinogenic mycotoxin,
produced by several Aspergillus- and Penicillium-strains. Humans
are exposed to OTA via food contamination, a causal relationship
of OTA to human endemic Balkan nephropathy is still under
debate. Since DNA-adducts of OTA or its metabolites could not be
identified unambiguously, its carcinogenic effectiveness might
be related to secondary effects, such as oxidative cell damage
or cell proliferation. In this study, OTA mediated induction of
(oxidative) DNA damage, cytotoxicity (necrosis, growth
inhibition, apoptosis) and modulation of glutathione were
investigated in cell lines (V79, CV-1) and primary rat kidney
cells. After 24 h incubation, viability of V79 cells was
strongly decreased by OTA concentrations >2.5 μmol/L, whereas
CV-1 cells were clearly less sensitive. Strong growth inhibition
occurred in both cell lines (IC50 2 μmol/L). Apoptosis, detected
with an immunochemical test and with flow cytometry, was induced
by >1 μmol/L OTA. Oxidative DNA damage, detected by comet assay
after additional treatment with repair enzymes, was induced in
all cell systems already at five-fold lower concentrations.
Glutathione in CV-1 cells was depleted after 1 h incubation
(>100 μmol/L). In contrast, an increase was measured after 24 h
incubation (>0.5 μmol/L). In conclusion, OTA induces oxidative
DNA damage at low, not yet cytotoxic concentrations. Oxidative
DNA damage might initiate cell transformation eventually in
connection with proliferative response following cytotoxic cell
death. Both events might represent pivotal factors in the chain
of cellular events leading into nephro-carcinogenicity of OTA. |
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