Decreased levels of lipid peroxidation-induced DNA damage in the onset of atherogenesis in apolipoprotein E deficient mice.

Increased oxidative stress and subsequent lipid peroxidation (LPO) are thought to be critical events in the formation of atherosclerotic lesions in apolipoprotein E deficient mice (ApoE-KO). LPO derived reactive aldehydes react with DNA to form exocyclic etheno-DNA adducts. These pro-mutagenic DNA lesions are known to be involved in the initiation of carcinogenesis, but their role in the development of atherosclerosis is unknown.

Formation of lysine 63-linked poly-ubiquitin chains protects human lung cells against benzo[a]pyrene-diol-epoxide-induced mutagenicity.

Benzo[a]pyrene exerts its mutagenic effects via induction of benzo[a]pyrene-diol-epoxide (BPDE)-DNA adducts. Such helix-distorting adducts are not always successfully repaired prior to DNA replication, which may result in a blocked replication fork. To alleviate this stall, cells utilize DNA damage tolerance systems involving either error-free damage avoidance or error-prone translesion synthesis.

The environmental carcinogen benzo[a]pyrene induces expression of monocyte-chemoattractant protein-1 in vascular tissue: a possible role in atherogenesis.

Exposure to carcinogenic polycyclic aromatic hydrocarbons (PAHs) has been implicated in the aetiology of atherosclerosis. Previously we showed that chronic exposure of ApoE-/- mice to the prototype PAH benzo[a]pyrene (B[a]P) causes enhanced progression of atherosclerosis, which was characterised by an increased inflammatory cell content in the atherosclerotic plaques. The aim of the present study was to evaluate the effect of B[a]P on vascular expression of monocyte-chemoattractant protein 1 (MCP-1), which is a crucial molecule promoting the recruitment of monocytes into atherosclerotic lesions.

The role of glutathione in the regulation of nucleotide excision repair during oxidative stress.

Nucleotide excision repair (NER) mainly repairs bulky DNA adducts and helix distorting lesions, but is additionally considered to be a back-up system for base excision repair to remove oxidative stress induced DNA damage. Therefore, it can be speculated that NER is up-regulated or primed by oxidative stress. Exposure of human pulmonary epithelial cells (A549) to non-toxic doses of 100muM H(2)O(2) indeed showed a 2 to 4.

Modulation of gene expression and DNA-adduct formation in precision-cut liver slices exposed to polycyclic aromatic hydrocarbons of different carcinogenic potency.

Polycyclic aromatic hydrocarbons (PAHs) differ markedly in their carcinogenic potencies. Differences in transcriptomic responses upon PAH exposures might improve our current understanding of the differences in carcinogenicity, and therefore gene expression modulation by six PAHs in precision-cut rat liver slices was investigated. Gene expression modulation by benzo[a]pyrene (B[a]P), dibenzo[a,l]pyrene (DB[a,l]P), benzo[b]fluoranthene (B[b]F), fluoranthene (FA), dibenzo[a,h]anthracene (DB[a,h]A) and 1-methylphenanthrene (1-MPA) was assessed after 6- (B[a]P, DB[a,l]P) and 24-h (all compounds) exposure, using oligonucleotide arrays.

Neutrophils and respiratory tract DNA damage and mutagenesis: a review.

Inflammation has been recognized as an important factor in cancer development. For the lung, experimental studies with rats, as well as molecular epidemiological studies in humans, have provided evidence that the influx of neutrophils into the airways may be an important process linking inflammation with carcinogenesis. Currently it is believed that the genotoxic capacity of neutrophils is a crucial aetiological factor in this carcinogenic response.

Interindividual variations in DNA adduct levels assessed by analysis of multiple genetic polymorphisms in smokers.

Genetic polymorphisms in genes involved in processes that affect DNA damage may explain part of the large interindividual variation in DNA adduct levels in smokers. We investigated the effect of 19 polymorphisms in 12 genes involved in carcinogen metabolism, DNA repair, and oxidant metabolism on DNA adduct levels (determined by (32)P post-labeling) in lymphocytes of 63 healthy Caucasian smokers. The total number of alleles that were categorized as putatively high-risk alleles seemed associated with bulky DNA adduct levels (P = 0.

Development and validation of a modified comet assay to phenotypically assess nucleotide excision repair.

There is an increasing need for simple and reliable approaches to phenotypically assess DNA repair capacities. Therefore, a modification of the alkaline comet assay was developed to determine the ability of human lymphocyte extracts to perform the initial steps of the nucleotide excision repair (NER) process, i.e.

Risk assessment of metals and organic pollutants for herbivorous and carnivorous small mammal food chains in a polluted floodplain (Biesbosch, The Netherlands).

A risk assessment was made for a carnivorous and a herbivorous food chain in a heavily polluted natural estuary (Biesbosch), by determining the most critical pollutants and the food chain most at risk. Exposure of food chains to metals, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) was assessed by analyzing dietary concentrations, internal concentrations, and biomarkers of exposure. Common shrew (Sorex araneus) and bank vole (Clethrionomys glareolus) were selected as representative small mammal species for the carnivorous and herbivorous food chain, respectively, and earthworms (Lumbricus rubellus) and snails (Cepaea nemoralis) as representative prey species for the carnivorous food chain.

Modulation of gene expression and DNA adduct formation in HepG2 cells by polycyclic aromatic hydrocarbons with different carcinogenic potencies.

Polycyclic aromatic hydrocarbons (PAHs) can occur in relatively high concentrations in the air, and many PAHs are known or suspected carcinogens. In order to better understand differences in carcinogenic potency between PAHs, we investigated modulation of gene expression in human HepG2 cells after 6 h incubation with varying doses of benzo[a]pyrene (B[a]P), benzo[b]fluoranthene (B[b]F), fluoranthene (FA), dibenzo[a,h]anthracene (DB[a,h]A), 1-methylphenanthrene (1-MPA) or dibenzo[a,l]pyrene (DB[a,l]P), by using cDNA microarrays containing 600 toxicologically relevant genes. Furthermore, DNA adduct levels induced by the compounds were assessed with (32)P-post-labeling, and carcinogenic potency was determined by literature study.

The crucial role of particle surface reactivity in respirable quartz-induced reactive oxygen/nitrogen species formation and APE/Ref-1 induction in rat lung.

Persistent inflammation and associated excessive oxidative stress have been crucially implicated in quartz-induced pulmonary diseases, including fibrosis and cancer. We have investigated the significance of the particle surface reactivity of respirable quartz dust in relation to the in vivo generation of reactive oxygen and nitrogen species (ROS/RNS) and the associated induction of oxidative stress responses in the lung. Therefore, rats were intratracheally instilled with 2 mg quartz (DQ12) or quartz whose surface was modified by either polyvinylpyridine-N-oxide (PVNO) or aluminium lactate (AL).

Application of four dyes in gene expression analyses by microarrays.

Background: DNA microarrays are widely used in gene expression analyses. To increase throughput and minimize costs without reducing gene expression data obtained, we investigated whether four mRNA samples can be analyzed simultaneously by applying four different fluorescent dyes.

Results: Following tests for cross-talk of fluorescence signals, Alexa 488, Alexa 594, Cyanine 3 and Cyanine 5 were selected for hybridizations.

Polycyclic aromatic hydrocarbons induce an inflammatory atherosclerotic plaque phenotype irrespective of their DNA binding properties.

Although it has been demonstrated that carcinogenic environmental polycyclic aromatic hydrocarbons (PAHs) cause progression of atherosclerosis, the underlying mechanism remains unclear. In the present study, we aimed to investigate whether DNA binding events are critically involved in the progression of PAH-mediated atherogenesis. Apolipoprotein E knockout mice were orally (24 wk, once/wk) exposed to 5 mg/kg benzo[a]pyrene (B[a]P), or its nonmutagenic, noncarcinogenic structural isoform benzo[e]pyrene (B[e]P).

Formation of PAH-DNA adducts after in vivo and vitro exposure of rats and lung cells to different commercial carbon blacks.

Objective: The current study was designed to test the possible release and bioavailability of polycyclic aromatic hydrocarbons (PAHs) from a set of commercial carbon blacks (CBs) as well as the ability of these PAHs to form bulky DNA adducts.

Methods: In four commercial CBs (Printex 90, Sterling V, N330, Lampblack 101), leaching of PAH was examined through (1) release of parent PAHs in saline with or without surfactant, and (2) PAH adducts in lung epithelial cells (A549) or in rat lungs after exposure to two CBs (Printex 90, Sterling V) for 13 weeks (50 mg/m(3)). In vitro experiments were done with original and extracted particles, as well as organic extracts of CB in DMSO.

Nitrite enhances neutrophil-induced DNA strand breakage in pulmonary epithelial cells by inhibition of myeloperoxidase.

Chronic inhalation of environmental particles is associated with pulmonary carcinogenesis. Although the mechanism has not yet been fully elucidated, influx of inflammatory cells, including neutrophils, is suggested to play a major role in this process. Typically, in the particle-exposed lung, influx of neutrophils is accompanied by an accumulation of nitrite.

Interaction between cadmium and aromatic DNA adducts in hprt mutagenesis during foetal development.

The foetus is exposed to multiple xenobiotics through the mother's circulation and this is possibly involved in the development of diseases in later life. Heavy metals and lipophilic genotoxins in umbilical cord blood of newborns may have synergistic effects on mutagenesis in the hypoxanthine-phosphoribosyltransferase (HPRT) reporter gene. Concentrations of zinc (Zn), lead (Pb) and cadmium (Cd) were determined in the peripheral and cord blood of 16 non-smoking and 9 smoking healthy mothers by atomic absorption spectrometry.

In vitro and in vivo studies on oxygen free radical and DNA adduct formation in rat lung and liver during benzo[a]pyrene metabolism.

Reactive oxygen species (ROS), possibly produced during the metabolic conversion of benzo(a)pyrene (B[a]P), could be involved in B[a]P-induced genotoxicity and, eventually, carcinogenicity. Therefore, ROS formation by rat lung and liver microsomes was studied in vitro by electron spin resonance (ESR/EPR) spectrometry. B[a]P-mediated generation of ROS was detected in incubations with rat lung, but not with liver microsomes.

Applicability of the black slug Arion ater for monitoring exposure to polycyclic aromatic hydrocarbons and their subsequent bioactivation into DNA binding metabolites.

The applicability of terrestrial black slugs Arion ater (Mollusca, Gastropoda) was studied for biomonitoring environmental exposure to polycyclic aromatic hydrocarbons (PAHs). In laboratory experiments, slugs were orally exposed to benzo[a]pyrene (BaP) for a short term (3 days) or a long term (119 days) period. Test animals were collected in the field, or were reared under laboratory conditions to ensure that they had no history of PAH-exposure.

Myeloperoxidase (MPO) -463G->A reduces MPO activity and DNA adduct levels in bronchoalveolar lavages of smokers.

The myeloperoxidase (MPO) -463G-->A genetic polymorphism is associated with a reduced risk for lung cancer, but the underlying mechanism is not yet elucidated. Therefore, the impact of this polymorphism on MPO activity and lipophilic DNA adducts was studied in respectively bronchoalveolar lavage (BAL) fluid and cells, from 106 smoking Caucasian lung patients. MPO activity was determined spectrophotometrically, aromatic DNA adducts by (32)P-postlabeling and MPO genotypes by RFLP analysis.

Benzo[a]pyrene enhances lipid peroxidation induced DNA damage in aorta of apolipoprotein E knockout mice.

The genotoxic compound benzo[a]pyrene (B[a]P) enhances atherosclerotic plaque progression, possibly by inducing oxidative stress and subsequent lipid peroxidation (LPO). Since LPO plays a key role in atherosclerosis, stable LPO derived DNA modifications such as 1,N6-ethenodeoxy-adenosine (epsilondA) and 3,N4-ethenodeoxy-cytidine (epsilondC) may be useful biomarkers for in vivo oxidative stress. In this study, benzo[a]pyrene-diol-epoxide (BPDE)-DNA, epsilondA and epsilondC were determined by 32P-postlabelling in apolipoprotein E knockout (ApoE-KO) mice treated with 5mg/kg B[a]P by gavage.

Chronic exposure to the carcinogenic compound benzo[a]pyrene induces larger and phenotypically different atherosclerotic plaques in ApoE-knockout mice.

Benzo[a]pyrene (B[a]P) is a polycyclic aromatic hydrocarbon with atherogenic and carcinogenic properties. The role of B[a]P in carcinogenesis is well established, and thought to exert via enzymatic activation into reactive metabolites that are capable of binding to the DNA leading to uncontrolled proliferation. However, the mechanism underlying the atherogenic properties of B[a]P is still unclear.

Modulation of plasma lipid levels affects benzo[a]pyrene-induced DNA damage in tissues of two hyperlipidemic mouse models.

The role of plasma lipids in the uptake, transportation, and distribution of lipophilic carcinogens like benzo[a]pyrene (B[a]P) remains unclear. Therefore, we studied the effects of dietary-modulated plasma lipids on B[a]P-induced DNA damage in several organs of two hyperlipidemic mouse models. Male apolipoprotein E (ApoE)*3-Leiden (n = 22) and ApoE knockout (ApoE-KO) mice (n = 20) were fed a high-fat cholesterol (HFC) diet or low-fat cholesterol (LFC; standard mouse chow) diet for 3 weeks, after which the animals were exposed to a single oral dose of 5 mg/kg bw B[a]P or vehicle and killed 4 days later.