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Genes and Environment : the Official... Jul 2021Perillaldehyde and cinnamaldehyde are natural substances found in plants that are used as flavoring ingredients. Due to the α,β-unsaturated aldehydes in their...
BACKGROUND
Perillaldehyde and cinnamaldehyde are natural substances found in plants that are used as flavoring ingredients. Due to the α,β-unsaturated aldehydes in their structures, these compounds are expected to be DNA reactive. Indeed, several reports have indicated that perillaldehyde and cinnamaldehyde show positive in in vitro and in vivo genotoxicity tests. However, their genotoxic potentials are currently disputed. To clarify the mutagenicity of perillaldehyde and cinnamaldehyde, we conducted in silico quantitative structure-activity relationship (QSAR) analysis, in vitro Ames tests, and in vivo transgenic rodent gene mutation (TGR) assays.
RESULTS
In Ames tests, perillaldehyde was negative and cinnamaldehyde was positive; these respective results were supported by QSAR analysis. In TGR assays, we treated Muta™ Mice with perillaldehyde and gpt-delta mice with cinnamaldehyde up to the maximum tested doses (1000 mg/kg/day). There was no increase in gene mutations in the liver, glandular stomach, or small intestine following all treatments except the positive control (N-ethyl-N-nitrosourea at 100 mg/kg/day).
CONCLUSIONS
These data clearly show no evidence of in vivo mutagenic potentials of perillaldehyde and cinnamaldehyde (administered up to 1000 mg/kg/day) in mice; however, cinnamaldehyde is mutagenic in vitro.
PubMed: 34271990
DOI: 10.1186/s41021-021-00204-3 -
Mutation Research. Reviews in Mutation... 2023Error-corrected Next Generation Sequencing (ecNGS) is rapidly emerging as a valuable, highly sensitive and accurate method for detecting and characterizing mutations in... (Review)
Review
Error-corrected Next Generation Sequencing (ecNGS) is rapidly emerging as a valuable, highly sensitive and accurate method for detecting and characterizing mutations in any cell type, tissue or organism from which DNA can be isolated. Recent mutagenicity and carcinogenicity studies have used ecNGS to quantify drug-/chemical-induced mutations and mutational spectra associated with cancer risk. ecNGS has potential applications in genotoxicity assessment as a new readout for traditional models, for mutagenesis studies in 3D organotypic cultures, and for detecting off-target effects of gene editing tools. Additionally, early data suggest that ecNGS can measure clonal expansion of mutations as a mechanism-agnostic early marker of carcinogenic potential and can evaluate mutational load directly in human biomonitoring studies. In this review, we discuss promising applications, challenges, limitations, and key data initiatives needed to enable regulatory testing and adoption of ecNGS - including for advancing safety assessment, augmenting weight-of-evidence for mutagenicity and carcinogenicity mechanisms, identifying early biomarkers of cancer risk, and managing human health risk from chemical exposures.
Topics: Humans; High-Throughput Nucleotide Sequencing; Mutagenicity Tests; Mutation; Mutagens; Carcinogens; Carcinogenesis; Risk Assessment
PubMed: 37643677
DOI: 10.1016/j.mrrev.2023.108466 -
Archives of Toxicology Dec 2019High-content screening (HCS) technology combining automated microscopy and quantitative image analysis can address biological questions in academia and the... (Review)
Review
High-content screening (HCS) technology combining automated microscopy and quantitative image analysis can address biological questions in academia and the pharmaceutical industry. Various HCS experimental applications have been utilized in the research field of in vitro toxicology. In this review, we describe several HCS application approaches used for studying the mechanism of compound toxicity, highlight some challenges faced in the toxicological community, and discuss the future directions of HCS in regards to new models, new reagents, data management, and informatics. Many specialized areas of toxicology including developmental toxicity, genotoxicity, developmental neurotoxicity/neurotoxicity, hepatotoxicity, cardiotoxicity, and nephrotoxicity will be examined. In addition, several newly developed cellular assay models including induced pluripotent stem cells (iPSCs), three-dimensional (3D) cell models, and tissues-on-a-chip will be discussed. New genome-editing technologies (e.g., CRISPR/Cas9), data analyzing tools for imaging, and coupling with high-content assays will be reviewed. Finally, the applications of machine learning to image processing will be explored. These new HCS approaches offer a huge step forward in dissecting biological processes, developing drugs, and making toxicology studies easier.
Topics: Animals; Cardiotoxins; Chemical and Drug Induced Liver Injury; High-Throughput Screening Assays; Humans; Kidney Diseases; Mutagenicity Tests; Neurotoxicity Syndromes; Toxicology
PubMed: 31664499
DOI: 10.1007/s00204-019-02593-5 -
Mutation Research. Reviews in Mutation... 2021The purpose of this review is to evaluate the literature on the genotoxicity of cumene (CAS # 98-82-8) and to assess the role of mutagenicity, if any, in the mode of... (Review)
Review
The purpose of this review is to evaluate the literature on the genotoxicity of cumene (CAS # 98-82-8) and to assess the role of mutagenicity, if any, in the mode of action for cumene-induced rodent tumors. The studies reviewed included microbial mutagenicity, DNA damage/ repair, cytogenetic effects, and gene mutations. In reviewing these studies, attention was paid to their conformance to applicable OECD test guidelines which are considered as internationally recognized standards for performing these assays. Cumene was not a bacterial mutagen and did not induce Hprt mutations in CHO cell cultures. In the primary rat hepatocyte cultures, cumene induced unscheduled DNA synthesis in one study but this response could not be reproduced in an independent study using a similar protocol. In a study that is not fully compliant to the current OECD guideline, no increase in chromosomal aberrations was observed in CHO cells treated with cumene. The weight of the evidence (WoE) from multiple in vivo studies indicates that cumene is not a clastogen or aneugen. The weak positive response in an in vivo comet assay in the rat liver and mouse lung tissues is of questionable significance due to several study deficiencies. The genotoxicity profile of cumene does not match that of a classic DNA-reactive molecule and the available data does not support a conclusion that cumene is an in vivo mutagen. As such, mutagenicity does not appear to be an early key event in cumene-induced rodent tumors and alternate hypothesized non-mutagenic modes-of-action are presented. Further data are necessary to rule in or rule out a particular MoA.
Topics: Animals; CHO Cells; Comet Assay; Cricetulus; DNA Damage; Humans; Mutagenesis; Mutagenicity Tests; Mutation; Rats
PubMed: 34083043
DOI: 10.1016/j.mrrev.2021.108364 -
Environmental and Molecular Mutagenesis Mar 2022Studies during the past 50 years have characterized the carcinogenicity and mutagenicity of extractable organic material (EOM) of particulate matter (PM) in ambient... (Review)
Review
Studies during the past 50 years have characterized the carcinogenicity and mutagenicity of extractable organic material (EOM) of particulate matter (PM) in ambient air and from combustion emissions. We have summarized conclusions from these studies and present data supporting those conclusions for 50 combustion emissions, including carcinogenic potencies on mouse skin (papillomas/mouse/mg EOM), mutagenic potencies (revertants/μg EOM) in the Salmonella (Ames) mutagenicity assay, and mutagenicity emission factors (revertants/kg fuel or revertants/MJ ) in Salmonella. Mutagenic potencies of EOM from PM in ambient air and combustion emissions span 1-2 orders of magnitude, respectively. In contrast, the revertants/m span >5 orders of magnitude due to variable PM concentrations in ambient air. Carcinogenic potencies of EOM from combustion emissions on mouse skin and EOM-associated human lung cancer risk from those emissions both span ~3 orders of magnitude and are highly associated. The ubiquitous presence of polycyclic aromatic hydrocarbons (PAHs), nitroarenes, and aromatic amines results in mutagenic and carcinogenic potencies of PM that span only 1-3 orders of magnitude; most PM induces primarily G to T mutations. Mutagenicity emission factors of combustion emissions span 3-5 orders of magnitude and correlate with PAH emission factors (r > 0.9). Mutagenicity emission factors were largely a function of how material was burned (highly efficient modern combustors versus open burning) rather than what materials were burned. Combustion systems that minimize kinetic and mass-transfer limitations and promote complete oxidation also minimize the mutagenicity of their emissions. This fundamental engineering principle can inform environmental and public health assessments of combustion emissions.
Topics: Air Pollutants; Animals; Carcinogens; Mice; Mutagenicity Tests; Mutagens; Particulate Matter; Polycyclic Aromatic Hydrocarbons; Technology
PubMed: 35253926
DOI: 10.1002/em.22475 -
International Journal of Environmental... Oct 2022Occupational exposure may involve a variety of toxic compounds. A mutagenicity analysis using the Ames test can provide valuable information regarding the toxicity of... (Review)
Review
Occupational exposure may involve a variety of toxic compounds. A mutagenicity analysis using the Ames test can provide valuable information regarding the toxicity of absorbed xenobiotics. Through a search of relevant databases, this systematic review gathers and critically discusses the published papers (excluding other types of publications) from 2001-2021 that have assessed urinary mutagenicity (Ames test with ) in an occupational exposure context. Due to the heterogeneity of the study methods, a meta-analysis could not be conducted. The characterized occupations were firefighters, traffic policemen, bus drivers, mail carriers, coke oven and charcoal workers, chemical laboratory staff, farmers, pharmacy workers, and professionals from several other industrial sectors. The genetically modified bacterial strains (histidine dependent) TA98, TA100, YG1041, YG1021, YG1024 and YG1042 have been used for the health risk assessment of individual (e.g., polycyclic aromatic hydrocarbons) and mixtures of compounds (e.g., diesel engine exhaust, fire smoke, industrial fumes/dyes) in different contexts. Although comparison of the data between studies is challenging, urinary mutagenicity can be very informative of possible associations between work-related exposure and the respective mutagenic potential. Careful interpretation of results and their direct use for occupational health risk assessment are crucial and yet complex; the use of several strains is highly recommended since individual and/or synergistic effects of complex exposure to xenobiotics can be overlooked. Future studies should improve the methods used to reach a standardized protocol for specific occupational environments to strengthen the applicability of the urinary mutagenicity assay and reduce inter- and intra-individual variability and exposure source confounders.
Topics: Humans; Mutagens; Mutagenicity Tests; Coke; Charcoal; Histidine; Vehicle Emissions; Polycyclic Aromatic Hydrocarbons; Smoke; Coloring Agents
PubMed: 36293654
DOI: 10.3390/ijerph192013074 -
Archives of Toxicology Sep 2022Methyl acrylate (MA) and ethyl acrylate (EA) had previously tested positive for mutagenicity in vitro, but in vivo studies were negative. One of the metabolism pathways...
Methyl acrylate (MA) and ethyl acrylate (EA) had previously tested positive for mutagenicity in vitro, but in vivo studies were negative. One of the metabolism pathways of alkyl acrylates is conjugation with glutathione. The glutathione availability is restricted in standard in vitro test systems so that they do not reflect the in vivo metabolism in this respect. We investigated whether the addition of glutathione to the in vitro L5178Y/TK mouse lymphoma mutagenicity test prevents alkyl acrylate's mutagenicity in vitro. We also investigated whether the quantitative relationships support the notion that the GSH supplemented in vitro systems reflect the true in vivo activity. Indeed, glutathione concentrations as low as 1 mM completely negate the mutagenicity of MA and EA in the L5178Y/TK mouse lymphoma mutagenicity test up to the highest concentrations of the two acrylates tested, 35 µg/ml, a higher concentration than that previously found to be mutagenic in this test (14 µg MA/ml and 20 µg EA/ml). 1 mM Glutathione reduced the residual MA and EA at the end of the exposure period in the mutagenicity tests by 96-97%, but in vivo up to 100 mg/kg body weight MA and EA left the glutathione levels in the mouse liver and forestomach completely intact. It is concluded that the in-situ levels of glutathione, 7.55 ± 0.57 and 2.84 ± 0.22 µmol/g mouse liver and forestomach, respectively, can efficiently protect against MA and EA-induced mutagenicity up to the high concentration of 100 mg MA and EA/kg body weight and that the negative in vivo mutagenicity tests on MA and EA reflect the true in vivo situation.
Topics: Acrylates; Animals; Body Weight; Glutathione; Lymphoma; Mice; Mutagenicity Tests; Mutagens
PubMed: 35704047
DOI: 10.1007/s00204-022-03322-1 -
Scientific Reports Oct 2023Concerns have recently increased that the integrity of some scientific research is questionable due to the inability to reproduce the claimed results of some experiments...
Concerns have recently increased that the integrity of some scientific research is questionable due to the inability to reproduce the claimed results of some experiments and thereby confirm that the original researcher's conclusions were justified. This phenomenon has been described as 'reproducibility crisis' and affects various fields from medicine to basic applied sciences. In this context, the REPLICA project aims to replicate previously conducted in vitro studies on the toxicity of cigarette smoke and e-cigarette aerosol, sometimes adding experiments or conditions where necessary, in order to verify the robustness and replicability of the data. In this work the REPLICA Team replicated biological and toxicological assessment published by Rudd and colleagues in 2020. As in the original paper, we performed Neutral Red Uptake (NRU) assay for the evaluation of cytotoxicity, Ames test for the evaluation of mutagenesis and In Vitro Micronuclei (IVMN) assay for the evaluation of genotoxicity on cells treated with cigarette smoke or e-cigarette aerosol. The results showed high cytotoxicity, mutagenicity and genotoxicity induced by cigarette smoke, but slight or no cytotoxic, mutagenic and genotoxic effects induced by the e-cigarette aerosol. Although the two studies presented some methodological differences, the findings supported those previously presented by Rudd and colleagues.
Topics: Mutagens; Electronic Nicotine Delivery Systems; Cigarette Smoking; Reproducibility of Results; Nicotiana; Mutagenesis; DNA Damage; Aerosols; Mutagenicity Tests
PubMed: 37903810
DOI: 10.1038/s41598-023-44626-1 -
Chemical Research in Toxicology Jul 2020Environmental exposures have long been known to impact public health and safety. For example, exposures to airborne particulates, heavy metals in water, or certain... (Review)
Review
Environmental exposures have long been known to impact public health and safety. For example, exposures to airborne particulates, heavy metals in water, or certain industrial chemicals can contribute to aging and to risk of developing cancer and other diseases. Environmental factors can impact health in a variety of ways, but a key concern is DNA damage, which can lead to mutations that cause cancer. Cancer can take years to develop following chemical exposure; however, one way to predict carcinogenicity in a more practical time frame is by studying the chemical's ability to induce DNA damage. The comet assay (or single-cell gel electrophoresis assay) has been used successfully for genotoxicity testing. The comet assay allows for the detection of DNA strand breaks via analysis of DNA migration during electrophoresis. Previously, the Engelward laboratory, in collaboration with the Bhatia laboratory, developed the CometChip for measurements of DNA damage and repair. The CometChip is a high-throughput comet assay that improves user reproducibility and significantly shortens total assay time. Here, we describe how the high-throughput CometChip platform can be used to measure DNA damage in established cell lines, animal models, and human samples. We also discuss technical challenges associated with these studies and provide recommendations on how to achieve optimal results for researchers interested in adopting this assay.
Topics: Animals; Comet Assay; DNA; DNA Damage; Environmental Health; Humans
PubMed: 32519858
DOI: 10.1021/acs.chemrestox.9b00393 -
Regulatory Toxicology and Pharmacology... Dec 2022Titanium dioxide is a ubiquitous white material found in a diverse range of products from foods to sunscreens, as a pigment and thickener, amongst other uses. Titanium... (Review)
Review
Titanium dioxide is a ubiquitous white material found in a diverse range of products from foods to sunscreens, as a pigment and thickener, amongst other uses. Titanium dioxide has been considered no longer safe for use in foods (nano and microparticles of E171) by the European Food Safety Authority (EFSA) due to concerns over genotoxicity. There are however, conflicting opinions regarding the safety of Titanium dioxide. In an attempt to clarify the situation, a comprehensive weight of evidence (WoE) assessment of the genotoxicity of titanium dioxide based on the available data was performed. A total of 192 datasets for endpoints and test systems considered the most relevant for identifying mutagenic and carcinogenic potential were reviewed and discussed for both reliability and relevance (by weight of evidence) and in the context of whether the physico-chemical properties of the particles had been characterised. The view of an independent panel of experts was that, of the 192 datasets identified, only 34 met the reliability and quality criteria for being most relevant in the evaluation of genotoxicity. Of these, 10 were positive (i.e. reported evidence that titanium dioxide was genotoxic), all of which were from studies of DNA strand breakage (comet assay) or chromosome damage (micronucleus or chromosome aberration assays). All the positive findings were associated with high cytotoxicity, oxidative stress, inflammation, apoptosis, necrosis, or combinations of these. Considering that DNA and chromosome breakage can be secondary to physiological stress, it is highly likely that the observed genotoxic effects of titanium dioxide, including those with nanoparticles, are secondary to physiological stress. Consistent with this finding, there were no positive results from the in vitro and in vivo gene mutation studies evaluated, although it should be noted that to definitively conclude a lack of mutagenicity, more robust in vitro and in vivo gene mutation studies would be useful. Existing evidence does not therefore support a direct DNA damaging mechanism for titanium dioxide (nano and other forms).
Topics: Reproducibility of Results; Metal Nanoparticles; Titanium; Comet Assay; DNA Damage; Mutagens; DNA
PubMed: 36228836
DOI: 10.1016/j.yrtph.2022.105263