Mutagenesis最新文献

In this study, we evaluated the genomic stability of oral mucosal epithelial cells (OMECs) cultured in complex media (COM) and xenobiotic-free media (XF) to assess their potential clinical application for limbal stem cell deficiency (LSCD) treatments. OMECs serve as a promising autologous cell source for bilateral LSCD treatment, offering an alternative to limbal epithelial cells (LECs). However, genomic integrity is crucial to ensure the long-term success of transplanted cells. We performed micronucleus (MNi) tests and comet assays to compare DNA damage in OMECs cultured in both media types. The results indicated no significant differences in cell morphology, viability, or size between the two conditions. The MNi frequency was similar, with 5.67 and 6.17 MNi per 1,000 cells in COM and XF conditions, respectively. Comet assay results showed low levels of strand breaks (SBs) and oxidized DNA lesions in both media, with XF showing a slightly lower, albeit statistically insignificant, percentage of tail DNA for net Fpg-sensitive sites. Our findings suggest that OMECs can be effectively cultivated in either COM or XF media without inducing significant DNA damage, supporting the potential use of XF media in clinical settings to reduce contamination risks. This study underscores the importance of genomic stability in cultured cells for ocular surface transplantation, contributing valuable insights into optimizing culture conditions for safer and more effective clinical applications.

Colorectal cancer is a global killer that causes approximately 940 thousand deaths annually. Terminalia ivorensis (TI) is a tropical tree, the bark of which is used in African traditional medicine for the treatment of diabetes, malaria, and ulcer. This study investigated TI as a potential anticancer agent in human colon cells in vitro. TI was extracted sequentially with petroleum ether, chloroform, ethyl acetate, and ethanol. Antioxidant activity was assessed by DPPH and FRAP, and differential effects on cell viability, growth, DNA damage, DNA repair, and migration were measured in human colon cancer cells (CaCo-2) and/or non-cancerous human colonocytes (NCM460). The TI phytochemicals most strongly associated with these effects were identified by partial least-squares discriminant analysis. DPPH and FRAP activity was highest in TI ethyl acetate and ethanol extracts (P = .001). All TI extracts significantly inhibited cell viability and growth and induced DNA damage and inhibited DNA repair in both cell models. The majority of TI extracts were significantly (P = .01) more toxic to cancer cells than non-cancerous colonocytes. DNA repair was significantly (P = .001) inhibited in CaCo-2 cells by ethyl acetate extract compared with NCM460 cells. Migration was also significantly inhibited (P < .001) in CaCo-2 by ethyl acetate (80%) and ethanol extracts (75%). Specific benzoic acids, flavonoids, and phenols were identified to be strongly associated with these effects. TI displayed strong antioxidant activity and specific anticancer effects by inducing cell death and DNA damage, and by inhibiting DNA repair, cell proliferation, and migration.

The objective of this longitudinal study was to jointly assess DNA damage, apoptosis, inflammatory marker levels, and white blood cell (WBC) counts in physicians occupationally exposed to inhalation anesthetics during specializations. Thus, we aimed to identify a possible cause-effect relationship between occupational exposure to waste anesthetic gases (WAGs), which were measured, and genotoxic, cytotoxic, and immunotoxic effects. Nineteen medical residents were evaluated at four time points: before entering medical residency (baseline) and at the beginning, middle, and end of medical residency. Peripheral blood mononuclear cells (PBMCs) were investigated for DNA damage, which was detected via the comet assay, and for apoptosis, which was detected via an annexin marker (flow cytometry). High-sensitivity C-reactive protein and serum inflammatory cytokines were evaluated via flow cytometry, and total and differential WBCs were counted. In addition, the concentrations of the WAGs measured in the workplace during the study were evaluated via an infrared spectrophotometer. The WAG concentrations were far higher than the internationally recommended values. Compared with those at previous time points, we observed increased DNA damage (P = .008) and apoptosis (P = .001) in PBMCs from the middle to the end of medical residency. Significant increases (P < .05) in the IL-8, IL-10, IL-12p70, IL-17A, IL-18, and IL-23 levels throughout medical residency were detected. There was no effect on the WBC count (P < .05), and all the means were within the reference range values. Occupational exposure to high levels of WAGs induces DNA damage, apoptosis, and changes in serum inflammatory marker levels, but not in leukocyte counts, in physicians who work in surgical theaters lacking an adequate scavenging system during medical residency.

The discovery of N-nitrosamines (NNAs) as impurities in several pharmaceuticals has renewed activities in assessing their mutagenic and carcinogenic potential. In the current investigation, the binary mutagenic potential of NNAs is re-investigated using the mechanism-based structure-activity approach of the TIMES models. Emphasis is placed on meeting the OECD (Q)SAR principles for model validation and the organization's (Q)SAR prediction principles. A curated data set of 41 small and complex NNA-containing substances tested in a standard battery of Salmonella typhimurium strains with and without rat microsomal activation was assessed for these tasks. Structural boundaries are initially derived from activating mechanisms for interactions of parent NNAs with DNA described in the literature. These activating mechanisms include direct-acting mutagenicity (denitrosation of parent molecules) or DNA interactions after S9 metabolic activation (alpha-hydroxylation). After analysis of the 41 NNAs, structural features that mitigate or 'mask' the covalent binding of NNAs to DNA expanded the original alert definition. The structural fragments' predictive capabilities (performance) for the activating and negating mechanisms of these 41 chemicals are excellent. Three false positives and no false negatives are reported. Moreover, the role of metabolism in the N-nitrosation of secondary amines and tertiary amines after conversion to secondary amines under in vivo conditions is explained with descriptions of new metabolic transformations. These transformation boundaries are applied to different inventories to search for parent structures that are potential in vivo metabolic precursors of NNAs.

Coal mining has significant economic and environmental implications. The extraction and combustion of coal release harmful chemicals and dust, impacting air, soil, and water quality, as well as natural habitats and human health. This study aimed to investigate the association between global DNA methylation, DNA damage biomarkers (including telomere length), and inorganic element concentrations in the blood of individuals exposed to coal mining dust. Additionally, polycyclic aromatic hydrocarbons were analyzed. The study included 150 individuals exposed to coal mining and 120 unexposed controls. Results showed significantly higher global DNA hypermethylation in the exposed group compared to controls. Moreover, in the exposed group, micronucleus frequency and age showed a significant correlation with global DNA hypermethylation. Blood levels of inorganic elements, including titanium, phosphorus, sodium, aluminum, iron, sulfur, copper, chromium, zinc, chlorine, calcium, and potassium, were potentially associated with DNA methylation and oxidative damage, as indicated by comet assay results. Furthermore, exposure to polycyclic aromatic hydrocarbons such as fluoranthene, naphthalene, and anthracene, emitted in mining particulate matter, may contribute to these effects. These findings highlight the complex interplay between genetic instability, global DNA hypermethylation, and environmental exposure in coal mining areas, emphasizing the urgent need for effective mitigation strategies.

Naturally, a wide range of genetic and environmental variables predominate, such as bacterial, viral, and parasite infective entities that have been identified as carcinogenic bioagents. Many helminth and protozoan parasitic diseases are liable to cause human cancer. Conveniently, three trematode parasites viz. Schistosoma haematobium, Opisthorchis viverrini, and Clonorchis sinensis have been reported to be intrinsically linked with human cancer. Similar studies for other parasitic infections are still imprecise and need further validation. Plasmodium falciparum is known to cause holoendemic Burkitt lymphoma despite the non-carcinogenic role of malaria. This review is endowed with a coupled correlation and underlying mechanisms by which parasitic infections lead to carcinogenicity. An empirical documentation covering the prevalence and incidence of viral, bacterial, and parasitic carcinogenicity is illustrated in this article. Moreover, some probable diagnostic and treatment procedures for parasitic carcinogenicity are also summarized. A detailed account of various mutational and genetic changes that lead to carcinogenesis via different pathways is appended in this article.

This review describes the use of the micronucleus (MN) assay with exfoliated cells from the oral mucosa in occupational studies. The molecular mechanisms leading to formation of MN (chromosomal breakage and aneuploidy) are well known. In total, 222 articles have been published since the method was developed in 1982. The majority of investigations was realized with agricultural workers, followed by petrol station attendants, painters, pathology/anatomy lab workers and miners. Positive results were reported in the majority of studies (86%); Brazil, Italy, Mexico and Turkey being the most productive countries. The use of this technique increased substantially in the last years and a recent correlation analyses with data from MN studies with lymphocytes indicate that the method is useful for the prediction of the cancer risks of chemically- and radiation-exposed workers. The methodological quality of the studies increased in recent years since standardized and validated guidelines have been published. However, major shortcomings are still the lack of adequate matching (in particular in regard to nutrition and intake of dietary supplements), the lack of chemical exposure measurements and the use of inadequate (DNA-non-specific) stains. The most pronounced effects were seen in metal production workers, miners, petrol station attendants, agricultural workers and pathologists. The sampling of the cells from the oral cavity is non-invasive and no cultivation under sterile conditions is required. The currently available data indicate that this fast and easy to perform procedure provides valuable information about combined effects of chemical exposures and about the efficiency of safety measurements. Therefore, it should be used in the future for the routine surveillance of workers.

Genotoxicity testing plays a crucial role in evaluating the hazards posed by various chemicals. Traditional methods, such as the Ames test, mammalian cell mutation assays and the transgenic rodent assay have certain limitations including laborious procedures and/or reliance on animal models. The aim of this study was to determine the potential of using error-corrected next-generation sequencing (ecNGS), specifically duplex sequencing (DS), as an alternative method for the detection of point mutations in conjunction with advanced in vitro models. This study establishes an easy to use, adaptable in vitro 3D HepG2 model, that shows good viability, and liver functionality over 14 days. 3D HepG2 spheroids were exposed to aristolochic acid in a repeated dose regime over 4 days. This was shown to significantly induce micronucleus formation, indicative of fixed DNA damage, in a dose dependent fashion. DS coupled with mutational signature analyses revealed a predominant treatment-specific T:A > A:T-enriched mutational signature explained by COSMIC signature SBS22 derived from human cancers associated with aristolochic acid exposure. De novo extraction provided a stable signature, of which more than 40% were unambiguously explained by SBS22 These results demonstrate that the presented 3D HepG2 spheroid model is appropriate for assessing chemically induced fixed DNA damage. Additionally, we provide evidence that DS applied to the studied in vitro 3D model has the capacity to reveal specific mutational signatures of mutagenic exposures. The modern integrative approach will improve the understanding of mechanisms of carcinogenesis related to chemical exposures by providing a cost-effective and efficient means to assess genotoxicity and mutagenicity. With the inclusion of mutational signature analyses, this approach would see a reduction in reliance on animal models and enhancement of hazard assessment accuracy.

Objective: To investigate the effects of polystyrene microplastics (PS-MPs) on human corneal epithelial cells (HCEP).

Methods: The cytotoxicity of PS-MPs on HCEP cells was evaluated using a CCK-8 assay to measure cell viability, flow cytometry to analyze cell cycle and status, immunofluorescence to detect reactive oxygen species (ROS) and γ-H2AX levels, and western blotting to assess protein expression.

Results: The effects of PS-MPs on HCEP cell morphology and viability were particle size- and concentration-dependent. Smaller particle sizes and higher concentrations of PS-MPs were associated with greater cytotoxicity. PS-MP exposure induced cell cycle arrest, necrosis, and apoptosis in HCEP cells, along with excessive ROS production and DNA damage. Furthermore, ROS scavengers significantly reduced PS-MP-induced ROS overproduction and DNA damage, thereby alleviating PS-MP-induced cell cycle arrest, necrosis, and apoptosis. At the molecular level, ROS scavengers reversed the PS-MP-induced changes in the expression of γ-H2AX, P53, cell cycle-related proteins (cyclin D1, CDK2, and CDK4), necrosis-related proteins (CypD, PARP-1, and SRX), and apoptosis-related proteins (Cyt C, AIF, and cleaved-caspase 3).

Conclusion: PS-MP exposure leads to cell cycle arrest, necrosis, and apoptosis in HCEP cells, which is associated with ROS overproduction and activation of the P53 pathway.

Nucleotide excision repair (NER) is crucial for repairing bulky lesions and crosslinks in DNA caused by exogenous and endogenous genotoxins. The number of studies that have considered DNA repair as a biomarker is limited, and therefore one of the primary objectives of the European COST Action hCOMET (CA15132) was to assemble and analyse a pooled database of studies with data on NER activity. The database comprised 738 individuals, gathered from 5 laboratories that ran population studies using the comet-based in vitro DNA repair assay. NER activity data in peripheral blood mononuclear cells were normalized and correlated with various host-related factors, including sex, age, body mass index (BMI), and smoking habits. This multifaceted analysis uncovered significantly higher NER activity in female participants compared to males (1.08 ± 0.74 vs. 0.92 ± 0.71; P = .002). Higher NER activity was seen in older subjects (>30 years), and the effect of age was most pronounced in the oldest females, particularly those over 70 years (P = .001). Females with a normal BMI (<25 kg/m2) exhibited the highest levels of NER, whereas the lowest NER was observed in overweight males (BMI ≥ 25 kg/m2). No independent effect of smoking was found. After stratification by sex and BMI, higher NER was observed in smoking males (P = .017). The biological implication of higher or lower repair capacity remains unclear; the inclusion of DNA repair as a biomarker in molecular epidemiological trials should elucidate the link between health and disease status.