Search Results (93)

Cellular senescence (CSEN) is caused by a variety of factors that trigger complex molecular pathways. These include telomere shortening, oncogene activation and replicative stress, as well as DNA damage caused by genotoxic anticancer drugs and endogenous and exogenous genotoxins. Here, we review the induction of CSEN by exogenous genotoxic insults resulting from food and environmental exposures. The available data show that genotoxins/carcinogens in tobacco smoke and smokeless tobacco, in the environment, in food, beverages and life-style products induce CNS. The exposures include N-nitroso compounds, polycyclic aromatic hydrocarbons, heterocyclic aromatic amines, acrylamide, heavy metals, fine dust, mycotoxins, phytotoxins, and phycotoxins. Also, heme in red meat contributes to CSEN as it catalyzes the formation of genotoxic species in the colon. Induction of CSEN by external genotoxins/carcinogens is bound on the DNA damage response pathway (DDR), which relies on activation of the ATM/ATR-CHK2/CHK1-p53-p21 axis and the p53-independent p16/p14 axis, eliciting cyclin-dependent kinase inhibition and permanent cell cycle arrest. Other factors that can be involved are DREAM, MAPK, cGAS/Sting, and NF-κB. The accumulation of non-repaired DNA damage triggering CSEN following external genotoxic exposures may contribute significantly to the amelioration of senescent cells and organ failure with age in humans. Senescent cells drive, via the senescence-associated secretory phenotype (SASP), inflammation that is involved in many diseases, including cancer. Although most of the studies were performed with in vitro cell systems, the consequences of CSEN induction by genotoxic nutritional components and environmental exposures seem to be underestimated. Since CSEN correlates with aging, it is reasonable to conclude that exogenous genotoxic pollutants contribute significantly to the aging process through CSEN induction. In light of these findings, it is deduced that reducing genotoxin exposures and using “rejuvenation” supplements (senotherapeutics) are reasonable strategies to counteract cellular senescence and the aging process. Full article

Colorectal cancer (CRC) remains a significant global health burden, with growing evidence highlighting microbial contributions to its pathogenesis. Certain genotoxigenic bacteria, such as Escherichia coli, Campylobacter jejuni, and Helicobacter pylori, produce virulence factors that induce DNA damage, genomic instability, and chronic inflammation—key features of carcinogenesis. At the same time, viruses such as JC polyomavirus (JCPyV), considered potentially oncogenic, and established oncogenic viruses like Epstein–Barr virus (EBV) and human papillomavirus (HPV) have been detected in colorectal tissues and are linked to cell cycle regulation, apoptosis, and DNA repair through their viral proteins. Intriguingly, recent findings suggest that bacterial genotoxins may promote the reactivation or transcriptional activity of persistent viruses such as JCPyV and EBV, possibly through DNA damage-induced stress and activation of NF-κB- or ATM-dependent signaling pathways. Despite these advances, interactions between oncogenic viruses and bacteria within the colon microbiome remain underexplored. This review integrates current evidence and provides future perspectives for addressing potential genotoxic collaboration between bacteria and viruses that could contribute to colorectal tumorigenesis. Elucidating these interactions could reveal novel biomarkers and therapeutic targets for the prevention and treatment of CRC. Full article

Colibactin, a genotoxin produced by pks⁺ E. coli, imprints highly specific mutational signatures SBS88 and ID18 in colorectal cancer (CRC) and even in normal colonic crypts. Population-scale analyses show these signatures are enriched in early-onset CRC, vary geographically, and are imprinted early during tumor evolution, where probabilistic attribution indicates that colibactin contributes to a measurable fraction of APC driver mutations in colibactin-positive cancers. Beyond colibactin, Fusobacterium nucleatum exerts clade-specific effects on tumor ecology and therapy response, with data supporting both chemoresistance and sensitization to anti-PD-1 in microsatellite stable (MSS) CRC. This article covers mechanistic, genomic, and molecular epidemiology evidence, outlines analytic standards for signature detection (whole-genome sequencing (WGS)/whole-exome sequencing (WES), single-sample fitting, and limits at low mutation counts), and charts translational paths spanning noninvasive screening (stool metagenomics + mutational signatures in tissue/circulating tumor DNA (ctDNA)), risk stratification, and microbial-targeted interventions (antibiotics, phages, ClbP inhibitors). Framing microbiome–genome crosstalk as a tractable axis enables testable clinical hypotheses for precision oncology. Full article

The contamination of ground and surface waters with micropollutants like estrogenic compounds and genotoxins is a major public health concern. Conventional wastewater treatment plants are currently not capable of completely removing those contaminants. In this study, we applied planar bioassays to investigate the genotoxicity and estrogenic activity of hospital and municipal wastewater from an Austrian treatment plant. Using the open-source 2LabsToGo platform in combination with the HPTLC-SOS-UmuC and HPTLC-YES assays, both genotoxic and estrogenic compound zones were detected in untreated wastewater. Genotoxic activity was found in sewage sludge filtrate and hospital wastewater, with bioanalytical concentrations ranging from 1.6 to 21.8 µg 4-NQO-EQ L⁻¹. Estrogenic responses were observed in the influent and hospital wastewater samples, with BEQ values between 3.5 and 16.0 µg E2-EQ L⁻¹. No activity was detected in the treated effluent, indicating efficient removal of these compounds during wastewater treatment. These results confirm the presence of biologically active micropollutants in hospitals and raw wastewater and demonstrate the suitability of planar bioassays for sensitive, spatially resolved detection. The use of portable equipment like the 2LabsToGo system suggests that on-site monitoring of estrogenic and genotoxic activities in wastewater is feasible and could support routine surveillance of treatment efficiency. Full article

The oral microbiome plays a key role in oral cancer pathogenesis through mechanisms such as chronic inflammation, dysregulated proliferation, and increased tumor invasiveness. Dysbiosis, frequently present in premalignant and malignant lesions, may initiate or accelerate malignant transformation. Oral squamous cell carcinoma (OSCC), representing over 90% of oral cancers and affecting more than 350,000 people worldwide each year, is strongly linked to microbial shifts. Common periodontal pathogens such as Fusobacterium nucleatum and Porphyromonas gingivalis are often enriched in OSCC. These bacteria may promote tumorigenesis by activating NF-κB and STAT3 pathways, suppressing apoptosis, and modulating host immune responses. Additional potential mechanisms include the production of reactive oxygen species (ROS) and genotoxins, inhibition of tumor suppressors such as p53, disruption of cell-cycle regulation via cyclin-dependent kinase pathway, and upregulation of β-catenin and toll-like receptor signaling. These molecular alterations cause DNA damage, immune surveillance evasion, angiogenesis, promoting tumor progression. Microbiota-modulating therapies, such as Lactobacillus probiotics, may complement standard treatments by restoring balance, boosting immunity, and limiting tumor growth. Engineered bacteriotherapy, microbiome-targeted immunomodulators, and microbiota-based diagnostics expand therapeutic options in oral cancer and, combined with advances in precision medicine, may support more personalized treatments and improved outcomes. Full article

Colorectal cancer (CRC) remains a major global challenge, with growing attention to its pathogenesis as mediated by the gut microbiome and epigenetic regulation. Despite therapeutic progress, clinical management remains difficult. CRC accounts for ~10% of cancers and is the second leading cause of cancer death worldwide. Romania bears a substantial burden, with many diagnoses at advanced stages. Etiology—Integrated Genetic, Environmental, and Microbial Determinants. Hereditary syndromes explain 10–15% of cases; most are sporadic, with hypermutated MSI/POLE (~15%), non-hypermutated chromosomal instability (~85%), and a CpG island methylator phenotype (~20%). GWAS implicate loci near SMAD7, TCF7L2, and CDH1; in Romania, SMAD7 rs4939827 associates with risk. Lifestyle exposures—high red/processed meat, low fiber, adiposity, alcohol, and smoking—shape susceptibility. Microbiome–Epigenome Interactions. Dysbiosis promotes carcinogenesis via genotoxins (e.g., colibactin), hydrogen sulfide, activation of NF-κB/STAT3, barrier disruption, and epigenetic remodeling of DNA methylation and microRNAs. Fusobacterium nucleatum, enterotoxigenic Bacteroides fragilis, and pks⁺ Escherichia coli exemplifies these links. Population-Specific Risk—Romania within Lifestyle–Microbiome Evidence. Incidence is rising, including early-onset disease. Romania lacks CRC-specific microbiome datasets. However, metabolic cohorts show loss of butyrate producers, enrichment of pathobionts, and SCFA imbalance—patterns that mirror European CRC cohorts—and exhibit regional heterogeneity. Beyond Fusobacterium nucleatum. Additional oncobacteria shape tumor biology. Peptostreptococcus stomatis activates integrin α6/β4→ERBB2–MAPK and can bypass targeted inhibitors, while Parvimonas micra enhances WNT/β-catenin programs and Th17-skewed immunity. Together, these data support a systems view in which microbial cues and host epigenetic control jointly drive CRC initiation, progression, metastasis, and treatment response. Full article

The genotoxin colibactin, a complex secondary metabolite, targets eukaryotic cell cycle machinery and contributes to neonatal sepsis and meningitis. Avian pathogenic Escherichia coli (APEC) XM, which produces this genotoxin, is an agent of poultry diseases with zoonotic potential. In this study, we confirmed that clbF was necessary for the APEC XM strain to produce colibactin, but it did not affect the growth, adhesion, or invasion of cells. Deletion of clbF substantially diminished both virulence and systemic dissemination, but it also changed the gene expression of the antiserum survival factor, adherence and invasion, iron acquisition genes, and the secretion system. In conclusion, clbF is necessary for the synthesis of the genotoxin colibactin and affects the development of APEC meningitis in mice. Full article

Replication timing (RT), the temporal order of DNA replication during S phase, influences regional mutation rates, yet the mechanistic basis for RT-associated mutagenesis remains incompletely defined. To identify drivers of RT-dependent mutation biases, we analyzed whole-genome sequencing data from cells with disruptions in DNA replication/repair genes or exposed to mutagenic compounds. Mutation distributions between early- and late-replicating regions were compared using bootstrapping and statistical modeling. We identified 14 genes that exhibit differential effects in early- or late-replicating regions, encompassing multiple DNA repair pathways, including mismatch repair (MLH1, MSH2, MSH6, PMS1, and PMS2), trans-lesion DNA synthesis (REV1) and double-strand break repair (DCLRE1A and PRKDC), DNA polymerases (POLB, POLE3, and POLE4), and other genes central to genomic instability (PARP1 and TP53). Similar analyses of mutagenic compounds revealed 19 compounds with differential effects on replication timing. These results establish replication timing as a critical modulator of mutagenesis, with distinct DNA repair pathways and exogenous agents exhibiting replication timing-specific effects on genomic instability. Our systematic bioinformatics approach identifies new DNA repair genes and mutagens that exhibit differential activity during the S phase. These findings pave the way for further investigation of factors that contribute to genome instability during cancer transformation. Full article

Platinum-based radiochemotherapy is associated with hematologic side effects, impacting patient outcomes. However, the clinical mechanisms of cisplatin and its interaction with ionizing radiation (IR), including in biodosimetry for radiotherapy, have not yet been fully clarified. For this purpose, healthy donors’ peripheral blood lymphocytes (PBLs) were pretreated with cisplatin in a pulse (1–4 h) or continuous (24 h) regimen followed by X-rays. DNA damage was assessed as DNA double-strand breaks using repair foci of γH2AX and 53BP1 after 0.5 h and 24 h in G1 PBLs and a proliferation-based cytokinesis-block micronucleus assay. Additionally, cell death and proliferation activity were measured. Unlike a 1 h pulse, a 24 h cisplatin pretreatment caused a concentration-dependent increase in cisplatin-induced foci while decreasing IR-induced foci, especially 24 h after irradiation. This was accompanied by increased apoptosis, with cisplatin and IR having additive effects. Both genotoxins alone caused a dose-dependent increase in micronuclei, while cisplatin significantly reduced binuclear cells, especially after the 24 h treatment, leading to lower micronuclei frequencies post-irradiation. Our results show that prolonged cisplatin exposure, even at low concentrations, impacts the vitality and division activity of PBLs, with significantly stronger effects post-irradiation. This has major implications and must be considered for the detection of DNA damage-associated biomarkers in PBLs used in clinical prediction or biodosimetry during radiotherapy. Full article

The gut microbiome, a complex community of microorganisms residing in the intestinal tract, plays a dual role in colorectal cancer (CRC) development, acting both as a contributing risk factor and as a protective element. This review explores the mechanisms by which gut microbiota contribute to CRC, emphasizing inflammation, oxidative stress, immune evasion, and the production of genotoxins and microbial metabolites. Fusobacterium nucleatum, Escherichia coli (pks+), and Bacteroides fragilis promote tumorigenesis by inducing chronic inflammation, generating reactive oxygen species, and producing virulence factors that damage host DNA. These microorganisms can also evade the antitumor immune response by suppressing cytotoxic T cell activity and increasing regulatory T cell populations. Additionally, microbial-derived metabolites such as secondary bile acids and trimethylamine-N-oxide (TMAO) have been linked to carcinogenic processes. Conversely, protective microbiota, including Lactobacillus, Bifidobacterium, and Faecalibacterium prausnitzii, contribute to intestinal homeostasis by producing short-chain fatty acids (SCFAs) like butyrate, which exhibit anti-inflammatory and anti-carcinogenic properties. These beneficial microbes enhance gut barrier integrity, modulate immune responses, and inhibit tumor cell proliferation. Understanding the dynamic interplay between pathogenic and protective microbiota is essential for developing microbiome-based interventions, such as probiotics, prebiotics, and fecal microbiota transplantation, to prevent or treat CRC. Future research should focus on identifying microbial biomarkers for early CRC detection and exploring personalized microbiome-targeted therapies. A deeper understanding of host–microbiota interactions may lead to innovative strategies for CRC management and improved patient outcomes. Full article

Genotoxins cause significant damage to the genetic material of aquatic organisms, requiring rapid and accurate assessment. Fish-derived cells sensitive to genotoxins have proven to be a useful tool for measuring genotoxicity, but the long treatment times required for measurement limit their application in situations requiring rapid testing. Previous studies have shown that fish cells can be kept unstarved for up to 6 h using media containing 1% FBS. In this study, the 1% FBS/6 h parameter was used for genotoxicity assessment. Therefore, genotoxicity assessment was performed after only 6 h of genotoxin treatment in a medium containing 1% FBS. The new genotoxicity assessment method provided faster and more accurate genotoxicity data for climbazole and metolachlor than the existing assessment system using the 15% FBS/96 h parameter. Furthermore, these advantages of the new platform enabled the determination of the genotoxicity of various genotoxins, such as dibenz[a,h]anthracene and ethoprophos. In summary, we have developed a genotoxicity assessment that can generate genotoxicity data rapidly and accurately. This new platform will serve as a foundation for rapid genotoxicity assessment of many genotoxins. Full article

The Saccharomyces cerevisiae chromosomal architectural protein Hmo1 is categorized as an HMGB protein, as it contains two HMGB motifs that bind DNA in a structure-specific manner. However, Hmo1 has a basic C-terminal domain (CTD) that promotes DNA bending instead of an acidic one found in a canonical HMGB protein. Hmo1 has diverse functions in genome maintenance and gene regulation. It is implicated in DNA damage tolerance (DDT) that enables DNA replication to bypass lesions on the template. Hmo1 is believed to direct DNA lesions to the error-free template switching (TS) pathway of DDT and to aid in the formation of the key TS intermediate sister chromatid junction (SCJ), but the underlying mechanisms have yet to be resolved. In this work, we used genetic and molecular biology approaches to further investigate the role of Hmo1 in DDT. We found extensive functional interactions of Hmo1 with components of the genome integrity network in cellular response to the genotoxin methyl methanesulfonate (MMS), implicating Hmo1 in the execution or regulation of homology-directed DNA repair, replication-coupled chromatin assembly, and the DNA damage checkpoint. Notably, our data pointed to a role for Hmo1 in directing SCJ to the nuclease-mediated resolution pathway instead of the helicase/topoisomerase mediated dissolution pathway for processing/removal. They also suggested that Hmo1 modulates both the recycling of parental histones and the deposition of newly synthesized histones on nascent DNA at the replication fork to ensure proper chromatin formation. We found evidence that Hmo1 counteracts the function of histone H2A variant H2A.Z (Htz1 in yeast) in DDT possibly due to their opposing effects on DNA resection. We showed that Hmo1 promotes DNA negative supercoiling as a proxy of chromatin structure and MMS-induced DNA damage checkpoint signaling, which is independent of the CTD of Hmo1. Moreover, we obtained evidence indicating that whether the CTD of Hmo1 contributes to its function in DDT is dependent on the host’s genetic background. Taken together, our findings demonstrated that Hmo1 can contribute to, or regulate, multiple processes of DDT via different mechanisms. Full article

In Europe, there is a growing concern for animal welfare, encompassing both their rights and health. Consequently, identifying biomarkers that predict serious pathological conditions has become crucial in veterinary medicine. The Buccal Micronucleus Cytome (BMCyt) assay is a minimally invasive method that uses biomarkers to evaluate DNA damage and chromosomal instability, using exfoliated buccal cells. A rising frequency of anomalies, such as micronuclei formation, strongly indicates an elevated risk of cancer, neurodegenerative diseases, or accelerated aging, potentially originating from exposure to genotoxins and cytotoxins. This method has been validated in humans, but very little research has been conducted on animals. This work aims to provide a detailed description of an optimized method for collecting buccal exfoliated cells in dogs and to characterize a biomarker related to genomic damage using optical and fluorescent microscopy. Samples from dogs in breeding kennels, including pregnant animals, were tested for chromosomal instability. By following procedures similar to those used in humans, we were able to detect and count major nuclear abnormalities. The percentage of micronuclei was higher compared to other studies. Technical aspects, such as avoiding artifacts and ensuring prior training of the operator, must be taken into account. This work validated the BMCyt method for collecting and processing samples in dogs, potentially enhancing the understanding of micronuclei as biomarkers for pre-pathological states in canines. Full article

Dysbiosis in the gut microbiota plays a significant role in GI cancer development by influencing immune function and disrupting metabolic functions. Dysbiosis can drive carcinogenesis through pathways like immune dysregulation and the release of carcinogenic metabolites, and altered metabolism, genetic instability, and pro-inflammatory signalling, contributing to GI cancer initiation and progression. Helicobacter pylori infection and genotoxins released from dysbiosis, lifestyle and dietary habits are other factors that contribute to GI cancer development. Emerging diagnostic and therapeutic approaches show promise in colorectal cancer treatment, including the multitarget faecal immunochemical test (mtFIT), standard FIT, and faecal microbiota transplantation (FMT) combined with PD-1 inhibitors. We used search engine databases like PubMed, Scopus, and Web of Science. This review discusses the role of dysbiosis in GI cancer onset and explores strategies such as FMT, probiotics, and prebiotics to enhance the immune response and improve cancer therapy outcomes. Full article

The present study investigates the influence of nitrosamines and etoposide on mesenchymal stromal cells (MSCs) in a differentiation state- and biological age-dependent manner. The genotoxic effects of the agents on both neonatal and adult stem cell populations after treatment, before, or during the course of differentiation, and the sensitivity of the different MSC types to different concentrations of MNU or etoposide were assessed. Hereby, the multipotent differentiation capacity of MSCs into osteoblasts, adipocytes, and chondrocytes was analyzed. Our findings reveal that while all cell types exhibit DNA damage upon exposure, neonatal CB-USSCs demonstrate enhanced resistance to genotoxic damage compared with their adult counterparts. Moreover, the osteogenic differentiation of MSCs was more susceptible to genotoxic damage, whereas the adipogenic and chondrogenic differentiation potentials did not show any significant changes upon treatment with genotoxin. Furthermore, we emphasize the cell-specific variability in responses to genotoxic damage and the differences in sensitivity and reaction across different cell types, thus advocating the consideration of these variabilities during drug testing and developmental biological research. Full article