Polymeric fibers are a prevalent form of airborne micro- and nanoplastics (MNPs), yet their inhalation hazards remain poorly constrained because toxicological studies have largely relied on spherical particles or heterogeneous fiber materials. Here, polystyrene (PS) and polyacrylonitrile (PAN) fiber MNPs were fabricated by electrospinning followed by cryomilling, probe sonication, and filtration, yielding discrete fibers with comparable diameters and lengths. FTIR confirmed preservation of polymer identity and showed no detectable residual solvent signal in the isolated fibers. Using A549 lung epithelial cells as an inhalation-relevant in vitro model, we found that PS and PAN fiber MNPs induced dose-dependent reductions in viability together with increased membrane damage, oxidative stress, and IL-8 release, whereas spherical PS particles elicited comparatively limited responses at the tested mass concentrations. Scanning electron microscopy further showed abnormal cell-fiber interactions, including membrane deformation and apparent partial membrane wrapping around fibers, consistent with morphology-dependent cellular injury. Together, these results show that engineered polymeric fiber MNPs elicit stronger epithelial stress and inflammatory responses than spherical particle controls under the tested conditions, supporting morphology-aware evaluation of airborne MNP hazards.

Enzyme-induced cytotoxicity can be considered the main challenge in modern cancer therapy that provides unique opportunities for targeted apoptosis. To address this challenge, we implemented enzyme-triggered activation of alkoxyamine-galactose conjugates with the formation of active carbon-centered radical species for the apoptosis of cancer cells. The comparative analysis of two alkoxyamine derivatives, bearing stable and self-immolative linkers between the radical precursor and galactose moiety, revealed the crucial role of molecular structure in anticancer activity. The study of cytotoxicity and induced oxidative stress of free amine and two galactosides revealed the enzyme-dependent nature of the activity of alkoxyamines having a self-immolative linker against distinct cancer cell lines such as PC-3 (prostate adenocarcinoma), SKOV-3 (ovarian adenocarcinoma), MCF-7 (breast adenocarcinoma), A-431 (epidermoid carcinoma), and Jurkat cells (human T-lymphoblastic leukemia). The collected data prove the applicability of enzyme-triggered glycosylated alkoxyamines as a new family of targeted prodrugs against cancer.

Nitrosamines (NA) are chemical impurities that are present in tobacco, foods, more recently in some pharmaceuticals and are associated with genotoxicity and carcinogenicity. We evaluated the in vivo mutagenicity of nicotine-derived nitrosamine ketone (NNK) or 4-(methyl nitrosamino)-1-(3-pyridyl)-1-butanone, a model compound used as an anchor molecule to estimate carcinogenic potency of unknown nitrosamine impurities. Big Blue rats were treated with NNK at doses ranging from 0.001 to 30 mg/kg for 28 days, following which liver and lung tissue were harvested 3 days later for nuclear genomic DNA isolation. Mutations in liver and lung were assessed with the cII transgene assay and endogenous genomic loci using Duplex Sequencing (DupSeq), a highly validated error-corrected sequencing (ECS) technology. The no genotoxic effect level (NOGEL) was 1 mg/kg in liver and 0.1 mg/kg in lung while the benchmark dose (BMD) analysis for cII mutagenicity determined a BMDL50 of 1.3 mg/kg in liver and 0.12 mg/kg in lung, consistent with lung being the more sensitive target organ for carcinogenicity for NNK. ECS-derived mutagenicity was highly correlated with cII-derived mutagenicity. Interestingly, the types of mutations formed appeared to be tissue-specific with higher C > T transitions and lower T > G transversions in lung compared to liver, differences that may reflect tissue-specific DNA repair capacity and/or metabolic differences. Collectively, these data support the use of in vivo mutagenicity data─from both TGR cII and ECS methods─for human health and cancer risk characterization of nitrosamines and for estimating acceptable daily intakes for unknown nitrosamine drug substance related impurities.

Nickel (Ni) is utilized in a wide range of applications, including the production of austenitic stainless steel, superalloys, rechargeable batteries, catalysts, and foundry products. Historically high exposure to mixed Ni dust has been associated with various health effects, including an increased risk of respiratory cancer. Different chemical forms of Ni exhibit distinct physicochemical properties and biological effects, and the role of these properties, including nanoparticles (NPs) vs microparticles (MPs), in the cellular uptake and fate is not completely understood. This study aims to explore the uptake, intracellular fate, and cytotoxicity of eight well-characterized Ni substances in BEAS-2B cells. Characterization was conducted using scanning electron microscopy, X-ray photoelectron spectroscopy, and dynamic light scattering. Uptake in BEAS-2B cells was investigated using transmission electron microscopy, Newport Green staining in combination with super-resolution microscopy, and atomic absorption spectroscopy. The characterization showed that the Ni substances differed in primary size but were all highly agglomerated under the conditions tested, with Ni3S2 having the largest size. At 48 h and based on the same mass of added Ni, Ni3S2 was the most cytotoxic, followed by the water-soluble salt NiSO4·6H2O and Ni metal NPs with a primary size of 80 nm (Ni80), while nickel oxide (NiO) NPs were noncytotoxic under the tested conditions. Biodissolution (released Ni per mass Ni added) in cell culture medium varied substantially across substances and generally increased with time. At 48 h, Ni biodissolution followed this order: Ni3S2 (55%) > Ni80 (9%) > NiO MPs (4%) > Ni 20 nm and NiO 80 nm (3%), > NiO 20 nm (2%) > Ni MPs (0.3%). All sparingly soluble Ni substances were clearly observable in intracellular membrane-bound structures in BEAS-2B cells. A key observation from the quantitative uptake was the distinctly lower uptake of Ni ions from the water-soluble NiSO4·6H2O compared to the sparingly soluble Ni substances. There was thus no clear correlation between apparent uptake and cytotoxicity. After fractionation into cytosolic, nuclear, and particulate fractions, followed by analysis of dissolved Ni from the particles within the cells, the three substances showing the highest amount of Ni per added Ni mass (indicating both uptake and intracellular Ni ion release) in both cytosol and nucleus were Ni20 NPs, Ni MPs, and Ni3S2. Super-resolution microscopy indicated increased Newport Green fluorescence, suggestive of intracellular Ni accumulation, predominantly in cells exposed to Ni MPs and Ni3S2. However, the findings were not sufficiently robust to allow firm conclusions. These findings highlight the complex interplay between biodissolution, cellular uptake and cytotoxicity of Ni substances.

DNA cross-linking agents remain a cornerstone of cancer chemotherapy. While their efficacy was traditionally attributed to direct genotoxicity, blocking DNA replication and transcription to induce cell death, recent evidence suggests that their therapeutic activity also involves innate immune activation. Aberrant repair of DNA lesions generates cytosolic DNA fragments, which are sensed by cyclic GMP-AMP synthase (cGAS). This activates the cGAS-STING (stimulator of interferon genes) pathway, driving the production of type I interferons and proinflammatory cytokines, thereby eliciting antitumor immunity. This review traces the molecular trajectory from DNA lesions formation to immune stimulation. We summarize the chemistry of classical and emerging DNA cross-linking agents, the replication stress they impose, and DNA damage response (DDR) generating cytosolic DNA as a trigger for innate immune activation. We then highlight key mechanistic insights into cGAS-STING signaling. Finally, we discuss therapeutic opportunities in their combinations with STING agonists for more effective immune activation. Collectively, this framework reframes DNA cross-linking agents from simple cytotoxins into in situ vaccines that harness DNA damage-driven immunity.

Smokeless tobacco, used by more than 360 million people worldwide, is an accepted cause of cancers of the oral cavity, esophagus, and pancreas. DNA adducts are considered as critical intermediates in the carcinogenic process, but there are no published studies that have used structure-specific methods to identify and quantify oral cell DNA adducts in people who use smokeless tobacco. In the study presented here, we used liquid chromatography-nanoelectrospray ionization-high resolution tandem mass spectrometry to identify and quantify DNA adducts in oral cells of 24 individuals who use smokeless tobacco and 25 individuals not using any tobacco or nicotine product. We quantified the following DNA adducts: (8R/S)-3-(2'-deoxyribos-1'-yl)-5,6,7,8-tetrahydro-8-hydroxypyrimido[1,2-a]purine-10(3H)-one (γ-OH-Acr-dGuo) from acrolein; (6S,8S and 6R,8R)-3-(2'-deoxyribos-1'-yl)-5,6,7,8-tetrahydro-8-hydroxy-6-methylpyrimido[1,2-a]purine-10(3H)-one [(S,R)γ-OH-Cro-dGuo] from crotonaldehyde and/or acetaldehyde; 3-methyladenine (3-Me-Ade); 7-ethylguanine (7-Et-Gua); and 8-oxo-deoxyguanosine (8-oxo-dGuo). Levels [median (min, max)] fmol/μmol dGuo or Gua, in samples in which analytes were detected, were: γ-OH-Acr-dGuo [350 (169, 2217) vs 114 (14, 278)], (6S,8S and 6R,8R)γ-OH-Cro-dGuo [1058 (222, 2569) vs not detected], and 7-Et-Gua [2445 (1052, 5389) vs 102 (13, 627)], which were significantly greater in the oral cell DNA of individuals who use smokeless tobacco than in those not using any tobacco or nicotine product (all adjusted Ps < 0.01), while amounts of 3-Me-Ade [3739 (93, 11495) vs 1447 (318, 3596) fmol/μmol Gua, adjusted P = 0.052] and 8-oxo-dGuo [1520 (513, 5232) vs 2092 (433, 3325) pmol/μmol dGuo, adjusted P = 0.13] were not significantly different between the two groups. The sizable and significant elevations of 7-Et-Gua and (6S,8S and 6R,8R)γ-OH-Cro-dGuo in oral cell DNA when smokeless tobacco was used versus controls were particularly notable and unexpected. The results of this study provide some potentially important new data regarding DNA adduct levels in oral cells of people who use smokeless tobacco.

MK-3207 was withdrawn from development because of drug-induced liver injury. Metabolic studies identified bioactivation to a protein-reactive 3,5-difluorophenylglyoxal (DFPG) intermediate. Although phenylglyoxal metabolites readily form protein adducts, their immunogenic potential has been poorly understood. We compared the immunogenicity of three DFPG isomers (3,5-, 2,4-, and 3,4-DFPG) using T-cell clones generated from treated healthy donor PBMCs. Reactive clones were detected against isomers with 3,5-DFPG inducing the strongest responses. Activation required antigen processing, and no cross-reactivity with MK-3207 was observed. These findings demonstrate the immunogenicity of 3,5-DFPG and show that structural differences among phenylglyoxal isomers influence T cell activation.

One of the most prevalent exocyclic DNA adducts is 3-(2-deoxy-β-D-erythro-pentofuranosyl) pyrimido[1,2-α]purin-10(3H)-one (M1dG), an oxidative DNA lesion that forms by the reaction of guanines in nucleic acids and pool nucleotides with oxidation-induced base propenals or with the lipid peroxidation product, malondialdehyde. Further oxidation converts M1dG to 6-oxo-M1dG, an even more deleterious lesion whose genotoxic and mutagenic properties have been characterized in vitro. The present work uses a site-specifically modified viral genome to evaluate the biochemical consequences of 6-oxo-M1dG in Escherichia coli cells and contrast them with the properties of the M1dG parent lesion. We found that 6-oxo-M1dG strongly inhibited replication, with a bypass efficiency of 1-2%, relative to an unmodified guanine. By contrast, under the same experimental conditions, the bypass efficiency of M1dG was 30-40%. Beyond its low bypass rate, 6-oxo-M1dG was 20 times more mutagenic than M1dG, with the majority of mutations being single base deletions. However, when the levels of bypass polymerases were increased by inducing the SOS response, the proportion of deletions decreased, at the expense of additional single base substitutions, primarily G → T and G → C mutations. Finally, two DNA repair pathways─the direct reversal dioxygenase AlkB and glycosylase MutY─were investigated for their putative activity on 6-oxo-M1dG. The results indicated that neither system was capable of repairing this highly mutagenic lesion.

The rapid expansion of in silico methodologies has reshaped modern drug discovery and toxicology research; however, robust prediction of ADMET endpoints remains limited by the scarcity and heterogeneity of experimental data. In particular, toxicological data sets are often fragmented across species, complicating the development of reliable and generalizable machine learning models. To address this challenge, we introduce a dedicated Python-based computational package, ADMET-XSpec, designed for the systematic development, training, and evaluation of ML models with an explicit consideration of interspecies data integration. The framework enables controlled incorporation of chemical space originating from different species and different assay types, allowing users to flexibly construct single-species models, as well as models augmented with cross-species information. This design facilitates systematic investigation of how additional data from other organisms influence model performance without imposing assumptions inherent to specific transfer learning paradigms. By supporting standardized preprocessing, scalable integration of heterogeneous data sets, and rigorous benchmarking, the proposed tool provides a unified environment for studying cross-species effects in ADMET modeling. Overall, this work delivers a practical resource for the ADMET modeling community and offers insights into how interspecies and interassay data integration can improve model robustness and generalizability while clarifying the conditions under which cross-species and cross-assay data information is beneficial for predictive toxicology. The package is freely available at https://github.com/hubertrybka/admet-xspec. ADMET-XSpec advances the state of the art by providing the first dedicated framework for controlled interspecies and interassay data integration in ADMET modeling, offering quantitative guidance on when and how cross-species and cross-assay data improve predictive performance.

Increasing global plastic production has intensified human exposure to nano- and microplastics (NMPs) through food, water, and air. Emerging evidence links NMP exposure to oxidative stress, inflammation, microbiome disruption, and metabolic dysfunction, although human exposure and health risk data remain limited.

Palladium nanoparticles (Pd NPs), extensively used in automobile catalytic converters, are increasingly released into the environment and represent an emerging nanopollution concern for aquatic ecosystems. This study examined the chronic effects of environmentally relevant Pd NP exposure on the freshwater vertebrate model Danio rerio, integrating bioaccumulation analysis, oxidative stress profiling, histopathology, and bulk RNA-seq transcriptomics with computational cell-type inference analyses. Adult zebrafish were exposed for 42 days to low (0.4 ng/L) and high (22 ng/L) Pd NP concentrations. Inductively coupled plasma-mass spectrometry confirmed dose-dependent Pd bioaccumulation in whole-body tissues. Biochemical analyses indicated a disruption of gonadal redox homeostasis, characterized by altered activities of superoxide dismutase, catalase, glutathione S-transferase, glutathione reductase, and lipid peroxidation, indicating sustained oxidative stress. Histological examination of ovaries and testes demonstrated progressive structural damage, including follicular atresia, delayed oocyte maturation, and impaired spermatogenesis, highlighting reproductive vulnerability. Transcriptomic profiling showed concentration-dependent transcriptional changes under Pd NP exposure, including reduced expression of mitochondrial energy metabolism genes and increased expression of DNA repair, cell cycle regulation, steroid biosynthesis, and stress-response pathways. High-dose Pd exposure strongly increased the expression of cell cycle and stress-response genes, including ccnb1 (41 to 8296 TPM), cdc25b (41 to 1937 TPM), and tp53 (110 to 604 TPM), while mitochondrial energy metabolism genes were consistently suppressed. Notably, PI3K-AKT-mTOR, p53, and cell cycle signaling axes exhibited biphasic regulation, reflecting compensatory and maladaptive stress responses. This study identifies potential ecological and human health risks associated with palladium nanoparticle dispersal and emphasizes the need for safer catalyst design and stricter environmental management of platinum group nanoparticles.

This study addresses current gaps in the 3D printing literature for filament composition (polymer type, color, and brand), aerosol emissions, and human health risks. Six metals (aluminum, magnesium, manganese, chromium, iron, and copper) were found in nonmetal filaments depending on polymer type, color, and brand using inductively coupled plasma-mass spectrometry. For copper- and steel-filled filaments, scanning electron microscopy and elemental analysis indicated a higher metal concentration within the filaments than on the surface. More VOCs were emitted from acrylonitrile butadiene styrene (ABS) filaments compared to polylactic acid (PLA) filaments, according to thermal desorption unit samples analyzed by gas chromatography. Styrene, emitted from ABS filaments, appears to pose the greatest potential health risk among known VOCs, given its concentration and reported effects. Toluene and benzaldehyde were emitted in lower concentrations from both ABS and PLA filaments and may pose a potential risk to human health. Based on three inflammatory markers across two exposure times using BEAS-2B epithelial lung cells, steel showed the highest proinflammatory response, possibly due to chromium and overall particulate matter. 3D printer users should minimize aerosolized emissions by taking proper precautions, such as ensuring adequate ventilation and wearing face masks, particularly during extended exposure.

Beta-1 adrenergic receptors (ADRβ1) are critical regulators of cardiac function; however, the potential modulation of ADRβ1 by environmental chemicals remains largely underexplored, raising concerns about unintended impacts on cardiovascular health. We applied a quantitative high-throughput screening (qHTS) approach to identify ADRβ1 agonists within the Tox21 10K compound library, which includes environmental chemicals, pharmaceuticals, industrial agents, and consumer products, using an HTRF-based cAMP assay in ADRβ1-overexpressing HEK293 cells. Primary screening of 8,947 unique compounds identified 118 potential ADRβ1 agonists. Among these, 94 were confirmed and further evaluated for β-adrenergic receptor subtype selectivity (ADRβ2 and ADRβ3) and hERG channel inhibition to assess potential cardiotoxicity liability. Known ADRβ1 agonists, isoproterenol (EC50, 0.91 nM) and dobutamine (EC50, 10 nM), were identified, supporting the validity of the assay. In addition, several compounds with limited prior ADRβ1-specific characterization, such as GR 103691 and N,N'-dibenzylethane-1,2-diamine, demonstrated subtype-selective or mixed agonist profiles, with some exhibiting minimal hERG inhibition. These findings expand the catalog of ADRβ1 modulators and demonstrate the utility of qHTS for identifying chemicals that may affect cardiovascular signaling pathways.

The global industrialization and rapid urbanization have elevated the risk of toxic pollutant exposure, which affects human health, especially during pregnancy. Pregnant mothers are daily exposed to bisphenol A (BPA), a common plastic leachate and a prominent toxic pollutant present in our environment. BPA acts as an endocrine-disrupting chemical (EDC) by altering feto-placental homeostasis. This persistent and potent exposure to BPA during gestation can trigger placental damage, affecting trophoblast cell function and survival. BPA even disrupts specific signaling cascades by altering post-translational protein phosphorylation. However, this BPA-mediated dysregulation of signaling nodes in the early trimester placenta remains unexplored. Therefore, this study investigates the global proteome changes in post-BPA-exposed extravillous trophoblast (EVT) cells, which revealed a BPA-mediated dynamic regulation of phospho-proteome signatures and their associated kinases. Further inspection shows that the altered phosphorylation of c-JUN (S63) and GSK3α (Y279) is associated with BPA toxicity in EVTs and the placenta. This altered phosphorylation affects cellular signaling downstream, imparting damage upon the growing feto-placental unit. This highlights an altered phosphorylation-mediated mechanism of BPA toxicity in the placenta, which can cause the onset of adverse pregnancy outcomes. Data are available via ProteomeXchange with the identifiers PXD074780 and PXD080006.