Toxicological Sciences : An Official Journal of the Society of Toxicology

The RAS gene family holds a central position in controlling key cellular activities such as migration, survival, metabolism, and other vital biological processes. The activation of RAS signaling cascades is instrumental in the development of various cancers. Although several RAS inhibitors have gained approval from the United States Food and Drug Administration (FDA) for their substantial antitumor effects, their widespread and severe adverse reactions significantly curtail their practical usage in the clinic...

There is a variety of electrophiles in the environment. In addition, there are precursor chemicals that undergo metabolic activation by enzymes and conversion to electrophiles in the body. Although electrophiles covalently bind to protein nucleophiles, they also form adducts associated with adaptive or toxic responses. Low molecular weight compounds containing sulfur are capable of blocking such adduct formation by capturing the electrophiles. In this review, we present out findings on the capture and inactivation of electrophiles by 1) intracellular glutathione, 2) reactive sulfur species and 3) extracellular cysteine (formed during the production of sulfur adducts)...

No abstract text is available yet for this article.

Persistent, mobile and toxic (PMT) compounds released to the environment are likely to pollute drinking water sources due to their slow environmental degradation (persistency) and high water solubility (mobility). The aim of the present study was to create in vitro hazard profiles for sixteen triazoles, nine triazines and eleven PFAS based on their agonistic and antagonistic effects in estrogen receptor (ER), androgen receptor (AR) and thyroid hormone receptor (TR) reporter gene assays, their ability to bind human transthyretin (TTR), and their effects on steroidogenesis...

Benzalkonium chlorides (BACs) are commonly used disinfectants in a variety of consumer and food-processing settings, and the COVID-19 pandemic has led to increased usage of BACs. The prevalence of BACs raises the concern that BAC exposure could disrupt the gastrointestinal microbiota, thus interfering with the beneficial functions of the microbes. We hypothesize that BAC exposure can alter the gut microbiome diversity and composition, which will disrupt bile acid homeostasis along the gut-liver axis. In this study, male and female mice were exposed orally to d7-C12- and d7-C16-BACs at 120 µg/g/day for one week...

The European regulatory framework on chemicals is at a crossroads. There are calls for the framework to be more effective, by better protecting people and the environment. There is also room for it to be more efficient and cost-effective, by harmonising assessment practices across sectors and avoiding the need for unnecessary testing. At the same time, there is a political commitment to phase out animal testing in chemical safety assessments. In this commentary, we argue that these needs are not at odds with other...

Regorafenib, an oral multikinase inhibitor of angiogenic, stromal, and oncogenic receptor tyrosine kinases, has been approved for the treatment of metastatic colorectal cancer, gastrointestinal stromal tumors and hepatocellular carcinoma by the US Food and Drug Administration and European Medicines Agency. However, regorafenib-induced cardiotoxicity increases the risk of mortality. Despite reports that regorafenib can cause mitochondrial dysfunction in cardiomyocytes, the molecular mechanism of regorafenib-induced cardiotoxicity is much less known and there is an urgent need for intervention strategies...

Welding fumes contain various metals. Past studies, however, mainly focused on Manganese (Mn)-related neurotoxicity. This study investigated welding-related mixed metal exposure effects on MRI metrics in the basal ganglia (BG) and their dose-response relationship. Subjects with (N = 23) and without (N = 24) a welding exposure history were examined. Metal exposure was estimated with exposure history questionnaire and whole blood metal levels. T1 (weighted-intensity and relaxation time; estimates of brain Mn accumulation), diffusion tensor imaging [Axial (AD), mean (MD), radial diffusivity (RD), and fractional anisotropy (FA); estimates of microstructural differences] metrics in BG [caudate nucleus, putamen, and globus pallidus (GP)] and voxel-based morphometry (for volume) were examined and related with metal exposure measures...

Mitotic arrest deficient 2 like 1 (MAD2L1) is a component of the mitotic spindle assembly checkpoint implicated in cancer cell proliferation and tumorigenesis. The functional role of MAD2L1 in hepatocellular carcinoma (HCC) has not been adequately investigated, especially in vivo. In the current manuscript, we sought to address the function of MAD2L1 in hepatocarcinogenesis. We found that MAD2L1 expression is upregulated in human HCCs, where its expression is associated with higher aggressive tumor grade, elevated proliferative activity, and poor prognosis...

Plasma half-life is a crucial pharmacokinetic parameter for estimating extralabel withdrawal intervals of drugs to ensure the safety of food products derived from animals. This study focuses on developing a quantitative structure-activity relationship (QSAR) model incorporating multiple machine learning and artificial intelligence algorithms, and aims to predict the plasma half-lives of drugs in six food animals, including cattle, chickens, goats, sheep, swine, and turkeys. By integrating four machine learning algorithms with five molecular descriptor types, 20 QSAR models were developed using data from the Food Animal Residue Avoidance Databank (FARAD) Comparative Pharmacokinetic Database...

Molnupiravir is registered or authorized in several countries as a 5-day oral COVID-19 treatment for adults. Molnupiravir is a prodrug of the antiviral ribonucleoside β-D-N4-hydroxycytidine (NHC) that distributes into cells, where it is phosphorylated to its pharmacologically active ribonucleoside triphosphate (NHC-TP) form. NHC-TP incorporates into SARS-CoV-2 RNA by the viral RNA-dependent RNA polymerase, resulting in an accumulation of errors in the viral genome, leading to inhibition of viral replication and loss of infectivity...

Bile acid (BA) signaling dysregulation is an important etiology for the development of Metabolic Dysfunction-associated Steatotic Liver Disease (MASLD). As diverse signaling molecules synthesized in the liver by pathways initiated with CYP7A1 and CYP27A1, BAs are endogenous modulators of farnesoid x receptor (FXR). FXR activation is crucial in maintaining BA homeostasis, regulating lipid metabolism, and suppressing inflammation. Additionally, BAs interact with membrane receptors and gut microbiota to regulate energy expenditure and intestinal health...

Per- and polyfluoroalkyl substances (PFAS) are a diverse class of anthropogenic chemicals; many are persistent, bioaccumulative, and mobile in the environment. Worldwide, PFAS bioaccumulation causes serious adverse health impacts, yet the physiochemical determinants of bioaccumulation and toxicity for most PFAS are not well understood, largely due to experimental data deficiencies. As most PFAS are proteinophilic, protein binding is a critical parameter for predicting PFAS bioaccumulation and toxicity. Among these proteins, human serum albumin (HSA) is the predominant blood transport protein for many PFAS...

Pharmaceutical developers are encouraged to adopt the best practices of being purposefully thoughtful about the use of animals, seeking alternatives wherever possible. They should engage with health authorities to increase their familiarity with the methods, study designs, data outputs and the context of use for new approach methodologies (NAMs). Although current state of technology does not yet provide adequate models to fully replace in vivo studies, many models are sufficiently good for an augmented approach that will enhance our understanding of in vitro to in vivo correlations and advance the long-term goal of reducing animal use through innovative NAMs...

Occupational exposure to 4,4'-methylenebis(2-chloroaniline) (MOCA) has been linked to an increased risk of bladder cancer among employees in Japanese plants, indicating its significance as a risk factor for urinary bladder cancer. To investigate the role of MOCA metabolism in bladder carcinogenesis, we administered MOCA to non-humanized (F1-TKm30 mice) and humanized-liver mice for 4 and 28 weeks. We compared MOCA-induced changes in metabolic enzyme expression, metabolite formation, and effects on the urinary bladder epithelium in the two models...

Myelosuppression is a major side effect of chemotherapy. Although decreased blood cells are restored with the recovery of bone marrow cells, insufficient recovery of decreased lymphocytes was observed in mice given azacitidine (AZA), a DNA methyltransferase (DNMT) inhibitor, even following the restoration of bone marrow cells. To understand the mechanisms behind this sustained lymphopenia, we examined AZA's impact on the hematopoietic progenitor cells and the expression of Dnmts and differentiation-related genes...

A growing body of clinical and experimental evidence indicates that immune checkpoint blockade enhances patient susceptibility to hypersensitivity reactions to co-administered medications. In this study, we utilized an in vitro T-cell priming assay to demonstrate one of the mechanistic hypotheses on how this occurs; through lowering of the threshold in patients to elicit aberrant T-cell responses. We outline the dependency of de novo T-cell priming responses to drug-associated antigens on dose at initial exposure...

Nicotine is an alkaloid found in tobacco. Human exposure to nicotine primarily occurs through the use of tobacco products. To date, limited nicotine pharmacokinetic data in animals have been reported. This study exposed male Sprague-Dawley rats to vehicle (and/or air) or four doses of nicotine via nose-only inhalation (INH), oral gavage (PO), and intravenous (IV) infusion. Plasma, six tissues (brain, heart, lung, liver, kidney, and muscle), and urine were collected at multiple timepoints from 5 minutes to 48 hours post-dose...

Peptides have emerged as promising therapeutic agents. However, their potential is hindered by hemotoxicity. Understanding the hemotoxicity of peptides is crucial for developing safe and effective peptide-based therapeutics. Here, we employed chemical space complex networks (CSNs) to unravel the hemotoxicity tapestry of peptides. CSNs are powerful tools for visualizing and analyzing the relationships between peptides based on their physicochemical properties and structural features. We constructed CSNs from the StarPepDB database, encompassing 2004 hemolytic peptides, and explored the impact of seven different (dis)similarity measures on network topology and cluster (communities) distribution...

Cannabinoids, derived from the Cannabis sativa plant, has garnered increasing attention for its potential therapeutic applications in various diseases. The pharmacologically active compounds in Cannabis, such as delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), exhibit diverse immunomodulatory properties. While studies have explored the effects of cannabinoids on immune function, their specific interactions with the thymus, a primary immune organ critical for T cell development and maturation, remain an intriguing area of investigation...