Search Results (130)

Background and Objectives: Colorectal cancer (CRC) is one of the most frequently diagnosed malignancies worldwide. Although chemotherapy is an effective treatment for colorectal cancer (CRC), its effectiveness is frequently hindered by the emergence of resistant cancer cells. Studies have demonstrated a linkage between drug resistance and the pregnane X receptor (PXR), which influences the metabolism and the transport of chemotherapeutic agents. Likewise, autophagy is also a well-established mechanism that contributes to chemotherapy resistance, and it is closely tied to tumor progression. This pre-clinical study aims to investigate the role of mtKRAS-dependent autophagy with PXR expression after treatment with Irinotecan in colorectal cancer. Methods: CRC lines were treated with specific inhibitors, such as 3-methyladeninee, hydroxychloroquine PI-103, and irinotecan hydrochloride, and subjected to various assays, including MTT for cell viability, Western blot for protein expression, siRNA-mediated PXR knock-out, and confocal microscopy for autophagic vacuole visualization. Protein quantification, gene knockdown, and subcellular localization studies were performed under standardized conditions to investigate treatment effects on autophagy and apoptosis pathways. Conclusions: Our experiments showed that PXR knockdown does not alter autophagy levels following Irinotecan treatment, but it promotes apoptotic cell death despite elevated autophagy. Moreover, late-stage autophagy inhibition reduces PXR expression, whereas induction through PI3K/AKT/mTOR inhibition leads to increased expression of PXR. Our experiments uncover a mechanism by which autophagy facilitates the nuclear translocation of the PXR, thereby promoting resistance to Irinotecan across multiple cell lines. Full article

The nuclear receptors pregnane X receptor (PXR), constitutive androstane receptor (CAR), and farnesoid X receptor (FXR) regulate the hepatic metabolism of androstenone, a testicular steroid that accumulates in the fat of intact male pigs and causes boar taint. This study evaluated natural product-derived compounds and conventional agonists targeting these nuclear receptors for their effects on androstenone metabolism in primary hepatocytes from slaughter-weight boars, to assess their potential as treatments for boar taint. Cells were incubated with natural products, conventional agonists, or dimethyl sulfoxide (DMSO; control), then being treated with androstenone. Culture media and cells were analyzed to assess changes in androstenone metabolism and gene expression. UGT1A6 was upregulated by treatments targeting both PXR and CAR and downregulated by FXR agonists. Additionally, PGC1α and NR2F1 were downregulated by compounds targeting PXR/CAR, while FXR and NR0B2 were upregulated and HNF4α downregulated by treatments acting on FXR. The natural products diallyl sulfide (DAS) and (Z)-guggulsterone (GUG) increased overall androstenone metabolism (DAS, GUG) and the production of Phase I androstenol metabolites (DAS), but only in hepatocyte culture replicates that responded positively to these treatments. Although gene expression was similar between positive-response and negative/non-responsive replicates following treatments, negative/non-responsive replicates for several treatments had higher basal expression of UGT2B31, UGT2A1, and SIRT1 and lower basal expression of FXR, PXR, and NR0B1 compared to positive-response replicates. These findings suggest that DAS and GUG may be promising treatments for boar taint, specifically in animals with lower basal rates of androstenone metabolism and higher expression of key nuclear receptors. Full article

Neurosteroids pregnenolone, progesterone, allopregnanolone, and dehydroepiandrosterone have been actively studied in the last years as candidates for the treatment of neurodegenerative diseases and postinjury rehabilitation. The neuroprotective mechanisms of these neurosteroids have been shown in clinical studies of depression, epilepsy, status epilepticus, traumatic brain injury, fragile X syndrome, and chemical neurotoxicity. However, only the allopregnanolone analogs brexanolone and zuranolone have been recently approved by the FDA for the treatment of depression. The aim of this review was to evaluate whether the endogenous neurosteroids can be used in clinical practice as neuroprotectors. Neurosteroids are multitarget compounds with strong anti-inflammatory, immunomodulatory, and cytoprotective action; they stimulate the synthesis and release of BDNF and increase remyelination and regeneration. In addition to nuclear and membrane steroid hormone receptors, such as PR, mPR, PGRMC1,2, ER, AR, CAR, and PXR, they can bind to GABAA receptors, NMDA receptors, Sigma-1 and -2 receptors (σ1-R/σ2-R). Among these, mPRs, PGRMC1,2, sigma receptors, and mitochondrial proteins attract comprehensive attention because of strong binding with the P4 and DHEA, but subsequent signaling is poorly studied. Other plasma membrane and mitochondrial proteins are involved in the rapid nongenomic neuroprotective action of neurosteroids. P-glycoprotein, BCL-2 proteins, and the components of the mitochondrial permeability transition pore (mPTP) play a significant role in the defense against the injuries of the brain and the peripheral nervous system. The role of these proteins in the molecular mechanisms of action in neuroprotection and neuroinflammation has not yet been clearly established. The aspects of their participation in these pathological processes are discussed. New formulations, such as lipophilic emulsions, nanogels, and microneedle array patches, are attractive strategies to overcome the low bioavailability of these neurosteroids for the amelioration and treatment of various nervous disorders. Full article

Bifenthrin (BF) is a widely used pyrethroid pesticide recognized as an endocrine-disrupting chemical (EDC). Previous studies have confirmed that chronic exposure to BF is associated with various health risks. However, its potential association with recurrent implantation failure (RIF) and recurrent pregnancy loss (RPL) remains unclear. In this study, the potential targets of BF were identified using several databases, including the Comparative Toxicogenomics Database (CTD), TargetNet, GeneCards, SwissTargetPrediction, and STITCH. Differentially expressed genes (DEGs) associated with RIF were obtained from bulk RNA-seq datasets in the GEO database. Candidate targets were identified by intersecting the predicted BF-related targets with the RIF-associated DEGs, followed by functional enrichment analysis using the DAVID and g:Profiler platforms. Subsequently, hub genes were identified based on the STRING database and Cytoscape. A diagnostic model was then constructed based on these hub genes in the RIF cohort and validated in an independent recurrent pregnancy loss (RPL) cohort. Additionally, we performed single-cell type distribution analysis and immune infiltration profiling based on single-cell RNA-seq and bulk RNA-seq data, respectively. Molecular docking analysis using AutoDock Vina was conducted to evaluate the binding affinity between BF and the four hub proteins, as well as several hormone-related receptors. Functional enrichment results indicated that the candidate genes were mainly involved in apoptotic and oxidative stress-related pathways. Ultimately, four hub genes—BCL2, HMOX1, CYCS, and PTGS2—were identified. The diagnostic model based on these genes exhibited good predictive performance in the RIF cohort and was successfully validated in the RPL cohort. Single-cell transcriptomic analysis revealed a significant increase in the proportion of myeloid cells in RPL patients, while immune infiltration analysis showed a consistent downregulation of M2 macrophages in both RIF and RPL. Moreover, molecular docking analysis revealed that BF exhibited high binding affinity to all four hub proteins and demonstrated strong binding potential with multiple hormone receptors, particularly pregnane X receptor (PXR), estrogen receptor α (ESRα), and thyroid hormone receptors (TR). In conclusion, the association of BF with four hub genes and multiple hormone receptors suggests a potential link to immune and endocrine dysregulation observed in RIF and RPL. However, in vivo and in vitro experimental evidence is currently lacking, and further studies are needed to elucidate the mechanisms by which BF may contribute to RIF and RPL. Full article

Background: Sucralose and benzo(a)pyrene (B[a]P) are widespread foodborne substances known to harm human health. However, the effects of their combined exposure on kidney function remain unclear. This study aimed to investigate the mechanisms by which sucralose and B[a]P induce kidney injury through P-glycoprotein (PGP/ABCB1), a crucial protein involved in cellular detoxification. Methods: C57BL/6N mice were co-treated with sucralose and B[a]P for 90 days to evaluate their impact on kidney histopathology and function. In vitro experiments assessed cell viability, reactive oxygen species (ROS) levels, and B[a]P accumulation by flow cytometry. Molecular docking and cellular thermal shift assay (CETSA) were used to determine the binding affinity of sucralose to PGP. Furthermore, PCR, Western blotting, and immunohistochemistry were performed to analyze the expression of PGP and its upstream transcription factors. Results: Ninety days of co-exposure to sucralose and B[a]P significantly exacerbated renal dysfunction in mice, as evidenced by the elevated level of serum creatinine and urea nitrogen, which could be reverted by ROS scavenger N-acetyl cysteine (NAC). In vitro, sucralose promoted cellular accumulation of B[a]P, consequently enhancing B[a]P-induced cell growth inhibition and ROS production. Consistently, B[a]P accumulation was enhanced by PGP knockdown in both HK2 and HEK-293 cells. Mechanistically, sucralose can directly bind to PGP, competitively inhibiting its efflux capacity and increasing intracellular B[a]P retention. Prolonged co-exposure further downregulated PGP expression, possibly through the reductions of its transcriptional regulators (PXR, NRF2, and NF-κB). Conclusions: Co-exposure to sucralose and B[a]P exacerbates renal injury by impairing PGP function. Mechanistically, sucralose inhibits PGP activity, resulting in the accumulation of B[a]P within renal cells. This accumulation triggers oxidative stress and inhibits cell growth, which demonstrates that sucralose potentiates B[a]P-induced nephrotoxicity by directly inhibiting PGP-mediated detoxification pathways, thus underscoring the critical need to evaluate toxicity risks associated with combined exposure to these compounds. Full article

Endocrine-disrupting chemicals (EDCs) are notable for their persistence, bioaccumulation, and associations with cancer. Human nuclear receptors (hNRs) are primary targets disrupted by these persistent EDCs, resulting in alterations to xenobiotic metabolism, lipid homeostasis, and endocrine function, which can lead to carcinogenic effects. Despite their hazardous effects, comprehensive studies on EDC interactions and their impacts on hNRs remain limited. Here, we profiled the interactions of persistent EDCs, including PFAS, plastic additives, bisphenols, polybrominated diphenyl ethers, and phthalates, with key hNRs such as PXR, CAR, PPARα, PPARγ, PPARδ, AR, and RORγt. Through controlled molecular docking simulations, we observed strong binding of the EDCs to these receptors. Further analysis showed that EDCs exhibit strong binding activity towards hNRs by preferentially interacting with hydrophobic amino acids, namely leucine, isoleucine, methionine, and phenylalanine. PFAS demonstrated the highest binding affinity, characterized by a combination of complementary hydrophobic interactions from their fluorinated carbon chains and polar interactions from their functional groups (e.g., carboxylate, sulfonate) across all receptors. Distinct polycyclic and hydrophobic trends, contributing to strong NR binding, were evident in non-PFAS and nonplastic EDCs. The hNR activity assay in HepG2 cells revealed agonistic effects of dicyclohexyl phthalate (DCHP) and di-2-ethylhexyl phthalate (DEHP) on most receptors, except for PPARα. The hNR transcription factor pathway assay in HepG2 cells demonstrated increased gene expression of VDRE and PXR, suggesting potential chronic effects on xenobiotic metabolism and calcium homeostasis. Overall, our findings demonstrate the need for further research into the endocrine disruption and carcinogenic effects of these persistent EDCs. Full article

Overdose intake of acetaminophen (APAP) causes liver injury involving hepatic drug metabolism and activation of oxidative stress pathways, and forsythiaside A (FA) has hepatoprotective pharmacological activity, but knowledge of the mechanism of FA treatment for APAP liver injury is still lacking the literature. In this study, we investigated the effects of FA on the pregnane X receptor (PXR) by molecular docking and reporter gene assays. In addition, we explored the effects of FA on oxidative stress, endoplasmic reticulum stress (ERS), apoptosis, and hepatic pathology by interfering with PXR in ex vivo and in vivo models. The results showed that FA decreased the PXR protein expression level and effectively reduced the oxidative stress level in the APAP model. In addition, FA reduced the expression of ERS pathway ProteinkinaseR-likeERkinase (PERK)-translation initiation factor 2 (eIF-2α)-activating transcription factor 4 (ATF4) by inhibiting PXR, and at the same time, decreased the expression of apoptotic proteins C/EBP homologous protein (CHOP), Bax, Caspase 3, and Caspase 7, and elevated the expression of apoptosis-suppressing protein Bcl-2, which ultimately treated the hepatic pathology injury of APAP in mice. The present study confirmed that FA improved APAP metabolism by inhibiting PXR-mediated CYP1A2 and CYP3A11 and alleviated APAP-induced hepatic impairment by inhibiting hepatic oxidative stress, ERS, and apoptosis. Full article

PEG400 is widely used as a pharmaceutical excipient in the biomedical field. Increasing evidence suggests that PEG400 is not an inert drug carrier; it can influence the activity of various drug-metabolizing enzymes and transporters, thereby affecting the in vivo process of drugs. It can also alleviate obesity and adipose tissue inflammation induced by a high-fat diet. In this study, we employed proteomics to investigate the impact of PEG400 on hepatic protein expression in rats. We found that over 40 metabolic enzymes were altered, with UDP-glucuronosyltransferase 1a9 (Ugt1a9) showing the most significant upregulation. This observation is consistent with our previous findings. KEGG pathway enrichment analysis revealed that PEG400 influences retinol metabolism, steroid hormone biosynthesis, drug metabolism, bile secretion, fatty acid degradation, peroxisome proliferator-activated receptor (PPAR) signaling pathway, and pentose and glucuronate interconversions. Western blot and molecular docking were used to quantitatively analyze related proteins. The results demonstrated that PEG400 promotes the metabolism of retinol to produce retinoic acid; enhances bile secretion by upregulating bile acid synthesis and transporter proteins; and activates the PPARα signaling pathway to regulate the expression of fat metabolism-related proteins, thereby reducing lipid accumulation. Furthermore, as natural ligands for nuclear receptors, retinoic acid and bile acids may activate nuclear receptors and initiate the regulation of target gene expression. We found upregulation of the nuclear receptors PPARα, retinoid X receptor alpha (RXRα), and pregnane X receptor (PXR). RXRα can form a dimer with PPARα or PXR to regulate the expression of target genes, which may explain the changes in the expression of numerous metabolic enzymes. This study provides a comprehensive understanding of the effects of PEG400 on liver metabolism in rats, reveals its potential biological functions, and offers new insights into the application and development of PEG400. Full article

Per- and polyfluoroalkyl substances (PFASs) are persistent and highly bioaccumulative emerging environmental contaminants of concern that display significant toxic and carcinogenic effects. An emerging PFAS is PFESA-BP2, a polyfluoroalkyl ether sulfonic acid found in drinking water and the serum of humans and animals. While PFESA-BP2-induced liver and intestinal toxicity has been demonstrated, the toxicological mechanisms and carcinogenic potential of PFESA-BP2 have remained relatively understudied. Here, we studied how different doses of PFESA-BP2 affect gene activity related to liver toxicity and the risk of liver cancer such as hepatocellular carcinoma (HCC) in mice exposed to PFESA-BP2 once daily through oral gavage for seven days. An analysis of key hepatic pathways suggested increased risk of hepatotoxicity as a result of PFESA-BP2 exposure. Increased oxidative stress response was associated with all concentrations of exposure. Liver toxicity pathways, including PXR/RXR activation and hepatic fibrosis, showed dose-dependent alteration with activation primarily at low doses, suggesting an increased risk of hepatic inflammation and injury. Additionally, an analysis of carcinogenic and HCC-specific pathways suggested PFESA-BP2-induced risk of liver cancer, particularly at low doses. Low-dose PFESA-BP2 exposure (0.03 and 0.3 mg/kg-day) was associated with an increased risk of HCC carcinogenesis, as indicated by the activation of tumor-related and HCC-associated pathways. In contrast, these pathways were inhibited at high doses (3.0 and 6.0 mg/kg-day), accompanied by the activation of HCC-suppressive pathways. The increased risk of HCC development at low doses was mechanistically linked to the activation of signaling pathways such as HIF, EGF, NOTCH4, HGF, and VEGF. Biomarkers linked to liver cancer risk, prognoses, and diagnoses were also identified as a result of exposure. Overall, our findings on liver carcinogenic and hepatotoxic pathway activation patterns suggest that PFESA-BP2 increases the risk of liver toxicity and HCC development, particularly at low doses. Full article

Sulfobutyl-ether-beta-cyclodextrin sodium salt (SBECD) is a modified cyclodextrin widely used in the pharmaceutical industry to enhance the solubility and stability of poorly water-soluble drugs. As a derivative of beta-cyclodextrin, it is produced by introducing sulfobutyl ether groups into the beta-cyclodextrin molecule, which significantly increases its water solubility and decreases its toxicity compared to unmodified cyclodextrins. This study investigates the spectral and PXR diffraction characterization of SBECD, its thermal stability profile, and decomposition mechanism using isoconversional methods. Since the simple ASTM E698 method does not provide realistic data, the Flynn–Wall–Ozawa, Friedman, and NPK methods were employed, leading to the kinetic triplet that characterizes the oxidative thermolysis of this compound. Full article

Multidrug resistance (MDR) is a process that constitutes a significant obstacle to effective anticancer therapy. Here, we examined whether unsymmetrical bisacridines (UAs) are substrates for ABC transporters and can influence their expression in human colon LS 174T and prostate DU 145 cancer cells. Moreover, we investigated the cytotoxicity and the cellular response induced by UAs in these cells. The ATPase activities of MDR1, MRP1, and MRP2 were measured using vesicles prepared from insect Sf9 cells expressing particular ABC transporters. The gene expression and protein levels were analyzed using qPCR and Western blotting. The cellular effects were studied by MTT (cytotoxicity), flow cytometry (cell cycle analysis and phosphatidylserine externalization), and fluorescence microscopy. We showed that UAs are substrates for MDR1. Importantly, they did not influence remarkably the expressions of the ABCB1, ABCC1, and ABCC2 genes and the levels of the MDR1 and PXR proteins in the studied cells. Furthermore, the cytotoxicity and the level of apoptosis triggered by UAs in LS 174T cells possessing higher expressions of metabolic enzymes were lower compared with DU 145 cells. These results indicate that during possible UA treatment, the occurrence of drug resistance could be limited, which could favor the use of such compounds as potential candidates for future studies. Full article

Leydig cells (LCs) in the testes produce the male sex hormone testosterone (T). Several xenobiotics, including clinical drugs, supplements, and environmental chemicals, are known to disrupt T homeostasis. Notably, some of these xenobiotics are known to activate the pregnane X receptor (PXR), a ligand-dependent nuclear receptor. However, it is currently unknown whether PXR is expressed in LCs and whether PXR activation alters T synthesis in rodent LCs. Therefore, in this study, we sought to determine whether PXR is expressed in rodent LCs and whether pregnenolone 16-alpha carbonitrile (PCN), the prototype agonist of rodent PXR, regulates T biosynthesis in rodent LCs. Hormonal as well as protein and gene expression analyses were conducted in rat primary LCs and MA-10 mouse Leydig cells. Results showed that PXR was expressed at the mRNA and protein level in both rat primary LCs and MA-10 cells. Incubation of rat primary LCs with PCN resulted in a significant decrease in T secretion. This PCN-induced decrease in T secretion was associated with decreased protein expression of key steroidogenic enzymes such as 3β-HSD and CYP17A1. RNA-seq results from MA-10 cells showed that PCN down-regulated the transcripts of steroidogenic enzymes and proteins involved in the T synthesis pathway. Together, these results suggest that PCN, an agonist of rodent PXR, can regulate T biosynthesis in rodent LCs by down-regulating the expression of the steroidogenic enzymes involved in T biosynthesis. Our results are significant as they provide a potential novel mechanism for disruption of testosterone homeostasis by a variety of xenobiotics. Full article

Presently, a major challenge is the search for new compounds that may exhibit an inhibitory effect on tumor progression. Recently, the 4-thiazolidinone (4-TZD) group has gained attention in this research field. The aim of the present study was to evaluate the anticancer effects of two new 4-TZD-based derivatives (Z)-5-[5-(2-hydroxyphenyl)- (Les- 4368) and (Z)-5-[5-(4-dimethylaminophenyl)-3-phenyl-4,5-dihydropyrazol-1-ylmethylene]-3-(3-acetoxyphenyl)-2-thioxothiazolidin-4-ones (Les-4370) on peroxisome proliferator-activated receptor gamma (PPARγ)-dependent cytotoxicity in human colorectal adenocarcinoma cells (CACO-2) and in normal human fibroblasts (BJ) in vitro. Les-4368 and Les-4370 exerted a toxic effect on both tested cell lines in high (micromolar) concentrations (10–100 µM). In addition, Les-4368 and Les-4370 applied in the BJ and CACO-2 cells in the concentration range of 10 µM to 100 µM increased the activity of caspase-3 and the production of reactive oxygen species (ROSs). The mRNA expression of PPARγ-related genes (PPARγ, AhR, PXR, and NF-κB) showed certain changes in these parameters, proving the engagement of this receptor in the induction of the biological effects of both tested 4-TZD derivatives. Moreover, the treatment of the BJ and CACO-2 cells with Les-4368, Les-4370, an antagonist (GW9662), or an agonist (rosiglitazone) of the PPARγ receptor also resulted in changes in the above-mentioned parameters. Unfortunately, the tested substances studied cell line work in a non-selective way at a relatively high concentration, which reduces their potential for clinical application. Our research is the preliminary study with the use of these compounds and requires further studies to elucidate the mechanisms of action of their anticancer potential. Full article

5β-Dihydrosteroids are produced by the reduction of Δ⁴-3-ketosteroids catalyzed by steroid 5β-reductase (AKR1D1). By analogy with steroid 5α-reductase, genetic deficiency exists in AKR1D1 which leads to errors in newborn metabolism and in this case to bile acid deficiency. Also, like the 5α-dihydrosteroids (e.g., 5α-dihydrotestosterone), the 5β-dihydrosteroids produced by AKR1D1 are not inactive but regulate ligand access to nuclear receptors, can act as ligands for nuclear and membrane-bound receptors, and regulate ion-channel opening. For example, 5β-reduction of cortisol and cortisone yields the corresponding 5β-dihydroglucocorticoids which are inactive on the glucocorticoid receptor (GR) and provides an additional mechanism of pre-receptor regulation of ligands for the GR in liver cells. By contrast, 5β-pregnanes can act as neuroactive steroids at the GABA_A and NMDA receptors and at low-voltage-activated calcium channels, act as tocolytic agents, have analgesic activity and act as ligands for PXR, while bile acids act as ligands for FXR and thereby control cholesterol homeostasis. The 5β-androstanes also have potent vasodilatory properties and work through blockade of Ca²⁺ channels. Thus, a preference for 5β-dihydrosteroids to work at the membrane level exists via a variety of mechanisms. This article reviews the field and identifies gaps in knowledge to be addressed in future research. Full article

Despite their significant impact, comprehensive screenings and detailed analyses of per- and polyfluoroalkyl substance (PFAS) binding strengths at the orthosteric and allosteric sites of NRs are currently lacking. This study addresses this gap by focusing on the binding interaction analysis of both common and uncommon PFAS with the nuclear receptors (NRs) vitamin D receptor (VDR), peroxisome proliferator-activated receptor gamma (PPARγ), pregnane X receptor (PXR), and estrogen receptor alpha (ERα). Advanced docking simulations were used to screen 9507 PFAS chemicals at the orthosteric and allosteric sites of PPARγ, PXR, VDR, and ERα. All receptors exhibited strong binding interactions at the orthosteric and allosteric site with a significant number of PFAS. We verified the accuracy of the docking protocol through multiple docking controls and validations. A mixture modeling analysis indicates that PFAS can bind in various combinations with themselves and endogenous ligands simultaneously, to disrupt the endocrine system and cause carcinogenic responses. These findings reveal that PFAS can interfere with nuclear receptor activity by displacing endogenous or native ligands by binding to the orthosteric and allosteric sites. The purpose of this study is to explore the mechanisms through which PFAS exert their endocrine-disrupting effects, potentially leading to more targeted therapeutic strategies. Importantly, this study is the first to explore the binding of PFAS at allosteric sites and to model PFAS mixtures at nuclear receptors. Given the high concentration and persistence of PFAS in humans, this study further emphasizes the urgent need for further research into the carcinogenic mechanisms of PFAS and the development of therapeutic strategies that target nuclear receptors. Full article