Search Results (164)

Gut microbiota regulate the intestinal expression of drug-metabolizing enzymes, transporters, and barrier properties that determine oral drug absorption and disposition. This study compares germ-free Swiss Webster mice to mice colonized with fecal microbiota from a single human donor, evaluating microbiota-driven differences in colonic gene expression and P-gp protein expression, as well as small intestinal mucosal permeability. Transcriptomic analysis of colonic tissue revealed microbiota-induced upregulation of genes encoding P-gp and other drug transporters, including MCT1 and OCTN2. Immunofluorescence also indicated greater P-gp expression and apical localization in colonized mice. Gene expression of drug-metabolizing enzymes was also higher in colonized mice, including phase I enzymes (carboxylesterase 2 paralogs), phase II enzymes (UDP-glucuronosyltransferases and glutathione S-transferases), and enzymes responsible for synthesizing their co-substrates, UDP-glucuronic acid and glutathione. Small intestinal mucosal explants demonstrated lower permeability to ¹⁴C-labeled polyethylene glycol 4000 in colonized mice compared to germ-free mice. In the colon, transcriptomic analysis identified microbiota-dependent changes in genes regulating paracellular tight junctions and actomyosin contractility. These results show that human-derived gut microbiota alter gene expression in the mouse colon, identifying candidate microbiota-responsive genes relevant to oral drug absorption and disposition. Full article

UDP-glucuronosyltransferases (UGTs) are a key family of phase II metabolic enzymes in humans that play a central role in maintenance of metabolic homeostasis and drug disposition by catalyzing glucuronidation of endogenous and exogenous substances. UGT-mediated metabolism of antitumor drugs plays a dual role in tumor drug resistance, emerging as a hotspot in cancer therapy. This review outlines the structural characteristics, classification system, tissue distribution, and multilevel regulation of UGTs, with a focus on their bidirectional roles in tumor drug resistance, i.e., promotion of resistance through metabolic clearance and inhibition of resistance through metabolic activation. This review also discusses strategies of multidimensional tumor resistance intervention based on UGTs, and we also discussed the challenges in the clinical translation of current UGT-targeting strategies. To date, most data on UGTs were derived from in vitro and preclinical models; clinical validation remains limited, and the dual roles of UGTs are highly context-dependent. This review article provides a perspective for comprehensive understanding of UGT-mediated tumor resistance and offers theoretical foundations and practical directions for development of novel antitumor strategies. Full article

Uridine diphosphate glucuronosyltransferase 2B (UGT2B) enzymes constitute a critical subgroup of phase II metabolizing enzymes that modulate the clearance of steroid hormones, carcinogens, and numerous anticancer agents, thereby influencing cancer susceptibility, progression, and therapeutic outcomes. This review provides a comprehensive synthesis of the genetic, regulatory, and functional roles of UGT2B family members, particularly UGT2B4, UGT2B7, UGT2B10, UGT2B15, UGT2B17, and UGT2B28, in oncogenesis and cancer treatment. We summarize evidence from molecular, epidemiological, pharmacogenetic, and clinical studies demonstrating how UGT2B expression patterns, polymorphisms, copy number variations, epigenetic regulation, and microRNA-mediated control shape intratumoral hormone homeostasis, carcinogen detoxification, and drug resistance across multiple malignancies, including prostate, breast, lung, colorectal, hematological, and hormone-dependent cancers. UGT2B enzymes metabolize several widely used anticancer drugs and active metabolites, thereby affecting pharmacokinetics, efficacy, and toxicity. Understanding the context-specific roles of UGT2B family members offers a compelling opportunity for therapeutic exploitation. In particular, rational combination strategies incorporating UGT2B inhibitors or modulators alongside standard anticancer agents may enhance drug effectiveness without increasing dosage, while simultaneously enabling the dose reduction of the partner agent to mitigate dose-dependent toxicities. Such approaches are especially relevant for therapies with narrow therapeutic indices. Overall, this review highlights UGT2B enzymes as multifunctional determinants of cancer risk and treatment response and underscores their promise as biomarkers and actionable targets for precision oncology and optimized combination regimens. Full article

Background/Objectives: Fraxetin (7,8-dihydroxy-6-methoxycoumarin), a coumarin constituent of Cortex Fraxini (Qinpi) used in traditional Chinese medicine, is metabolised mainly by UGT1A9, but its potential to inhibit UGT enzymes and cause herb–drug interactions (HDIs) is largely unstudied. Methods: Fraxetin and four related coumarins were screened against 11 recombinant human UGTs; isoforms inhibited ≥80% underwent full kinetic analysis with 4-methylumbelliferone as probe. Binding was examined by molecular docking on AlphaFold structures with PLIP, triplicate 100 ns molecular dynamics, and MM/GBSA and MM/PBSA free-energy calculations, and interaction risk by FDA 2020 in vitro–in vivo extrapolation (IVIVE). Results: Fraxetin alone inhibited both UGT1A1 and UGT1A9 by >80% and was characterised in detail, acting as a mainly competitive mixed-type inhibitor (UGT1A1 IC₅₀ 15.99 μM, K_i 8.32 μM; UGT1A9 IC₅₀ 8.44 μM, K_i 5.90 μM). A structure–activity comparison identified a dual-element pharmacophore comprising the C-6 methoxy group and the 7,8-dihydroxycoumarin aglycone. MM/GBSA favoured UGT1A9 over UGT1A1 (ΔΔG = −4.06 kcal/mol, p = 0.005), concordant with the kinetic ranking. IVIVE predicted a borderline systemic signal (R₁ > 1.02) but an intestinal R_1,gut approximately five- to seven-fold above the high-risk threshold of 11 after capping the luminal concentration at fraxetin aqueous solubility. Conclusions: This is the first characterisation of fraxetin as a moderate-potency inhibitor of UGT1A1 and UGT1A9 and points to a previously under-recognised herb–drug interaction risk concentrated in the intestinal lumen rather than systemically; the finding constitutes an interaction signal requiring clinical confirmation rather than an established risk. Full article

Oxytetracycline (OTC) is widely used in aquaculture to treat bacterial diseases, but its effects on drug metabolism and immune responses remain poorly understood in olive flounder (Paralichthys olivaceus). This study investigated the effects of OTC immersion for 1 h at different concentrations on the expression profile of drug metabolism- and immune-related genes and the histopathological changes in the gills and liver of olive flounder. The expression of Paralichthys olivaceus cytochrome P450 (PoCYP), Paralichthys olivaceus diphosphate (UDP)-glucuronosyltransferases (PoUGTs), and immune-related genes significantly increased at 12 and 24 h and then decreased at 72 h in the 100 and 200 ppm groups. By contrast, the 400 ppm group exhibited variable expression patterns depending on the gene and tissue. The highest expression levels were observed for PoIL-1β in the gills (22.7-fold) and PoCYP27B1 in the liver (58.0-fold) in the 400 ppm group. Histopathological analysis revealed macrophage activation in the liver at 72 h in the 200 ppm group, whereas epithelial edema and mild aneurysmal changes in the gills and macrophage activation in the liver were observed in the 400 ppm group. These findings provide insights into the effects of OTC exposure on drug metabolism and immune responses in olive flounder. Full article

Background: Glucuronidation is a major phase II biotransformation reaction responsible for the inactivation and elimination of endogenous compounds and pharmaceuticals. This process is catalyzed by enzymes belonging to the UDP-glucuronosyltransferase (UGT) family, among which UGT1A1 is the most extensively studied. UGT1A1 plays a critical role in the metabolism of numerous drugs and is essential for bilirubin glucuronidation. Due to this specific function, it has significant clinical relevance, as impaired enzyme activity resulting from genetic polymorphisms or mutations can lead to the accumulation of unconjugated bilirubin in the bloodstream. This study aimed to evaluate the association between the UGT1A1*28 allele and the gene expression and protein levels in human liver tissue, in relation to different liver diseases. Methods: Liver tissues were obtained from patients with various liver pathologies and the control group consisted of tissues showing no pathological symptoms. A total of 143 patients were included in the study. Pyrosequencing was used to analyze PCR products for the UGT1A1*28 polymorphism (variable number of TA repeats in the TATA sequence of the promoter). Results: In both the control and study groups, UGT1A1 gene expression at the mRNA level and protein concentration in liver tissue decreased with the increasing number of UGT1A1*28 alleles. The association between UGT1A1 genotype and mRNA/protein content was most pronounced in HCV and AIH, and slightly weaker in the ALK and PBC groups. The significant association between UGT1A1*28 allele and bilirubin concentration was observed in control group but not in liver pathology. Conclusions: The UGT1A1*28 polymorphism is associated with reduced hepatic mRNA and protein abundance in patients with liver disease. However, the significance of this observation for the metabolism of the enzyme substrates should be further investigated. Full article

Uridine diphosphate glucuronosyltransferases (UGTs) are critical phase II detoxification enzymes; however, their mutational landscape and protective roles against chemical carcinogenesis in hepatocellular carcinoma (HCC) remain poorly defined. Here, targeted sequencing of ten liver-enriched UGT genes in 38 paired tissues from a Chinese HCC cohort revealed striking mutation frequencies in UGT2B15 (44.74%), UGT2B10 (36.84%), and UGT2B17 (26.32%). This genomic instability was accompanied by a profound downregulation of UGT2B15 mRNA (9.02-fold decrease, p < 0.001) and protein levels (Z-score = 2.32, p = 0.0093) in tumors, with higher UGT2B15 expression correlating with improved overall survival in TCGA cohorts (HR = 1.724, p = 0.012). Mechanistically, we identified the androgen receptor (AR) as a direct transcriptional regulator of UGT2B15 and UGT2B17, with dihydrotestosterone (DHT) inducing dose-dependent increases in their expression, thereby linking endocrine signaling to hepatic detoxification. Transcriptomic profiling following UGT2B15 knockdown in HCC cells revealed a significant enrichment in chemical carcinogenesis-related pathways. Crucially, UGT2B15 deficiency severely exacerbated carbon tetrachloride (CCl₄)- and ethanol-induced hepatotoxicity both in vitro and in vivo. Our study uncovers a profound impairment of UGT-mediated detoxification in HCC and establishes the AR–UGT2B15 axis as a critical barrier against chemical-induced liver injury, highlighting its potential as a chemopreventive target in carcinogen-exposed populations. Full article

Background/Objectives: Many chronic diseases, including cancer, can be developed in conjunction with excessive intracellular oxidative stress and persistent inflammation. The importance of preventive strategies is highlighted by the potential of phytochemical interventions to mitigate these diseases. The purpose of this study was to investigate how Citrus depressa leaf (CDL) extracts can prevent 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced carcinogenesis in JB6 P+ mouse skin epidermal cells. Methods: CDL extracts were prepared and characterized for their phenolic and flavonoid contents. Effects of the potent extract on cell viability, TPA-induced colony formation, intracellular reactive oxygen species (ROS) levels, and nuclear factor erythroid 2–related factor 2 (Nrf2)-related protein and mRNA expression, mediated by epigenetic modifications, were evaluated in JB6 P+ cells. Results: Both the water extract (CDL-WE) and the 95% ethanol extract (CDL-95EE) contain abundant flavonoids that inhibit TPA-induced cell transformation and colony formation without minimal cytotoxicity. Mechanistic studies indicated that CDL-95EE increased the gene expression of Nrf2-related detoxification and antioxidant enzymes, such as UDP-glucuronosyltransferase 1A (UGT1A) and heme oxygenase-1 (HO-1), and decreased intracellular ROS accumulation. Furthermore, CDL-95EE reduced the expression of epigenetic modifiers, including DNA methyltransferases (DNMTs) and histone deacetylases (HDACs), suggesting involvement in epigenetic regulation. Conclusions: These findings indicate that CDL, an agricultural by-product, may be useful in cancer prevention through antioxidant and epigenetic mechanisms. Full article

Background: Tamoxifen is widely used in the treatment of hormone receptor-positive breast cancer and has been shown to successfully reduce recurrence and mortality rates. Nonetheless, variability in patient response to tamoxifen treatment is observed with up to 40% of patients experiencing recurrence. Genetic polymorphisms in pharmacogenes encoding enzymes involved in tamoxifen metabolism have been linked to some of this observed interindividual variability. The pharmacogenetics of tamoxifen in populations of African descent remain understudied, creating difficulties in pinpointing the primary factors behind the observed variable response. To address this gap, this study aimed to investigate the role of genetic variation in tamoxifen treatment outcomes in a South African cohort. Methods: Participants included 166 Mixed and African Ancestry breast cancer patients who had received tamoxifen treatment. Genetic characterization was performed for 53 single nucleotide polymorphisms (SNPs) and two copy number variations across eight drug-metabolizing enzymes, including cytochrome P450s (CYP2D6, CYP3A4, CYP3A5, CYP2B6), UDP-glucuronosyltransferases (UGT1A4), and sulfotransferases (SULT1A1, SULT1E1, SULT2A1). The association between genotypes and disease-free survival (DFS) was evaluated using Cox proportional hazards regression models. Results: The CYP2B6*1/*6 or *4/*9 genotype showed a nominal association with improved DFS (p = 0.049), with a similar trend observed for UGT1A4 rs11888492. In contrast, SULT1E1 rs3775779 heterozygosity showed a nominal association with reduced DFS (p = 0.044). SULT1A1 SNPs (rs4149393, rs4149394, rs1042157) demonstrated trends toward reduced DFS. Conclusions: These exploratory findings highlight the need for more inclusive pharmacogenomic research and point to potential biomarkers for optimizing tamoxifen therapy in African populations. Full article

Background/Objectives: Eudesmin is a tetrahydrofurofuranoid lignan known for its diverse pharmacological activities, including anti-tumor, anti-inflammatory, and neuroprotective effects. However, its metabolism has not been well characterized. Methods: This study examined the in vitro metabolism of eudesmin using human and mouse hepatocytes, human liver microsomes, and recombinant drug-metabolizing enzymes. Liquid chromatography–high-resolution mass spectrometry combined with ion identity molecular networking enabled the comprehensive visualization and annotation of eudesmin metabolites. Results: Eudesmin exhibited moderate metabolic stability in human and mouse hepatocytes, with half-lives of 181.0 min and 132.9 min, and intrinsic clearance values of 27.7 mL/min/kg and 154.0 mL/min/kg, respectively. Incubation of eudesmin with human hepatocytes resulted in the formation of 13 metabolites, including five phase I metabolites (M1–M5) and eight phase II conjugates. Phase I metabolism was dominated by O-demethylation of the 3,4-dimethoxyphenyl moieties, yielding mono-O-demethylated (M1 and M2) and di-O-demethylated metabolites (M3 and M4), as well as a hydroxylated metabolite (M5). Enzyme phenotyping, kinetic analyses, and chemical inhibition experiments identified cytochrome P450 2C9 (CYP2C9) as the major contributor to O-demethylation, with additional contributions from CYP2C19, CYP2C8, CYP3A4, and CYP3A5, whereas hydroxylation was mediated primarily by CYP3A4 and CYP3A5. The O-demethylated metabolites subsequently underwent phase II metabolism, forming glucuronide conjugates of M1–M4 and sulfate conjugates of M1–M3, including a disulfate of M3. Uridine 5′-diphospho-glucuronosyltransferase and sulfotransferase screening revealed the involvement of multiple conjugative enzymes, indicating extensive and distributed phase II metabolism. Specifically, di-O-demethylated metabolites and their conjugates were detected in human hepatocytes but not in mouse hepatocytes, suggesting that the sequential O-demethylation pathway is limited in mice. Conclusions: This study characterizes eudesmin metabolism, with CYP2C9-mediated O-demethylation and significant species differences between humans and mice, and provides a basis for its further pharmaceutical development. Full article

Background/Objectives: Macrophages polarized into M1 and M2 phenotypes differentially regulate immune and drug responses. Despite their distinct functional roles, differences in UDP-glucuronosyltransferase (UGT) expression and enzymatic activity between M1 and M2 macrophages remain poorly understood. This study aimed to characterize differential UGT expression in M1 and M2 macrophages and to elucidate how UGT-mediated prostaglandin E₂ (PGE₂) glucuronidation modulates macrophage inflammatory responses. Methods: THP-1 cells were chemically differentiated into macrophages (M0) and subsequently polarized into M1 and M2 phenotypes. UGT expression profiles were assessed using RT-PCR, quantitative RT-PCR (qRT-PCR), and Western blot. UGT activity was compared by quantifying glucuronide metabolites derived from UGT-specific substrates using LC-MS/MS, along with measurement of free PGE₂ and PGE₂-glucuronide by ELISA. Pro-inflammatory cytokine expression and secretion in M1 macrophages were quantified using qRT-PCR and ELISA. Results: Expression of UGT1A1, UGT1A4, UGT1A5, UGT1A9, and UGT2B7 were markedly higher in M1 compared with M2 macrophages at both the mRNA and protein levels. Enhanced UGT activity in M1 macrophages was reflected by increased formation of estradiol-3-glucuronide and naloxone-3-glucuronide (both p < 0.01) and was attenuated in a concentration-dependent manner by diclofenac. Furthermore, PGE₂ glucuronidation was more pronounced in M1 macrophages, and inhibition of UGTs with atazanavir reduced PGE₂-glucuronide formation and pro-inflammatory cytokine production, including IL-1β, IL-6, and TNF-α. Conclusion: UGT-mediated PGE₂ glucuronidation in M1 macrophages contributes to the regulation of pro-inflammatory cytokine production. Collectively, these findings support a role for UGTs as modulators of inflammatory signaling, with differential expression and activity between M1 and M2 macrophages. Full article

Background: Tamoxifen remains the cornerstone of endocrine therapy for hormone receptor-positive breast cancer across Africa. Understanding the factors that influence tamoxifen tolerability is critical, as treatment-related side effects can reduce adherence and compromise therapeutic outcomes. Yet, the contribution of pharmacogenetic variation to tamoxifen-related toxicity remains poorly characterized in African populations. This study, therefore, investigated whether genetic variation in key pharmacogenes influences the risk of treatment-related side effects in a South African breast cancer cohort. Methods: A total of 166 women of Mixed and African Ancestry treated with 20 mg/day tamoxifen at Groote Schuur Hospital, South Africa, were included in the study. Genetic variation across 28 variants in nine pharmacogenes, including CYP2D6, CYP3A4/5, UGT1A4, UGT2B7/15, SULT1A1/2, and SULT1E1, was assessed using various genotyping methods. Associations between genetic and non-genetic factors and tamoxifen side effects were evaluated with logistic regression. Results: Over 70% of participants reported at least one treatment-related side effect. Overall side-effect burden was associated with SULT1A1 copy number variation (p = 0.030) and SULT1E1 rs3736599 (p = 0.042). Musculoskeletal complaints were the most common (40%) and were associated with UGT2B7 rs7439366 (p = 0.040) and CYP3A4 rs2242480 (p = 0.051). Gynecological symptoms affected more than 20% of participants and were linked to SULT1A2*2 (p = 0.050), SULT1E1 rs3736599 (p = 0.016), and UGT2B15 rs4148269 (p = 0.039). Hot flashes were frequent, affecting 33% of patients, but showed no clear pharmacogenetic associations. Conclusions: This study demonstrates that pharmacogenetic variation is associated with interindividual differences in treatment-related side effects, underscoring the need to expand research in African populations to better inform precision endocrine therapy. Full article

Background and Objective: Male individuals diagnosed with metabolic dysfunction-associated steatotic liver disease (MASLD) frequently present with decreased blood testosterone concentrations concomitant with increased levels of hepatic cholesterol, the fundamental substrate for testosterone synthesis; however, the mechanistic relationship between these phenomena remains inadequately elucidated. This study aimed to examine the involvement of hepatic cholesterol biosynthesis and testosterone metabolism in the pathogenesis of MASLD. Methods: An MASLD model was established in male C57BL/6J mice subjected to a high-fat diet (HFD). Comprehensive analyses, including hepatic transcriptomics, metabolomics, enzyme-linked immunosorbent assay, Western blotting, and quantitative polymerase chain reaction, were conducted. Additionally, in vitro experiments were performed using AML-12 hepatocytes treated with oleic acid and testosterone, with or without the presence of a uridine diphosphate-glucuronosyltransferase family 2 member B (UGT2B) enzyme inhibitor. Results: The HFD elevated cholesterol levels and activated cholesterol synthesis and testosterone metabolic pathways, notably characterized by upregulation of UGT2B enzymes and their transcriptional regulator, the aryl hydrocarbon receptor (AHR). Blood testosterone increased initially but decreased after 24 weeks of HFD. In vitro, testosterone alone did not affect oleic acid-induced lipid accumulation, but inhibiting UGT2B enabled testosterone levels to reduce lipid deposition and downregulate lipid uptake and synthesis pathways. Conclusions: The HFD induces dynamic, UGT2B-mediated hepatic testosterone metabolism. Compensatory early testosterone increase is offset by enhanced UGT2B-mediated clearance, resulting in eventual testosterone depletion and the loss of its protective effects against hepatic lipid accumulation. This explains the clinical paradox and suggests targeting the hepatic UGT2B enzymes as a potential MASLD treatment. Full article

Drug- and alcohol-induced liver injury involves impaired bile acids or bilirubin secretion, but it is not known how senescence influences the secretion of hepatocytes exposed to drugs and alcohol. In this study, the toxic effects of ritonavir, lopinavir, and alcohol on hepatocyte transporters and the secretion of bile acids and bilirubin were investigated in hydrogen peroxide-induced senescent HepG2 and doxorubicin-induced senescent primary human hepatocytes. In HepG2, intracellular conjugated bilirubin increased upon senescence and extracellular conjugated bilirubin in culture medium was decreased by ritonavir and lopinavir treatment. In the primary hepatocytes, intracellular bile acids or medium bilirubin were not significantly changed upon senescence. However, intracellular bile acids were increased, and medium conjugated bilirubin were decreased in senescent primary hepatocytes treated with alcohol and the two drugs. Transcriptional expressions of adenosine triphosphate (ATP)-binding cassette (ABC) transporters (ABCB4, ABCC6, ABCB11, and ABCD3) were decreased whereas UDP-glucuronosyltransferase (UGT1A1) was increased by ritonavir and lopinavir in senescent HepG2. In senescent primary hepatocytes, expressions of ABCB11, ABCC1, ABCC2, ABCC3, ABCC4, and ABCC6 were apparently reduced whereas UGT1A1 and the cytochrome P450 enzyme CYP7A1 were markedly increased by alcohol combined with ritonavir and lopinavir. Selective ABCC6 knockdown in the primary hepatocytes altered expressions of two senescence markers, Lamin A/C and cyclin-dependent kinase inhibitor CKI (p21), increased expressions of CYP7A1 and hydroxy methyl glutaryl-CoA reductase (HMGCR), and increased intracellular bile acids. Further, anti-cholestasis agents, ursodeoxycholic acid and glycyrrhizin, significantly ameliorated the impaired secretions of bile acids and bilirubin as well as reducing intracellular lipid accumulation and cell death caused by ritonavir, lopinavir, and alcohol in the primary hepatocytes with ABCC6 knockdown. These results indicate that senescence moderately impairs the ABC transporters of hepatocytes and secretion of bile acids or bilirubin, which become worse in the presence of the drugs and alcohol but could be improved by anti-cholestasis agents. Full article

Introduction: Opioids are the most commonly used analgesic drugs for acute and chronic severe pain and are metabolized in the liver via cytochrome P450 (CYP) enzymes and UDP-glucuronosyltransferases (UGTs). Methods: A narrative review of the literature was conducted by searching the PubMed database up to December 2025, with English as the only language restriction. Relevant studies were identified using the keywords “opioids,” “pharmacogenetic,” “cytochrome mutations,” and “interactions.” Results: Polymorphisms in CYP2D6 and CYP3A4 genes can affect the pharmacokinetics, clinical effect, and safety of opioids. Furthermore, enzyme induction and inhibition by concomitant drugs or compounds (herbal products or food) are sources of variability factors in drug response that may be predictable. Conclusions: This review article summarizes current evidence on the role of pharmacogenetics and opioid-related interactions, offering a framework to better understand interindividual variability in opioid response and to inform future multimodal approaches. Full article