Regulation of UGT2B Expression and Activity by miR-216b-5p in Liver Cancer Cell Lines

Novel Approaches to Characterize Individual Drug Metabolism and Advance Precision Medicine

Interindividual variability in drug metabolism can significantly affect drug concentrations in the body and subsequent drug response. Understanding an individual's drug metabolism capacity is important for predicting drug exposure and developing precision medicine strategies. The goal of precision medicine is to individualize drug treatment for patients to maximize efficacy and minimize drug toxicity. While advances in pharmacogenomics have improved our understanding of how genetic variations in drug-metabolizing enzymes (DMEs) affect drug response, nongenetic factors are also known to influence drug metabolism phenotypes. This minireview discusses approaches beyond pharmacogenetic testing to phenotype DMEs-particularly the cytochrome P450 enzymes-in clinical settings. Several phenotyping approaches have been proposed: traditional approaches include phenotyping with exogenous probe substrates and the use of endogenous biomarkers; newer approaches include evaluating circulating noncoding RNAs and liquid biopsy-derived markers relevant to DME expression and function. The goals of this minireview are to 1) provide a high-level overview of traditional and novel approaches to phenotype individual drug metabolism capacity, 2) describe how these approaches are being applied or can be applied to pharmacokinetic studies, and 3) discuss perspectives on future opportunities to advance precision medicine in diverse populations. SIGNIFICANCE STATEMENT: This minireview provides an overview of recent advances in approaches to characterize individual drug metabolism phenotypes in clinical settings. It highlights the integration of existing pharmacokinetic biomarkers with novel approaches; also discussed are current challenges and existing knowledge gaps. The article concludes with perspectives on the future deployment of a liquid biopsy-informed physiologically based pharmacokinetic strategy for patient characterization and precision dosing.

Biochemical and genetic biomarkers associated with nicotine dependence in Mexican smokers

Cigarette smoking remains an important health concern and is still a leading cause of preventable mortality. Nicotine is the substance responsible for sustained tobacco use and dependence. Identification of biomarkers underlying nicotine dependence behavior is important to identify people at risk for this dependence. In the present study, we identified biochemical and genetic biomarkers of nicotine dependence detected by the Fagerström Test for Nicotine Dependence (FTDN) in Mexican smokers. The nicotine metabolites nicotine-N'-oxide, trans-3'-hydroxycotinine-glucuronide (3HC-O-Gluc), and nicotine-N-Gluc (Gluc) were useful to differentiate nicotine-dependent from non-dependent subjects (p < .0001) with an area under the curve (AUC) of 0.7818. Genetic variants in CYP2A6, FMO3, and UGT2B7 (rs2431413, rs28363545, and rs7439326, respectively) were associated with nicotine dependence (p = .03, p = .01, p = .01, respectively). Variations in the enzymatic activity of CYP2A6 were associated with altered nicotine-N'-oxide and 3HC-O-Gluc levels. Decreased urinary levels of 3HC-O-Gluc and increased nicotine-N'-oxide were associated with a decrease in the functional activity of CYP2A6. A strong positive correlation was observed between the ratio of urinary 3HC/cotinine, a measure of CYP2A6 activity, and the levels of 3HC-O-Gluc (p < .0001, r = .6835), while a strong negative correlation was observed with nicotine-N'-oxide (p < .0001, r = .6522) in nicotine-dependent subjects. No correlations were observed in non-nicotine-dependent subjects. These data suggest that particular urinary nicotine metabolites and genetic variants involved in nicotine metabolism are useful to identify subjects with nicotine dependence in the Mexican population.

The Uridine diphosphate (UDP)-glycosyltransferases (UGTs) superfamily: the role in tumor cell metabolism

UDP-glycosyltransferases (UGTs), important enzymes in biotransformation, control the levels and distribution of numerous endogenous signaling molecules and the metabolism of a wide range of endogenous and exogenous chemicals. The UGT superfamily in mammals consists of the UGT1, UGT2, UGT3, and UGT8 families. UGTs are rate-limiting enzymes in the glucuronate pathway, and in tumors, they are either overexpressed or underexpressed. Alterations in their metabolism can affect gluconeogenesis and lipid metabolism pathways, leading to alterations in tumor cell metabolism, which affect cancer development and prognosis. Glucuronidation is the most common mammalian conjugation pathway. Most of its reactions are mainly catalyzed by UGT1A, UGT2A and UGT2B. The body excretes UGT-bound small lipophilic molecules through the bile, urine, or feces. UGTs conjugate a variety of tiny lipophilic molecules to sugars, such as galactose, xylose, acetylglucosamine, glucuronic acid, and glucose, thereby inactivating and making water-soluble substrates, such as carcinogens, medicines, steroids, lipids, fatty acids, and bile acids. This review summarizes the roles of members of the four UGT enzyme families in tumor function, metabolism, and multiple regulatory mechanisms, and its Inhibitors and inducers. The function of UGTs in lipid metabolism, drug metabolism, and hormone metabolism in tumor cells are among the most important topics covered.

Epigenetics in drug disposition & drug therapy: symposium report of the 24th North American meeting of the International Society for the Study of Xenobiotics (ISSX)

The 24th North American International Society for the Study of Xenobiotics (ISSX) meeting, held virtually from September 13 to 17, 2021, embraced the theme of "Broadening Our Horizons." This reinforces a key mission of ISSX: striving to share innovative science related to drug discovery and development. Session speakers and the ISSX New Investigators Group, which supports the scientific and professional development of student and early career ISSX members, elected to highlight the scientific content presented during the captivating session titled, "Epigenetics in Drug Disposition & Drug Therapy." The impact genetic variation has on drug response is well established; however, this session underscored the importance of investigating the role of epigenetics in drug disposition and drug discovery. Session speakers, Drs. Ning, McClay, and Lazarus, detailed mechanisms by which epigenetic players including long non-coding RNA (lncRNAs), microRNA (miRNAs), DNA methylation, and histone acetylation can alter the expression of genes involved in pharmacokinetics, pharmacodynamics, and toxicity. Dr. Ning detailed current knowledge about miRNAs and lncRNAs and the mechanisms by which they can affect the expression of drug metabolizing enzymes (DMEs) and nuclear receptors. Dr. Lazarus discussed the potential role of miRNAs on UDP-glucuronosyltransferase (UGT) expression and activity. Dr. McClay provided evidence that aging alters methylation and acetylation of DMEs in the liver, affecting gene expression and activity. These topics, compiled by the symposium organizers, presenters, and the ISSX New Investigators Group, are herein discussed, along with exciting future perspectives for epigenetics in drug disposition and drug discovery research.

The miR-216/miR-217 Cluster Regulates Lipid Metabolism in Laying Hens With Fatty Liver Syndrome via PPAR/SREBP Signaling Pathway

Fatty liver syndrome (FLS), a common metabolic disease in laying hens, caused by excessive hepatic fat deposition is a bottleneck in the poultry industry. However, no specific therapeutic methods have been developed. Evidence suggests that microRNAs (miRNAs) are essential for liver lipid metabolism and homeostasis, providing strong evidence for targeting miRNAs as a potential treatment option for liver diseases. However, the roles of miRNAs in the pathogenesis of FLS remain unclear. In present study, RNA-sequencing was performed to discern the expression patterns of miRNAs in normal and fatty livers of laying hens. In total, 12 dysregulated miRNAs (2 down-regulated and 10 up-regulated) were detected between the normal and fatty livers. Functional enrichment analysis showed the potential impacts of the dysregulated miRNAs on lipid metabolism. Notably, miR-216a/b and miR-217-5p, which belong to the miR-216/miR-217 cluster, were up-regulated in the sera and livers of FLS chickens, as well as free fatty acid (FFA)-induced LMH cells. Oil-red O staining revealed that up-regulation of the miR-216/miR-217 cluster induced lipid accumulation in FFA-induced LMH cells. Furthermore, the dual luciferase gene reporter assay and RT-qPCR analysis demonstrated that 3-hydroxyacyl-CoA dehydratase 2, F-box protein 8, and transmembrane 9 superfamily member 3 (TM9SF3) were directly targeted by miR-216a/b and miR-217-5p, respectively, and suppressed in the fatty livers of laying hens. Moreover, overexpression of the miR-216/miR-217 cluster or reduction in TM9SF3 levels led to activation of the proliferator-activated receptor/sterol regulatory-element binding protein (PPAR/SREBP) pathway. Overall, these results demonstrate that the miR-216/miR-217 cluster regulates lipid metabolism in laying hens with FLS, which should prove helpful in the development of new interventional strategies.

LINC01578 affects the radiation resistance of lung cancer cells through regulating microRNA-216b-5p/TBL1XR1 axis

Radiation resistance largely limits the survival of patients with non-small-cell lung cancer (NSCLC). To understand the mechanism underlying radiation resistance, we explored the influence of LINC01578 in radiation-resistant NSCLC cells. LINC01578, miR-216b-5p and Transducin (beta)-like 1 X-linked receptor 1 (TBL1XR1) expression was evaluated in patients with NSCLC, and their correlation with patients' prognosis was examined. Radiation-resistant NSCLC cell line (A549-RR) was induced and treated with oligonucleotide or plasmid transfection, and cell biological functions were captured. The interplay between LINC01578, miR-216b-5p and TBL1XR1 was clarified. NSCLC patients showed high LINC01578 and TBL1XR1 expression, and low miR-216b-5p expression, which was correlated to shorter patients' prognosis, respectively. LINC01578 or TBL1XR1 deficiency or miR-216b-5p elevation suppressed the functional activities of A549-RR cells. LINC01578 suppression elevated miR-216b-5p expression, consequently leading to the down-regulation of TBL1XR1. miR-216b-5p silencing or TBL1XR1 overexpression compromised LINC01578 knockdown's effects on radiation resistance of A549-RR cells. In brief, LINC01578 suppresses miR-216b-5p and enhances TBL1XR1 expression, thus to promote biological functions of radiation-resistant NSCLC cells.

Regulation of human UDP-glycosyltransferase (UGT) genes by miRNAs

The human UGT gene superfamily is divided into four subfamilies (UGT1, UGT2, UGT3 and UGT8) that encodes 22 functional enzymes. UGTs are critical for the metabolism and clearance of numerous endogenous and exogenous compounds, including steroid hormones, bile acids, bilirubin, fatty acids, carcinogens, and therapeutic drugs. Therefore, the expression and activities of UGTs are tightly regulated by multiple processes at the transcriptional, post-transcriptional and post-translational levels. During recent years, nearly twenty studies have investigated the post-transcriptional regulation of UGT genes by miRNAs using human cancer cell lines (predominantly liver cancer). Overall, 14 of the 22 UGT mRNAs (1A1, 1A3, 1A4, 1A6, 1A8, 1A9, 1A10, 2A1, 2B4, 2B7, 2B10, 2B15, 2B17, UGT8) have been shown to be regulated by various miRNAs through binding to their respective 3' untranslated regions (3'UTRs). Three 3'UTRs (UGT1A, UGT2B7 and UGT2B15) contain the largest number of functional miRNA target sites; in particular, the UGT1A 3'UTR contains binding sites for 12 miRNAs (548d-5p, 183-5p, 214-5p, 486-3p, 200a-3p, 491-3p, 141-3p, 298, 103b, 376b-3p, 21-3p, 1286). Although all nine UGT1A family members have the same 3'UTR, these miRNA target sites appear to be functional in an isoform-specific and cellular context-dependent manner. Collectively, these observations demonstrate that miRNAs represent important post-transcriptional regulators of the UGT gene superfamily. In this article, we present a comprehensive review of reported UGT/miRNA regulation studies, describe polymorphisms within functional miRNA target sites that may affect their functionalities, and discuss potential cooperative and competitive regulation of UGT mRNAs by miRNAs through adjacently located miRNA target sites.

The Roles of microRNAs in Cancer Multidrug Resistance

Simple Summary

The resistance of neoplastic cells to multiple drugs is a serious problem in cancer chemotherapy. The molecular causes of multidrug resistance in cancer are largely known, but less is known about the mechanisms by which cells deliver phenotypic changes that resist the attack of anticancer drugs. The findings of RNA interference based on microRNAs represented a breakthrough in biology and pointed to the possibility of sensitive and targeted regulation of gene expression at the post-transcriptional level. Such regulation is also involved in the development of multidrug resistance in cancer. The aim of the current paper is to summarize the available knowledge on the role of microRNAs in resistance to multiple cancer drugs.

Abstract

Cancer chemotherapy may induce a multidrug resistance (MDR) phenotype. The development of MDR is based on various molecular causes, of which the following are very common: induction of ABC transporter expression; induction/activation of drug-metabolizing enzymes; alteration of the expression/function of apoptosis-related proteins; changes in cell cycle checkpoints; elevated DNA repair mechanisms. Although these mechanisms of MDR are well described, information on their molecular interaction in overall multidrug resistance is still lacking. MicroRNA (miRNA) expression and subsequent RNA interference are candidates that could be important players in the interplay of MDR mechanisms. The regulation of post-transcriptional processes in the proteosynthetic pathway is considered to be a major function of miRNAs. Due to their complementarity, they are able to bind to target mRNAs, which prevents the mRNAs from interacting effectively with the ribosome, and subsequent degradation of the mRNAs can occur. The aim of this paper is to provide an overview of the possible role of miRNAs in the molecular mechanisms that lead to MDR. The possibility of considering miRNAs as either specific effectors or interesting targets for cancer therapy is also analyzed.

A potential implication of UDP-glucuronosyltransferase 2B10 in the detoxification of drugs used in pediatric hematopoietic stem cell transplantation setting: an in silico investigation

Background

Sinusoidal occlusion syndrome (SOS) is a potentially severe complication following hematopoietic stem cell transplantation (HSCT) in pediatric patients. Treatment related risk factors such as intensity of conditioning, hepatotoxic co-medication and patient related factors such as genetic variants predispose individuals to develop SOS. The variant allele for SNP rs17146905 in UDP-glucuronosyl transferase 2B10 (UGT2B10) gene was correlated with the occurrence of SOS in an exome-wide association study. UGT2B10 is a phase II drug metabolizing enzyme involved in the N-glucuronidation of tertiary amine containing drugs.

Methods

To shed light on the functionality of UGT2B10 enzyme in the metabolism of drugs used in pediatric HSCT setting, we performed in silico screening against custom based library of putative ligands. First, a list of potential substrates for in silico analysis was prepared using a systematic consensus-based strategy. The list comprised of drugs and their metabolites used in pediatric HSCT setting. The three-dimensional structure of UGT2B10 was not available from the Research Collaboratory Structural Bioinformatics - Protein Data Bank (RCSB - PDB) repository and thus we predicted the first human UGT2B10 3D model by using multiple template homology modeling with MODELLER Version 9.2 and molecular docking calculations with AutoDock Vina Version 1.2 were implemented to quantify the estimated binding affinity between selected putative substrates or ligands and UGT2B10. Finally, we performed molecular dynamics simulations using GROMACS Version 5.1.4 to confirm the potential UGT2B10 ligands prioritized after molecular docking (exhibiting negative free binding energy).

Results

Four potential ligands for UGT2B10 namely acetaminophen, lorazepam, mycophenolic acid and voriconazole n-oxide intermediate were identified. Other metabolites of voriconazole satisfied the criteria of being possible ligands of UGT2B10. Except for bilirubin and 4-Hydroxy Voriconazole, all the ligands (particularly voriconazole and hydroxy voriconazole) are oriented in substrate binding site close to the co-factor UDP (mean ± SD; 0.72 ± 0.33 nm). Further in vitro screening of the putative ligands prioritized by in silico pipeline is warranted to understand the nature of the ligands either as inhibitors or substrates of UGT2B10.

Conclusions

These results may indicate the clinical and pharmacological relevance UGT2B10 in pediatric HSCT setting. With this systematic computational methodology, we provide a rational-, time-, and cost-effective way to identify and prioritize the interesting putative substrates or inhibitors of UGT2B10 for further testing in in vitro experiments.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12860-021-00402-5.

Expression of UDP Glucuronosyltransferases 2B15 and 2B17 is associated with methylation status in prostate cancer cells

Studies have suggested that abrogated expression of detoxification enzymes, UGT2B15 and UGT2B17, are associated with prostate tumour risk and progression. We investigated the role of EGF on the expression of these enzymes since it interacts with signalling pathways to also affect prostate tumour progression and is additionally associated with decreased DNA methylation. The expression of UGT2B15, UGT2B17, de novo methyltransferases, DNMT3A and DNMT3B was assessed in prostate cancer cells (LNCaP) treated with EGF, an EGFR inhibitor PD16893, and the methyltransferase inhibitor, 5-azacytidine, respectively. The results showed that EGF treatment decreased levels of expression of all four genes and that their expression was reversed by PD16893. Treatment with 5-azacytidine, markedly decreased expression of UGT2B15 and UGT2B17 over 85% as well as significantly decreased expression of DNMT3B, but not the expression of DNMT3A. DNMT3B siRNA treated LNCaP cells had decreased expression of UGT2B15 and UGT2B17, while DNMT3A siRNA treated cells had only moderately decreased UGT2B15 expression. Treatment with DNMT methyltransferase inhibitor, RG108, significantly decreased UGT2B17 expression. Additionally, methylation differences between prostate cancer samples and benign prostate samples from an Illumina 450K Methylation Array study were assessed. The results taken together suggest that hypomethylation of the UGT2B15 and UGT2B17 genes contributes to increased risk of prostate cancer and may provide a putative biomarker or epigenetic target for chemotherapeutics. Mechanistic studies are warranted to determine the role of the methylation marks in prostate cancer.

MiR-216a-3p regulates the proliferation, apoptosis, migration, and invasion of lung cancer cells via targeting COPB2

Effect of miR-216a-3p on lung cancer hasn't been investigated. Here, we explored its effects on lung cancer. MiR-216a-3p expression in lung cancer tissues and cells was detected by RT-qPCR. The target gene of miR-216a-3p was predicted by bioinformatics and confirmed by luciferase-reporter assay. After transfection, cell viability, migration, invasion, proliferation, and apoptosis were detected by MTT, scratch, transwell, colony formation, and flow cytometry. The expressions of COPB2 and apoptosis-related factors were detected by RT-qPCR or western blot. MiR-216a-3p was low-expressed and COPB2 was high-expressed in lung cancer tissues and cells. MiR-216a-3p targeted COPB2 and regulated its expression. MiR-216a-3p inhibited lung cancer cell viability, migration, invasion, and proliferation, while promoted apoptosis. Effect of miR-216a-3p on lung cancer was reversed by COPB2. MiR-216a-3p regulated proliferation, apoptosis, migration, and invasion of lung cancer cells via targeting COPB2.

Genetic Susceptibility to Hepatic Sinusoidal Obstruction Syndrome in Pediatric Patients Undergoing Hematopoietic Stem Cell Transplantation

Sinusoidal obstruction syndrome (SOS) is a well-recognized and potentially life-threatening complication of hematopoietic stem cell transplantation (HSCT). SOS arises from endothelial cell damage and hepatocellular injury mostly due to the transplantation conditioning regimens but also to other patient, disease, and treatment-related factors. Understanding risk factors associated with the development of SOS is critical for early initiation of treatment or prophylaxis. The knowledge about genetic contribution is limited; few studies investigated so far selected a set of genes. To get more comprehensive insight in the genetic component, we performed an exome-wide association study using genetic variants derived from whole-exome sequencing. The analyses were performed in a discovery cohort composed of 87 pediatric patients undergoing HSCT following a busulfan-containing conditioning regimen. Eight lead single-nucleotide polymorphisms (SNPs) were identified after correction for multiple testing and subsequently analyzed in a validation cohort (n = 182). Three SNPs were successfully replicated, including rs17146905 (P = .001), rs16931326 (P = .04), and rs2289971 (P = .03), located respectively in the UGT2B10, BHLHE22, and KIAA1715 genes. UGT2B10 and KIAA1715 were retained in a multivariable model while controlling for nongenetic covariates and previously identified risk variants in the GSTA1 promoter. The modulation of associations by conditioning regimens was noted; KIAA1715 was dependent on the intensity of the conditioning regimen, whereas the effect of UGT2B10 was equally applicable to all of them. Combined effect of associated loci was also observed (P = .00006) with a genotype-related SOS risk of 9.8. To our knowledge, this is the first study addressing the genetic component of SOS at an exome-wide level and identifying novel genetic variations conferring a higher risk of SOS, which might be useful for personalized prevention and treatment strategies.

Identification of key genes and long non-coding RNA associated ceRNA networks in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths worldwide. Although multiple efforts have been made to understand the development of HCC, morbidity, and mortality rates remain high. In this study, we aimed to discover the mRNAs and long non-coding RNAs (lncRNAs) that contribute to the progression of HCC. We constructed a lncRNA-related competitive endogenous RNA (ceRNA) network to elucidate the molecular regulatory mechanism underlying HCC.

Methods

A microarray dataset (GSE54238) containing information about both mRNAs and lncRNAs was downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) and lncRNAs (DElncRNAs) in tumor tissues and non-cancerous tissues were identified using the limma package of the R software. The miRNAs that are targeted by DElncRNAs were predicted using miRcode, while the target mRNAs of miRNAs were retrieved from miRDB, miRTarBas, and TargetScan. Functional annotation and pathway enrichment of DEGs were performed using the EnrichNet website. We constructed a protein–protein interaction (PPI) network of DEGs using STRING, and identified the hub genes using Cytoscape. Survival analysis of the hub genes and DElncRNAs was performed using the gene expression profiling interactive analysis database. The expression of molecules with prognostic values was validated on the UALCAN database. The hepatic expression of hub genes was examined using the Human Protein Atlas. The hub genes and DElncRNAs with prognostic values as well as the predictive miRNAs were selected to construct the ceRNA networks.

Results

We found that 10 hub genes (KPNA2, MCM7, CKS2, KIF23, HMGB2, ZWINT, E2F1, MCM4, H2AFX, and EZH2) and four lncRNAs (FAM182B, SNHG6, SNHG1, and SNHG3) with prognostic values were overexpressed in the hepatic tumor samples. We also constructed a network containing 10 lncRNA–miRNA–mRNA pathways, which might be responsible for regulating the biological mechanisms underlying HCC.

Conclusion

We found that the 10 significantly overexpressed hub genes and four lncRNAs were negatively correlated with the prognosis of HCC. Further, we suggest that lncRNA SNHG1 and the SNHG3-related ceRNAs can be potential research targets for exploring the molecular mechanisms of HCC.

Potential Regulation of UGT2B10 and UGT2B7 by miR-485-5p in Human Liver

The UDP-glucuronosyltransferase (UGT) family of enzymes is important in the metabolic elimination of a variety of endogenous compounds such as bile acids, steroids, and fat-soluble vitamins, as well as exogenous compounds including many pharmaceuticals. The UGT2B subfamily is a major family of UGT enzymes expressed in human liver. The identification of novel mechanisms including post-transcriptional regulation by microRNA (miRNA) contributes to interindividual variability in UGT2B expression and is a crucial component in predicting patient drug response. In the present study, a high-resolution liquid chromatography-tandem mass spectrometry method was employed to measure UGT2B protein levels in a panel of human liver microsomal samples (n = 62). Concurrent in silico analysis identified eight candidate miRNAs as potential regulators of UGT2B enzymes. Comparison of UGT2B protein expression and candidate miRNA levels from human liver samples demonstrated a significant inverse correlation between UGT2B10 and UGT2B15 and one of these candidate miRNAs, miR-485-5p. A near-significant correlation was also observed between UGT2B7 and miR-485-5p expression. In vitro analysis using luciferase-containing vectors suggested an interaction of miR-485-5p within the UGT2B10 3'-untranslated region (UTR), and significant reduction in luciferase activity was also observed for a luciferase vector containing the UGT2B7 3'-UTR; however, none was observed for the UBT2B15 3'-UTR. UGT2B10 and UGT2B7 activities were probed using nicotine and 3'-azido-3'-deoxythymidine, respectively, and significant decreases in glucuronidation activity were observed for both substrates in HuH-7 and Hep3B cells upon overexpression of miR-485-5p mimic. This is the first study demonstrating a regulatory role of miR-485-5p for multiple UGT2B enzymes. SIGNIFICANCE STATEMENT: The purpose of this study was to identify novel epigenetic miRNA regulators of the UGT2B drug-metabolizing enzymes in healthy human liver samples. Our results indicate that miRNA 485-5p is a novel regulator of UGT2B7 and UGT2B10, which play an important role in the metabolism of many commonly prescribed medications, carcinogens, and endogenous compounds. This study identified potential miRNA-UGT2B mRNA interactions using a novel proteomic approach, with in vitro experiments undertaken to validate these interactions.

MicroRNAs hsa-miR-495-3p and hsa-miR-486-5p suppress basal and rifampicin-induced expression of human sulfotransferase 2A1 (SULT2A1) by facilitating mRNA degradation

Drug metabolizing enzymes mediate biotransformation of drugs and play an essential role in drug efficacy and toxicity. Human sulfotransferases are a superfamily of Phase II detoxification enzymes that metabolize a wide spectrum of endogenous compounds and xenobiotics. SULT2A1 is one of the most abundant hepatic sulfotransferases and it catalyzes the sulfate conjugation of many endogenous substrates, such as bile acids and steroids. In the current study, we utilized a systematic approach by combining a series of computational analyses and in vitro methods to identify miRNAs that repress SULT2A1 expression post-transcriptionally. Our in silico analyses predicted miRNA response elements for hsa-miR-495-3p and hsa-miR-486-5p within the 3'-UTR of SULT2A1 mRNA and the levels of these miRNAs were inversely correlated with that of SULT2A1 mRNA in human liver. Using fluorescence-based RNA electrophoretic mobility shift assays, we found that hsa-miR-495-3p and hsa-miR-486-5p interacted directly with the SULT2A1 3'-UTR. The activity of a luciferase reporter gene construct containing sequences from the SULT2A1 3-UTR was suppressed by hsa-miR-486-5p and hsa-miR-495-3p. Furthermore, gain- and loss-of-function assays demonstrated that hsa-miR-486-5p and hsa-miR-495-3p negatively modulate basal and rifampicin-induced expression of SULT2A1 in HepG2 cells by decreasing mRNA stability.

Regulation of UGT2A1 by miR-196a-5p and miR-196b-5p

UDP-glucuronosyltransferase (UGT) 2A1 is an important enzyme in the detoxification of polycyclic aromatic hydrocarbons found in cigarette smoke. This enzyme is expressed in aerodigestive tract tissues including lung as both its wild-type and exon 4-deleted splice variant isoforms, with the latter acting as a negative regulator of wild-type UGT2A1 activity. UGT2A1 regulation may also be mediated by microRNA (miRNA). To identify miRNA important in the regulation of UGT2A1, expression analysis in tandem with in silico analysis suggested miR-196a-5p and miR-196b-5p as potential top candidates. Significant reductions in firefly luciferase activity were observed in human embryonic kidney cell line 293 cells cotransfected with the wild-type UGT2A1 3'-untranslated region (UTR)-containing luciferase plasmid and either miR-196a-5p (62%, P = 0.00080) or miR-196b-5p (60%, P = 0.00030) mimics. In pull-down assays, there was a 3.4- and 5.2-fold increase in miR-196a-5p (P = 0.054) and miR-196b-5p (P = 0.035), respectively, using the UGT2A1 3'-UTR biotinylated mRNA probe as compared with the β-actin coding region control mRNA probe. UGT2A1 mRNA was reduced by 25% (P = 0.058) and 35% (P = 0.023) in H146 and H1944 cells, respectively, after overexpression of the miR196a-5p mimic. A similar 32% (P = 0.030) and 41% (P = 0.016) reduction was observed after over-expression of the miR-196b-5p mimic. In H146 cells transfected with miRNA mimic together with a small interfering RNA (siRNA) specific for the UGT2A1 splice variant, a significant reduction in 3-hydroxy-benzo[a]pyrene-glucuronide formation was observed. The miR-196a-5p- and miR-196b-55p-treated cells exhibited reductions of 35% (P = 0.047) and 44% (P = 0.0063), respectively. These data suggest that miR-196a-5p and miR-196b-5p play an important role in UGT2A1 regulation within the lung and potentially other aerodigestive tract tissues.

The UDP-Glycosyltransferase (UGT) Superfamily: New Members, New Functions, and Novel Paradigms

UDP-glycosyltransferases (UGTs) catalyze the covalent addition of sugars to a broad range of lipophilic molecules. This biotransformation plays a critical role in elimination of a broad range of exogenous chemicals and by-products of endogenous metabolism, and also controls the levels and distribution of many endogenous signaling molecules. In mammals, the superfamily comprises four families: UGT1, UGT2, UGT3, and UGT8. UGT1 and UGT2 enzymes have important roles in pharmacology and toxicology including contributing to interindividual differences in drug disposition as well as to cancer risk. These UGTs are highly expressed in organs of detoxification (e.g., liver, kidney, intestine) and can be induced by pathways that sense demand for detoxification and for modulation of endobiotic signaling molecules. The functions of the UGT3 and UGT8 family enzymes have only been characterized relatively recently; these enzymes show different UDP-sugar preferences to that of UGT1 and UGT2 enzymes, and to date, their contributions to drug metabolism appear to be relatively minor. This review summarizes and provides critical analysis of the current state of research into all four families of UGT enzymes. Key areas discussed include the roles of UGTs in drug metabolism, cancer risk, and regulation of signaling, as well as the transcriptional and posttranscriptional control of UGT expression and function. The latter part of this review provides an in-depth analysis of the known and predicted functions of UGT3 and UGT8 enzymes, focused on their likely roles in modulation of levels of endogenous signaling pathways.

Current knowledge of microRNA-mediated regulation of drug metabolism in humans

INTRODUCTION

Understanding the factors causing inter- and intra-individual differences in drug metabolism potencies is required for the practice of personalized or precision medicine, as well as for the promotion of efficient drug development. The expression of drug-metabolizing enzymes is controlled by transcriptional regulation by nuclear receptors and transcriptional factors, epigenetic regulation, such as DNA methylation and histone acetylation, and post-translational modification. In addition to such regulation mechanisms, recent studies revealed that microRNAs (miRNAs), endogenous ~22-nucleotide non-coding RNAs that regulate gene expression through the translational repression and degradation of mRNAs, significantly contribute to post-transcriptional regulation of drug-metabolizing enzymes. Areas covered: This review summarizes the current knowledge regarding miRNAs-dependent regulation of drug-metabolizing enzymes and transcriptional factors and its physiological and clinical significance. We also describe recent advances in miRNA-dependent regulation research, showing that the presence of pseudogenes, single-nucleotide polymorphisms, and RNA editing affects miRNA targeting. Expert opinion: It is unwavering fact that miRNAs are critical factors causing inter- and intra-individual differences in the expression of drug-metabolizing enzymes. Consideration of miRNA-dependent regulation would be a helpful tool for optimizing personalized and precision medicine.

Epigenetics and MicroRNAs in Pharmacogenetics

Germline pharmacogenetics has so far mainly studied common variants in "pharmacogenes," i.e., genes encoding drug metabolizing enzymes and transporters (DMET genes), certain auxiliary and regulatory genes, and drug target genes. Despite remarkable progress in understanding genetically determined differences in pharmacokinetics and pharmacodynamics of drugs, currently known common variants even in important pharmacogenes explain genetic variability only partially. This suggests "missing heritability" that may in part be due to rare variants in the classical pharmacogenes, but current evidence suggests that largely unexplored resources with potential for pharmacogenetics exist, both within already known pharmacogenes and in entirely new areas. In particular, recent studies suggest that epigenetic processes and noncoding RNAs, including mostly microRNAs (miRNAs), represent important and largely unexplored layers of DMET gene regulation that may fill some of the gaps in understanding interindividual variability and lead to new biomarkers. In this chapter we summarize recent advances in the understanding of genetic variability in epigenetic and miRNA-mediated processes with focus on their significance for DMET regulation and pharmacokinetic or pharmacological endpoints.

Analysis of microRNA Expression Profiles Induced by Yiqifumai Injection in Rats with Chronic Heart Failure

Background: Yiqifumai Injection (YQFM) is clinically used to treat various cardiovascular diseases including chronic heart failure (CHF). The efficacy of YQFM for treating heart failure has been suggested, but the mechanism of action for pharmacological effects of YQFM is unclear. Methods: Echocardiography detection, left ventricular intubation evaluation, histopathology and immunohistochemical examination were performed in CHF rats to evaluate the cardioprotective effect of YQFM. Rat miRNA microarray and bioinformatics analysis were employed to investigate the differentially expressed microRNAs. In vitro models of AngII-induced hypertrophy and t-BHP induced oxidative stress in H9c2 myocardial cells were used to validate the anti-hypertrophy and anti-apoptosis effects of YQFM. Measurement of cell surface area, ATP content and cell viability, Real-time PCR and Western blot were performed. Results: YQFM significantly improved the cardiac function of CHF rats by increasing left ventricular ejection fraction and fractional shortening, decreasing left ventricular internal diameter and enhancing cardiac output. Seven microRNAs which have a reversible regulation by YQFM treatment were found. Among them, miR-21-3p and miR-542-3p are related to myocardial hypertrophy and cell proliferation, respectively and were further verified by RT-PCR. Target gene network was established and potential related signaling pathways were predicted. YQFM could significantly alleviate AngII induced hypertrophy in cellular model. It also significantly increased cell viabilities and ATP content in t-BHP induced apoptotic cell model. Western blot analysis showed that YQFM could increase the phosphorylation of Akt. Conclusion: Our findings provided scientific evidence to uncover the mechanism of action of YQFM on miRNAs regulation against CHF by miRNA expression profile technology. The results indicated that YQFM has a potential effect on alleviate cardiac hypertrophy and apoptosis in chronic heart failure.

Regulation of UDP-Glucuronosyltransferase 2B15 by miR-331-5p in Prostate Cancer Cells Involves Canonical and Noncanonical Target Sites

UGT2B15 is an important androgen-metabolizing UDP-glucuronosyltransferase (UGT) and the mechanisms controlling its expression are of considerable interest. Recent studies showed that miR-376c regulates UGT2B15 in prostate cancer cells via a canonical target site in the 3' untranslated region (3'UTR). The UGT2B15 3'UTR also contains a canonical miR-331-5p target site; previous work indicated that deleting this site reduced, but did not abolish, the ability of miR-331-5p to repress a luciferase reporter carrying the UGT2B15 3'UTR We report here the discovery and characterization of a second, noncanonical miR-331-5p target site in the UGT2B15 3'UTR miR-331-5p-mediated repression of a UGT2B15 3'UTR-reporter was partly inhibited by mutating either of the two miR-331-5p target sites separately, but completely abolished by mutating the two sites simultaneously, indicating that the two sites act cooperatively. miR-331-5p mimics significantly reduced both UGT2B15 mRNA levels and glucuronidation activity in prostate cancer cells, confirming that the native transcript is a miR-331-5p target. Transfection of either miR-331-5p or miR-376c mimics repressed the activity of the UGT2B15 3'UTR-reporter; however, cotransfection of both microRNAs (miRNAs) further reduced activity, indicating cooperative regulation by these two miRNAs. A significant negative correlation between miR-331 and UGT2B15 mRNA levels was observed in a tissue RNA panel, and analysis of The Cancer Genome Atlas (TCGA) hepatocellular carcinoma data set provided further evidence that miR-331 may play an important role in regulation of UGT2B15 in vivo. There was no significant correlation between miR-331 and UGT2B15 mRNA levels in the TCGA prostate adenocarcinoma cohort, which may reflect the complexity of androgen-mediated regulation in determining UGT2B15 levels in prostate cancer. Finally, we show that miR-331-5p does not regulate UGT2B17, providing the first evidence for a post-transcriptional mechanism that differentially regulates these two important androgen-metabolizing UGTs.

Comparative transcriptomics of hepatic differentiation of human pluripotent stem cells and adult human liver tissue

Hepatocytes derived from human pluripotent stem cells (hPSC-HEP) have the potential to replace presently used hepatocyte sources applied in liver disease treatment and models of drug discovery and development. Established hepatocyte differentiation protocols are effective and generate hepatocytes, which recapitulate some key features of their in vivo counterparts. However, generating mature hPSC-HEP remains a challenge. In this study, we applied transcriptomics to investigate the progress of in vitro hepatic differentiation of hPSCs at the developmental stages, definitive endoderm, hepatoblasts, early hPSC-HEP, and mature hPSC-HEP, to identify functional targets that enhance efficient hepatocyte differentiation. Using functional annotation, pathway and protein interaction network analyses, we observed the grouping of differentially expressed genes in specific clusters representing typical developmental stages of hepatic differentiation. In addition, we identified hub proteins and modules that were involved in the cell cycle process at early differentiation stages. We also identified hub proteins that differed in expression levels between hPSC-HEP and the liver tissue controls. Moreover, we identified a module of genes that were expressed at higher levels in the liver tissue samples than in the hPSC-HEP. Considering that hub proteins and modules generally are essential and have important roles in the protein-protein interactions, further investigation of these genes and their regulators may contribute to a better understanding of the differentiation process. This may suggest novel target pathways and molecules for improvement of hPSC-HEP functionality, having the potential to finally bring this technology to a wider use.

Anti-Obesity Effect of Bombus ignitus Queen Glycosaminoglycans in Rats on a High-Fat Diet

The mechanism of functional insect glycosaminoglycan (GAG) on obesity caused a high fat diet has not yet been elucidated. Therefore, insect glycosaminoglycans derived from Isaria sinclairii, Bombus ignitus (a type of bumblebee) queen, and Gryllus bimaculatus were purified and investigated as a potential functional food. 14-week old male Wistar rats were fed a high-fat diet (HFD) for 6 weeks. There were five groups that received daily intraperitoneal administration of phosphate buffered saline (PBS, control), GbG (GAG from Gryllus bimaculatus) 10 mg/kg, ISG (GAG from Isaria sinclairii) 10 mg/kg, IQG (GAG from Bombus ignites) 10 mg/kg, or Pravastatin (2 mg/kg). All treatments were performed for one month. IQG produced a potential anti-inflammatory effect with the inhibition of c-reactive protein and sero-biochemical parameters of phospholipids and free fatty acids indicative of an anti-hyperlipidemic effect. Abdominal and epididymidal fat weight were reduced in conjunction with a mild increase in body weight. The level of laminin in HMVEC-C cells or fibronectin in HFD rat hepatocytes was significantly affected by these GAG treatments, which regulated adipogenesis and adipocyte function. Compared to the control rats, IQG-treated rats displayed up-regulation of 87 genes (test:control ratio >2.0) including fatty acid synthase and 3-hydroxy-3-methylglutaryl-coenzyme A reductase, with the down-regulation of 47 genes including the uridine diphosphate (UDP) glycosyltransferase 2 families, polypeptidase B, and insulin-like growth factor binding protein 1. The data suggest that IQG could potentially prevent or treat fatty liver or hyperlipidemia.