Cytochrome P450 enzymes in drug metabolism: regulation of gene expression, enzyme activities, and impact of genetic variation. Pharmacol Ther. 2013;138:103-141. [PMID: 23333322 DOI: 10.1016/j.pharmthera.2012.12.007]

The potential implication of SCN1A and CYP3A5 genetic variants on antiepileptic drug resistance among Egyptian epileptic children

PURPOSE

Despite the advances in the pharmacological treatment of epilepsy, pharmacoresistance still remains challenging. Understanding of the pharmacogenetic causes is critical to predict drug response hence providing a basis for personalized medications. Genetic alteration in activity of drug target and drug metabolizing proteins could explain the development of pharmacoresistant epilepsy. So the aim of this study was to explore whether SCN1A c.3184 A/G (rs2298771) and CYP3A5*3 (rs776746) polymorphisms could serve as genetic based biomarkers to predict pharmacoresistance among Egyptian epileptic children.

METHODS

Genotyping of SCN1A c.3184 A/G and CYP3A5*3 polymorphisms using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was performed in 65 healthy control subjects and 130 patients with epilepsy, of whom 50 were drug resistant and 80 were drug responsive.

RESULTS

There was a significant higher frequency of the AG genotype (p=0.001) and G allele (p=0.006) of SCN1A polymorphism in epileptic patients than in controls. Also their frequency was significantly higher in drug resistant patients in comparison with drug responders (p=0.005 and 0.054 respectively). No significant association between CYP3A5*3 polymorphism and drug-resistance was found.

CONCLUSIONS

Overall, results confirmed the claimed role of SCN1A c.3184 A/G polymorphism in epilepsy and moreover in development of pharmacoresistance among Egyptian epileptic children. CYP3A5*3 variants have no contributing effect on pharmacoresistance among Egyptian epileptic children.

Characterization of the hepatic cytochrome P450 enzymes involved in the metabolism of 25I-NBOMe and 25I-NBOH

The dimethoxyphenyl-N-((2-methoxyphenyl)methyl)ethanamine (NBOMe) compounds are potent serotonin 5-HT2A receptor agonists and have recently been subject to recreational use due to their hallucinogenic effects. Use of NBOMe compounds has been known since 2011, and several non-fatal and fatal intoxication cases have been reported in the scientific literature. The aim of this study was to determine the importance of the different cytochrome P450 enzymes (CYP) involved in the metabolism of 2-(4-iodo-2,5-dimethoxyphenyl)-N-(2methoxybenzyl)ethanamine (25I-NBOMe) and 2-[[2-(4-iodo-2,5dimethoxyphenyl)ethylamino]methyl]phenol (25I-NBOH) and to characterize the metabolites. The following approaches were used to identify the main enzymes involved in primary metabolism: incubation with a panel of CYP and monoamine oxidase (MAO) enzymes and incubation in pooled human liver microsomes (HLM) with and without specific CYP chemical inhibitors. The study was further substantiated by an evaluation of 25I-NBOMe and 25I-NBOH metabolism in single donor HLM. The metabolism pathways of 25I-NBOMe and 25I-NBOH were NADPHdependent with intrinsic clearance values of (CLint) of 70.1 and 118.7 mL/min/kg, respectively. The biotransformations included hydroxylation, O-demethylation, N-dealkylation, dehydrogenation, and combinations thereof. The most abundant metabolites were all identified by retention time and spectrum matching with synthesized reference standards. The major CYP enzymes involved in the metabolism of 25I-NBOMe and 25INBOH were identified as CYP3A4 and CYP2D6, respectively. The compound 25I-NBOH was also liable to direct glucuronidation, which may diminish the impact of CYP2D6 genetic polymorphism. Users of 25I-NBOMe may be subject to drug-drug interactions (DDI) if 25I-NBOMe is taken with a strong CYP3A4 inhibitor. Copyright © 2016 John Wiley & Sons, Ltd.

Regulation of Human Pluripotent Stem Cell-Derived Hepatic Cell Phenotype by Three-Dimensional Hydrogel Models

Human-induced pluripotent stem cell (hiPSC)-derived hepatocytes are anticipated as important surrogates for primary human hepatocytes in applications ranging from basic research to drug discovery and regenerative medicine. Although methods for differentiating hepatocyte-like cells (HLCs) from hiPSCs have developed remarkably, the limited yield of fully functional HLCs is still a major obstacle to their utility. A three-dimensional (3D) culture environment could improve the in vitro hepatic maturation of HLCs. Here we compare 3D hydrogel models of hiPSC-derived HLCs in agarose microwells (3D Petri Dish; 3DPD), nanofibrillar cellulose hydrogels (Growdex; 3DNFC), or animal extracellular matrix-based hydrogels (3D Matrigel; 3DMG). In all the tested 3D biomaterial systems, HLCs formed aggregates. In comparison with two-dimensional monolayer culture, 3DPD and 3DMG models showed both phenotypic and functional enhancement in HLCs over 2.5 weeks of 3D culture. Specifically, we found higher hepatocyte-specific gene expression levels and enhanced cytochrome P450 functions. Our work suggests that transferring HLCs into 3D hydrogel systems can expedite the hepatic maturation of HLCs irrespective of the biochemical nature of the 3D hydrogel. Both plant-based nonembedding and animal-based embedding 3D hydrogel models enhanced the maturation.

Time-dependent effects of dexamethasone plasma concentrations on glucocorticoid receptor challenge tests

Glucocorticoid challenge tests such as the dexamethasone suppression test (DST) and the combined dexamethasone/corticotropin-releasing hormone (dex-CRH) test are considered to be able to sensitively measure hypothalamic-pituitary-adrenal (HPA) axis activity in stress-related psychiatric and endocrine disorders. We used mass-spectrometry to assess the relationship of plasma dexamethasone concentrations and the outcome of these tests in two independent cohorts. Dexamethasone concentrations were measured after oral ingestion of 1.5mg dexamethasone in two cohorts that underwent a standard (dexamethasone at 23:00h) as well as modified (18:00h) DST and dex-CRH test. The first study population was a case/control cohort of 105 depressed patients and 133 controls in which peripheral blood mRNA expression was also measured. The second was a cohort of 261 depressed patients that underwent a standard dex-CRH test at baseline and after 12 weeks' treatment with cognitive-behavioral therapy or antidepressants. Dexamethasone concentrations explained significant proportions of the variance in the DST in both the first (24.6%) and the second (5.2%) cohort. Dexamethasone concentrations explained a higher proportion of the variance in the dex-CRH test readouts, with 41.9% of the cortisol area under the curve (AUC) in the first sample and 24.7% in the second sample. In contrast to these strong effects at later time points, dexamethasone concentrations did not impact cortisol or ACTH concentrations or mRNA expression 3hours after ingestion. In the second sample, dexamethasone concentrations at baseline and week 12 were highly correlated, independent of treatment type and response status. Importantly, a case/control effect in the Dex-CRH test was only apparent when controlling for dexamethasone concentrations. Our results suggest that the incorporation of plasma dexamethasone concentration or measures of earlier endocrine read-outs may help to improve the assessment of endocrine dysfunction in depression.

Screening for genotypic and phenotypic variations in CYP450 activity in patients with therapeutic problems in a psychiatric setting, a retrospective study

OBJECTIVES

This retrospective study aimed to assess to what extent an adverse drug reaction (ADR), an abnormal therapeutic drug monitoring (TDM) or a non-response, was attributable to an abnormal cytochrome P450 activity in a psychiatric setting.

METHOD

We collected the results of investigations performed in these situations related to psychotropic drugs between January 2005 and November 2014. Activities of different cytochrome P450 were assessed by genotyping and/or phenotyping. Two experienced clinical pharmacologists assessed independently the possible association between the event and the results of the investigations.

RESULTS

One hundred and thirty eight clinical or biological situations had a complete assessment of all major metabolic pathways of the target drug. A majority of clinical or biological situations were observed with antidepressants (n=93, 67.4%), followed by antipsychotics (n=28, 20.3%), benzodiazepines and hypnotics (n=13, 9.4%), and psychostimulants (n=4, 2.9%). Genotype and/or phenotype determination was mainly performed because of ADRs (n=68, 49.3%) or non-response (n=46, 33.3%). Inter-rate reliability of the scoring system between the pharmacologists was excellent (kappa=0.94). The probability of an association between ADR, TDM or non-response and metabolic status was rated as intermediate to high in 34.7% of all cases, with proportions of 30.4% and 36.7%, for non-response and ADR respectively.

CONCLUSION

When indicated by clinical pharmacologists, ADR, TDM or non-response may be attributable to a variation of the metabolic status with an intermediate to high probability in 34.7% of patients, based on the congruent assessment made by two clinical pharmacologists. Further studies assessing the clinical relevance of prospective explorations and clarifying the appropriate method according to the clinical context are needed.

Development of a cell viability assay to assess drug metabolite structure-toxicity relationships

Many adverse drug reactions are caused by the cytochrome P450 (CYP)-dependent activation of drugs into reactive metabolites. In order to reduce attrition due to metabolism-induced toxicity and to improve the safety of drug candidates, we developed a simple cell viability assay by combining a bioactivation system (human CYP3A4, CYP2D6 and CYP2C9) with Hep3B cells. We screened a series of drugs to explore structural motifs that may be responsible for CYP450-dependent activation caused by reactive metabolite formation, which highlighted specific liabilities regarding certain phenols and anilines.

Computational Identification of the Paralogs and Orthologs of Human Cytochrome P450 Superfamily and the Implication in Drug Discovery

The human cytochrome P450 (CYP) superfamily consisting of 57 functional genes is the most important group of Phase I drug metabolizing enzymes that oxidize a large number of xenobiotics and endogenous compounds, including therapeutic drugs and environmental toxicants. The CYP superfamily has been shown to expand itself through gene duplication, and some of them become pseudogenes due to gene mutations. Orthologs and paralogs are homologous genes resulting from speciation or duplication, respectively. To explore the evolutionary and functional relationships of human CYPs, we conducted this bioinformatic study to identify their corresponding paralogs, homologs, and orthologs. The functional implications and implications in drug discovery and evolutionary biology were then discussed. GeneCards and Ensembl were used to identify the paralogs of human CYPs. We have used a panel of online databases to identify the orthologs of human CYP genes: NCBI, Ensembl Compara, GeneCards, OMA ("Orthologous MAtrix") Browser, PATHER, TreeFam, EggNOG, and Roundup. The results show that each human CYP has various numbers of paralogs and orthologs using GeneCards and Ensembl. For example, the paralogs of CYP2A6 include CYP2A7, 2A13, 2B6, 2C8, 2C9, 2C18, 2C19, 2D6, 2E1, 2F1, 2J2, 2R1, 2S1, 2U1, and 2W1; CYP11A1 has 6 paralogs including CYP11B1, 11B2, 24A1, 27A1, 27B1, and 27C1; CYP51A1 has only three paralogs: CYP26A1, 26B1, and 26C1; while CYP20A1 has no paralog. The majority of human CYPs are well conserved from plants, amphibians, fishes, or mammals to humans due to their important functions in physiology and xenobiotic disposition. The data from different approaches are also cross-validated and validated when experimental data are available. These findings facilitate our understanding of the evolutionary relationships and functional implications of the human CYP superfamily in drug discovery.

Long-term exposure to abnormal glucose levels alters drug metabolism pathways and insulin sensitivity in primary human hepatocytes

Hyperglycemia in type 2 diabetes mellitus has been linked to non-alcoholic fatty liver disease, which can progress to inflammation, fibrosis/cirrhosis, and hepatocellular carcinoma. Understanding how chronic hyperglycemia affects primary human hepatocytes (PHHs) can facilitate the development of therapeutics for these diseases. Conversely, elucidating the effects of hypoglycemia on PHHs may provide insights into how the liver adapts to fasting, adverse diabetes drug reactions, and cancer. In contrast to declining PHH monocultures, micropatterned co-cultures (MPCCs) of PHHs and 3T3-J2 murine embryonic fibroblasts maintain insulin-sensitive glucose metabolism for several weeks. Here, we exposed MPCCs to hypo-, normo- and hyperglycemic culture media for ~3 weeks. While albumin and urea secretion were not affected by glucose level, hypoglycemic MPCCs upregulated CYP3A4 enzyme activity as compared to other glycemic states. In contrast, hyperglycemic MPCCs displayed significant hepatic lipid accumulation in the presence of insulin, while also showing decreased sensitivity to insulin-mediated inhibition of glucose output relative to a normoglycemic control. In conclusion, we show for the first time that PHHs exposed to hypo- and hyperglycemia can remain highly functional, but display increased CYP3A4 activity and selective insulin resistance, respectively. In the future, MPCCs under glycemic states can aid in novel drug discovery and mechanistic investigations.

The genetic profiles of CYP1A1, CYP1A2 and CYP2E1 enzymes as susceptibility factor in xenobiotic toxicity in Turkish population

Evaluation and sequencing of heritable alterations in the human genome and the large-scale identification of gene polymorphism for understanding the genetic background of individuals in response to potential toxicants are provided by toxicogenetics. Cytochrome P450 (CYP) enzymes play role not only phase I-dependent metabolism of xenobiotics but also metabolism of endogenous compounds. CYP1A1, CYP1A2 and CYP2E1 enzymes, which are in phase I enzymes, are responsible for metabolic activation and detoxification of several chemical compounds. In the present study, it was determined the genotype and allele frequency of CYP1A1∗2A, CYP1A2∗1C, CYP1A2∗1F, CYP2E1 and CYP2E1∗6, very common and functional single-nucleotide polymorphisms (SNPs), in Turkish healthy volunteers. It is believed that the determination of polymorphisms in the enzymes may be beneficial to prevent and reduce and adverse effects and death in response to drugs. The allele frequencies of these genes were 24%, 9%, 33%, 42%, and 12%, respectively. In the present study, the genotype profile of Turkish population was determined about critical enzymes for xenobiotic metabolism. It is suggested that the obtained results might be beneficial in order to dose adjustment of drugs and prevention of adverse reactions, and further investigation about mentioned enzymes and their polymorphisms.

MicroRNA hsa-miR-25-3p suppresses the expression and drug induction of CYP2B6 in human hepatocytes

Cytochrome P450 2B6 (CYP2B6), mainly expressed in the liver and brain, is important for processing a number of widely used drugs. Variations in CYP2B6 expression are associated with decreased drug efficacy or adverse effects in some patients. Although CYP2B6 genetic variants are associated with its differential expression, epigenetic mechanisms affecting CYP2B6 gene regulation have not been established. Sequence analysis identified 29 domains in the CYP2B6 mRNA transcript that could be subject to regulation by microRNAs. Inverse correlations were found in human hepatocytes for the levels of the microRNAs hsa-miR-504-5p and hsa-miR-25-3p compared with CYP2B6 mRNA. Reporter gene assays showed that hsa-miR-25-3p suppresses CYP2B6 expression by targeting a specific sequence in the 3'-untranslated region of the mRNA transcript. Electrophoretic mobility shift assays confirmed that hsa-miR-25-3p forms stable complexes with its cognate mRNA sequence and that it recruits cellular factors, including Ago-4. Transfection of HepaRG cells with hsa-miR-25-3p mimics inhibited expression of the endogenous CYP2B6 gene and it also decreased rifampicin-dependent induction of CYP2B6 at the mRNA and protein levels. In summary, in silico and in vitro analyses show that hsa-miR-25-3p suppresses CYP2B6 expression in human liver cells via an epigenetic mechanism.

Identification of genetic variants in pharmacokinetic genes associated with Ewing Sarcoma treatment outcome

BACKGROUND

Despite the effectiveness of current treatment protocols for Ewing sarcoma (ES), many patients still experience relapse, and survival following recurrence is <15%. We aimed to identify genetic variants that predict treatment outcome in children diagnosed with ES.

PATIENTS AND METHODS

We carried out a pharmacogenetic study of 384 single-nucleotide polymorphisms (SNPs) in 24 key transport or metabolism genes relevant to drugs used to treat in pediatric patients (<30 years) with histologically confirmed ES. We studied the association of genotypes with tumor response and overall survival (OS) in a discovery cohort of 106 Spanish children, with replication in a second cohort of 389 pediatric patients from across Europe.

RESULTS

We identified associations with OS (P < 0.05) for three SNPs in the Spanish cohort that were replicated in the European cohort. The strongest association observed was with rs7190447, located in the ATP-binding cassette subfamily C member 6 (ABCC6) gene [discovery: hazard ratio (HR) = 14.30, 95% confidence interval (CI) = 1.53-134, P = 0.020; replication: HR = 9.28, 95% CI = 2.20-39.2, P = 0.0024] and its correlated SNP rs7192303, which was predicted to have a plausible regulatory function. We also replicated associations with rs4148737 in the ATP-binding cassette subfamily B member 1 (ABCB1) gene (discovery: HR = 2.96, 95% CI = 1.08-8.10, P = 0.034; replication: HR = 1.60, 95% CI = 1.05-2.44, P = 0.029), which we have previously found to be associated with poorer OS in pediatric osteosarcoma patients, and rs11188147 in cytochrome P450 family 2 subfamily C member 8 gene (CYP2C8) (discovery : HR = 2.49, 95% CI = 1.06-5.87, P = 0.037; replication: HR = 1.77, 95% CI = 1.06-2.96, P = 0.030), an enzyme involved in the oxidative metabolism of the ES chemotherapeutic agents cyclophosphamide and ifosfamide. None of the associations with tumor response were replicated.

CONCLUSION

Using an integrated pathway-based approach, we identified polymorphisms in ABCC6, ABCB1 and CYP2C8 associated with OS. These associations were replicated in a large independent cohort, highlighting the importance of pharmacokinetic genes as prognostic markers in ES.

In Silico Prediction of Cytochrome P450-Drug Interaction: QSARs for CYP3A4 and CYP2C9

Cytochromes P450 (CYP) are the main actors in the oxidation of xenobiotics and play a crucial role in drug safety, persistence, bioactivation, and drug-drug/food-drug interaction. This work aims to develop Quantitative Structure-Activity Relationship (QSAR) models to predict the drug interaction with two of the most important CYP isoforms, namely 2C9 and 3A4. The presented models are calibrated on 9122 drug-like compounds, using three different modelling approaches and two types of molecular description (classical molecular descriptors and binary fingerprints). For each isoform, three classification models are presented, based on a different approach and with different advantages: (1) a very simple and interpretable classification tree; (2) a local (k-Nearest Neighbor) model based classical descriptors and; (3) a model based on a recently proposed local classifier (N-Nearest Neighbor) on binary fingerprints. The salient features of the work are (1) the thorough model validation and the applicability domain assessment; (2) the descriptor interpretation, which highlighted the crucial aspects of P450-drug interaction; and (3) the consensus aggregation of models, which largely increased the prediction accuracy.

Pre-absorption physicochemical compatibility assessment of 8-drug metabolic cocktail

A comprehensive 8-drug metabolic cocktail was designed to simultaneously target 6 Cytochrome P450 enzymes and 2 membrane transporters. This study aimed to assess the pre-absorption risk of this new metabolic cocktail which contained metoprolol, caffeine, midazolam, pravastatin, flurbiprofen, omeprazole, digoxin and montelukast. This paper describes a systematic approach to understand whether the co-administration of the 8 selected drug products, i.e., the physical mixing of these products in the human gastro-intestinal environment, will create any issue that may interfere with the individual drug dissolution which in turns modify the total amount or timing of their availability for absorption. The evaluation consisted of two steps. An initial evaluation was based on theoretical understanding of the physicochemical properties of the drugs and the gastro intestinal environment, followed by in vitro dissolution tests. The results indicated that the designer 8-drug cocktail has acceptable pre-absorption compatibility when dosed simultaneously, and recommended the progression of the cocktail into clinical validation study.

Aryl morpholino triazenes inhibit cytochrome P450 1A1 and 1B1

Many cytochrome P450 1A1 and 1B1 (CYP1A1 and CYP1B1) inhibitors, such as resveratrol, have planar, hydrophobic, aromatic rings in their structure and exhibit anti-cancer activity. Aryl morpholino triazenes have similar structural features and in addition contain a triazene unit consisting of three consecutive, conjugated nitrogen atoms. Several aryl morpholino triazenes, including 4-[(E)-2-(3,4,5-trimethoxyphenyl)diazenyl]-morpholine (2), were prepared from a reaction involving morpholine and a diazonium ion produced from different aniline derivatives, such as 3,4,5-trimethoxyaniline. The aryl morpholino triazenes were then screened at 100μM for their ability to inhibit CYP1A1 and CYP1B1 using ethoxyresorufin as the substrate. Triazenes that inhibited the enzymes to less than 80% of the uninhibited enzyme activity were assayed to determine their IC50 value. Compound 2 was the only triazene to inhibit both CYP1A1 and CYP1B1 to the same degree as resveratrol with IC50 values of 10μM and 18μM, respectively. Compounds 3 and 6 selectively inhibited CYP1B1 over CYP1A1 with IC values of 2μM and 7μM, respectively. Thus, aryl morpholino triazenes are a new class of compounds that can inhibit CYP1A1 and CYP1B1 and potentially prevent cancer.

The independent contribution of miRNAs to the missing heritability in CYP3A4/5 functionality and the metabolism of atorvastatin

To evaluate the independent contribution of miRNAs to the missing heritability in CYP3A4/5 functionality and atorvastatin metabolism, the relationships among three levels of factors, namely (1) clinical characteristics, CYP3A4/5 genotypes, and miRNAs, (2) CYP3A4 and CYP3A5 mRNAs, and (3) CYP3A activity, as well as their individual impacts on atorvastatin metabolism, were assessed in 55 human liver tissues. MiR-27b, miR-206, and CYP3A4 mRNA respectively accounted for 20.0%, 5.8%, and 9.5% of the interindividual variations in CYP3A activity. MiR-142 was an independent contributor to the expressions of CYP3A4 mRNA (partial R(2) = 0.12, P = 0.002) and CYP3A5 mRNA (partial R(2) = 0.09, P = 0.005) but not CYP3A activity or atorvastatin metabolism. CYP3A activity was a unique independent predictor of variability of atorvastatin metabolism, explaining the majority of the variance in reduction of atorvastatin (60.0%) and formation of ortho-hydroxy atorvastatin (78.8%) and para-hydroxy atorvastatin (83.9%). MiR-27b and miR-206 were found to repress CYP3A4 gene expression and CYP3A activity by directly binding to CYP3A4 3'-UTR, while miR-142 was found to indirectly repress CYP3A activity. Our study indicates that miRNAs play significant roles in bridging the gap between epigenetic effects and missing heritability in CYP3A functionality.

Influence of the cytochrome P450 2D6 *10/*10 genotype on the pharmacokinetics of paroxetine in Japanese patients with major depressive disorder: a population pharmacokinetic analysis

OBJECTIVE

Although the reduced function of the cytochrome P450 2D6*10 (CYP2D6*10) allele is common among Asian populations, existing evidence does not support paroxetine therapy adjustments for patients who have the CYP2D6*10 allele. In this study, we attempted to evaluate the degree of the impact of different CYP2D6 genotypes on the pharmacokinetic (PK) variability of paroxetine in a Japanese population using a population PK approach.

METHODS

This retrospective study included 179 Japanese patients with major depressive disorder who were being treated with paroxetine. CYP2D6*1, *2, *5, *10, and *41 polymorphisms were observed. A total of 306 steady-state concentrations for paroxetine were collected from the patients. A nonlinear mixed-effects model identified the apparent Michaelis-Menten constant (Km) and the maximum velocity (Vmax) of paroxetine; the covariates included CYP2D6 genotypes, patient age, body weight, sex, and daily paroxetine dose.

RESULTS

The allele frequencies of CYP2D6*1, *2, *5, *10, and *41 were 39.4, 14.5, 4.5, 41.1, and 0.6%, respectively. There was no poor metabolizer who had two nonfunctional CYP2D6*5 alleles. A one-compartment model showed that the apparent Km value was decreased by 20.6% in patients with the CYP2D6*10/*10 genotype in comparison with the other CYP2D6 genotypes. Female sex also influenced the apparent Km values. No PK parameters were affected by the presence of one CYP2D6*5 allele.

CONCLUSION

Unexpectedly, elimination was accelerated in individuals with the CYP2D6*10/*10 genotype. Our results show that the presence of one CYP2D6*5 allele or that of any CYP2D6*10 allele may have no major effect on paroxetine PKs in the steady state.

Enzymatic oxidative biodegradation of nanoparticles: Mechanisms, significance and applications

Biopersistence of carbon nanotubes, graphene oxide (GO) and several other types of carbonaceous nanomaterials is an essential determinant of their health effects. Successful biodegradation is one of the major factors defining the life span and biological responses to nanoparticles. Here, we review the role and contribution of different oxidative enzymes of inflammatory cells - myeloperoxidase, eosinophil peroxidase, lactoperoxidase, hemoglobin, and xanthine oxidase - to the reactions of nanoparticle biodegradation. We further focus on interactions of nanomaterials with hemoproteins dependent on the specific features of their physico-chemical and structural characteristics. Mechanistically, we highlight the significance of immobilized peroxidase reactive intermediates vs diffusible small molecule oxidants (hypochlorous and hypobromous acids) for the overall oxidative biodegradation process in neutrophils and eosinophils. We also accentuate the importance of peroxynitrite-driven pathways realized in macrophages via the engagement of NADPH oxidase- and NO synthase-triggered oxidative mechanisms. We consider possible involvement of oxidative machinery of other professional phagocytes such as microglial cells, myeloid-derived suppressor cells, in the context of biodegradation relevant to targeted drug delivery. We evaluate the importance of genetic factors and their manipulations for the enzymatic biodegradation in vivo. Finally, we emphasize a novel type of biodegradation realized via the activation of the "dormant" peroxidase activity of hemoproteins by the nano-surface. This is exemplified by the binding of GO to cyt c causing the unfolding and 'unmasking' of the peroxidase activity of the latter. We conclude with the strategies leading to safe by design carbonaceous nanoparticles with optimized characteristics for mechanism-based targeted delivery and regulatable life-span of drugs in circulation.

Semi-mechanistic autoinduction model of midazolam in critically ill patients: population pharmacokinetic analysis

WHAT IS KNOWN AND OBJECTIVE

Midazolam (MDZ) is commonly used for sedating critically ill patients. The daily dose required for adequate sedation increases in increments over 100 h after administration. The objectives of this study were to characterize the MDZ pharmacokinetics in critically ill patients and to describe the phenomenon of increasing daily dose by means of population pharmacokinetic analysis.

METHODS

Data were obtained from 30 patients treated in an intensive care unit. The patients received MDZ intravenously as a combination of bolus and continuous infusion. Serum MDZ concentration was assayed by high-performance liquid chromatography. Population pharmacokinetic analysis was performed using the NONMEM software package. The alteration of clearance unexplained by demographic factors and clinical laboratory data was described as an autoinduction of MDZ clearance using a semi-mechanistic pharmacokinetic-enzyme turnover model.

RESULTS AND DISCUSSION

The final population pharmacokinetic model was a one-compartment model estimated by incorporating a semi-mechanistic pharmacokinetic-enzyme turnover model for clearance, taking autoinduction into account. A significant covariate for MDZ clearance was total bilirubin. An increase in total bilirubin indicated a reduction in MDZ clearance. From simulation using the population pharmacokinetic parameters obtained in this study, MDZ clearance increased 2·3 times compared with pre-induced clearance 100 h after the start of 12·5 mg/h continuous infusion.

WHAT IS NEW AND CONCLUSION

Autoinduction and total bilirubin were significant predictors of the clearance of MDZ in this population. Step-by-step dosage adjustment using this population pharmacokinetic model may be useful for establishing a MDZ dosage regimen in critically ill patients.

Forced Degradation Studies of Ivabradine and In Silico Toxicology Predictions for Its New Designated Impurities

All activities should aim to eliminate genotoxic impurities and/or protect the API against degradation. There is a necessity to monitor impurities from all classification groups, hence ivabradine forced degradation studies were performed. Ivabradine was proved to be quite durable active substance, but still new and with insufficient stability data. Increased temperature, acid, base, oxidation reagents and light were found to cause its degradation. Degradation products were determined with the usage of HPLC equipped with Q-TOF-MS detector. Calculations of pharmacological and toxicological properties were performed for six identified degradation products. Target prediction algorithm was applied on the basis of Hyperpolarization-activated cyclic nucleotide-gated cation channels, as well as more general parameters like logP and aqueous solubility. Ames test and five cytochromes activities were calculated for toxicity assessment for selected degradation products. Pharmacological activity of photodegradation product (UV4), which is known as active metabolite, was qualified and identified. Two other degradation compounds (Ox1 and N1), which were formed during degradation process, were found to be pharmacologically active.

A mollusk VDR/PXR/CAR-like (NR1J) nuclear receptor provides insight into ancient detoxification mechanisms

The origin and diversification of the metazoan endocrine systems represents a fundamental research issue in biology. Nuclear receptors are critical components of these systems. A particular group named VDR/PXR/CAR (NR1I/J) is central in the mediation of detoxification responses. While orthologues have been thoroughly characterized in vertebrates, a sparse representation is currently available for invertebrates. Here, we provide the first isolation and characterization of a lophotrochozoan protostome VDR/PXR/CAR nuclear receptor (NR1J), in the estuarine bivalve the peppery furrow shell (Scrobicularia plana). Using a reporter gene assay, we evaluated the xenobiotic receptor plasticity comparing the human PXR with the S. plana NR1Jβ. Our results show that the molluscan receptor responds to a natural toxin (okadaic acid) in a similar fashion to that reported for other invertebrates. In contrast, the pesticide esfenvalerate displayed a unique response, since it down regulated transactivation at higher concentrations, while for triclosan no response was observed. Additionally, we uncovered lineage specific gene duplications and gene loss in the gene group encoding NRs in protostomes with likely impacts on the complexity of detoxification mechanisms across different phyla. Our findings pave the way for the development of multi-specific sensor tools to screen xenobiotic compounds acting via the NR1I/J group.

Integrin Receptors Play a Key Role in the Regulation of Hepatic CYP3A

Landmark studies describing the effect of microbial infection on the expression and activity of hepatic CYP3A used bacterial lipopolysaccharide as a model antigen. Our efforts to determine whether these findings were translatable to viral infections led us to observations suggesting that engagement of integrin receptors is key in the initiation of processes responsible for changes in hepatic CYP3A4 during infection and inflammation. Studies outlined in this article were designed to evaluate whether engagement of integrins, receptors commonly used by a variety of microbes to enter cellular targets, is vital in the regulation of CYP3A in the presence and absence of virus infection. Mice infected with a recombinant adenovirus (AdlacZ) experienced a 70% reduction in hepatic CYP3A catalytic activity. Infection with a mutant virus with integrin-binding arginine-glycine-aspartic acid (RGD) sequences deleted from the penton base protein of the virus capsid (AdΔRGD) did not alter CYP3A activity. CYP3A mRNA and protein levels in AdlacZ-treated animals were also suppressed, whereas those of mice given AdΔRGD were not significantly different from uninfected control mice. Silencing of the integrinβ-subunit reverted adenovirus-mediated CYP3A4 suppression in vitro. Silencing of theα-subunit did not. Suppression of integrin subunits had a profound effect on nuclear receptors pregnane X receptor and constitutive androstane receptor, whereas retinoid X receptorαwas largely unaffected. To our knowledge, this is the first time that extracellular receptors, like integrins, have been indicated in the regulation of CYP3A. This finding has several implications owing to the important role of integrins in normal physiologic process and in many disease states.

Genetic determinants of metamizole metabolism modify the risk of developing anaphylaxis

Metamizole is a NSAID that has been banned in several countries because of its toxicity. It is often involved in selective hypersensitivity reactions and most hypersensitivity patients develop anaphylaxis. Metamizole is rapidly metabolized, and metabolic profiles are related to genetic factors. We analyzed whether genetic determinants of metamizole metabolism influence the risk of developing hypersensitivity in 265 patients diagnosed with hypersensitivity to metamizole and 362 healthy individuals who tolerated metamizole. Slow acetylation is associated with an increased risk of developing selective hypersensitivity to metamizole [odds ratio for slow alleles=2.17 (95% confidence interval=1.44-3.27); P=0.00016], and particularly anaphylaxis [odds ratio=4.77 (95% confidence interval=2.28-9.98); P=0.000006], with a significant gene-dose effect. The association was not identified in patients with cross-hypersensitivity. Cytochrome P450 2C9 (CYP2C9) and cytochrome P450 2C19 (CYP2C19) genotypes did not influence risk association. Our findings raise the hypothesis of genetically determined metabolic variability as a risk factor for developing anaphylaxis with metamizole.

Systematic Analysis of Adverse Event Reports for Sex Differences in Adverse Drug Events

Increasing evidence has shown that sex differences exist in Adverse Drug Events (ADEs). Identifying those sex differences in ADEs could reduce the experience of ADEs for patients and could be conducive to the development of personalized medicine. In this study, we analyzed a normalized US Food and Drug Administration Adverse Event Reporting System (FAERS). Chi-squared test was conducted to discover which treatment regimens or drugs had sex differences in adverse events. Moreover, reporting odds ratio (ROR) and P value were calculated to quantify the signals of sex differences for specific drug-event combinations. Logistic regression was applied to remove the confounding effect from the baseline sex difference of the events. We detected among 668 drugs of the most frequent 20 treatment regimens in the United States, 307 drugs have sex differences in ADEs. In addition, we identified 736 unique drug-event combinations with significant sex differences. After removing the confounding effect from the baseline sex difference of the events, there are 266 combinations remained. Drug labels or previous studies verified some of them while others warrant further investigation.

Immunohistochemical markers of CYP3A4 and CYP3A7: a new tool towards personalized pharmacotherapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) represents a major global health problem, since more than 90% of primary liver cancers worldwide are HCC. Most cases of HCC are secondary to viral hepatitis infection (hepatitis B or C), alcoholism and cirrhosis. Sorafenib, an oral tyrosine kinase inhibitor that suppresses tumor proliferation and angiogenesis, emerged as the first effective systemic treatment for HCC after 30 years of research, and is currently the standard-of-care for patients with advanced HCC. Sorafenib is metabolized by cytochrome P450 (CYP450), particularly from the 3A4 isoform, producing two main metabolites: the N-oxide and the N-hydroxymethyl metabolite. We studied 11 HCC sample showing the presence of CYP3A4 and CYP3A7 in most of the samples analysed. Specifically, the immunoreactivity of CYP3A4 was stronger and more widespread than that of CYP3A7. The CYP3A4 immunoreactivity was observed in surrounding hepatocytes in 8 out of 11 cases; while the CYP3A7 immunostaining was found in normal liver cells, in 7 out of 11 cases. These results suggest the existence of a marked inter-individual variability regarding the presence of the isoforms of CYP3A. In addition, since sorafenib is metabolized by CYP3A4, but not by CYP3A7, an overexpression of CYP3A4 may lead to an increase in the degradation of the drug and then to clinical ineffectiveness. These results might implicate the necessity of an individualized approach in the treatment of HCC as positivity to CYP3A4 in HCC liver samples might predict a scarce response to sorafenib.

The relevance of cytochrome P450 polymorphism in forensic medicine and akathisia-related violence and suicide

Adverse drug reactions and interactions are among the major causes of death in the United States. Antidepressants have been reported as causing suicide and homicide and share the class attribute of frequently producing akathisia, a state of severe restlessness associated with thoughts of death and violence. Medical examiners can now identify some pharmacogenetic interactions that cause drugs, deemed safe for most, to be lethal to others. Such deaths do not yet include medication-induced, akathisia-related suicides and homicides. An extrapyramidal side effect, akathisia is a manifestation of drug toxicity whose causes lie, inter alia, in drugs, doses, and co-prescribed medications that inhibit and compete for metabolizing enzymes, which may themselves be defective. In this paper, we report our investigation into adverse drug reactions/interactions in three persons who committed homicide, two also intending suicide, while on antidepressants prescribed for stressful life events. Their histories of medication use, adverse reactions and reasons for changes in medications are presented. DNA samples were screened for variants in the cytochrome P450 gene family; that produce drug metabolizing enzymes. All three cases exhibit genotype-based diminished metabolic capability that, in combination with their enzyme inhibiting/competing medications, decreased metabolism further and are the likely cause of these catastrophic events.

Pharmacogenetics of CYP2D6 and tamoxifen therapy: Light at the end of the tunnel?

The clinical usefulness of assessing the enzymatic activity of CYPD6 in patients taking tamoxifen had been longly debated. In favour of preemptive evaluation of phenotypic profile of patients is the strong pharmacologic rationale, being that the formation of endoxifen, the major and clinically most important metabolite of tamoxifen, is largely dependent on the activity of CYP2D6. This enzyme is highly polymorphic for which the activity is largely depending on genetics, but that can also be inhibited by a number of drugs, i.e. antidepressants, which are frequently used in patients with cancer. Unfortunately, the clinical trials that have been published in the last years are contradicting each other on the association between CYP2D6 and significant clinical endpoints, and for this reason CYP2D6 genotyping is at present not generally recommended. Despite this, the CYP2D6 genotyping test for tamoxifen is available in many laboratories and it may still be an appropriate test to use it in specific cases.

Evaluating the impact of missenses mutations in CYP2D6*7 and CYP2D6*14A: does it compromise tamoxifen metabolism?

CYP2D6 is a high polymorphic enzyme from P450, responsible for metabolizing almost 25% of drugs. The distribution of different mutations among CYP2D6 alleles has been associated with poor, intermediate, extensive and ultra-metabolizers.

AIM

To evaluate how missenses mutations in CYP2D6*7 and CYP2D6*14A poor metabolizer alleles affect CYP2D6 stability and function.

MATERIALS & METHODS

CYPalleles database was used to collect polymorphisms data present in 105 alleles. We selected only poor metabolizers alleles that presented exclusively missenses mutations. They were analyzed through seven algorithms to predict the impact on CYP2D6 structure and function.

RESULTS

H324P, the unique mutation in CYP2D6*7, has high impact in enzyme function due to its occurrence between two alpha-helixes involved in active site dynamics. G169R, a mutation that occurs only in CYP2D6*14A, leads to the gain of solvent accessibility and severe protein destabilization.

CONCLUSION

Our in silico analysis showed that missenses mutations in CYP2D6*7 and CYP2D6*14A cause CYP2D6 dysfunction.

Review of Scientific Evidence of Medicinal Convoy Plants in Traditional Persian Medicine

One concept used in traditional Persian medicine (TPM) for multidrug therapy is that of the convoy drug (Mobadregh). According to TPM texts, convoy drugs are substances (or drugs), which facilitate the access of drugs or foods to the whole body or to specific organs. This study reviewed some convoy drugs presented in TPM, their biological effects, and their probable interactions with main drugs, considering the increased absorption through inhibition of P-glycoprotein (P-gp) efflux function, bioavailability-enhancing effects, and decreased metabolism of the main drug using electronic databases including PubMed, Scopus, ScienceDirect, and Google Scholar in November and December, 2013. Recent studies have proven the beneficial effects of Crocus sativus L. (saffron) and camphor on the heart and brain, the cerebral therapeutic effects of Asarum europaeum (hazelwort), the hepatoprotective effects of Cichorium intybus (chicory), and Apium graveolens (celery) seeds, and the diuretic effects of Cinnamomum zeylanicum (cinnamon), and Cucumis melo (melon) seeds. The effects of vinegar in targeting the liver and brain have also been demonstrated. An evaluation of the results demonstrated that the suggested convoy drugs, including Piper nigrum (black pepper), Piper longum (long pepper), red wine, Camellia sinensis (tea), hazelwort, Mentha longifolia (pennyroyal), Anethum graveolens (dill), Foeniculum vulgare (fennel), cinnamon, and Sassafras albidum (sassafras) can increase the bioavailability of coadministered drugs by inhibition of P-gp or cytochrome P450s (CYP450s) or both of them. This evidence could be a good basis for the use of these agents as convoys in TPM.

The microbial pharmacists within us: a metagenomic view of xenobiotic metabolism

Although the importance of human genetic polymorphisms in therapeutic outcomes is well established, the role of our 'second genome' (the microbiome) has been largely overlooked. In this Review, we highlight recent studies that have shed light on the mechanisms that link the human gut microbiome to the efficacy and toxicity of xenobiotics, including drugs, dietary compounds and environmental toxins. Continued progress in this area could enable more precise tools for predicting patient responses and for the development of a new generation of therapeutics based on, or targeted at, the gut microbiome. Indeed, the admirable goal of precision medicine may require us to first understand the microbial pharmacists within.

The Role of Protein-Protein and Protein-Membrane Interactions on P450 Function

This symposium summary, sponsored by the ASPET, was held at Experimental Biology 2015 on March 29, 2015, in Boston, Massachusetts. The symposium focused on: 1) the interactions of cytochrome P450s (P450s) with their redox partners; and 2) the role of the lipid membrane in their orientation and stabilization. Two presentations discussed the interactions of P450s with NADPH-P450 reductase (CPR) and cytochrome b5. First, solution nuclear magnetic resonance was used to compare the protein interactions that facilitated either the hydroxylase or lyase activities of CYP17A1. The lyase interaction was stimulated by the presence of b5 and 17α-hydroxypregnenolone, whereas the hydroxylase reaction was predominant in the absence of b5. The role of b5 was also shown in vivo by selective hepatic knockout of b5 from mice expressing CYP3A4 and CYP2D6; the lack of b5 caused a decrease in the clearance of several substrates. The role of the membrane on P450 orientation was examined using computational methods, showing that the proximal region of the P450 molecule faced the aqueous phase. The distal region, containing the substrate-access channel, was associated with the membrane. The interaction of NADPH-P450 reductase (CPR) with the membrane was also described, showing the ability of CPR to "helicopter" above the membrane. Finally, the endoplasmic reticulum (ER) was shown to be heterogeneous, having ordered membrane regions containing cholesterol and more disordered regions. Interestingly, two closely related P450s, CYP1A1 and CYP1A2, resided in different regions of the ER. The structural characteristics of their localization were examined. These studies emphasize the importance of P450 protein organization to their function.

Effect of Ondansetron on Metformin Pharmacokinetics and Response in Healthy Subjects

The 5-hydroxytryptamine-3 (5-HT3) receptor antagonists such as ondansetron have been used to prevent and treat nausea and vomiting for over 2 decades. This study was to determine whether ondansetron could serve as a perpetrator drug causing transporter-mediated drug-drug interactions in humans. Twelve unrelated male healthy Chinese volunteers were enrolled into a prospective, randomized, double-blind, crossover study to investigate the effects of ondansetron or placebo on the pharmacokinetics of and the response to metformin, a well-characterized substrate of organic cation transporters and multidrug and toxin extrusions (MATEs). Ondansetron treatment caused a statistically significantly higher Cmax of metformin compared with placebo (18.3 ± 5.05 versus 15.2 ± 3.23; P = 0.006) and apparently decreased the renal clearance of metformin by 37% as compared with placebo (P = 0.001). Interestingly, ondansetron treatment also statistically significantly improved glucose tolerance in subjects, as indicated by the smaller glucose area under the curve in the oral glucose tolerance test (10.4 ± 1.43) as compared with placebo (11.5 ± 2.29 mmol∙mg/l) (P = 0.020). It remains possible that ondansetron itself may affect glucose homeostasis in human subjects, but our clinical study, coupled with our previous findings in cells and in animal models, indicates that ondansetron can cause a drug-drug interaction via its potent inhibition of MATE transporters in humans.

Interactive effects of selected pharmaceutical mixtures on bioaccumulation and biochemical status in crucian carp (Carassius auratus)

The aim of this study was to evaluate the interactive effects of fluoxetine (FLU), roxithromycin (ROX) and propranolol (PRP) on the bioaccumulation and biochemical responses in the crucian carp Carassius auratus. After 7 days of binary exposure (ROX + FLU and PRP + FLU), the addition of waterborne FLU at nominal concentrations of 4, 20 and 100 μg L(-1) significantly increased the accumulation of ROX and PRP in fish livers in most cases, although elevated ROX and PRP bioaccumulation levels were not observed in muscles or gills. The inductive response of 7-ethoxyresorufin O-deethylase (EROD) to PRP and that of 7-benzyloxy-4-trifluoromethyl-coumarin O-dibenzyloxylase (BFCOD) to ROX were inhibited by the co-administration of FLU at all tested concentrations. Correspondingly, marked inhibition of CYP1A and CYP3A mRNA expression levels was observed in the livers of fish co-treated with FLU + PRP and FLU + ROX relative to their PRP- and ROX-only counterparts, respectively. In addition, as reflected by superoxide dismutase (SOD) activity and malondialdehyde (MDA) content, co-exposure to ROX + FLU and PRP + FLU seemed to induce stronger antioxidant responses than single pharmaceutical exposure in fish livers. This work indicated that the interactive effects of pharmaceutical mixtures could lead to perturbations in the bioaccumulation and biochemical responses in fish.

Defective Cytochrome P450-Catalysed Drug Metabolism in Niemann-Pick Type C Disease

Niemann-Pick type C (NPC) disease is a neurodegenerative lysosomal storage disease caused by mutations in either the NPC1 or NPC2 gene. NPC is characterised by storage of multiple lipids in the late endosomal/lysosomal compartment, resulting in cellular and organ system dysfunction. The underlying molecular mechanisms that lead to the range of clinical presentations in NPC are not fully understood. While evaluating potential small molecule therapies in Npc1-/- mice, we observed a consistent pattern of toxicity associated with drugs metabolised by the cytochrome P450 system, suggesting a potential drug metabolism defect in NPC1 disease. Investigation of the P450 system in the context of NPC1 dysfunction revealed significant changes in the gene expression of many P450 associated genes across the full lifespan of Npc1-/- mice, decreased activity of cytochrome P450 reductase, and a global decrease of multiple cytochrome P450 catalysed dealkylation reactions. In vivo drug metabolism studies using a prototypic P450 metabolised drug, midazolam, confirmed dysfunction in drug clearance in the Npc1-/- mouse. Expression of the Phase II enzyme uridinediphosphate-glucuronosyltransferase (UGT) was also significantly reduced in Npc1-/- mice. Interestingly, reduced activity within the P450 system was also observed in heterozygous Npc1+/- mice. The reduced activity of P450 enzymes may be the result of bile acid deficiency/imbalance in Npc1-/- mice, as bile acid treatment significantly rescued P450 enzyme activity in Npc1-/- mice and has the potential to be an adjunctive therapy for NPC disease patients. The dysfunction in the cytochrome P450 system were recapitulated in the NPC1 feline model. Additionally, we present the first evidence that there are alterations in the P450 system in NPC1 patients.

Increased expression of CYP1A1 and CYP1B1 in ovarian/peritoneal endometriotic lesions

Endometriosis is an estrogen-dependent disease affecting up to 10% of all premenopausal women. There is evidence that different endometriosis sites show distinct local estrogen concentration, which, in turn, might be due to a unique local estrogen metabolism. We aimed to investigate whether there was a site-specific regulation of selected enzymes responsible for the oxidative metabolism of estrogens in biopsy samples and endometrial and endometriotic stromal cells. Cytochrome P450 (CYP) 1A1 and CYP1B1 mRNA and protein expressions in deep-infiltrating (rectal, retossigmoidal, and uterossacral) lesions, superficial (ovarian and peritoneal) lesions, and eutopic and healthy (control) endometrium were evaluated by real-time PCR and western blot. Using a cross-sectional study design with 58 premenopausal women who were not under hormonal treatment, we were able to identify an overall increased CYP1A1 and CYP1B1 mRNA expression in superficial lesions compared with the healthy endometrium. CYP1A1 mRNA expression in superficial lesions was also greater than in the eutopic endometrium. Interestingly, we found a similar pattern of CYP1A1 and CYP1B1 expression in in vitro stromal cells isolated from ovarian lesions (n=3) when compared with stromal cells isolated from either rectum lesions or eutopic endometrium. In contradiction, there was an increased half-life of estradiol (measured by HPLC-MS-MS) in ovarian endometriotic stromal cells compared with paired eutopic stromal endometrial cells. Our results indicate that there is a site-dependent regulation of CYP1A1 and CYP1B1 in ovarian/peritoneal lesions and ovarian endometriotic stromal cells, whereas a slower metabolism is taking place in these cells.

Primaquine pharmacology in the context of CYP 2D6 pharmacogenomics: Current state of the art

Primaquine is the only antimalarial drug available to clinicians for the treatment of relapsing forms of malaria. Primaquine development and usage dates back to the 1940s and has been administered to millions of individuals to treat and eliminate malaria infections. Primaquine therapy is not without disadvantages, however, as it can cause life threatening hemolysis in humans with glucose-6-phosphate dehydrogenase (G6PD) deficiency. In addition, the efficacy of primaquine against relapsing malaria was recently linked to CYP 2D6 mediated activation to an active metabolite, the structure of which has escaped definitive identification for over 75years. CYP 2D6 is highly polymorphic among various human populations adding further complexity to a comprehensive understanding of primaquine pharmacology. This review aims to discuss primaquine pharmacology in the context of state of the art understanding of CYP 2D6 mediated 8-aminoquinoline metabolic activation, and shed light on the current knowledge gaps of 8-aminoquinoline mechanistic understanding against relapsing malaria.

Effects of CYP3A5 genetic polymorphism and smoking on the prognosis of non-small-cell lung cancer

Objective

We aimed to explore the impacts of the rs776746 polymorphism in the CYP3A5 gene and smoking on the prognosis of non-small-cell lung cancer (NSCLC).

Materials and methods

Our study enrolled 104 early NSCLC patients undergoing surgery and 107 advanced NSCLC patients undergoing chemotherapy, hospitalized between December 2009 and December 2012 at the First Affiliated Hospital of Liaoning Medical University. All subjects with complete follow-up data were pathologically diagnosed. The rs776746 polymorphism and different genotypes (*1/*1, *1/*3, and *3/*3) were identified by polymerase chain-reaction restriction fragment-length polymorphism.

Results

Clinical response to chemotherapy in NSCLC patients with *1/*1 + *1/*3 genotypes were significantly worse than in those with the *3/*3 genotype (17.78% vs 56.45%, P<0.001), and after Bonferroni adjustment, the differences still showed significance (P_c<0.01). The mortality risk of NSCLC patients undergoing chemotherapy with the *3/*3 genotype was 0.617 times those with *1/*1 + *1/*3 genotypes (relative risk [RR] 0.617, 95% confidence interval [CI] 0.402–0.948; P=0.028), while the mortality risk of smoking patients was 1.743 times greater than that of nonsmoker patients (RR 1.743, 95% CI 1.133–2.679; P=0.042). Furthermore, a 3.087-fold mortality risk was found in NSCLC patients undergoing surgery with the *3/*3 genotype compared with those with *1/*1 + *1/*3 genotypes (RR 3.087, 95% CI 1.197–7.961; P=0.020). In NSCLC patients undergoing surgery, the mortality risk of smokers was 1.896 times greater than nonsmokers (RR 1.896, 95% CI 1.040–3.455; P=0.037).

Conclusion

Our study demonstrated that the CYP3A5 rs776746 polymorphism and smoking may influence the prognosis of NSCLC patients undergoing chemotherapy and surgery.

Untargeted plasma and tissue metabolomics in rats with chronic kidney disease given AST-120

Chronic kidney disease (CKD) results in the accumulation of metabolic waste products that are normally cleared by the kidney, known as uremia. Many of these waste products are from bacteria metabolites in the gut. Accumulation of uremic toxins in plasma and tissue, as well as the gut-plasma-tissue metabolic axis are important for understanding pathophysiological mechanisms of comorbidities in CKD. In this study, an untargeted metabolomics approach was used to determine uremic toxin accumulation in plasma, liver, heart and kidney tissue in rats with adenine-induced CKD. Rats with CKD were also given AST-120, a spherical carbon adsorbent, to assess metabolic changes in plasma and tissues with the removal of gut-derived uremic toxins. AST-120 decreased >55% of metabolites that were increased in plasma, liver and heart tissue of rats with CKD. CKD was primarily defined by 8 gut-derived uremic toxins, which were significantly increased in plasma and all tissues. These metabolites were derived from aromatic amino acids and soy protein including: indoxyl sulfate, p-cresyl sulfate, hippuric acid, phenyl sulfate, pyrocatechol sulfate, 4-ethylphenyl sulfate, p-cresol glucuronide and equol 7-glucuronide. Our results highlight the importance of diet and gut-derived metabolites in the accumulation of uremic toxins and define the gut-plasma-tissue metabolic axis in CKD.

Cytochrome P450 and matrix metalloproteinase genetic modifiers of disease severity in Cerebral Cavernous Malformation type 1

BACKGROUND

Familial Cerebral Cavernous Malformation type 1 (CCM1) is an autosomal dominant disease caused by mutations in the Krev Interaction Trapped 1 (KRIT1/CCM1) gene, and characterized by multiple brain lesions. CCM lesions manifest across a range of different phenotypes, including wide differences in lesion number, size and susceptibility to intracerebral hemorrhage (ICH). Oxidative stress plays an important role in cerebrovascular disease pathogenesis, raising the possibility that inter-individual variability in genes related to oxidative stress may contribute to the phenotypic differences observed in CCM1 disease. Here, we investigated whether candidate oxidative stress-related cytochrome P450 (CYP) and matrix metalloproteinase (MMP) genetic markers grouped by superfamilies, families or genes, or analyzed individually influence the severity of CCM1 disease.

METHODS

Clinical assessment and cerebral susceptibility-weighted magnetic resonance imaging (SWI) were performed to determine total and large (≥5mm in diameter) lesion counts as well as ICH in 188 Hispanic CCM1 patients harboring the founder KRIT1/CCM1 'common Hispanic mutation' (CCM1-CHM). Samples were genotyped on the Affymetrix Axiom Genome-Wide LAT1 Human Array. We analyzed 1,122 genetic markers (both single nucleotide polymorphisms (SNPs) and insertion/deletions) grouped by CYP and MMP superfamily, family or gene for association with total or large lesion count and ICH adjusted for age at enrollment and gender. Genetic markers bearing the associations were then analyzed individually.

RESULTS

The CYP superfamily showed a trend toward association with total lesion count (P=0.057) and large lesion count (P=0.088) in contrast to the MMP superfamily. The CYP4 and CYP8 families were associated with either large lesion count or total lesion count (P=0.014), and two other families (CYP46 and the MMP Stromelysins) were associated with ICH (P=0.011 and 0.007, respectively). CYP4F12 rs11085971, CYP8A1 rs5628, CYP46A1 rs10151332, and MMP3 rs117153070 single SNPs, mainly bearing the above-mentioned associations, were also individually associated with CCM1 disease severity.

CONCLUSIONS

Overall, our candidate oxidative stress-related genetic markers set approach outlined CYP and MMP families and identified suggestive SNPs that may impact the severity of CCM1 disease, including the development of numerous and large CCM lesions and ICH. These novel genetic risk factors of prognostic value could serve as early objective predictors of disease outcome and might ultimately provide better options for disease prevention and treatment.

Cytochrome P450 2C19 polymorphisms and valproic acid-induced weight gain

OBJECTIVES

Cytochrome P450 (CYP) 2C19 plays a role in the biotransformation of clinically relevant drugs as well as endogenous compounds, including sex hormones, which are known to be modulators of food intake and energy balance in humans. We attempted to investigate the influence of CYP2C19 polymorphisms on valproic acid (VPA)-induced weight gain.

MATERIALS AND METHODS

This retrospective longitudinal study included 85 VPA-treated and 93 carbamazepine (CBZ)-treated (as a reference) young patients with epilepsy. The body mass index (BMI) gap between the patient's BMI and the cutoff value for being overweight was calculated in each patient during the follow-up period. The longitudinal associations of the CYP2C19 genotype with the BMI gap and risk for becoming overweight during VPA or CBZ therapy were examined retrospectively using the generalized estimating equations approach and the Kaplan-Meier method.

RESULTS

During the follow-up period, the values of the BMI gap were significantly greater (P = 0.002 or P = 0.005) and the cumulative incidence of becoming overweight tended to be higher (P = 0.032) in the VPA-treated female patients with one or two loss-of-function CYP2C19 alleles than in the females without the loss-of-function CYP2C19 alleles. No associations were observed among the VPA-treated male patients and CBZ-treated male and female patients (P > 0.05).

CONCLUSIONS

This is the first report to show a relationship between the CYP2C19 polymorphism and VPA-induced weight gain in female patients with epilepsy. Further investigations are needed to verify these findings.

Design and synthesis of novel flexible ester-containing analogs of tamoxifen and their evaluation as anticancer agents

Background: Tamoxifen (TAM) is metabolized to the more active 4-hydroxytamoxifen by CYP2D6 enzyme. Due to the genetic polymorphisms in CYP2D6, clinical outcomes of TAM treatment vary. Novel flexible TAM analogs with altered activation pathway were synthesized and were tested for their antiproliferative action on MCF-7 cell lines and their binding affinity for ERα and ERβ. Results: All compounds showed better antiproliferative activity than TAM. Compound 3 showed 80-times more ERα binding than TAM, 900-times more selectivity toward ERα. Compound 3 was tested on the entire National Cancer Institute cancerous cell lines; results indicated a broad spectrum anticancer activity. Conclusion: The novel analogs were more potent than TAM with higher selectivity toward ERα and with potential metabolic stability toward CYP2D6.

Drug metabolism and clearance system in tumor cells of patients with multiple myeloma

Resistance to chemotherapy is a major limitation of cancer treatments with several molecular mechanisms involved, in particular altered local drug metabolism and detoxification process. The role of drug metabolism and clearance system has not been satisfactorily investigated in Multiple Myeloma (MM), a malignant plasma cell cancer for which a majority of patients escapes treatment. The expression of 350 genes encoding for uptake carriers, xenobiotic receptors, phase I and II Drug Metabolizing Enzymes (DMEs) and efflux transporters was interrogated in MM cells (MMCs) of newly-diagnosed patients in relation to their event free survival. MMCs of patients with a favourable outcome have an increased expression of genes coding for xenobiotic receptors (RXRα, LXR, CAR and FXR) and accordingly of their gene targets, influx transporters and phase I/II DMEs. On the contrary, MMCs of patients with unfavourable outcome displayed a global down regulation of genes coding for xenobiotic receptors and the downstream detoxification genes but had a high expression of genes coding for ARNT and Nrf2 pathways and ABC transporters. Altogether, these data suggests ARNT and Nrf2 pathways could be involved in MM primary resistance and that targeting RXRα, PXR, LXR and FXR through agonists could open new perspectives to alleviate or reverse MM drug resistance.