BACKGROUND: Hepatocellular carcinoma (HCC) is a major contributor to the worldwide cancer burden. Recent studies on HCC have demonstrated dramatic alterations in expression of several cytochrome P450 (CYP) family members that play a crucial role in biotransformation of many drugs and other xenobiotics; however, the mechanisms responsible for their deregulation remain unclear. METHODS: We investigated a potential involvement of miRNAs in downregulation of expression of CYPs observed in HCC tumors. We compared miRNA expression profiles (TaqMan Array Human MicroRNA v3.0 TLDA qPCR) between HCC human patient tumors with strong (CYP-) and weak/no (CYP+) downregulation of drug-metabolizing CYPs. The role of significantly deregulated miRNAs in modulation of expression of the CYPs and associated xenobiotic receptors was then investigated in human liver HepaRG cells transfected with relevant miRNA mimics or inhibitors. RESULTS: We identified five differentially expressed miRNAs in CYP- versus CYP+ tumors, namely miR-29c, miR-125b1, miR-505, miR-653 and miR-675. The two most-upregulated miRNAs found in CYP- tumor samples, miR-29c and miR-653, were found to act as efficient suppressors of CYP1A2 or AHR expression. CONCLUSIONS: Our results revealed a novel role of miR-653 and miR-29c in regulation of expresion of CYPs involved in crucial biotransformation processes in liver, which are often deregulated during liver cancer progression.
- MeSH
- biotransformace MeSH
- cytochrom P-450 CYP1A2 metabolismus MeSH
- down regulace MeSH
- hepatocelulární karcinom * genetika metabolismus MeSH
- hepatocyty metabolismus MeSH
- lidé MeSH
- mikro RNA metabolismus MeSH
- nádorové buněčné linie MeSH
- nádory jater * genetika metabolismus MeSH
- regulace genové exprese u nádorů MeSH
- xenobiotika metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Objectives Cytochromes P450 play a role in human drugs metabolic pathways and their genes are among the most variable in humans. The aim of this study was to analyze genotype frequencies of five common polymorphisms of cytochromes P450 in Roma/Gypsy and Czech (non-Roma) population samples with Czech origin. Methods Roma/Gypsy (n=302) and Czech subjects (n=298) were genotyped for CYP1A2 (rs762551), CYP2A6 (rs4105144), CYP2B6 (rs3745274) and CYP2D6 (rs3892097; rs1065852) polymorphisms using PCR-RFLP or Taqman assay. Results We found significant allelic/genotype differences between ethnics in three genes. For rs3745274 polymorphism, there was increased frequency of T allele carriers in Roma in comparison with Czech population (53.1 vs. 43.7%; p=0.02). For rs4105144 (CYP2A6) there was higher frequency of T allele carriers in Roma in comparison with Czech population (68.7 vs. 49.8%; p<0.0001). For rs3892097 (CYP2D6) there was more carriers of the A allele between Roma in comparison with Czech population (39.2 vs. 38.2%; p=0.048). Genotype/allelic frequencies of CYP2D6 (rs1065852) and CYP1A2 (rs762551) variants did not significantly differ between the ethnics. Conclusions There were significant differences in allelic/genotype frequencies of some, but not all cytochromes P450 polymorphisms between the Czech Roma/Gypsies and Czech non-Roma subjects.
- MeSH
- cytochrom P-450 CYP1A2 genetika metabolismus MeSH
- cytochrom P-450 CYP2D6 genetika metabolismus MeSH
- cytochrom P450 CYP2A6 genetika metabolismus MeSH
- cytochrom P450 CYP2B6 genetika metabolismus MeSH
- dospělí MeSH
- genotyp MeSH
- lidé MeSH
- polymorfismus genetický genetika MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
The selection of a suitable combination of reference genes (RGs) for data normalization is a crucial step for obtaining reliable and reproducible results from transcriptional response analysis using a reverse transcription-quantitative polymerase chain reaction. This is especially so if a three-dimensional multicellular model prepared from liver tissues originating from biologically diverse human individuals is used. The mRNA and miRNA RGs stability were studied in thirty-five human liver tissue samples and twelve precision-cut human liver slices (PCLS) treated for 24 h with dimethyl sulfoxide (controls) and PCLS treated with β-naphthoflavone (10 μM) or rifampicin (10 μM) as cytochrome P450 (CYP) inducers. Validation of RGs was performed by an expression analysis of CYP3A4 and CYP1A2 on rifampicin and β-naphthoflavone induction, respectively. Regarding mRNA, the best combination of RGs for the controls was YWHAZ and B2M, while YWHAZ and ACTB were selected for the liver samples and treated PCLS. Stability of all candidate miRNA RGs was comparable or better than that of generally used short non-coding RNA U6. The best combination for the control PCLS was miR-16-5p and miR-152-3p, in contrast to the miR-16-5b and miR-23b-3p selected for the treated PCLS. Our results showed that the candidate RGs were rather stable, especially for miRNA in human PCLS.
- MeSH
- beta-2-mikroglobulin genetika metabolismus MeSH
- beta-naftoflavon farmakologie MeSH
- cytochrom P-450 CYP1A2 genetika metabolismus MeSH
- cytochrom P-450 CYP3A genetika metabolismus MeSH
- dimethylsulfoxid farmakologie MeSH
- dospělí MeSH
- játra účinky léků metabolismus MeSH
- kvantitativní polymerázová řetězová reakce normy MeSH
- lidé středního věku MeSH
- lidé MeSH
- messenger RNA genetika metabolismus MeSH
- mikro RNA genetika metabolismus MeSH
- proteiny 14-3-3 genetika metabolismus MeSH
- referenční standardy MeSH
- rifampin farmakologie MeSH
- senioři MeSH
- stanovení celkové genové exprese normy MeSH
- systém (enzymů) cytochromů P-450 farmakologie MeSH
- transkriptom MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
In the present study, time-dependency of the induction effect of a selective inducer on the activity, protein and mRNA levels of cytochromes P450 1A1/2 (CYP1A1/2), NAD(P)H:quinone oxidoreductase 1 (NQO1) and glutathione S-transferases (GSTA), in primary culture of rat hepatocytes was tested and evaluated. To show the differences in responses of tested enzymes, the common aryl hydrocarbon receptor (AhR) ligand agonist, beta-naphthoflavone (BNF), was used. Induction of CYP1A1/2 by BNF was detected at all time intervals and at all levels (i.e., mRNA, protein, enzyme activity). Different responses of NQO1 and GSTA upon BNF treatment were observed. Our results demonstrate that the responses of different xenobiotic-metabolizing enzymes to the inducer vary in time and depend on the measured parameter. For these reasons, an induction study featuring only one-time interval treatment and/ or one parameter testing could produce misleading information.
- MeSH
- beta-naftoflavon metabolismus MeSH
- cytochrom P-450 CYP1A1 metabolismus MeSH
- cytochrom P-450 CYP1A2 metabolismus MeSH
- glutathiontransferasa metabolismus MeSH
- hepatocyty metabolismus MeSH
- játra metabolismus MeSH
- krysa rodu rattus MeSH
- ligandy MeSH
- messenger RNA metabolismus MeSH
- NAD(P)H dehydrogenasa (chinon) metabolismus MeSH
- receptory aromatických uhlovodíků metabolismus MeSH
- xenobiotika metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Sesquiterpenes, the main components of plant essential oils, are often taken in the form of folk medicines and dietary supplements. Several sesquiterpenes possess interesting biological activities but they could interact with concurrently administered drugs via inhibition of drug-metabolizing enzymes. Therefore, the present study was designed to test the potential inhibitory effect of tree structurally relative sesquiterpenes β-caryophyllene (CAR), β-caryophyllene oxide (CAO) and α-humulene (HUM) on the activities of the main drug-metabolizing enzymes. For this purpose, rat and human hepatic subcellular fractions were incubated with CAR, CAO or HUM together with specific substrates for oxidation, reduction and conjugation enzymes and their coenzymes. HPLC, spectrophotometric and spectrofluorimetric analyses of product formations were used. All tested sesquiterpenes significantly inhibited cytochromes P4503A (CYP3A) activities in rats as well as in human hepatic microsomes, with CAO being the strongest inhibitor. A non-competitive type of inhibition was found. On the other hand, none of the tested sesquiterpenes significantly affected the activities of carbonyl-reducing enzymes (CBR1, AKRs, NQO1) or conjugation enzymes (UGTs, GSTs, SULTs, COMT). As CYP3A enzymes metabolize many drugs, their inhibition by CAO, CAR and HUM might affect the pharmacokinetics of concurrently administered drugs. Similar results obtained in rat and human hepatic microsomes indicate that rats could be used for further testing of possible drug-sesquiterpenes interactions in vivo.
- MeSH
- antiflogistika nesteroidní chemie metabolismus MeSH
- cytochrom P-450 CYP1A2 chemie metabolismus MeSH
- cytochrom P-450 CYP3A chemie metabolismus MeSH
- inhibiční koncentrace 50 MeSH
- jaterní mikrozomy enzymologie MeSH
- játra enzymologie MeSH
- kinetika MeSH
- krysa rodu rattus MeSH
- lidé MeSH
- potkani Wistar MeSH
- seskviterpeny chemie metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- lidé MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Stevia rebaudiana Bertoni is a herb known for the high content of natural sweeteners in its leaves. Its main secondary metabolite stevioside is used as non-caloric sweetener. No information, however, is available on whether stevioside or steviol interact with drug-metabolizing enzymes and pose the potential risk of food-drug interactions. Similarly, data are lacking on the interactions of steviol and stevioside with key nuclear receptors controlling the expression of the main drug metabolizing enzymes. We studied the interactions of steviol and stevioside with the pregnane X (PXR), vitamin D (VDR), constitutive androstane (CAR), farnesoid X (FXR), glucocorticoid (GR) and aryl hydrocarbon (AHR) receptors, which control expression of genes of xenobiotic metabolism. In addition, the inhibitory activities of steviol and stevioside towards the major cytochrome P450 enzymes CYP3A4, CYP2C9, CYP2D6, CYP1A2 and CYP2B6 were evaluated in vitro. We found that steviol moderately activated the PXR and AHR, resulting in the induction of their target genes including CYP3A4 and CYP1A2 in primary human hepatocytes. A weak inhibition of CYP3A4 and CYP2C9 with steviol was also found. Our results provide mechanistic data indicating that stevioside and stevia sweeteners may have the potential to induce food-drug interactions, a finding that warrants future prospective clinical investigation.
- MeSH
- cytochrom P-450 CYP1A2 genetika metabolismus MeSH
- diterpeny kauranové metabolismus MeSH
- hepatocyty metabolismus MeSH
- kultivované buňky MeSH
- lidé MeSH
- metabolická inaktivace MeSH
- receptory aromatických uhlovodíků genetika metabolismus MeSH
- rostlinné extrakty metabolismus MeSH
- senioři MeSH
- sladidla metabolismus MeSH
- steroidní receptory genetika metabolismus MeSH
- Stevia chemie MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Článek shrnuje dosavadní zásadní literaturu a doporučení týkající se monitorování plazmatických koncentrací (therapeutic drug monitoring = TDM) antipsychotik, se zaměřením na olanzapin a klozapin. Vysvětluje pojem TDM, referenční rozmezí, shrnuje indikace k provádění TDM. Zabývá se faktory které mohou plazmatické koncentrace (PC = plasmatic concetration) ovlivnit, a naopak faktory, které mohou být PC ovlivněny. Uvádí, kde a jak se dá v České republice TDM provádět.
The article summarizes existing basic literature and recommendations concerning therapeutic drug monitoring (TDM) of antipsychotics. It is focused on olanzapine and clozapine. Moreover, the terms "therapeutic drug monitoring" and "therapeutic reference range" are explained and indications for TDM are summarized. The factors that can influence plasma levels and that can be influenced by plasma levels are also mentioned. The article reports, where and how TDM can be done in the Czech Republic.
- MeSH
- adherence k farmakoterapii statistika a číselné údaje MeSH
- antipsychotika * krev metabolismus MeSH
- benzothiepiny krev metabolismus MeSH
- cytochrom P-450 CYP1A2 genetika metabolismus MeSH
- induktory cytochromu P450 CYP1A2 metabolismus MeSH
- induktory cytochromu P450 MeSH
- inhibitory cytochromu P450 metabolismus MeSH
- klozapin krev metabolismus MeSH
- lékové interakce MeSH
- lidé MeSH
- monitorování léčiv ekonomika metody MeSH
- psychotické poruchy * farmakoterapie MeSH
- sexuální faktory MeSH
- tělesná hmotnost MeSH
- věkové faktory MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
In the recent years, a therapeutic potential of disulfiram (Antabuse) complex with copper, as an anticancer drug, was recognized towards several cancer cell lines. The proteasome was suggested as one of the cellular targets for this compound. As the therapeutic use of diethyldithiocarbamate-copper complex (CuET) is expected to increase, it is of great interest to know whether this compound may be the source of drug-drug interactions via the induction of biotransformation enzymes, especially cytochromes P450 (CYPs). To this purpose, we examined the effect of CuET and compared it with typical inducers (rifampicin and dioxin) of CYPs and with well-established proteasome inhibitors (MG132 and bortezomib). Diethyldithiocarbamate-copper complex revealed inconsistent and rather modulatory effect on the expression of CYP1A2 and CYP3A4 in several cultures of human hepatocytes. Moreover, it was able to cause neither ubiquitin accumulation nor significant and dose-dependent inhibition of proteasome activity. It had no effect on essential transcription factors involved in regulation of selected CYPs, aryl hydrocarbon (AhR) nor pregnane X receptor (PXR). However, the AhR protein was increased in majority of examined hepatocyte cultures. The main finding of this study is that: (i) disulfiram-copper complex is not the cause of drug-drug interactions via CYP1A2/3A4 induction; (ii) proteasome inhibitors may have different impact on studied parameters in given in vitro system.
- MeSH
- cytochrom P-450 CYP1A2 metabolismus MeSH
- cytochrom P-450 CYP3A metabolismus MeSH
- dithiokarb farmakologie MeSH
- dospělí MeSH
- hepatocyty účinky léků metabolismus MeSH
- inhibitory proteasomu farmakologie MeSH
- kultivované buňky MeSH
- lékové interakce MeSH
- lidé středního věku MeSH
- lidé MeSH
- měď farmakologie MeSH
- proteasomový endopeptidasový komplex metabolismus MeSH
- senioři MeSH
- steroidní receptory metabolismus MeSH
- transkripční faktory metabolismus MeSH
- uhlovodíky metabolismus MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Eukaryotic cytochromes P450 (P450) are membrane-bound enzymes oxidizing a broad spectrum of hydrophobic substrates, including xenobiotics. Protein-protein interactions play a critical role in this process. In particular, the formation of transient complexes of P450 with another protein of the endoplasmic reticulum membrane, cytochrome b5 (cyt b5), dictates catalytic activities of several P450s. To lay a structural foundation for the investigation of these effects, we constructed a model of the membrane-bound full-length human P450 1A2-cyt b5 complex. The model was assembled from several parts using a multiscale modeling approach covering all-atom and coarse-grained molecular dynamics (MD). For soluble P450 1A2-cyt b5 complexes, these simulations yielded three stable binding modes (sAI, sAII, and sB). The membrane-spanning transmembrane domains were reconstituted with the phospholipid bilayer using self-assembly MD. The predicted full-length membrane-bound complexes (mAI and mB) featured a spontaneously formed X-shaped contact between antiparallel transmembrane domains, whereas the mAII mode was found to be unstable in the membrane environment. The mutual position of soluble domains in binding mode mAI was analogous to the sAI complex. Featuring the largest contact area, the least structural flexibility, the shortest electron transfer distance, and the highest number of interprotein salt bridges, mode mAI is the best candidate for the catalytically relevant full-length complex.
- MeSH
- cytochrom P-450 CYP1A2 chemie metabolismus MeSH
- cytochromy b5 chemie metabolismus MeSH
- fosfolipidy chemie metabolismus MeSH
- lidé MeSH
- lipidové dvojvrstvy chemie metabolismus MeSH
- proteinové domény MeSH
- sekundární struktura proteinů MeSH
- simulace molekulární dynamiky MeSH
- vazba proteinů MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
