Following the discovery of 2-(3-methoxyphenyl)-3,4-dihydroquinazoline-4-one and 2-(3-methoxyphenyl)quinazoline-4-thione as potent, but non-specific activators of the human Constitutive Androstane Receptor (CAR, NR1I3), a series of quinazolinones substituted at the C2 phenyl ring was prepared to examine their ability to selectively modulate human CAR activity. Employing cellular and in vitro TR-FRET assays with wild-type CAR or its variant 3 (CAR3) ligand binding domains (LBD), several novel partial human CAR agonists and antagonists were identified. 2-(3-Methylphenyl) quinazolinone derivatives 7d and 8d acted as partial agonists with the recombinant CAR LBD, the former in nanomolar units (EC50 = 0.055 μM and 10.6 μM, respectively). Moreover, 7d did not activate PXR, and did not show any signs of cytotoxicity. On the other hand, 2-(4-bromophenyl)quinazoline-4-thione 7l possessed significant CAR antagonistic activity, although the compound displayed no agonistic or inverse agonistic activities. A compound possessing purely antagonistic effect was thus identified for the first time. These and related compounds may serve as a remedy in xenobiotic intoxication or, conversely, in suppression of undesirable hepatic CAR activation.
The nuclear constitutive androstane receptor (CAR, NR1I3) plays significant roles in many hepatic functions, such as fatty acid oxidation, biotransformation, liver regeneration, as well as clearance of steroid hormones, cholesterol, and bilirubin. CAR has been proposed as a hypothetical target receptor for metabolic or liver disease therapy. Currently known prototype high-affinity human CAR agonists such as CITCO (6-(4-chlorophenyl)imidazo[2,1-b][1,3]thiazole-5-carbaldehyde-O-(3,4-dichlorobenzyl)oxime) have limited selectivity, activating the pregnane X receptor (PXR) receptor, a related receptor of the NR1I subfamily. We have discovered several derivatives of 3-(1H-1,2,3-triazol-4-yl)imidazo[1,2-a]pyridine that directly activate human CAR in nanomolar concentrations. While compound 39 regulates CAR target genes in humanized CAR mice as well as human hepatocytes, it does not activate other nuclear receptors and is nontoxic in cellular and genotoxic assays as well as in rodent toxicity studies. Our findings concerning potent human CAR agonists with in vivo activity reinforce the role of CAR as a possible therapeutic target.
- MeSH
- hepatocyty účinky léků metabolismus MeSH
- konstitutivní androstanový receptor * agonisté chemie MeSH
- lidé MeSH
- myši MeSH
- pyridiny farmakologie MeSH
- receptory cytoplazmatické a nukleární metabolismus MeSH
- steroidní receptory * agonisté chemie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
AIM: To investigate the effect of resveratrol on biliary secretion of cholephilic compounds in healthy and bile duct-obstructed rats. METHODS: Resveratrol (RSV) or saline were administered to rats by daily oral gavage for 28 d after sham operation or reversible bile duct obstruction (BDO). Bile was collected 24 h after the last gavage during an intravenous bolus dose of the Mdr1/Mrp2 substrate azithromycin. Bile acids, glutathione and azithromycin were measured in bile to quantify their level of biliary secretion. Liver expression of enzymes and transporters relevant for bile production and biliary secretion of major bile constituents and drugs were analyzed at the mRNA and protein levels using qRT-PCR and Western blot analysis, respectively. The TR-FRET PXR Competitive Binding Assay kit was used to determine the agonism of RSV at the pregnane X receptor. RESULTS: RSV increased bile flow in sham-operated rats due to increased biliary secretion of bile acids (BA) and glutathione. This effect was accompanied by the induction of the hepatic rate-limiting transporters for bile acids and glutathione, Bsep and Mrp2, respectively. RSV also induced Cyp7a1, an enzyme that is crucial for bile acid synthesis; Mrp4, a transporter important for BA secretion from hepatocytes to blood; and Mdr1, the major apical transporter for xenobiotics. The findings were supported by increased biliary secretion of azithromycin. The TR-FRET PXR competitive binding assay confirmed RSV as a weak agonist of the human nuclear receptor PXR, which is a transcriptional regulator of Mdr1/Mrp2. RSV demonstrated significant hepatoprotective properties against BDO-induced cirrhosis. RSV also reduced bile flow in BDO rats without any corresponding change in the levels of the transporters and enzymes involved in RSV-mediated hepatoprotection. CONCLUSION: Resveratrol administration for 28 d has a distinct effect on bile flow and biliary secretion of cholephilic compounds in healthy and bile duct-obstructed rats.
- MeSH
- ABC transportéry metabolismus MeSH
- antiflogistika nesteroidní farmakologie terapeutické užití MeSH
- antioxidancia farmakologie terapeutické užití MeSH
- aplikace orální MeSH
- azithromycin farmakokinetika MeSH
- cholestáza farmakoterapie etiologie patofyziologie MeSH
- glutathion sekrece MeSH
- hepatocyty účinky léků metabolismus sekrece MeSH
- játra účinky léků metabolismus patofyziologie MeSH
- krysa rodu rattus MeSH
- lidé MeSH
- modely nemocí na zvířatech MeSH
- potkani Wistar MeSH
- steroidní receptory agonisté MeSH
- stilbeny farmakologie terapeutické užití MeSH
- žlučové kyseliny a soli chemie sekrece MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- lidé MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The pregnane X receptor (PXR) is a transcription factor regulating P-glycoprotein (P-gp; ABCB1)-mediated transport and cytochrome P450 3A4 (CYP3A4)-mediated metabolism of xenobiotics thereby affecting the pharmacokinetics of many drugs and potentially modulating clinical efficacy. Thus, pharmacokinetic drug-drug interactions can arise from PXR activation. Here, we examined whether the selective α1-adrenoreceptor blocker tamsulosin or the antagonist of muscarinic receptors tolterodine affect PXR-mediated regulation of CYP3A4 and of P-gp at the messenger RNA (mRNA) and protein level in an enantiomer-specific way. In addition, the effect of tamsulosin and tolterodine on P-gp activity was evaluated. We used quantitative real-time PCR, gene reporter assay, western blotting, rhodamine efflux assay, and calcein assay for determination of expression, activity, and inhibition of P-glycoprotein. The studied compounds significantly and concentration-dependently increased PXR activity in the ABCB1-driven luciferase-based reporter gene assay. We observed much stronger induction of ABCB1 mRNA by S-tamsulosin as compared to the R or racemic form. R or racemic form of tolterodine and R-tamsulosin concentration-dependently increased P-gp protein expression; the latter also enhanced P-gp efflux function in a rhodamine-based efflux assay. R-tamsulosin and all forms of tolderodine slightly inhibited P-gp. The effect on CYP3A4 expression followed the same pattern but was much weaker. Taken together, tamsulosin and tolterodine are demonstrated to interfere with P-gp and CYP3A4 regulation in an enantiomer-specific way.
- MeSH
- cytochrom P-450 CYP3A genetika metabolismus MeSH
- isomerie MeSH
- lidé MeSH
- LLC-PK1 buňky MeSH
- messenger RNA genetika metabolismus MeSH
- myši MeSH
- nádorové buněčné linie MeSH
- P-glykoproteiny antagonisté a inhibitory genetika metabolismus MeSH
- prasata MeSH
- promotorové oblasti (genetika) MeSH
- regulace genové exprese enzymů účinky léků MeSH
- steroidní receptory agonisté metabolismus MeSH
- sulfonamidy chemie farmakologie MeSH
- tolterodin tartarát chemie farmakologie MeSH
- transfekce MeSH
- upregulace MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- vztahy mezi strukturou a aktivitou MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
Cytochrome P450 (CYP) expression and activity are not homogeneous in the liver lobules. Indeed, CYPs are mainly expressed and induced in centrilobular hepatocytes. The wingless-type MMTV integration site family (WNT)/β-catenin pathway was identified as a major regulator of this zonal organization. We have recently demonstrated that in primary human hepatocytes (PHHs), the expression of CYP2E1, CYP1A2, and aryl hydrocarbon receptor (AhR), but not of CYP3A4, is regulated by the WNT/β-catenin pathway in response to WNT3a, its canonical activator. Here, we investigated whether glycogen synthase kinase 3β (GSK3β) inhibitors, which mimic the action of WNT molecules, could be used in PHHs to activate the β-catenin pathway to study CYP expression. We assessed the activity of 6BIO (6-bromoindirubin-3'-oxime), CHIR99021 (6-((2-((4-(2,4-dichlorophenyl)-5-(4methyl-1H-imidazol-2-yl)pyrimidin-2-yl)amino)ethyl)amino) nicotinonitrile), and GSK3iXV (Pyridocarbazolo-cyclopentadienyl Ruthenium complex GSK3 inhibitor XV) that belong to structurally different families of GSK3β inhibitors. Using small interfering RNAs, reporter gene assays, and molecular docking predictions, we demonstrated that GSK3β inhibitors can activate the WNT/β-catenin pathway in PHHs to regulate CYP2E1 expression. We also found that 6BIO and GSK3iXV are AhR full agonists that participate, through AhR signaling, to CYP1A2 induction. Conversely, CHIR99021 is an AhR partial agonist, and a pregnane X receptor ligand and partial agonist, thus regulating CYP1A2 and CYP3A4 gene expression in a β-catenin-independent manner. In conclusion, GSK3β inhibitors can activate the WNT/β-catenin pathway in PHHs. Nevertheless, their role in CYP regulation should be analyzed with caution as these molecules can interact with xenosensors.
- MeSH
- beta-katenin agonisté antagonisté a inhibitory genetika metabolismus MeSH
- enzymová indukce účinky léků MeSH
- hepatocyty cytologie účinky léků metabolismus MeSH
- indoly farmakologie MeSH
- induktory cytochromu P450 chemie metabolismus farmakologie MeSH
- inhibitory proteinkinas chemie metabolismus farmakologie MeSH
- kinasa 3 glykogensynthasy antagonisté a inhibitory metabolismus MeSH
- kultivované buňky MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- organokovové sloučeniny farmakologie MeSH
- oximy farmakologie MeSH
- pyridiny farmakologie MeSH
- pyrimidiny farmakologie MeSH
- receptory aromatických uhlovodíků agonisté chemie genetika metabolismus MeSH
- rekombinantní fúzní proteiny chemie metabolismus MeSH
- reportérové geny účinky léků MeSH
- RNA interference MeSH
- signální dráha Wnt účinky léků MeSH
- simulace molekulového dockingu MeSH
- steroidní receptory agonisté genetika metabolismus MeSH
- systém (enzymů) cytochromů P-450 chemie genetika metabolismus MeSH
- transkripční faktory bHLH agonisté chemie genetika metabolismus MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
In the past decade, a large number of enantiopure drugs were introduced to clinical practice, since improved therapeutic effects were demonstrated for one of the enantiomers from originally racemic drug. While the therapeutic effects and safety of enantiopure drugs were tested prior to their approval, various biological enantiospecific activities of these, often "old" drugs, remain to be elucidated. In the current paper, we examined enantiospecific effects of clinically used enantiopure drugs containing one chiral center in the structure (i.e. zopiclone, tamsulosin, tolterodine, modafinil, citalopram) towards aryl hydrocarbon (AhR), glucocorticoid (GR) and pregnane X (PXR) receptors in human reporter cell lines. The cytotoxicity (IC50), agonist (EC50) and antagonist effects (IC50) of R-form, S-form and racemic mixture for each tested drugs were determined and compared in AhR-, GR- and PXR-gene reporter cell lines. Since AhR, GR and PXR are key regulators of drug metabolism, energy metabolism, immunity and play many other physiological functions, the data presented here might be of toxicological significance.
- MeSH
- azabicyklické sloučeniny chemie farmakologie MeSH
- benzhydrylové sloučeniny chemie farmakologie MeSH
- buněčné linie MeSH
- buňky Hep G2 MeSH
- citalopram chemie farmakologie MeSH
- fenylpropanolamin chemie farmakologie MeSH
- kresoly chemie farmakologie MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- piperaziny chemie farmakologie MeSH
- receptory aromatických uhlovodíků agonisté antagonisté a inhibitory metabolismus MeSH
- receptory glukokortikoidů agonisté antagonisté a inhibitory metabolismus MeSH
- reportérové geny genetika MeSH
- stereoizomerie MeSH
- steroidní receptory agonisté antagonisté a inhibitory metabolismus MeSH
- sulfonamidy chemie farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Steroid hormone receptors represent a major target in drug discovery. As ligand inducible transcription factors, their activity can be modulated by small lipophilic molecules. Here we describe two panels of potent and selective luciferase reporter cell lines based on cells with low endogenous steroid receptor activity (U2OS). The panels contain reporter cell lines for estrogen receptors α and β, androgen, glucocorticoid, mineralocorticoid, and progesterone receptors. In the first panel, the activation of either synthetic, steroid response elements containing promoter or viral promoter is mediated by full-length steroid receptors. The second panel is based on the expression of the chimeric receptor, which was created by the replacement of the N-terminal part of the molecule by Gal4 DBD and that binds to multiple UAS sites in the reporter promoter. Both panels were extensively characterized by profiling 28 ligands in dose response manner in agonist and antagonist mode. We have analyzed and compared the responses to tested ligands from both panels and concluded that in general both systems generated similar qualitative response in terms of potency, efficacy, partial agonism/antagonism, mixed agonistic/antagonistic profiles and the rank of potencies was well conserved between both panels. However, we have also identified some artifacts introduced by the Gal4/LBD reporter assays in contrast to their full-length receptor reporter counterparts. Keeping in mind the advantages and drawbacks of each reporter format, these cell lines represent powerful and selective tools for profiling large compound libraries (HTS) and for detailed study of mechanisms by which compounds exert their biological effects.
- MeSH
- aktivace transkripce účinky léků MeSH
- genetické inženýrství metody MeSH
- knihovny malých molekul analýza MeSH
- lidé MeSH
- luciferasy genetika metabolismus MeSH
- nádorové buněčné linie MeSH
- objevování léků metody MeSH
- plazmidy genetika MeSH
- promotorové oblasti (genetika) účinky léků MeSH
- rekombinantní proteiny genetika metabolismus MeSH
- reportérové geny MeSH
- rychlé screeningové testy metody MeSH
- sekvenční delece MeSH
- steroidní receptory agonisté antagonisté a inhibitory genetika metabolismus MeSH
- steroidy farmakologie MeSH
- transfekce MeSH
- transkripční faktory genetika metabolismus MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Drugs for weight loss have been in use for nearly hundred years. Orlistat (Xenical) is a non-centrally acting anti-obesity drug that inactivates gastric and intestinal lipases, thus, preventing absorption of dietary triglycerides. There are reports indicating that Orlistat reduces bioavailability of Cyclosporin to a clinically relevant degree. Since Cyclosporin is metabolized by cytochrome P450 CYP3A4, we examined whether interaction between Orlistat and Cyclosporin involves induction of CYP3A4. Human Caucasian colon adenocarcinoma cells LS174T and primary cultures of human hepatocytes were used, as in vitro models of intestinal and hepatic cells, respectively. Treatment of LS174T cells for 24h with Orlistat (1-100mg/L) did not cause induction of CYP3A4 mRNA levels as compared to control cells while Orlistat (100mg/L) slightly induced CYP3A4 mRNA in human hepatocytes. Rifampicin, a model CYP3A4 inducer, significantly induced CYP3A4 mRNA in both types of cells. The level of CYP3A4 protein in human hepatocytes was increased by Orlistat after 48h, while rifampicin strongly induced CYP3A4 protein level. In addition, Orlistat moderately dose-independently activated pregnane X receptor (PXR) in LS174T cells transiently transfected with p3A4-luc reporter construct containing the basal promoter (-362/+53) with proximal PXR response element and the distal xenobiotic responsive enhancer module (-7836/-7208) of the CYP3A4 gene 5'-flanking region. In conclusion, we report here that Orlistat is weak PXR activator and CYP3A4 inducer in human hepatocytes, but it has no effect on CYP3A4 in intestinal cells, implying no role of CYP3A4 induction in the interaction between Orlistat and Cyclosporin in absorption process.
- MeSH
- biologická dostupnost MeSH
- cytochrom P-450 CYP3A genetika metabolismus MeSH
- hepatocyty cytologie účinky léků MeSH
- inhibitory enzymů farmakologie MeSH
- laktony farmakologie MeSH
- lidé MeSH
- messenger RNA genetika MeSH
- nádorové buněčné linie MeSH
- promotorové oblasti (genetika) MeSH
- steroidní receptory agonisté MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
