Agonism of human pregnane X receptor by rilpivirine and etravirine: Comparison with first generation non-nucleoside reverse transcriptase inhibitors

Sharma, Devinder; Lau, Aik Jiang; Sherman, Matthew A.; Chang, Thomas K. H.

doi:10.1016/j.bcp.2013.04.002

Cited by 35 publications

(44 citation statements)

References 54 publications

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“…As such, human hepatocellular carcinoma HepG2 cells were transfected with the plasmid pGL3-basic-CYP3A4–362(7836/7208ins)-luc, containing a firefly luciferase gene under the control of the PXR-activated regulatory elements in order to assay for PXR transcriptional activity [9] . In agreement with previously published data, we observe activation of PXR by EFV (10 µM; an approximate 4.3-fold increase in luciferase activity) (Figure 2) [10] ; however, treatment with 8-OHEFV did not result in activation of PXR. RIF, a prototypic activator of human PXR employed here as a positive control, yielded the greatest increase in firefly luciferase activity of 9.5-fold relative to empty vector drug treatment (Figure 2).…”

Section: Resultssupporting

confidence: 93%

Probing Ligand Structure–Activity Relationships in Pregnane X Receptor (PXR): Efavirenz and 8‐Hydroxyefavirenz Exhibit Divergence in Activation

et al. 2018

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Efavirenz (EFV), an antiretroviral that interacts clinically with co-administered drugs via activation of the pregnane X receptor (PXR), is extensively metabolized by the cytochromes P450. We tested whether its primary metabolite, 8-hydroxyEFV (8-OHEFV) can activate PXR and potentially contribute to PXR-mediated drug-drug interactions attributed to EFV. Luciferase reporter assays revealed that despite only differing from EFV by an oxygen atom, 8-OHEFV does not activate PXR. Corroborating this, treatment with EFV for 72 h elevated the mRNA abundance of the PXR target gene, Cyp3a11, by approximately 28-fold in primary hepatocytes isolated from PXR-humanized mice, whereas treatment with 8-OHEFV did not result in a change in Cyp3A11 mRNA levels. FRET-based competitive binding assays and isothermal calorimetry demonstrated that even with the lack of ability to activate PXR, 8-OHEFV displays an affinity for PXR (IC 12.1 μm; K 7.9 μm) nearly identical to that of EFV (IC 18.7 μm; K 12.5 μm). The use of 16 EFV analogues suggest that other discreet changes to the EFV structure beyond the 8-position are well tolerated. Molecular docking simulations implicate an 8-OHEFV binding mode that may underlie its divergence in PXR activation from EFV.

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Section: Resultssupporting

confidence: 93%

Probing Ligand Structure–Activity Relationships in Pregnane X Receptor (PXR): Efavirenz and 8‐Hydroxyefavirenz Exhibit Divergence in Activation

et al. 2018

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“…Our screen identified metolazone (MET) as an activator of PXR. We also found PXR activation by other drugs that have been previously published, including rifampicin [39], nimodipine [40], phenylbutazone [41], efavirenz [42, 43], montelukast [44], and diclofenac [45]. Analysis of the screening data showed that rifampicin and MET induced 193% and 182% activation of the CYP3A4-luc reporter (DMSO set as 0% and rifampicin at 5 μM set as 100%).…”

Section: Resultssupporting

confidence: 57%

Thiazide-like diuretic drug metolazone activates human pregnane X receptor to induce cytochrome 3A4 and multidrug-resistance protein 1

Banerjee

Chen

2014

Biochemical Pharmacology

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Human pregnane X receptor (hPXR) regulates the expression of drug-metabolizing enzyme cytochrome P450 3A4 (CYP3A4) and drug transporters such as multidrug-resistance protein 1 (MDR1). PXR can be modulated by small molecules, including Federal Drug Administration (FDA)–approved drugs, thus altering drug metabolism and causing drug-drug interactions. To determine the role of FDA-approved drugs in PXR-mediated regulation of drug metabolism and clearance, we screened 1481 FDA-approved small-molecule drugs by using a luciferase reporter assay in HEK293T cells and identified the diuretic drug metolazone as an activator of PXR. Our data showed that metolazone activated hPXR-mediated expression of CYP3A4 and MDR1 in human hepatocytes and intestine cells and increased CYP3A4 promoter activity in various cell lines. Mammalian two-hybrid assays showed that hPXR recruits its co-activator SRC-1 upon metolazone binding in HepG2 cells, explaining the mechanism of hPXR activation. To understand the role of other commonly-used diuretics in PXR activation and the structure-activity relationship of metolazone, thiazide and non-thiazide diuretics drugs were also tested but only metolazone activates PXR. To understand the molecular mechanism, docking studies and mutational analysis were carried out and showed that metolazone binds in the ligand-binding pocket and interacts with mostly hydrophobic amino acid residues. This is the first report showing that metolazone activates PXR. Because activation of hPXR might cause drug-drug interactions, metolazone should be used with caution for drug treatment in patients undergoing combination therapy.

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“…PXR is a ligand-activated transcription factor involved in regulating the expression of biologically important genes that are involved in various physiological processes [43, 44]. PXR functions as a xenobiotic sensor mainly due to its ability to accommodate structurally diverse xenobiotics.…”

Section: Discussionmentioning

confidence: 99%

Differential regulation of CYP3A4 promoter activity by a new class of natural product derivatives binding to pregnane X receptor

Banerjee

Chen

2013

Biochemical Pharmacology

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The pregnane X receptor (PXR) regulates drug metabolism by regulating the expression of drug-metabolizing enzymes such as cytochrome P450 3A4 (CYP3A4), which is involved in the metabolism of >50% of clinically prescribed drugs. The activity of PXR can be controlled by the binding of small molecule agonists or antagonists. Because of its unique ligand binding pocket, PXR binds promiscuously to structurally diverse chemicals. To study the structure-activity relationship, novel modulators for PXR are needed. Here we report the virtual screening of ~25,000 natural product derivatives from the ZINC database using the Molecular Operating Environment docking software tool against the PXR-rifampicin complex x-ray crystal structure. Our screening resulted in identification of compounds based on the lowest S score, which measures Gibbs free energy. Interestingly, we found that the compounds that bind directly to PXR, as revealed in an intrinsic tryptophan fluorescence assay, modulate CYP3A4 promoter activity differentially in HepG2 cells. Mutational analysis and docking studies showed that these compounds bind broadly in the ligand binding pocket but interact with different amino acid residues. We further investigated the mechanism of binding by analyzing the functional groups that are important for distinguishing agonists from antagonists. The approach we used to identify novel modulators that bind to PXR can be useful for finding novel modulators of PXR.

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Agonism of human pregnane X receptor by rilpivirine and etravirine: Comparison with first generation non-nucleoside reverse transcriptase inhibitors

Cited by 35 publications

References 54 publications

Probing Ligand Structure–Activity Relationships in Pregnane X Receptor (PXR): Efavirenz and 8‐Hydroxyefavirenz Exhibit Divergence in Activation

Probing Ligand Structure–Activity Relationships in Pregnane X Receptor (PXR): Efavirenz and 8‐Hydroxyefavirenz Exhibit Divergence in Activation

Thiazide-like diuretic drug metolazone activates human pregnane X receptor to induce cytochrome 3A4 and multidrug-resistance protein 1

Differential regulation of CYP3A4 promoter activity by a new class of natural product derivatives binding to pregnane X receptor

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