CYP3A4 Induction Research Articles

Nirmatrelvir combined with ritonavir for preventing and treating COVID-19.

Nirmatrelvir combined with ritonavir for preventing and treating COVID-19.

Ibrexafungerp: A new triterpenoid antifungal.

The pharmacology, microbiology, pharmacokinetics, pharmacodynamics, efficacy, safety, and role of ibrexafungerp in the treatment of fungal infections are reviewed. Ibrexafungerp is the first triterpenoid antifungal. Similarly to echinocandins, it inhibits the synthesis of 1,3-β-d-glucan. However, it binds to a different site on the enzyme than echinocandins, resulting in limited cross-resistance. Ibrexafungerp exerts concentration-dependent fungicidal activity against Candida species and retains in vitro activity against most fluconazole-resistant strains. It is also active against Aspergillus species. Ibrexafungerp has been shown to be safe and effective in the treatment of vulvovaginal candidiasis caused by Candida albicans in phase 2 and phase 3 clinical trials. It is approved for vulvovaginal candidiasis in adult and postmenarchal pediatric females and is given as two 150-mg tablets orally, administered 12 hours apart. Ibrexafungerp is contraindicated in pregnancy. The most commonly reported adverse reactions were diarrhea, nausea, abdominal pain, dizziness, and vomiting. Ibrexafungerp should be avoided with strong or moderate CYP3A inducers, and the dose should be reduced with strong CYP3A inhibitors. Ibrexafungerp may be useful for patients who are not able to receive fluconazole or prefer oral therapy for the treatment of vulvovaginal candidiasis. However, it is more expensive than the 150-mg tablet of generic fluconazole, which is the current standard of care for vulvovaginal candidiasis. Clinical trials are ongoing for recurrent and complicated vulvovaginal candidiasis as well as invasive candidiasis and pulmonary aspergillosis. Ibrexafungerp is an alternative to fluconazole for the treatment of vulvovaginal candidiasis in nonpregnant females. It has the potential to be useful for recurrent and complicated vulvovaginal candidiasis as well as certain invasive fungal infections.

Discovery of CH7057288 as an Orally Bioavailable, Selective, and Potent pan-TRK Inhibitor.

Kinase fusions involving tropomyosin receptor kinases (TRKs) have been proven to act as strong oncogenic drivers and are therefore recognized as attractive therapeutic targets. We screened an in-house kinase-focused library and identified a promising hit compound with a unique tetracyclic scaffold. Compound 1 showed high TRK selectivity but moderate cell growth inhibitory activity as well as a potential risk of inducing CYP3A4. In this report, chemical modification intended to improve TRK inhibition and avoid CYP3A4 induction enabled us to identify an orally bioavailable, selective, and potent TRK inhibitor 7.

Abstract A25: Copanlisib population pharmacokinetics (popPK) and exposure-response (ER) in relapsed indolent non-Hodgkin lymphoma (iNHL): Analysis from the 1-year follow-up of the phase III, randomized CHRONOS-3 trial

Abstract Introduction: CHRONOS-3 randomized patients (pts) with relapsed iNHL to the PI3K inhibitor copanlisib 60 mg administered on Day 1, 8, 15 of 28-day cycle in combination with standard rituximab (C+R) or placebo plus rituximab (P+R) and demonstrated superior progression-free survival (PFS) of C+R vs. P+R (hazard ratio[HR]: 0.52; Matasar et al. Lancet Oncol 2021). In an updated 1-year follow-up analysis, the benefit of C+R was confirmed in the overall relapsed iNHL population (Zinzani et al., EHA 2022) and in the subset of pts with FL (see Capra et al. AACR Lymphoma 2022 abstract). We investigated popPK and ER relationships for copanlisib efficacy and safety from a pooled analysis, with a particular focus on the 1-year follow-up of CHRONOS-3 to confirm copanlisib dose selection. Methods: A comprehensive popPK model for copanlisib was developed using plasma concentrations from 712 pts across 9 copanlisib clinical Phase 1-3 studies. Demographic, laboratory, and comedication covariates were investigated for their influence on copanlisib between-patient PK variability. Individual static and time-varying exposure estimates for pts enrolled in CHRONOS-3 were derived to investigate relationships to efficacy (PFS, overall response rate [ORR], complete response [CR]) and key treatment-emergent safety events using multivariate cox proportional hazards (CPH) and logistic regression analyses, after accounting for predefined potentially prognostic demographic, laboratory, and/or disease related baseline covariates. Results: Copanlisib PK was best described by a 3-compartment PK model with first-order elimination from the central compartment following intravenous infusion. Copanlisib PK was dose proportional and time independent with no accumulation. Covariates statistically selected as influencing copanlisib PK included rifampin (strong CYP3A inducer) and itraconazole (strong CYP3A inhibitor) co-administration, female sex, Japanese pts, mild or worse hepatic impairment, and a CHRONOS-3 study effect, however all identified covariates, aside from rifampin/itraconazole, had no clinically relevant effect (≤ 35%) on copanlisib AUC. In CHRONOS-3, CPH analyses demonstrated a statistically significant positive ER relationship for PFS where greater copanlisib exposure was associated with prolonged PFS. Relative to P+R, the HR for C+R at the 5th and 95th percentile of copanlisib time-varying exposure was 0.875 and 0.217, respectively. Thus, lower copanlisib doses may result in reduced efficacy in relapsed iNHL. CPH and/or logistic regression analyses demonstrated no significant ER relationship for ORR and investigated adverse events. Based on the modelling, lower starting doses of copanlisib are not anticipated to improve safety and tolerability. The ER analyses support the overall positive benefit/risk assessment of copanlisib reported from the clinical efficacy and results of CHRONOS-3 in iNHL. Conclusions: PopPK and ER analyses support copanlisib 60 mg administered on Day 1, 8, 15 of 28-day cycle dose selection in the relapsed iNHL population. Citation Format: Jonathan Moss, Dirk Garmann, Rupert Austin, Florian Hiemeyer, Patricia DeLora, Matthew J Matasar, Pier Luigi Zinzani, Vita Beckert, Lidia Mongay Soler, Barrett H Childs, Peter N Morcos. Copanlisib population pharmacokinetics (popPK) and exposure-response (ER) in relapsed indolent non-Hodgkin lymphoma (iNHL): Analysis from the 1-year follow-up of the phase III, randomized CHRONOS-3 trial [abstract]. In: Proceedings of the Third AACR International Meeting: Advances in Malignant Lymphoma: Maximizing the Basic-Translational Interface for Clinical Application; 2022 Jun 23-26; Boston, MA. Philadelphia (PA): AACR; Blood Cancer Discov 2022;3(5_Suppl):Abstract nr A25.

Transcriptomics and metabolomics reveal the role of CYP1A2 in psoralen/isopsoralen-induced metabolic activation and hepatotoxicity.

Psoralen and isopsoralen are the pharmacologically important but hepatotoxic components in Psoraleae Fructus. The purpose of this study was to reveal the underlying mechanism of psoralen/isopsoralen-induced hepatotoxicity. Initially, we applied integrated analyses of transcriptomic and metabolomic profiles in mice treated with psoralen and isopsoralen, highlighting the xenobiotic metabolism by cytochromes P450 as a potential pathway. Then, with verifications of expression levels by qRT-PCR and western blot, affinities by molecular docking, and metabolic contributions by recombinant human CYP450 and mouse liver microsomes, CYP1A2 was screened out as the key metabolic enzyme. Afterwards, CYP1A2 induction and inhibition models in HepG2 cells and mice were established to verify the role of CYP1A2, demonstrating that induction of CYP1A2 aggravated the hepatotoxicity, and conversely inhibition alleviated the hepatotoxic effects. Additionally, we detected glutathione adducts with reactive intermediates of psoralen and isopsoralen generated by CYP1A2 metabolism in biosystems of recombinant human CYP1A2 and mouse liver microsomes, CYP1A2-overexpressed HepG2 cells, mice livers and the chemical reaction system using UPLC-Q-TOF-MS/MS. Ultimately, the high-content screening presented the cellular oxidative stress and relevant hepatotoxicity due to glutathione depletion by reactive intermediates. In brief, our findings illustrated that CYP1A2-mediated metabolic activation is responsible for the psoralen/isopsoralen-induced hepatotoxicity.

Sub-toxic events induced by truck speed-facilitated PM2.5 and its counteraction by epigallocatechin-3-gallate in A549 human lung cells

To distinguish the influences of fuel type and truck speed on chemical composition and sub-toxic effects of particulates (PM2.5) from engine emissions, biomarkers—interleukin-6 (IL-6), cytochrome P450 (CYP) 1A1, heme oxygenase (HO)-1, and NADPH-quinone oxidoreductase (NQO)-1—were studied in A549 human lung cells. Fuel type and truck speed preferentially affected the quantity and ion/polycyclic aromatic hydrocarbon (PAH) composition of PM2.5, respectively. Under idling operation, phenanthrene was the most abundant PAH. At high speed, more than 50% of the PAHs had high molecular weight (HMW), of which benzo[a]pyrene (B[a]P), benzo[ghi]perylene (B[ghi]P), and indeno[1,2,3-cd]pyrene (I[cd]P) were the main PAHs. B[a]P, B[ghi]P, and I[cd]P caused potent induction of IL-6, CYP1A1, and NQO-1, whereas phenanthrene mildly induced CYP1A1. Based on the PAH-mediated induction, the predicted increases in biomarkers were positively correlated with the measured increases. HMW-PAHs contribute to the biomarker induction by PM2.5, at high speed, which was reduced by co-exposure to epigallocatechin-3-gallate.

EP08.02-090 Sotorasib Drug-Drug Interactions: Essential Guidance Requested by Physicians Worldwide

The life expectancy of advanced stage non-small cell lung cancer patients has increased significantly over the last years due to the introduction of immunotherapy and multiple targeted therapies. One of the most recent important developments is the registration of the KRAS p.G12C targeting agent sotorasib (LUMAKRAS/LUMYKRAS®). The KRAS p.G12C driver mutation is one the most prevalent driver mutations in NSCLC, occurring in 13% of lung adenocarcinomas. Sotorasib causes relevant drug-drug interactions (DDIs), both as a perpetrator (P-gp inhibitor, CYP3A4 inducer) and as a victim (CYP3A4 and P-gp substrate) which may lead to (cancer) treatment inefficacy or serious side effects.

Physiologically based pharmacokinetic modeling of ponatinib to describe drug-drug interactions in patients with cancer.

This study aimed to investigate the drug-drug interactions of ponatinib with strong, moderate, or weak CYP3A4 inhibitors/inducers by developing physiologically based pharmacokinetic (PBPK) models. Simcyp® Ver 20.1 (Certara Inc., Sheffield, UK) was used to construct a PBPK model for ponatinib and to predict its interaction with strong, moderate, or weak CYP3A4 inhibitors/inducers. The constructed model was validated by comparing predicted values with actual observed values. Inhibitors or inducers that increased or decreased the area under the plasma concentration curve of ponatinib by more than two-fold when used in combination were considered significant. The PBPK model of ponatinib accurately represented its oral pharmacokinetics. It also reasonably predicted its pharmacokinetics when combined with ketoconazole and rifampicin. No weak to strong CYP3A4 inhibitor combinations significantly increased the AUC of ponatinib. However, the strong CYP3A4 inducers rifampicin (oral, 600mg QD) and phenytoin (oral, 100mg TID) decreased AUC by 60-70% and 50%, respectively. The PBPK model predicted a significant drug interaction when ponatinib was combined with a strong CYP3A4 inducer. Conversely, the combination with weak-to-strong CYP3A4 inhibitors did not suggest a drug interaction with ponatinib.

A novel differentiated HuH-7 cell model to examine bile acid metabolism, transport and cholestatic hepatotoxicity

Hepatic cell lines serve as economical and reproducible alternatives for primary human hepatocytes. However, the utility of hepatic cell lines to examine bile acid homeostasis and cholestatic toxicity is limited due to abnormal expression and function of bile acid-metabolizing enzymes, transporters, and the absence of canalicular formation. We discovered that culturing HuH-7 human hepatoma cells with dexamethasone (DEX) and 0.5% dimethyl sulfoxide (DMSO) for two weeks, with Matrigel overlay after one week, resulted in a shorter and improved differentiation process. These culture conditions increased the expression and function of the major bile acid uptake and efflux transporters, sodium taurocholate co-transporting polypeptide (NTCP) and the bile salt export pump (BSEP), respectively, in two-week cultures of HuH-7 cells. This in vitro model was further characterized for expression and function of bile acid-metabolizing enzymes, transporters, and cellular bile acids. Differentiated HuH-7 cells displayed a marked shift in bile acid composition and induction of cytochrome P450 (CYP) 7A1, CYP8B1, CYP3A4, and bile acid-CoA: amino acid N-acyltransferase (BAAT) mRNAs compared to control. Inhibition of taurocholate uptake and excretion after a 24-h treatment with prototypical cholestatic drugs suggests that differentiated HuH-7 cells are a suitable model to examine cholestatic hepatotoxicity.

Drug-Drug Interaction Studies to Evaluate the Effect of Inhibition of UGT1A1 and CYP3A4 and Induction of CYP3A4 on the Pharmacokinetics of Tropifexor in Healthy Subjects.

Tropifexor, a farnesoid X receptor agonist, is currently under clinical development for the treatment of nonalcoholic steatohepatitis. Tropifexor undergoes glucuronidation by uridine 5'-diphosphoglucuronosyltransferase (UGT) 1A1 and oxidation by cytochrome P450 (CYP) 3A4, as reported in in vitro studies. Here, we report the results from 2 drug-drug interaction studies. Study 1 enrolled 20 healthy subjects to investigate the effect of the UGT1A1 inhibitor atazanavir (ATZ) on tropifexor pharmacokinetics (PK). Study 2 had 2 cohorts with 16 healthy subjects each to investigate the effect of the strong CYP3A4 inhibitor itraconazole and strong CYP3A4 inducer rifampin on the PK of tropifexor. Coadministration of ATZ reduced the maximum plasma concentration (Cmax ) of tropifexor by 40%; however, it did not lead to increased exposure of tropifexor (both area under the plasma concentration-time curve [AUC] from time 0 to the last quantifiable concentration [AUClast ] and AUC from time 0 to infinity [AUCinf ] reduced by only 10%), suggesting minor relevance of the UGT1A1 pathway for clearance of tropifexor and no expected drug-drug interactions based on UGT1A1 inhibition. Inhibition of CYP3A4 by itraconazole increased the Cmax of tropifexor by only 9% and exposure (both AUClast and AUCinf ) by 47%, suggesting a weak effect of strong CYP3A4 inhibitors on tropifexor PK. Inducing CYP3A4 with rifampin decreased Cmax (55%) and AUC (AUClast by 79% and AUCinf by 77%). Coadministration of tropifexor with either ATZ, itraconazole, or rifampin was well tolerated.

Complexity and clinical significance of drug-drug interactions (DDIs) in oncology: challenging issues in the care of patients regarding cancer-associated thrombosis (CAT).

Cancer patients have an increased risk of developing venous thromboembolic events. Anticoagulation management includes prophylactic or therapeutic doses of low molecular weight heparins (LMWHs) or direct oral anticoagulants (DOACs). However, the management of thrombosis in patients with cancer is complex due to various individual and disease-related factors, including drug–drug interactions (DDIs). Furthermore, DDIs may impact both, cancer and venous thrombosis, treatment effectiveness and safety; their relevance is highlighted by the advances in cancer therapeutics. Given that these new oncology drugs are extensively used, more attention should be given to monitoring potential DDIs to minimize risks. Recognition of DDIs is of utmost importance in an era of rapid developments in cancer treatments and introduction of novel treatments and protocols. When managing cancer-associated thrombosis (CAT), the concomitant use of a DOAC and a moderate or strong modulator (inhibitor or inducer) of CYP3A4 or a P-glycoprotein (P-gp) is most likely to be associated with significant DDIs. Therefore, LMWHs remain the first-line option for the long-term management of CAT under these circumstances and physicians must consider utilizing LMWHs as first line. This review describes the risk of DDIs and their potential impact and outcomes in patients with cancer associated thrombosis (CAT) receiving anticoagulation.

Phase 1 study to evaluate the effects of rifampin on pharmacokinetics of pevonedistat, a NEDD8-activating enzyme inhibitor in patients with advanced solid tumors

SummaryPevonedistat (TAK-924/MLN4924) is an investigational small molecule inhibitor of the NEDD8-activating enzyme that has demonstrated clinical activity across solid tumors and hematological malignancies. Here we report the results of a phase 1 study evaluating the effect of rifampin, a strong CYP3A inducer, on the pharmacokinetics (PK) of pevonedistat in patients with advanced solid tumors (NCT03486314). Patients received a single 50 mg/m2 pevonedistat dose via a 1-h infusion on Days 1 (in the absence of rifampin) and 10 (in the presence of rifampin), and daily oral dosing of rifampin 600 mg on Days 3–11. Twenty patients were enrolled and were evaluable for PK and safety. Following a single dose of pevonedistat at 50 mg/m2, the mean terminal half-life of pevonedistat was 5.7 and 7.4 h in the presence and in the absence of rifampin, respectively. The geometric mean AUC0–inf of pevonedistat in the presence of rifampin was 79% of that without rifampin (90% CI: 69.2%–90.2%). The geometric mean Cmax of pevonedistat in the presence of rifampin was similar to that in the absence of rifampin (96.2%; 90% CI: 79.2%–117%). Coadministration of pevonedistat with rifampin, a strong metabolic enzyme inducer, did not result in clinically meaningful decreases in systemic exposures of pevonedistat. The study results support the recommendation that no pevonedistat dose adjustment is needed for patients receiving concomitant CYP3A inducers.ClinicalTrials.gov identifierNCT03486314.

Evaluation of Safety and Clinically Relevant Drug-Drug Interactions with Tucatinib in Healthy Volunteers.

Background and ObjectiveTucatinib is approved for treatment of human epidermal growth factor receptor 2-positive metastatic breast cancer. Understanding potential drug–drug interactions (DDIs) informs proper dosing when co-administering tucatinib with other therapies. The aim of this study was to evaluate DDIs between tucatinib and metabolizing enzymes and transporters in healthy volunteers.MethodsParts A–C assessed the impact of itraconazole (cytochrome P450 [CYP] 3A4 inhibitor), rifampin (CYP3A4/CYP2C8 inducer), or gemfibrozil (CYP2C8 inhibitor) on the pharmacokinetics of a single 300 mg dose of tucatinib administered orally and its primary metabolite, ONT-993. Parts D and E assessed the effect of steady-state tucatinib on the pharmacokinetics of repaglinide (CYP2C8 substrate), tolbutamide (CYP2C9 substrate), midazolam (CYP3A4 substrate), and digoxin (P-glycoprotein substrate).ResultsTucatinib area under the concentration–time curve from time 0 extrapolated to infinity (AUC0–inf) increased by ~ 1.3- and 3.0-fold with itraconazole and gemfibrozil, respectively, and decreased by 48% with rifampin, indicating that tucatinib is metabolized primarily by CYP2C8, and to a lesser extent via CYP3A. Tucatinib was a strong inhibitor of CYP3A (midazolam AUC0–inf increased 5.7-fold), a weak inhibitor of CYP2C8 and P-glycoprotein, and had no impact on CYP2C9-mediated metabolism in humans. Tucatinib was well tolerated, alone and with co-administered drugs.ConclusionThe potential DDIs identified here may be mitigated by avoiding concomitant use of tucatinib with strong CYP3A inducers, moderate CYP2C8 inducers, CYP3A substrates with a narrow therapeutic window (modifying substrate dose where concomitant use is unavoidable), and strong CYP2C8 inhibitors (decreasing tucatinib dose where concomitant use is unavoidable), or by reducing the dose of P-glycoprotein substrates with a narrow therapeutic window.Trial RegistrationThis trial (NCT03723395) was registered on October 29, 2018.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40262-022-01144-z.

COVID-19 and antiepileptic drugs: an approach to guide practices when nirmatrelvir/ritonavir is co-prescribed.

Management and dose adjustment are a major concern for clinicians in the absence of specific clinical outcome data for patients on antiepileptic drugs (AEDs), in the event of short-term (5 days) nirmatrelvir/ritonavir co-exposure. Therefore, in this report, we identified drugs that require dose adjustment because of drug-drug interactions (DDIs) between nirmatrelvir/ritonavir and AEDs. We hereby used four databases (Micromedex Drug Interaction, Liverpool Drug Interaction Group for COVID-19 Therapies, Medscape Drug Interaction Checker, and Lexicomp Drug Interactions) and DDI-Predictor.In the light of applying the DDI-Predictor, for carbamazepine, clobazam, oxcarbazepine, eslicarbazepine, phenytoin, phenobarbital, pentobarbital, rufinamide, and valproate as CYP3A4 inducers, we recommend that a dose adjustment of short-term nirmatrelvir/ritonavir as a substrate (victim) drug would be more appropriate instead of these AEDs to avoid impending DDI-related threats in patients with epilepsy.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00228-022-03370-7.

Artemisia extracts differ from artemisinin effects on human hepatic CYP450s 2B6 and 3A4 in vitro

Ethnopharmacological relevanceThe Chinese medicinal herb, Artemisia annua L., has been used for >2,000 yr as traditional tea infusions to treat a variety of infectious diseases including malaria, and its use is spreading globally (along with A. afra Jacq. ex Willd.) mainly through grassroots efforts. Aim of the studyArtemisinin is more bioavailable delivered from the plant, Artemisia annua L. than the pure drug, but little is known about how delivery via a hot water infusion (tea) alters induction of hepatic CYP2B6 and CYP3A4 that metabolize artemisinin. Materials and methodsHepaRG cells were treated with 10 μM artemisinin or rifampicin (positive control), and teas (10 g/L) of A. annua SAM, and A. afra SEN and MAL with 1.6, 0.05 and 0 mg/g DW artemisinin in the leaves, respectively; qPCR and Western blots were used to measure CYP2B6 and CYP3A4 responses. Enzymatic activity of these P450s was measured using human liver microsomes and P450-Glo assays. ResultsAll teas inhibited activity of CYP2B6 and CYP3A4. Artemisinin and the high artemisinin-containing tea infusion (SAM) induced CYP2B6 and CYP3A4 transcription, but artemisinin-deficient teas, MAL and SEN, did not. Artemisinin increased CYP2B6 and CYP3A4 protein levels, but none of the three teas did, indicating a post-transcription inhibition by all three teas. ConclusionsThis study showed that Artemisia teas inhibit activity and artemisinin autoinduction of CYP2B6 and CYP3A4 post transcription, a response likely the effect of other phytochemicals in these teas. Results are important for understanding Artemisia tea posology.

Early Life Short-Term Exposure to Polychlorinated Biphenyl 126 in Mice Leads to Metabolic Dysfunction and Microbiota Changes in Adulthood.

Early life exposure to environmental pollutants may have long-term consequences and harmful impacts on health later in life. Here, we investigated the short- and long-term impact of early life 3,3′,4,4′,5-pentacholorobiphenyl (PCB 126) exposure (24 μg/kg body weight for five days) in mice on the host and gut microbiota using 16S rRNA gene sequencing, metagenomics, and 1H NMR- and mass spectrometry-based metabolomics. Induction of Cyp1a1, an aryl hydrocarbon receptor (AHR)-responsive gene, was observed at 6 days and 13 weeks after PCB 126 exposure consistent with the long half-life of PCB 126. Early life, Short-Term PCB 126 exposure resulted in metabolic abnormalities in adulthood including changes in liver amino acid and nucleotide metabolism as well as bile acid metabolism and increased hepatic lipogenesis. Interestingly, early life PCB 126 exposure had a greater impact on bacteria in adulthood at the community structure, metabolic, and functional levels. This study provides evidence for an association between early life environmental pollutant exposure and increased risk of metabolic disorders later in life and suggests the microbiome is a key target of environmental chemical exposure.

Alternatives to rifampicin: A review and perspectives on the choice of strong CYP3A inducers for clinical drug-drug interaction studies.

N‐Nitrosamine (NA) impurities are considered genotoxic and have gained attention due to the recall of several marketed drug products associated with higher‐than‐permitted limits of these impurities. Rifampicin is an index inducer of multiple cytochrome P450s (CYPs) including CYP2B6, 2C8, 2C9, 2C19, and 3A4/5 and an inhibitor of OATP1B transporters (single dose). Hence, rifampicin is used extensively in clinical studies to assess drug–drug interactions (DDIs). Despite NA impurities being reported in rifampicin and rifapentine above the acceptable limits, these critical anti‐infective drugs are available for therapeutic use considering their benefit–risk profile. Reports of NA impurities in rifampicin products have created uncertainty around using rifampicin in clinical DDI studies, especially in healthy volunteers. Hence, a systematic investigation through a literature search was performed to determine possible alternative index inducer(s) to rifampicin. The available strong CYP3A inducers were selected from the University of Washington DDI Database and their in vivo DDI potential assessed using the data from clinical DDI studies with sensitive CYP3A substrates. To propose potential alternative CYP3A inducers, factors including lack of genotoxic potential, adequate safety, feasibility of multiple dose administration to healthy volunteers, and robust in vivo evidence of induction of CYP3A were considered. Based on the qualifying criteria, carbamazepine, phenytoin, and lumacaftor were identified to be the most promising alternatives to rifampicin for conducting CYP3A induction DDI studies. Strengths and limitations of the proposed alternative CYP3A inducers, the magnitude of in vivo CYP3A induction, appropriate study designs for each alternative inducer, and future perspectives are presented in this paper.

CYP1A1, VEGFA and Adipokine Responses of Human Adipocytes Co-exposed to PCB126 and Hypoxia.

It is increasingly recognized that hypoxia may develop in adipose tissue as its mass expands. Adipose tissue is also the main reservoir of lipophilic pollutants, including polychlorinated biphenyls (PCBs). Both hypoxia and PCBs have been shown to alter adipose tissue functions. The signaling pathways induced by hypoxia and pollutants may crosstalk, as they share a common transcription factor: aryl hydrocarbon receptor nuclear translocator (ARNT). Whether hypoxia and PCBs crosstalk and affect adipokine secretion in human adipocytes remains to be explored. Using primary human adipocytes acutely co-exposed to different levels of hypoxia (24 h) and PCB126 (48 h), we observed that hypoxia significantly inhibits the PCB126 induction of cytochrome P450 (CYP1A1) transcription in a dose-response manner, and that Acriflavine (ACF)—an HIF1α inhibitor—partially restores the PCB126 induction of CYP1A1 under hypoxia. On the other hand, exposure to PCB126 did not affect the transcription of the vascular endothelial growth factor-A (VEGFA) under hypoxia. Exposure to hypoxia increased leptin and interleukin-6 (IL-6), and decreased adiponectin levels dose-dependently, while PCB126 increased IL-6 and IL-8 secretion in a dose-dependent manner. Co-exposure to PCB126 and hypoxia did not alter the adipokine secretion pattern observed under hypoxia and PCB126 exposure alone. In conclusion, our results indicate that (1) hypoxia inhibits PCB126-induced CYP1A1 expression at least partly through ARNT-dependent means, suggesting that hypoxia could affect PCB metabolism and toxicity in adipose tissue, and (2) hypoxia and PCB126 affect leptin, adiponectin, IL-6 and IL-8 secretion differently, with no apparent crosstalk between the two factors.

Psoralen and isopsoralen from Psoraleae Fructus aroused hepatotoxicity via induction of aryl hydrocarbon receptor-mediated CYP1A2 expression

Ethnopharmacological relevancePsoraleae Fructus (PF), a traditional Chinese medicine, has long been used to treat diseases such as cancer, osteoporosis and leukoderma. Psoralen and isopsoralen are main bioactive ingredients of PF with anti-tumor, anti-inflammatory, estrogen-like neuroprotection, etc., meanwhile they are also representative hepatotoxic components of PF. Hepatic CYP1A2 has been reported to be the important metabolic enzymes involved in psoralen and isopsoralen-induced hepatotoxicity. However, the relationship between the hepatotoxicity and CYP1A2 expression, and the underlying mechanism of regulating CYP1A2 expression remain unclear. Aim of studyThe aim of this study was to explore the associated mechanism between psoralen or isopsoralen induced hepatotoxicity and activated aryl hydrocarbon receptor (AhR)-mediated transcriptional induction of CYP1A2 in vitro and in vivo. Materials and methodsPsoralen and isopsoralen at different doses were treated on HepG2 cells (10, 25, 50, 100, 200 μM for 2, 12, 24, 36, 48 h) and mice (20, 80, 160 mg/kg for 3, 7, 14 days) for different time, to assess the correlation of induced hepatotoxicity and CYP1A2 mRNA and protein expression in vivo and in vitro, as well as the effect on CYP1A2 enzyme activity evaluated by phenacetin metabolism. In addition, the potential mechanism of the regulation of CYP1A2 expression mediated by AhR was explored through nucleocytoplasmic shuttling, immunofluorescence, cellular thermal shift assay and molecular docking, etc. ResultsPsoralen and isopsoralen induced cytotoxicity in HepG2 cells, and hepatomegaly, biochemicals disorder and tissue pathological impairment in mice, respectively in dose- and time-dependent manners. Simultaneously accompanied with elevated levels of CYP1A2 mRNA and protein in the same trend, and the CYP1A2 activity was remarkably inhibited in vitro but significantly elevated overall in vivo. Besides, psoralen and isopsoralen bound to AhR and activated translocation of AhR from the cytoplasm to the nucleus, leading to the transcriptional induction of target gene CYP1A2. ConclusionsHepatotoxicities in HepG2 cells and mice aroused by psoralen and isopsoralen were related to the induction of CYP1A2 expression and activity, whose underlying mechanism might be psoralen or isopsoralen activated AhR translocation and induced increase of CYP1A2 transcriptional expression. Hopefully, these finding are conductive to propose an alert about the combined usage of psoralen or isopsoralen and AhR ligands or CYP1A2 substrates in clinical practice.

444 In vitro and clinical improvement of sensitive skin functions by ADE-G3 formulations

Sensitive skin is a common condition that can severely impact quality of life. Several mechanisms are thought to be involved, including those affecting the skin barrier function, hydration and skin innervation. Our Goal was to investigate clinically and on in vitro models, the benefit of formulations dedicated to sensitive skin and containing Aquaphilus dolomiae extract-G3 (ADE-G3) on skin barrier function and hydration, as well as protective responses to dry and pollution stresses. In vitro sensitized reconstructed human epidermis (RHE) were subjected to dehydration and pollution stress with or without the formulations. Endpoint measurements included transepithelial electric resistance (TEER), and protein expression. Clinical measurements included transepithelial water loss (TEWL), skin pH, the lipid index, and hydration scores. When applied topically in formulations, ADE-G3, increased the TEER in sensitized RHEs. In dehydrated RHEs, formulations increased recovery of skin barrier integrity, evident as a return of the ratios of filaggrin/pro-filaggrin and Caspase-14/pro-Caspase-14 to values measured in control RHEs, as well as the “natural moisturizing factors”. In clinical studies, performed on dry human skin, the formulations helped to improve the skin barrier function and the level of hydration as maintained over 24 h after application. This was evident as an intense and sustained moisturization, with total lipids and lipid esters increase, an increase in pH, and a decrease in the TEWL. Moreover, when exposed to pollution stress by treating the RHE with benzo[a]pyrene and airborne particulate matter (PM10), application of formulations prior to exposure attenuated the induction of CYP1A1, CYP1B1 and UGT1A7 expression, indicating a protective effect. ADE-G3 formulations increased the hydration of the skin but also protected and improved the skin barrier integrity of sensitive skin exposed to dry and cold and airborne pollutant induced stress environments.