Magnolol derivatives as specific and noncytotoxic inhibitors of breast cancer resistance protein (BCRP/ABCG2)

The breast cancer resistance protein (BCRP/ABCG2) transporter mediates the efflux of numerous antineoplastic drugs, playing a central role in multidrug resistance related to cancer. The absence of successful clinical trials using specific ABCG2 inhibitors reveals the urge to identify new compounds to attend this critical demand. In this work, a series of 13 magnolol derivatives was tested as ABCG2 inhibitors. Only two compounds, derivatives 10 and 11, showed partial and complete ABCG2 inhibitory effect, respectively. This inhibition was selective toward ABCG2, since none of the 13 compounds inhibited neither P-glycoprotein nor MRP1. Both inhibitors (10 and 11) were not transported by ABCG2 and demonstrated a low cytotoxic profile even at high concentrations (up to 100 µM). 11 emerged as the most promising compound of the series, considering the ratio between cytotoxicity (IG50) and ABCG2 inhibition potency (IC50), showing a therapeutic ratio (TR) higher than observed for 10 (10.5 versus 1.6, respectively). This derivative showed a substrate-independent and a mixed type of inhibition. The effect of compound 11 on the ABCG2 ATPase activity and thermostability revealed allosteric protein changes. This compound did not affect the expression levels of ABCG2 and increased the binding of the conformational-sensitive antibody 5D3. A docking study showed that 11 did not share the same binding site with ABCG2 substrate mitoxantrone. Finally, 11 could revert the chemoresistance to SN-38 mediated by ABCG2.

Clinical assessment of momelotinib drug-drug interactions via CYP3A metabolism and transporters

Momelotinib-approved for treatment of myelofibrosis in adults with anemia-and its major active metabolite, M21, were assessed as drug-drug interaction (DDI) victims with a strong cytochrome P450 (CYP) 3A4 inhibitor (multiple-dose ritonavir), an organic anion transporting polypeptide (OATP) 1B1/1B3 inhibitor (single-dose rifampin), and a strong CYP3A4 inducer (multiple-dose rifampin). Momelotinib DDI perpetrator potential (multiple-dose) was evaluated with CYP3A4 and breast cancer resistance protein (BCRP) substrates (midazolam and rosuvastatin, respectively). DDI was assessed from changes in maximum plasma concentration (Cmax), area under the concentration-time curve (AUC), time to reach Cmax, and half-life. The increase in momelotinib (23% Cmax, 14% AUC) or M21 (30% Cmax, 24% AUC) exposure with ritonavir coadministration was not clinically relevant. A moderate increase in momelotinib (40% Cmax, 57% AUC) and minimal change in M21 was observed with single-dose rifampin. A moderate decrease in momelotinib (29% Cmax, 46% AUC) and increase in M21 (31% Cmax, 15% AUC) were observed with multiple-dose rifampin compared with single-dose rifampin. Due to potentially counteracting effects of OATP1B1/1B3 inhibition and CYP3A4 induction, multiple-dose rifampin did not significantly change momelotinib pharmacokinetics compared with momelotinib alone (Cmax no change, 15% AUC decrease). Momelotinib did not alter the pharmacokinetics of midazolam (8% Cmax, 16% AUC decreases) or 1'-hydroxymidazolam (14% Cmax, 16% AUC decreases) but increased rosuvastatin Cmax by 220% and AUC by 170%. Safety findings were mild in this short-term study in healthy volunteers. This analysis suggests that momelotinib interactions with OATP1B1/1B3 inhibitors and BCRP substrates may warrant monitoring for adverse reactions or dose adjustments.

Evaluation of the drug-drug interaction potential of brigatinib using a physiologically-based pharmacokinetic modeling approach

Brigatinib is an oral anaplastic lymphoma kinase (ALK) inhibitor approved for the treatment of ALK-positive metastatic non-small cell lung cancer. In vitro studies indicated that brigatinib is primarily metabolized by CYP2C8 and CYP3A4 and inhibits P-gp, BCRP, OCT1, MATE1, and MATE2K. Clinical drug-drug interaction (DDI) studies with the strong CYP3A inhibitor itraconazole or the strong CYP3A inducer rifampin demonstrated that CYP3A-mediated metabolism was the primary contributor to overall brigatinib clearance in humans. A physiologically-based pharmacokinetic (PBPK) model for brigatinib was developed to predict potential DDIs, including the effect of moderate CYP3A inhibitors or inducers on brigatinib pharmacokinetics (PK) and the effect of brigatinib on the PK of transporter substrates. The developed model was able to predict clinical DDIs with itraconazole (area under the plasma concentration-time curve from time 0 to infinity [AUC∞] ratio [with/without itraconazole]: predicted 1.86; observed 2.01) and rifampin (AUC∞ ratio [with/without rifampin]: predicted 0.16; observed 0.20). Simulations using the developed model predicted that moderate CYP3A inhibitors (e.g., verapamil and diltiazem) may increase brigatinib AUC∞ by ~40%, whereas moderate CYP3A inducers (e.g., efavirenz) may decrease brigatinib AUC∞ by ~50%. Simulations of potential transporter-mediated DDIs predicted that brigatinib may increase systemic exposures (AUC∞) of P-gp substrates (e.g., digoxin and dabigatran) by 15%-43% and MATE1 substrates (e.g., metformin) by up to 29%; however, negligible effects were predicted on BCRP-mediated efflux and OCT1-mediated uptake. The PBPK analysis results informed dosing recommendations for patients receiving moderate CYP3A inhibitors (40% brigatinib dose reduction) or inducers (up to 100% increase in brigatinib dose) during treatment, as reflected in the brigatinib prescribing information.

Maximum likelihood estimation of renal transporter ontogeny profiles for pediatric PBPK modeling

Optimal treatment of infants with many renally cleared drugs must account for maturational differences in renal transporter (RT) activity. Pediatric physiologically-based pharmacokinetic (PBPK) models may incorporate RT activity, but this requires ontogeny profiles for RT activity in children, especially neonates, to predict drug disposition. Therefore, RT expression measurements from human kidney postmortem cortical tissue samples were normalized to represent a fraction of mature RT activity. Using these data, maximum likelihood estimated the distributions of RT activity across the pediatric age spectrum, including preterm and term neonates. PBPK models of four RT substrates (acyclovir, ciprofloxacin, furosemide, and meropenem) were evaluated with and without ontogeny profiles using average fold error (AFE), absolute average fold error (AAFE), and proportion of observations within the 5-95% prediction interval. Novel maximum likelihood profiles estimated ontogeny distributions for the following RT: OAT1, OAT3, OCT2, P-gp, URAT1, BCRP, MATE1, MRP2, MRP4, and MATE-2 K. Profiles for OAT3, P-gp, and MATE1 improved infant furosemide and neonate meropenem PBPK model AFE from 0.08 to 0.70 and 0.53 to 1.34 and model AAFE from 12.08 to 1.44 and 2.09 to 1.36, respectively, and improved the percent of data within the 5-95% prediction interval from 48% to 98% for neonatal ciprofloxacin simulations, respectively. Even after accounting for other critical population-specific maturational differences, novel RT ontogeny profiles substantially improved neonatal PBPK model performance, providing validated estimates of maturational differences in RT activity for optimal dosing in children.

Transplacental transport of per- and polyfluoroalkyl substances (PFAS): Mechanism exploration via BeWo cell monolayer model

Per- and polyfluoroalkyl substances (PFAS) have received global concern on adverse effects on pregnancy outcomes. Although human studies have reported fetal exposure to PFAS, the underlying mechanisms driving transplacental transfer of PFAS have not been sufficiently understood. The present study aimed to investigate chemical-specific transplacental transfer of PFAS and potential mechanisms based on a BeWo cell monolayer model. The findings of concentration- and time-dependent transport, asymmetry in bidirectional transport, molecular docking and transporter inhibition experiments indicate that passive diffusion and membrane transporter-involved active transport could collectively determine transplacental transport of PFAS. Membrane transporters could play important roles in chemical-specific transport. The inhibition of OAT transporter resulted in promotion of trans-monolayer transport for most PFAS, while an opposite trend was observed when P-gp, BCRP and MRP transporters were prohibited. By contrast, inhibition of OCT resulted in inhibitory effects on the transport of some PFAS (i.e., PFHxA, PFHpA, PFOA, and PFNA), and promotive effects on the other substances (i.e., PFUdA, PFHpS, PFOS, 6:2 Cl-PFESA and PFOSA). Therefore, simultaneous involvement of diverse membrane transporters in utero could result in complicated influence on transplacental transport. Our work constitutes a solid ground for further exploration of the effects of gestational PFAS exposure on birth outcomes.

ABCG2 is an itaconate exporter that limits antibacterial innate immunity by alleviating TFEB-dependent lysosomal biogenesis

Itaconate is a metabolite that synthesized from cis-aconitate in mitochondria and transported into the cytosol to exert multiple regulatory effects in macrophages. However, the mechanism by which itaconate exits from macrophages remains unknown. Using a genetic screen, we reveal that itaconate is exported from cytosol to extracellular space by ATP-binding cassette transporter G2 (ABCG2) in an ATPase-dependent manner in human and mouse macrophages. Elevation of transcription factor TFEB-dependent lysosomal biogenesis and antibacterial innate immunity are observed in inflammatory macrophages with deficiency of ABCG2-mediated itaconate export. Furthermore, deficiency of ABCG2-mediated itaconate export in macrophages promotes antibacterial innate immune defense in a mouse model of S. typhimurium infection. Thus, our findings identify ABCG2-mediated itaconate export as a key regulatory mechanism that limits TFEB-dependent lysosomal biogenesis and antibacterial innate immunity in inflammatory macrophages, implying the potential therapeutic utility of blocking itaconate export in treating human bacterial infections.

Utility of Coproporphyrin-I Determination in First-in-Human Study for Early Evaluation of OATP1B Inhibitory Potential Based on Investigation of Ensitrelvir, an Oral SARS-CoV-2 3C-Like Protease Inhibitor

Coproporphyrin-I (CP-I) has been investigated as an endogenous biomarker of organic anion transporting polypeptide (OATP) 1B. Here, we determined the CP-I concentrations in a cocktail drug-drug interaction (DDI) study of ensitrelvir to evaluate the OATP1B inhibitory potential because ensitrelvir had increased plasma concentrations of rosuvastatin in this study, raising concerns about breast cancer resistance protein and OATP1B inhibition. Furthermore, CP-I concentrations were compared between active and placebo groups in a first-in-human (FIH) study of ensitrelvir to verify whether the OATP1B inhibitory potential could be estimated at an early drug development stage. In the cocktail DDI study, CP-I did not differ between with/without administration of ensitrelvir, indicating that ensitrelvir has no OATP1B inhibitory effect. Although there were some individual variabilities in CP-I concentrations among the treatment groups in the FIH study, the normalization of CP-I concentrations with pre-dose values minimized these variabilities, suggesting that this normalized method would be helpful for comparing the CP-I from different participants. Finally, we concluded that CP-I concentrations were not affected by ensitrelvir in the FIH study. These results suggested that the CP-I determination in an FIH study and its normalized method can be useful for an early evaluation of the OATP1B-mediated DDI potential in humans.

Foretinib, a c-MET receptor tyrosine kinase inhibitor, tackles multidrug resistance in cancer cells by inhibiting ABCB1 and ABCG2 transporters

BACKGROUND

ABC transporter-mediated multidrug resistance (MDR) remains a major obstacle for cancer pharmacological treatment. Some tyrosine kinase inhibitors (TKIs) have been shown to reverse MDR. The present study was designed to evaluate for the first time whether foretinib, a multitargeted TKI, can circumvent ABCB1 and ABCG2-mediated MDR in treatment-resistant cancer models.

METHODS

Accumulation of fluorescent substrates of ABCB1 and ABCG2 in ABCB1-overexpressing MES-SA/DX5 and ABCG2-overexpressing MCF-7/MX and their parenteral cells was evaluated by flow cytometry. The growth inhibitory activity of single and combination therapy of foretinib and chemotherapeutic drugs on MDR cells was examined by MTT assay. Analysis of combined interaction effects was performed using CalcuSyn software.

RESULTS

It was firstly proved that foretinib increased the intracellular accumulation of rhodamine 123 and mitoxantrone in MES-SA/DX5 and MCF-7/MX cancer cells, with accumulation ratios of 12 and 2.2 at 25 μM concentration, respectively. However, it did not affect the accumulation of fluorescent substrates in the parental cells. Moreover, foretinib synergistically improved the cytotoxic effects of doxorubicin and mitoxantrone. The means of combination index (CI) values at fraction affected (Fa) values of 0.5, 0.75, and 0.9 were 0.64 ± 0.08 and 0.47 ± 0.09, in MES-SA/DX5 and MCF-7/MX cancer cells, respectively. In silico analysis also suggested that the drug-binding domain of ABCB1 and ABCG2 transporters could be considered as potential target for foretinib.

CONCLUSION

Overall, our results suggest that foretinib can target MDR-linked ABCB1 and ABCG2 transporters in clinical cancer therapy.

Low-dose daily folic acid (400 μg) supplementation does not affect regulation of folate transporters found present throughout the terminal ileum and colon of humans: a randomized clinical trial

BACKGROUND

Folic acid supplementation during the periconceptional period reduces the risk of neural tube defects in infants, but concern over chronic folic acid exposure remains. An improved understanding of folate absorption may clarify potential risks. Folate transporters have been characterized in the small intestine, but less so in the colon of healthy, free-living humans. The impact of folic acid fortification or supplementation on regulation of these transporters along the intestinal tract is unknown.

OBJECTIVE

The objective was to characterize expression of folate transporters/receptor (FT/R) and folate hydrolase, glutamate carboxypeptidase II (GCPII), from the terminal ileum and throughout the colon of adults and assess the impact of supplemental folic acid.

METHODS

In this 16-wk open-labeled randomized clinical trial, adults consumed a low folic acid-containing diet, a folate-free multivitamin, and either a 400 μg folic acid supplement or no folic acid supplement. Dietary intakes and blood were assessed at baseline, 8 wk, and 16 wk (time of colonoscopy). Messenger RNA (mRNA) expression and protein expression of FT/R and GCPII were assessed in the terminal ileum, cecum, and ascending and descending colon.

RESULTS

Among 24 randomly assigned subjects, no differences in dietary folate intake or blood folate were observed at baseline. Mean ± SD red blood cell folate at 16 wk was 1765 ± 426 and 911 ± 242 nmol/L in the 400 and 0 μg folic acid group, respectively (P < 0.0001). Reduced folate carrier, proton-coupled folate transporter, and folate-receptor alpha expression were detected in the terminal ileum and colon, as were efflux transporters of breast cancer resistance protein and multidrug resistance protein-3. Other than a higher mRNA expression of FR-alpha and GCPII in the 400 μg supplement group in the ascending colon, no treatment differences were observed (P < 0.02).

CONCLUSIONS

Folate transporters are present throughout the terminal ileum and colon; there is little evidence that a low dose of folic acid supplementation affects colonic absorption. This trial was registered at clinicaltrials.gov as NCT03421483.

Identification of Novel, Selective Ataxia-Telangiectasia Mutated Kinase Inhibitors with the Ability to Penetrate the Blood-Brain Barrier: The Discovery of AZD1390

The inhibition of ataxia-telangiectasia mutated (ATM) has been shown to chemo- and radio-sensitize human glioma cells in vitro and therefore might provide an exciting new paradigm in the treatment of glioblastoma multiforme (GBM). The effective treatment of GBM will likely require a compound with the potential to efficiently cross the blood-brain barrier (BBB). Starting from clinical candidate AZD0156, 4, we investigated the imidazoquinolin-2-one scaffold with the goal of improving likely CNS exposure in humans. Strategies aimed at reducing hydrogen bonding, basicity, and flexibility of the molecule were explored alongside modulating lipophilicity. These studies identified compound 24 (AZD1390) as an exceptionally potent and selective inhibitor of ATM with a good preclinical pharmacokinetic profile. 24 showed an absence of human transporter efflux in MDCKII-MDR1-BCRP studies (efflux ratio <2), significant BBB penetrance in nonhuman primate PET studies (Kp,uu 0.33) and was deemed suitable for development as a clinical candidate to explore the radiosensitizing effects of ATM in intracranial malignancies.

Mass Spectrometry Investigation of Some ATP-Binding Cassette (ABC) Proteins

Drug resistance remains one of the main causes of poor outcome in cancer therapy. It is also becoming evident that drug resistance to both chemotherapy and to antibiotics is driven by more than one mechanism. So far, there are at least eight recognized mechanisms behind such resistance. In this review, we choose to discuss one of these mechanisms, which is known to be partially driven by a class of transmembrane proteins known as ATP-binding cassette (ABC) transporters. In normal tissues, ABC transporters protect the cells from the toxic effects of xenobiotics, whereas in tumor cells, they reduce the intracellular concentrations of anticancer drugs, which ultimately leads to the emergence of multidrug resistance (MDR). A deeper understanding of the structures and the biology of these proteins is central to current efforts to circumvent resistance to both chemotherapy, targeted therapy, and antibiotics. Understanding the biology and the function of these proteins requires detailed structural and conformational information for this class of membrane proteins. For many years, such structural information has been mainly provided by X-ray crystallography and cryo-electron microscopy. More recently, mass spectrometry-based methods assumed an important role in the area of structural and conformational characterization of this class of proteins. The contribution of this technique to structural biology has been enhanced by its combination with liquid chromatography and ion mobility, as well as more refined labelling protocols and the use of more efficient fragmentation methods, which allow the detection and localization of labile post-translational modifications. In this review, we discuss the contribution of mass spectrometry to efforts to characterize some members of the ATP-binding cassette (ABC) proteins and why such a contribution is relevant to efforts to clarify the link between the overexpression of these proteins and the most widespread mechanism of chemoresistance.

Transport and interaction mechanism of four pesticide residues from Chaenomeles speciosa across Caco-2 cells

The presence of multiple pesticide residues in agricultural production highlights the need for studying mixture interaction during transepithelial transport. This study applied the Caco-2 cell model to investigate the interaction of four pesticide residues (carbendazim, epoxiconazole, phoxim, and chlorpyrifos) in Chaenomeles speciosa during transepithelial transport. Results demonstrated that co-treatment with pesticide mixtures generally increased the cumulative transport amount of carbendazim and epoxiconazole by 0.32-1.60 times and 0.32-0.98 times, respectively, compared to individual treatments. Notably, the combination of carbendazim and epoxiconazole displayed a significant synergistic effect. The use of transporter inhibitors and molecular docking analysis provided insights into the interaction mechanism, suggesting that the competitive inhibition of MRP2 and/or BCRP binding via π-bonds contributed to the inhibition of BL-to-AP efflux and a significant increase in AP-to-BL influx of carbendazim and epoxiconazole. The results are of great theoretical significance and practical value for risk assessment of multiple pesticide residues in agricultural products.

Screening of anti-functional dyspepsia compounds in Cynanchum auriculatum: A spectrum-effect relationship analysis, and ATP-binding cassette transporters inhibitor evaluation

ETHNOPHARMACOLOGICAL RELEVANCE

Functional dyspepsia (FD) is a disorder caused by abnormal gut-brain axis regulation and is highly prevalent in China. Cynanchum auriculatum (CA) is often used to treat FD in the ethnic minority areas of Guizhou. Although several CA-based products are currently available in the market, it is unclear which components of CA are efficacious and what their oral absorption mechanism is.

AIM OF THE STUDY

This study aimed to screen anti-FD components of CA based on the spectrum-effect relationship. In addition, the study evaluated the intestinal absorption mechanism of these components using transporter inhibitors.

MATERIALS AND METHODS

The fingerprinting of compounds from CA extract and plasma after oral administration was conducted using ultra-high-performance liquid chromatography quadrupole-time-of-flight tandem mass spectrometry (UHPLC-Q-TOF-MS). The intestinal contractile parameters were then measured in vitro using the BL-420F Biofunctional Experiment System. Multivariate statistical analysis of the result of spectrum-effect relationship assessment was used to elucidate the correlation between prominent peaks of CA-containing plasma and intestinal contractile activity. The effect of ATP-binding cassette (ABC) transporter inhibitors, such as the P-gp inhibitor verapamil, the MRR inhibitor indomethacin, and the BCRP inhibitor Ko143, on the directional transport of the predicted active ingredients was assessed in vivo.

RESULTS

Twenty chromatographic peaks were identified in the CA extract. Of these, three were C21 steroids, four were organic acids, and one was a coumarin, and acetophenone by comparing with reference compounds. Additionally, it is discovered that there are totally 39 migratory components in CA-containing plasma, which was found to significantly promote the contractility of the isolated duodenum. Moreover, multivariate analysis of the spectrum-effect relationship demonstrated that 16 characteristic peaks (3, 6, 8, 10, 11, 13, 14, 18, 21, m1-m4, m7, m15, and m24) in CA-containing plasma were significantly associated with the anti-FD effect. These compounds included seven prototype compounds, i.e., cynanoneside A, syringic acid, deacylmetaplexigenin, ferulic acid, scopoletin, baishouwubenzophenone, and qingyangshengenin. The inhibition of ABC transporters demonstrated that the inhibitors verapamil and Ko143 significantly increased (P < 0.05) the uptake of scopoletin and qingyangshengenin. Thus, these compounds may be substrates for P-gp and BCRP.

CONCLUSIONS

The potential anti-FD components of CA and the effect of ABC transporter inhibitors on these active components were preliminarily clarified. These findings lay a foundation for subsequent in vivo studies.

Cocaine regulates antiretroviral therapy CNS access through pregnane-x receptor-mediated drug transporter and metabolizing enzyme modulation at the blood brain barrier

BACKGROUND

Appropriate interactions between antiretroviral therapies (ART) and drug transporters and metabolizing enzymes at the blood brain barrier (BBB) are critical to ensure adequate dosing of the brain to achieve HIV suppression. These proteins are modulated by demographic and lifestyle factors, including substance use. While understudied, illicit substances share drug transport and metabolism pathways with ART, increasing the potential for adverse drug:drug interactions. This is particularly important when considering the brain as it is relatively undertreated compared to peripheral organs and is vulnerable to substance use-mediated damage.

METHODS

We used an in vitro model of the human BBB to determine the extravasation of three first-line ART drugs, emtricitabine (FTC), tenofovir (TFV), and dolutegravir (DTG), in the presence and absence of cocaine, which served as our illicit substance model. The impact of cocaine on BBB integrity and permeability, drug transporters, metabolizing enzymes, and their master transcriptional regulators were evaluated to determine the mechanisms by which substance use impacted ART central nervous system (CNS) availability.

RESULTS

We determined that cocaine had a selective impact on ART extravasation, where it increased FTC's ability to cross the BBB while decreasing TFV. DTG concentrations that passed the BBB were below quantifiable limits. Interestingly, the potent neuroinflammatory modulator, lipopolysaccharide, had no effect on ART transport, suggesting a specificity for cocaine. Unexpectedly, cocaine did not breach the BBB, as permeability to albumin and 4 kDa FITC-dextran, as well as tight junction proteins and adhesion molecules remained unchanged. Rather, cocaine selectively decreased the pregnane-x receptor (PXR), but not constitutive androstane receptor (CAR). Consequently, drug transporter expression and activity decreased in endothelial cells of the BBB, including p-glycoprotein (P-gp), breast cancer resistance protein (BCRP), and multidrug resistance-associated protein 4 (MRP4). Further, cytochrome P450 3A4 (CYP3A4) enzymatic activity increased following cocaine treatment that coincided with decreased expression. Finally, cocaine modulated adenylate kinases that are required to facilitate biotransformation of ART prodrugs to their phosphorylated, pharmacologically active counterparts.

CONCLUSION

Our findings indicate that additional considerations are needed in CNS HIV treatment strategies for people who use cocaine, as it may limit ART efficacy through regulation of drug transport and metabolizing pathways at the BBB.

Investigation of the Effect of Lasmiditan on the Pharmacokinetics of P-Glycoprotein and Breast Cancer Resistance Protein Substrates

Lasmiditan is an in vitro inhibitor of P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) efflux transporters. We aimed to confirm predictions from physiologically based pharmacokinetic models of lasmiditan, and assess the safety and tolerability of rosuvastatin and dabigatran co-administered with lasmiditan. In this open-label, post-marketing drug-drug interaction, phase 1 clinical trial, eligible participants were adults aged 21-70 years with a body mass index of 18.5-35.0 kg/m2 . Part 1 (P-gp, 150 mg dabigatran etexilate with 200 mg lasmiditan) and part 2 (BCRP, 10 mg rosuvastatin with 200 mg lasmiditan) employed similar designs: a single dose of probe substrate administered on day -2 with pharmacokinetic evaluation; 1-week washout; lasmiditan administered on days 8 and 9 alone; lasmiditan co-administered with a single dose of probe substrate on day 10, with pharmacokinetic evaluation of probe substrate and lasmiditan. Sixty-six participants were included in part 1 and 30 participants were included in part 2. Following dabigatran co-administration with lasmiditan, versus dabigatran alone, 90% confidence intervals for geometric least-squares (LS) mean ratios of area under the plasma concentration-time curve from time 0 extrapolated to infinity (AUC0-∞ ) and maximum observed drug concentration (Cmax ) were not contained within the non-effect boundaries (0.80 to 1.25). Dabigatran AUC0-∞ increased by 25% and Cmax increased by 22%. The median time of maximum observed drug concentration (tmax ) for dabigatran was 2.0 to 3.0 hours. Following rosuvastatin co-administration with lasmiditan, versus rosuvastatin alone, 90%CIs for geometric LS mean ratios of AUC0-∞ and Cmax were contained within non-effect boundaries (0.80-1.25). Rosuvastatin AUC0-∞ increased by 15% and Cmax increased by 7%. The median tmax for rosuvastatin was 4.0 hours. Results suggest that lasmiditan has a weak effect on P-gp substrates and no clinically relevant effect on BCRP substrates.

Overexpression of SCN5A overcomes ABC transporter-mediated multidrug resistance in acute myeloid leukemia through promoting apoptosis

BACKGROUND

This study aimed to explore the effect and mechanism of SCN5A overcoming ATP-binding cassette (ABC) transporter-mediated multidrug resistance (MDR) in acute myeloid leukemia (AML) through promoting apoptosis.

RESEARCH DESIGN AND METHODS

The tissues derived from AML patients were divided into Sensitive group and Resistance group according to the presence of drug-resistance. Human AML cell line HL-60 and drug-resistant strain HL-60/ADR were divided into HL-60/ADR-vector group, HL-60/ADR-SCN5A group, HL-60-vector group and HL-60-SCN5A group. RT-qPCR was used to detect the mRNA expression level of SCN5A; MTT assay to assess the survival rate and proliferation level of cells; flow cytometry to determine the apoptosis level; and western blot to check the levels of SCN5A, P-glycoprotein (P-gp), MDR protein 1 (MRP1), MDR gene 1 (MDR1), breast cancer resistance protein (BCRP), Bcl-2-associated X protein (Bax), and B-cell lymphoma 2 (Bcl-2) proteins in cells.

RESULTS

SCN5A expressed lowly in drug-resistant AML tissues and cells. Up-regulation of SCN5A inhibited MDR in HL-60 cells, enhanced the chemosensitivity of HL-60/ADR, and increased the apoptosis levels of HL-60 and HL-60/ADR cells. However, over-expression of SCN5A inhibited the expression of MDR-related proteins.

CONCLUSIONS

SCN5A may overcome ABC transporter-mediated MDR in AML through enhancing the apoptosis and inhibiting the expression of MDR proteins.

Cannabidiol's impact on drug-metabolization

IMPORTANCE

Products containing cannabidiol(CBD) are easily accessible. CBD is reported to inhibit the drug-metabolizing proteins(DMP) Cytochrome P450(CYP)3A4/5, CYP2C9, CYP2B6, CYP2D6, CYP2E1, CYP1A2, CYP2C19, carboxylesterase 1(CES1), uridine 5'diphospho-glucoronosyltransferase(UGT)1A9, UGT2B7, P-glycoprotein(P-gp) and Breast Cancer Resistance Protein(BCRP). The relevance of CBD-drug interactions is largely unknown. Aim of the study was to identify drugs, potentially interacting with orally ingested CBD, to assess whether CBD-drug interactions have been reported, and if substrates of DMP are frequently prescribed drugs.

OBSERVATIONS

Identified were 403 drugs as substrates of DMP. CBD-drug interactions were reported for 53/403 substrates in humans (n = 25), in vivo (n = 13) or in vitro (n = 15). In 31/53 substrates, CBD induced an increase, in 1/53 a decrease, in 4/53 no change in the substrate level. For 5/53 substrates, the results were controversial, and in 12/53 no substrate levels were reported. Among the 30 most frequently prescribed drugs in Germany were 67% substrates of DMP and among the 50 most frequently prescribed drugs in the USA 68%.

RELEVANCE AND CONCLUSIONS

There is an urgent need for pharmacologic studies on CBD-drug interactions. Patients should be educated on the potential risk and awareness should be increased among physicians. Regulatory authorities should become aware of the problem and start an initiative on an international level to increase the safety of CBD.

The cardiac glycoside ZINC253504760 induces parthanatos-type cell death and G2/M arrest via downregulation of MEK1/2 phosphorylation in leukemia cells

Overcoming multidrug resistance (MDR) represents a major obstacle in cancer chemotherapy. Cardiac glycosides (CGs) are efficient in the treatment of heart failure and recently emerged in a new role in the treatment of cancer. ZINC253504760, a synthetic cardenolide that is structurally similar to well-known GCs, digitoxin and digoxin, has not been investigated yet. This study aims to investigate the cytotoxicity of ZINC253504760 on MDR cell lines and its molecular mode of action for cancer treatment. Four drug-resistant cell lines (P-glycoprotein-, ABCB5-, and EGFR-overexpressing cells, and TP53-knockout cells) did not show cross-resistance to ZINC253504760 except BCRP-overexpressing cells. Transcriptomic profiling indicated that cell death and survival as well as cell cycle (G2/M damage) were the top cellular functions affected by ZINC253504760 in CCRF-CEM cells, while CDK1 was linked with the downregulation of MEK and ERK. With flow cytometry, ZINC253504760 induced G2/M phase arrest. Interestingly, ZINC253504760 induced a novel state-of-the-art mode of cell death (parthanatos) through PARP and PAR overexpression as shown by western blotting, apoptosis-inducing factor (AIF) translocation by immunofluorescence, DNA damage by comet assay, and mitochondrial membrane potential collapse by flow cytometry. These results were ROS-independent. Furthermore, ZINC253504760 is an ATP-competitive MEK inhibitor evidenced by its interaction with the MEK phosphorylation site as shown by molecular docking in silico and binding to recombinant MEK by microscale thermophoresis in vitro. To the best of our knowledge, this is the first time to describe a cardenolide that induces parthanatos in leukemia cells, which may help to improve efforts to overcome drug resistance in cancer. A cardiac glycoside compound ZINC253504760 displayed cytotoxicity against different multidrug-resistant cell lines. ZINC253504760 exhibited cytotoxicity in CCRF-CEM leukemia cells by predominantly inducing a new mode of cell death (parthanatos). ZINC253504760 downregulated MEK1/2 phosphorylation and further affected ERK activation, which induced G2/M phase arrest.

Combining pharmacometric models with predictive and prognostic biomarkers for precision therapy in Crohn's disease: A case study of brazikumab

Pharmacometric models were used to investigate the utility of biomarkers in predicting the efficacy (Crohn's Disease Activity Index [CDAI]) of brazikumab and provide a data-driven framework for precision therapy for Crohn's disease (CD). In a phase IIa trial in patients with moderate to severe CD, treatment with brazikumab, an anti-interleukin 23 monoclonal antibody, was associated with clinical improvement. Brazikumab treatment effect was determined to be dependent on the baseline IL-22 (BIL22) or baseline C-reactive protein (BCRP; predictive biomarkers), and placebo effect was found to be correlated with the baseline CDAI (a prognostic biomarker). A maximal total inhibition on CDAI input function of 50.6% and 42.4% was predicted for patients with extremely high BIL22 or BCRP, compared to a maximal total inhibition of 20.9% and 17.8% for patients with extremely low BIL22 or BCRP, respectively, which were mainly due to the placebo effect. We demonstrated that model-derived baseline biomarker levels that achieve 50% of maximum unbound systemic concentration of 22.8 pg/mL and 8.03 mg/L for BIL22 and BCRP as the cutoffs to select subpopulations can effectively identify high-response subgroup patients with improved separation of responders when compared to using the median values as the cutoff. This work exemplifies the utility of pharmacometrics to quantify biomarker-driven responses in biologic therapies and distinguish between predictive and prognostic biomarkers, complementing clinical efforts of identifying subpopulations with higher likelihood of response to brazikumab.

USP10 suppresses ABCG2-induced malignant characteristics of doxorubicin-resistant thyroid cancer by inhibiting PI3K/AKT pathway

Doxorubicin (DOX) is the most extensively used drug in the chemotherapy of thyroid cancer (TC). However, the existence of DOX resistance is not conducive to TC treatment. Here, we investigated the role of USP10 in DOX-resistant TC and explored the underlying molecular mechanism. CCK-8 assay was used to measure cell viability in thyroid cancer FTC133 and DOX-resistant FTC133-DOX cells. RT-qPCR and western blot were used to evaluate USP10 expression. Cell migration, invasion, and apoptotic assays were conducted. Western blot was used to detect cellular signaling proteins, EMT-related proteins, and apoptosis-related proteins. We found a lower expression of USP10 in the human TC cell line FTC133 as compared to the normal human thyroid Htori-3 cells. Notably, USP10 expression was further reduced in DOX-resistant (FTC133-DOX) cells compared to the FTC133 cells. FTC133-DOX cells had increased invasion, migration, and EMT properties while less apoptosis by activating the PI3K/AKT pathway. Interestingly, overexpressing USP10 increased the chemosensitivity of FTC133 cells to DOX therapy. Overexpressing USP10 inhibited invasion, migration, and EMT properties of FTC133-DOX cells and promoted apoptosis. Mechanistically, overexpressing USP10 inhibited PI3K/AKT pathway by activating PTEN. Furthermore, overexpressed USP10 controlled all these processes by downregulating ABCG2. This study demonstrates that USP10 could reduce DOX-induced resistance of TC cells to DOX therapy and could suppress TC malignant behavior by inhibiting the PI3K/AKT pathway. Furthermore, USP10 targeted ABCG2 to inhibit all these malignant processes, therefore, either increasing USP10 expression or inhibiting ABCG2 could be used as novel targets for treating DOX-resistant thyroid cancer.

The effect of paclitaxel- and fisetin-loaded PBM nanoparticles on apoptosis and reversal of drug resistance gene ABCG2 in ovarian cancer

BACKGROUND

High-grade serous ovarian cancer (OvCa) is the most common type of epithelial OvCa. It is usually diagnosed in advanced stages, leaving a woman's chance of survival below 50%. Despite traditional chemotherapeutic therapies, there is often a high recurrence rate following initial treatments. Hence, a targeted drug delivery system is needed to attack the cancer cells and induce apoptosis, overcome acquired drug resistance, and protect normal cells from cytotoxicity. The present study shows that targeting folate receptor alpha (FRα) through planetary ball milling (PBM) nanoparticles (NPs) induces apoptosis in OvCa cells.

RESULTS

Human tissue microarrays (TMAs) show overexpression of FRα in Stage IV OvCa tissues compared to matched normal tissues. They provide a focus for a targeted delivery system. We formulated PBM nanoparticles encapsulated with paclitaxel (PTX) or fisetin (Fis) and conjugated with folic acid (FA). The cytotoxic effect of these PBM NPs reduced the concentration of the toxic chemotherapy drug PTX by five-fold. The combined treatment of PTX-FA NPs and Fis-FA NPs inhibited cell proliferation and induced apoptosis more extensively than the individual drugs alone. Apoptosis of OvCa cells, determined by flow cytometry, showed an increase from 14.4 to 80.4% (OVCAR3 cells) and from 2.69 to 90.0% (CAOV3 cells) in the number of apoptotic cells. Also, expressions of the pro-apoptotic markers, BAK and active caspase-3, were increased after PTX-FA + Fis-FA PBM NP treatment. In addition to looking at targeted treatment effects on apoptosis, drug resistance was investigated. Drug resistance in OvCa cells was reversed by ABCG2, an ABC-transporter marker.

CONCLUSIONS

Our study shows that PTX-FA and Fis-FA PBM NPs directly target platinum-resistant OvCa cells, induce cytotoxic/apoptotic effects, and reverse multi-drug resistance (MDR). These findings allow us to create new clinical applications using PTX-FA and Fis-FA combination nanoparticles to treat drug-resistant cancers.

Effects of short-chain per- and polyfluoroalkyl substances (PFAS) on toxicologically relevant gene expression profiles in a liver-on-a-chip model

Short-chain per- and polyfluoroalkyl substances (PFAS) are highly stable and widely used environmental contaminants that pose potential health risks to humans. Aggregating reliable mechanistic information for safety assessments necessitates physiologically relevant high-throughput screening approaches. Here, we demonstrated the utility of a liver-on-a-chip model to investigate the effects of five short-chain PFAS at low (1 nM) and high (1 μM) concentrations on toxicologically-relevant gene expression profiles using the QuantiGene® Plex Assay. We found that the short-chain PFAS tested in this study modulated the expression of ABCG2, a gene encoding for the breast cancer resistance protein (BCRP), with marked and significant upregulation (up to 4-fold) observed for all but one of the short-chain PFAS tested. PFBS and HFPO-DA repressed SLCO1B3 expression, a gene that encodes for an essential liver-specific organic anion transporter. High concentrations of PFBS, PFHxA, and PFHxS upregulated the expression of genes encCYP1A1,CYP2B6 and CYP2C19 with the same treatments resulting in the repression of the expression of the gene encoding CYP1A2. This dysregulation could have consequences for the clearance of endogenous compounds and xenobiotics. However, we acknowledge that increased expression of genes encoding for transporters and biotransformation enzymes may or may not indicate changes to their protein expression or activity. Overall, our study provides important insights into the effects of short-chain PFAS on liver function and their potential implications for human health. The use of the liver-on-a-chip model in combination with the QuantiGene® Plex Assay may be a valuable tool for future high-throughput screening and gene expression profiling in toxicology studies.

Tetrazole and oxadiazole derivatives as bioisosteres of tariquidar and elacridar: New potent P-gp modulators acting as MDR reversers

New 2,5- and 1,5-disubstituted tetrazoles, and 2,5-disubstituted-1,3,4-oxadiazoles were synthesized as tariquidar and elacridar derivatives and studied as multidrug resistance (MDR) reversers. Their behaviour on the three ABC transporters P-gp, MRP1 and BCRP was investigated. All compounds inhibited the P-gp transport activity in MDCK-MDR1 cells overexpressing P-gp, showing EC50 values even in the low nanomolar range (compounds 15, 22). Oxadiazole derivatives were able to increase the antiproliferative effect of doxorubicin in MDCK-MDR1 and in HT29/DX cells confirming their nature of P-gp modulators, with derivative 15 being the most potent in these assays. Compound 15 also displayed a dual inhibitory effect showing good activities towards both P-gp and BCRP. A computational study suggested a common interaction pattern on P-gp for most of the potent compounds. The bioisosteric substitution of the amide group of lead compounds allowed identifying a new set of potent oxadiazole derivatives that modulate MDR through inhibition of the P-gp efflux activity. If compared to previous amide derivatives, the introduction of the heterocycle rings greatly enhances the activity on P-gp, introduces in two compounds a moderate inhibitory activity on MRP1 and maintains in some cases the effect on BCRP, leading to the unveiling of dual inhibitor 15.

Effect of Daridorexant on the Pharmacokinetics of P-Glycoprotein Substrate Dabigatran Etexilate and Breast Cancer Resistance Protein Substrate Rosuvastatin in Healthy Subjects

BACKGROUND AND OBJECTIVE

The dual orexin receptor antagonist daridorexant was approved in 2022 for the treatment of insomnia at doses up to 50 mg once per night. This study aimed at investigating the effect of daridorexant 50 mg at steady state on the pharmacokinetics of dabigatran, the active moiety of dabigatran etexilate, and rosuvastatin, sensitive substrates of P-glycoprotein and breast cancer resistance protein, respectively.

METHODS

This single-center, open-label, fixed-sequence study enrolled 24 healthy male subjects who were dosed orally with dabigatran etexilate 75 mg on days 1 (Treatment A1) and 9 (Treatment C1) as well as rosuvastatin 10 mg on days 3 (Treatment A2) and 11 (Treatment C2). On days 7-14, daridorexant (50 mg once daily) was administered. Blood samples for the pharmacokinetics of both substrates and the pharmacodynamics of dabigatran, i.e., two coagulation tests, were collected and safety assessments performed. Noncompartmental pharmacokinetic parameters and pharmacodynamic variables were evaluated with geometric mean ratios and 90% confidence intervals of Treatment C1/C2 versus A1/A2.

RESULTS

Geometric mean ratios (90% confidence interval) of dabigatran maximum plasma concentration and area under the plasma concentration-time curve were 1.3 (1.0-1.7) and 1.4 (1.1-1.9), respectively, whereas the time to maximum plasma concentration and terminal half-life were comparable between treatments. Pharmacodynamic variables showed a similar pattern as dabigatran pharmacokinetics in both treatments. Rosuvastatin pharmacokinetics were unchanged upon concomitant daridorexant administration. All treatments were well tolerated.

CONCLUSIONS

A mild inhibition of P-glycoprotein was observed after administration of daridorexant (50 mg once daily) at steady state, whereas breast cancer resistance protein was not affected.

CLINICAL TRIAL REGISTRATION

NCT05480475; date of registration: 29 July, 2022.

Utilization of Rosuvastatin and Endogenous Biomarkers in Evaluating the Impact of Ritlecitinib on BCRP, OATP1B1, and OAT3 Transporter Activity

PURPOSE

Ritlecitinib, an inhibitor of Janus kinase 3 and tyrosine kinase expressed in hepatocellular carcinoma family kinases, is in development for inflammatory diseases. This study assessed the impact of ritlecitinib on drug transporters using a probe drug and endogenous biomarkers.

METHODS

In vitro transporter-mediated substrate uptake and inhibition by ritlecitinib and its major metabolite were evaluated. Subsequently, a clinical drug interaction study was conducted in 12 healthy adult participants to assess the effect of ritlecitinib on pharmacokinetics of rosuvastatin, a substrate of breast cancer resistance protein (BCRP), organic anion transporting polypeptide 1B1 (OATP1B1), and organic anion transporter 3 (OAT3). Plasma concentrations of coproporphyrin I (CP-I) and pyridoxic acid (PDA) were assessed as endogenous biomarkers for OATP1B1 and OAT1/3 function, respectively.

RESULTS

In vitro studies suggested that ritlecitinib can potentially inhibit BCRP, OATP1B1 and OAT1/3 based on regulatory cutoffs. In the subsequent clinical study, coadministration of ritlecitinib decreased rosuvastatin plasma exposure area under the curve from time 0 to infinity (AUCinf) by  ~ 13% and maximum concentration (Cmax) by  ~ 27% relative to rosuvastatin administered alone. Renal clearance was comparable in the absence and presence of ritlecitinib coadministration. PK parameters of AUCinf and Cmax for CP-I and PDA were also similar regardless of ritlecitinib coadministration.

CONCLUSION

Ritlecitinib does not inhibit BCRP, OATP1B1, and OAT3 and is unlikely to cause a clinically relevant interaction through these transporters. Furthermore, our findings add to the body of evidence supporting the utility of CP-I and PDA as endogenous biomarkers for assessment of OATP1B1 and OAT1/3 transporter activity.

Altered Gene Expression of Cytochrome P450 and ABC Transporter in Human Hepatocellular Carcinoma HepG2 Cells Exposed to Bardoxolone Methyl

Bardoxolone methyl (BX) is expected to be an innovate therapeutic agent for chronic kidney disease (CKD). The aim of the present study was to examine whether the expression of subtypes of cytochrome P450 (CYP) and ABC transporters was altered in human hepatocellular carcinoma HepG2 cells by exposure to BX. The expression of mRNAs for CYP1A2, CYP2E1, P-glycoprotein, multidrug resistance-associated protein 1-3, and breast cancer resistance protein was significantly increased by exposure of HepG2 cells to BX, while the expression of CYP3A4 mRNA was significantly decreased under the same conditions. BX had no significant effect on the expression of mRNAs for CYP2C9 and CYP2C19 in HepG2 cells. In conclusion, this study demonstrated that the gene expression of several CYPs and ABC transporters in HepG2 cells was altered when exposed to BX, suggesting the need to pay careful attention to drug-drug interactions in patients receiving BX for CKD treatment.

Co-Delivery of Silymarin and Metformin Dual-Loaded in Mesoporous Silica Nanoparticles Synergistically Sensitizes Breast Cancer Cell Line to Mitoxantrone Chemotherapy

The development nano-carriers based therapeutic methods is a potent strategy for enhancing cellular delivery of drugs and therapeutic efficiency in cancer chemotherapy. In the study, silymarin(SLM) and metformin (Met) were co-loaded into mesoporous silica nanoparticles (MSNs) and evaluated the synergistic inhibitory effect of these natural herbal compound in improving chemotherapeutic efficiency against MCF7MX and MCF7 human breast cancer cells. Nanoparticles have been synthesized and characterized by FTIR, BET, TEM, SEM, and X-ray diffraction. Drug loading capacity and release determined. The both single and combined form of SLM and Met (free and loaded MSN) were used for MTT assay, colony formation and real time-PCR in cellular study. The synthesis MSN were uniformity in size and shape with particle size of approximately 100 nm and pore size of approximately 2 nm. The Met-MSNs IC30, SLM -MSNs IC50 and dual-drug loaded MSNs IC50 were much lower than of free-Met IC30, free-SLM IC50 and free Met-SLM IC50 MCF7MX and MCF7cells. The co-loaded MSNs treated cells were increased sensitivity to mitoxantrone with the inhibition of BCRP mRNA expressions and could induce apoptosis in MCF7MX and MCF7 cells in comparison with other groups. Colony numbers were significantly reduced in comparison to with other groups in the co-loaded MSNs -treated cells ( ). Our results indicate that Nano-SLM enhances the anti-cancer effects of SLM against human breast cancer cells. The findings of the present study suggest that the anti-cancer effects of both metformin and silymarin enhances against breast cancer cells when MSNs are used as a drug delivery system.

Understanding Statin-Roxadustat Drug-Drug-Disease Interaction Using Physiologically-Based Pharmacokinetic Modeling

A different drug-drug interaction (DDI) scenario may exist in patients with chronic kidney disease (CKD) compared with healthy volunteers (HVs), depending on the interplay between drug-drug and disease (drug-drug-disease interaction (DDDI)). Physiologically-based pharmacokinetic (PBPK) modeling, in lieu of a clinical trial, is a promising tool for evaluating these complex DDDIs in patients. However, the prediction confidence of PBPK modeling in the severe CKD population is still low when nonrenal pathways are involved. More mechanistic virtual disease population and robust validation cases are needed. To this end, we aimed to: (i) understand the implications of severe CKD on statins (atorvastatin, simvastatin, and rosuvastatin) pharmacokinetics (PK) and DDI; and (ii) predict untested clinical scenarios of statin-roxadustat DDI risks in patients to guide suitable dose regimens. A novel virtual severe CKD population was developed incorporating the disease effect on both renal and nonrenal pathways. Drug and disease PBPK models underwent a four-way validation. The verified PBPK models successfully predicted the altered PKs in patients for substrates and inhibitors and recovered the observed statin-rifampicin DDIs in patients and the statin-roxadustat DDIs in HVs within 1.25- and 2-fold error. Further sensitivity analysis revealed that the severe CKD effect on statins PK is mainly mediated by hepatic BCRP for rosuvastatin and OATP1B1/3 for atorvastatin. The magnitude of statin-roxadustat DDI in patients with severe CKD was predicted to be similar to that in HVs. PBPK-guided suitable dose regimens were identified to minimize the risk of side effects or therapeutic failure of statins when co-administered with roxadustat.

Ensemble Machine Learning Approaches Based on Molecular Descriptors and Graph Convolutional Networks for Predicting the Efflux Activities of MDR1 and BCRP Transporters

Multidrug resistance (MDR1) and breast cancer resistance protein (BCRP) play important roles in drug absorption and distribution. Computational prediction of substrates for both transporters can help reduce time in drug discovery. This study aimed to predict the efflux activity of MDR1 and BCRP using multiple machine learning approaches with molecular descriptors and graph convolutional networks (GCNs). In vitro efflux activity was determined using MDR1- and BCRP-expressing cells. Predictive performance was assessed using an in-house dataset with a chronological split and an external dataset. CatBoost and support vector regression showed the best predictive performance for MDR1 and BCRP efflux activities, respectively, of the 25 descriptor-based machine learning methods based on the coefficient of determination (R2). The single-task GCN showed a slightly lower performance than descriptor-based prediction in the in-house dataset. In both approaches, the percentage of compounds predicted within twofold of the observed values in the external dataset was lower than that in the in-house dataset. Multi-task GCN did not show any improvements, whereas multimodal GCN increased the predictive performance of BCRP efflux activity compared with single-task GCN. Furthermore, the ensemble approach of descriptor-based machine learning and GCN achieved the highest predictive performance with R2 values of 0.706 and 0.587 in MDR1 and BCRP, respectively, in time-split test sets. This result suggests that two different approaches to represent molecular structures complement each other in terms of molecular characteristics. Our study demonstrated that predictive models using advanced machine learning approaches are beneficial for identifying potential substrate liability of both MDR1 and BCRP.

Intestinal organoids as an in vitro platform to characterize disposition, metabolism, and safety profile of small molecules

Intestinal organoids derived from LGR5+ adult stem cells allow for long-term culturing, more closely resemble human physiology than traditional intestinal models, like Caco-2, and have been established for several species. Here we evaluated intestinal organoids for drug disposition, metabolism, and safety applications. Enterocyte-enriched human duodenal organoids were cultured as monolayers to enable bidirectional transport studies. 3D enterocyte-enriched human duodenal and colonic organoids were incubated with probe substrates of major intestinal drug metabolizing enzymes (DMEs). To distinguish human intestinal toxic (high incidence of diarrhea in clinical trials and/or black box warning related to intestinal side effects) from non-intestinal toxic compounds, ATP-based cell viability was used as a readout, and compounds were ranked based on their IC50 values in relation to their 30-times maximal total plasma concentration (Cmax). To assess if rat and dog organoids reproduced the respective in vivo intestinal safety profiles, ATP-based viability was assessed in rat and dog organoids and compared to in vivo intestinal findings when available. Human duodenal monolayers discriminated high and low permeable compounds and demonstrated functional activity for the main efflux transporters Multi drug resistant protein 1 (MDR1, P-glycoprotein P-gp) and Breast cancer resistant protein (BCRP). Human 3D duodenal and colonic organoids also showed metabolic activity for the main intestinal phase I and II DMEs. Organoids derived from specific intestinal segments showed activity differences in line with reported DMEs expression. Undifferentiated human organoids accurately distinguished all but one compound from the test set of non-toxic and toxic drugs. Cytotoxicity in rat and dog organoids correlated with preclinical toxicity findings and observed species sensitivity differences between human, rat, and dog organoids. In conclusion, the data suggest intestinal organoids are suitable in vitro tools for drug disposition, metabolism, and intestinal toxicity endpoints. The possibility to use organoids from different species, and intestinal segment holds great potential for cross-species and regional comparisons.

A TOX-ic axis of epigenetic stem cell maintenance and chemoresistance in colon cancer

Cancer stem cells drive tumor growth and survival via self-renewal and therapeutic resistance, but the upstream mechanisms are not well defined. In this issue of PLOS Biology, a study in colon cancer reveals a new signalling network that links epigenetic regulation to these phenotypes.

Machine Learning Techniques Applied to the Study of Drug Transporters

With the advancement of computer technology, machine learning-based artificial intelligence technology has been increasingly integrated and applied in the fields of medicine, biology, and pharmacy, thereby facilitating their development. Transporters have important roles in influencing drug resistance, drug-drug interactions, and tissue-specific drug targeting. The investigation of drug transporter substrates and inhibitors is a crucial aspect of pharmaceutical development. However, long duration and high expenses pose significant challenges in the investigation of drug transporters. In this review, we discuss the present situation and challenges encountered in applying machine learning techniques to investigate drug transporters. The transporters involved include ABC transporters (P-gp, BCRP, MRPs, and BSEP) and SLC transporters (OAT, OATP, OCT, MATE1,2-K, and NET). The aim is to offer a point of reference for and assistance with the progression of drug transporter research, as well as the advancement of more efficient computer technology. Machine learning methods are valuable and attractive for helping with the study of drug transporter substrates and inhibitors, but continuous efforts are still needed to develop more accurate and reliable predictive models and to apply them in the screening process of drug development to improve efficiency and success rates.

C-subfamily ATP binding cassette transporters extrude the calcium fluorescent probe fluo-4 from a cone photoreceptor cell line

Whole transcriptome sequencing has revealed the existence of mRNAs for multiple membrane transporters in photoreceptors. Except for ATP binding cassette (ABC) member A4, involved in the retinoid cycle, an understanding of the function of most transport proteins in photoreceptors is lacking. In this research paper, extrusion of fluo-4, a Ca2+ fluorescent probe, from 661W cells, a cone photoreceptor murine cell line was studied with online fluorometry and immunocytochemistry. Fluo-4 efflux was temperature dependent, required ATP but not extracellular Na+, was not affected by pH in the range 5.4-8.4, and followed saturating kinetics with a Km of nearly 4 μM, suggesting it was effected by ABC type transporters. A panel of antagonists showed an inhibitory profile typical of the C subfamily of ABC transporters. Immunofluorescence staining was positive for ABCC3, ABCC4 and ABCC5. These experimental results are compatible with fluo-4 being extruded from 661W cones by one or a combination of C-type ABC transporters. Examination of physicochemical descriptors related to drug membrane permeability and ABC substrate binding region further suggested efflux of fluo-4 by C-type ABC transporters. Possible functions of this transport mechanism in photoreceptors are discussed.

Clinical Pharmacokinetics and Pharmacodynamics of the Next Generation Androgen Receptor Inhibitor-Darolutamide

Darolutamide is a next-generation androgen receptor signaling inhibitor (ARSI) currently approved for the treatment of nonmetastatic castration-resistant prostate cancer (nmCRPC) and metastatic hormone sensitive prostate cancer (mHSPC). Studies suggest that darolutamide also has the potential to be used to treat other stages of prostate cancer (PC), suggesting that its indications will broaden in the near future. Since ARSIs show similar efficacy for the treatment of PC, pharmacokinetic properties of these drugs and patient characteristics could help physicians decide which drug to select. This review provides an overview of the pharmacokinetic and pharmacodynamic properties of darolutamide. One of the most important pharmacological advantages of darolutamide is its low brain distribution and therefore limited seizure potential and central nervous system adverse effects. In addition, darolutamide has little drug-drug interaction potential and is unlikely to alter the exposure of other cytochrome P450 or P-glycoprotein substrates. Nevertheless, it may significantly increase the exposure of breast cancer resistant protein (BCRP) substrates. The limited solubility and bioavailability of darolutamide increases when taken together with food, regardless of the fat content. Darolutamide is excessively metabolized by oxidation and glucuronidation and excreted in the urine and feces. For this reason, dose reduction is required in patients with moderate and severe renal or severe hepatic impairment. Although no exposure-response relationship was observed with darolutamide, less advanced stages of PC showed better PSA response on treatment. Overall, darolutamide has some advantageous pharmacological properties that may lead to its preferred use, when broader registered, in selected patients across different disease stages.

Modes of Action of a Novel c-MYC Inhibiting 1,2,4-Oxadiazole Derivative in Leukemia and Breast Cancer Cells

The c-MYC oncogene regulates multiple cellular activities and is a potent driver of many highly aggressive human cancers, such as leukemia and triple-negative breast cancer. The oxadiazole class of compounds has gained increasing interest for its anticancer activities. The aim of this study was to investigate the molecular modes of action of a 1,2,4-oxadiazole derivative (ZINC15675948) as a c-MYC inhibitor. ZINC15675948 displayed profound cytotoxicity at the nanomolar range in CCRF-CEM leukemia and MDA-MB-231-pcDNA3 breast cancer cells. Multidrug-resistant sublines thereof (i.e., CEM/ADR5000 and MDA-MB-231-BCRP) were moderately cross-resistant to this compound (<10-fold). Molecular docking and microscale thermophoresis revealed a strong binding of ZINC15675948 to c-MYC by interacting close to the c-MYC/MAX interface. A c-MYC reporter assay demonstrated that ZINC15675948 inhibited c-MYC activity. Western blotting and qRT-PCR showed that c-MYC expression was downregulated by ZINC15675948. Applying microarray hybridization and signaling pathway analyses, ZINC15675948 affected signaling routes downstream of c-MYC in both leukemia and breast cancer cells as demonstrated by the induction of DNA damage using single cell gel electrophoresis (alkaline comet assay) and induction of apoptosis using flow cytometry. ZINC15675948 also caused G2/M phase and S phase arrest in CCRF-CEM cells and MDA-MB-231-pcDNA3 cells, respectively, accompanied by the downregulation of CDK1 and p-CDK2 expression using western blotting. Autophagy induction was observed in CCRF-CEM cells but not MDA-MB-231-pcDNA3 cells. Furthermore, microarray-based mRNA expression profiling indicated that ZINC15675948 may target c-MYC-regulated ubiquitination, since the novel ubiquitin ligase (ELL2) was upregulated in the absence of c-MYC expression. We propose that ZINC15675948 is a promising natural product-derived compound targeting c-MYC in c-MYC-driven cancers through DNA damage, cell cycle arrest, and apoptosis.

Evaluation of the inhibitory effects of itraconazole on letermovir

AIMS

Letermovir, a cytomegalovirus (CMV) DNA terminase complex inhibitor, is a substrate of ABCB1 (P-glycoprotein; P-gp), organic anion transporting polypeptide (OATP)1B1/3, UDP-glucuronosyltransferase (UGT)1A1, UGT1A3 and possibly ABCG2 (breast cancer resistance protein; BCRP). A study was conducted to evaluate the effects of itraconazole, a prototypic ABCB1/ABCG2 inhibitor, on letermovir pharmacokinetics (PK) and the effects of letermovir on itraconazole PK.

METHODS

In an open-label, fixed-sequence study in 14 healthy participants, 200 mg oral itraconazole was administered once daily for 4 days. Following a 10-day washout, 480 mg oral letermovir was administered once daily for 14 days (Days 1-14) and then coadministered with 200 mg itraconazole once daily for 4 days (Days 15-18). Intensive PK sampling was performed for letermovir and itraconazole. PK and safety were evaluated.

RESULTS

Letermovir geometric mean ratio (GMR; 90% confidence interval [CI]) for area under the concentration-time curve from time 0 to 24 h (AUC0-24 ) was 1.33 (1.17, 1.51) and for maximum concentration (Cmax ) was 1.21 (1.05, 1.39) following administration with/without itraconazole. Itraconazole GMR (90% CI) for AUC0-24 was 0.76 (0.71, 0.81) and for Cmax was 0.84 (0.76, 0.92) following administration with/without letermovir. Coadministration of letermovir with itraconazole was generally well tolerated.

CONCLUSIONS

The increase in letermovir exposure with coadministration of itraconazole is likely predominantly due to inhibition of intestinal ABCB1 and potentially ABCG2 transport. The mechanism for the decrease in itraconazole exposure is unknown. The modest changes in letermovir and itraconazole PK are not considered clinically meaningful.

Rhabdomyolysis during concomitant ticagrelor and rosuvastatin: A breast cancer resistance protein-mediated drug interaction?

We present 3 patients diagnosed with rhabdomyolysis 1-6 months after the initiation of concomitant rosuvastatin and ticagrelor medication. A literature review and Food and Drug Administration adverse event reporting system revealed >40 reports of rhabdomyolysis during concomitant ticagrelor and rosuvastatin, including 3 with a fatal outcome. We show that ticagrelor inhibits breast cancer resistance protein-, organic anion transporting polypeptide (OATP) 1B1-, 1B3- and 2B1-mediated transport of rosuvastatin in vitro with half-maximal unbound inhibitory concentrations of 0.36, 4.13, 7.5 and 3.26 μM, respectively. A static drug interaction model predicted that ticagrelor may inhibit intestinal breast cancer resistance protein and thus increase rosuvastatin plasma exposure 2.1-fold, whereas the OATP-mediated hepatic uptake of rosuvastatin should not be inhibited due to relatively low portal ticagrelor concentrations. Taken together, concomitant use of ticagrelor with rosuvastatin may increase the systemic exposure to rosuvastatin and the risk of rosuvastatin-induced rhabdomyolysis. Further studies are warranted to investigate the potential pharmacokinetic interaction between ticagrelor and rosuvastatin in humans.

Complex components of Shengmai formula interact with organic cation transporter 2 (OCT2) in MDCK cells

ETHNOPHARMACOLOGICAL RELEVANCE

Shengmai formula (SMF) is a well-known Chinese herbal compound preparation, which is utilized extensively for the treatment of myocardial ischemia, arrhythmia and other life-threatening conditions. Our previous researches have shown that some of the active ingredients in SMF can interact with organic anion transport polypeptide 1B1 (OATP1B1), breast cancer resistance protein (BCRP) and organic anion transporter 1 (OAT1), etc. Organic cation transporter 2 (OCT2) is a highly expressed uptake transporter in the kidney, and its interaction with the major active components in SMF remains unclear.

AIM OF THE STUDY

We purposed to explore OCT2-mediated interactions and compatibility mechanisms of the main active compounds in SMF.

MATERIALS AND METHODS

Fifteen active ingredients of SMF, including ginsenoside Rb1, Rd, Re, Rg1, Rf, Ro and Rc, methylophiopogonanone A and B, ophiopogonin D and D', schizandrin A and B, schizandrol A and B, were selected to investigate OCT2-mediated interactions in Madin-Darby cacine kidney (MDCK) cells stably expressing OCT2.

RESULTS

Among the above 15 main active components, only ginsenosides Rd, Re and schizandrin B could significantly inhibit the uptake of 4-(4-(dimethylamino)styryl)-N-methyl pyridiniumiodide (ASP⁺), a classical substrate of OCT2. Ginsenoside Rb1 and methylophiopogonanone A can be transported by MDCK-OCT2 cells, and their uptake was significantly reduced when OCT2 inhibitor decynium-22 was added. Ginsenoside Rd could remarkably reduce the uptake of methylophiopogonanone A and ginsenoside Rb1 by OCT2, ginsenoside Re only decreased the uptake of ginsenoside Rb1, while schizandrin B had no effect on the uptake of both.

CONCLUSIONS

OCT2 mediates the interaction of the major active components in SMF. Ginsenosides Rd, Re and schizandrin B are the potential inhibitors of OCT2, while ginsenosides Rb1 and methylophiopogonanone A are the potential substrates of OCT2. There is an OCT2-mediated compatibility mechanism among these active ingredients of SMF.

Evaluation of the Herb-Drug Interaction (HDI) Potential of Zingiber officinale and Its Major Phytoconstituents

Ginger is currently one of the most popular herbs commonly added to diverse foods, beverages, and dietary supplements. We evaluated the ability of a well-characterized ginger extract, and several of its phytoconstituents, to activate select nuclear receptors as well as modulate the activity of various cytochrome P450s and ATP-binding cassette (ABC) transporters because phytochemical-mediated modulation of these proteins underlies many clinically relevant herb-drug interactions (HDI). Our results revealed ginger extract activated the aryl hydrocarbon receptor (AhR) in AhR-reporter cells and pregnane X receptor (PXR) in intestinal and hepatic cells. Among the phytochemicals investigated, (S)-6-gingerol, dehydro-6-gingerdione, and (6S,8S)-6-gingerdiol activated AhR, while 6-shogaol, 6-paradol, and dehydro-6-gingerdione activated PXR. Enzyme assays showed that ginger extract and its phytochemicals dramatically inhibited the catalytic activity of CYP3A4, 2C9, 1A2, and 2B6, and efflux transport capabilities of P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP). Dissolution studies with ginger extract conducted in biorelevant simulated intestinal fluid yielded (S)-6-gingerol and 6-shogaol concentrations that could conceivably exceed cytochrome P450 (CYP) IC50 values when consumed in recommended doses. In summary, overconsumption of ginger may disturb the normal homeostasis of CYPs and ABC transporters, which in turn, may elevate the risk for HDIs when consumed concomitantly with conventional medications.

Evaluation of the Potential for Cytochrome P450 and Transporter-Mediated Drug-Drug Interactions for Cilofexor, a Selective Nonsteroidal Farnesoid X Receptor (FXR) Agonist

BACKGROUND AND OBJECTIVE

Cilofexor is a selective farnesoid X receptor (FXR) agonist in development for the treatment of nonalcoholic steatohepatitis and primary sclerosing cholangitis. Our objective was to evaluate potential drug-drug interactions of cilofexor as a victim and as a perpetrator.

METHODS

In this Phase 1 study, healthy adult participants (n = 18-24 per each of the 6 cohorts) were administered cilofexor in combination with either perpetrators or substrates of cytochrome P-450 (CYP) enzymes and drug transporters.

RESULTS

In total, 131 participants completed the study. As a victim, cilofexor area under the curve (AUC) was 651%, 795%, and 175% when administered following single-dose cyclosporine (600 mg; organic anion transporting polypeptide [OATP]/P-glycoprotein [P-gp]/CYP3A inhibitor), single-dose rifampin (600 mg; OATP1B1/1B3 inhibitor), and multiple-dose gemfibrozil (600 mg twice daily [BID]; CYP2C8 inhibitor), respectively, compared with the administration of cilofexor alone. Cilofexor AUC was 33% when administered following multiple-dose rifampin (600 mg; OATP/CYP/P-gp inducer). Multiple-dose voriconazole (200 mg BID; CYP3A4 inhibitor) and grapefruit juice (16 ounces; intestinal OATP inhibitor) did not affect cilofexor exposure. As a perpetrator, multiple-dose cilofexor did not affect the exposure of midazolam (2 mg; CYP3A substrate), pravastatin (40 mg; OATP substrate), or dabigatran etexilate (75 mg; intestinal P-gp substrate), but atorvastatin (10 mg; OATP/CYP3A4 substrate) AUC was 139% compared with atorvastatin administered alone.

CONCLUSION

Cilofexor may be coadministered with inhibitors of P-gp, CYP3A4, or CYP2C8 without the need for dose modification. Cilofexor may be coadministered with OATP, BCRP, P-gp, and/or CYP3A4 substrates-including statins-without dose modification. However, coadministration of cilofexor with strong hepatic OATP inhibitors, or with strong or moderate inducers of OATP/CYP2C8, is not recommended.

A pharmacokinetic drug-drug interaction study between rosuvastatin and emvododstat, a potent anti-SARS-CoV-2 (COVID-19) DHODH (dihydroorotate dehydrogenase) inhibitor

A therapeutic agent that targets both viral replication and the hyper-reactive immune response would offer a highly desirable treatment for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; COVID-19) management. Emvododstat (PTC299) was found to be a potent inhibitor of immunomodulatory and inflammation-related processes by the inhibition of dihydroorotate dehydrogenase (DHODH) to reduce SARS-CoV-2 replication. DHODH is the rate-limiting enzyme of the de novo pyrimidine nucleotide biosynthesis pathway. This drug interaction study was performed to determine whether emvododstat was an inhibitor of breast cancer resistance protein (BCRP) transporters in humans. Potential drug-drug interactions (DDIs) between emvododstat and a BCRP transporter substrate (rosuvastatin) were investigated by measuring plasma rosuvastatin concentrations before and after emvododstat administration. There was no apparent difference in rosuvastatin plasma exposure. The geometric means of maximum plasma rosuvastatin concentrations (Cmax ) were 4369 (rosuvastatin) and 5141 pg/mL (rosuvastatin + emvododstat) at 4 h postdose. Geometric mean rosuvastatin area under the concentration-time curve (AUC) from time 0 to the last measurable plasma concentration was 45 616 and 48 975 h·pg/mL when administered alone and after 7 days of b.i.d. emvododstat dosing, respectively. Geometric least squares mean ratios for Cmax and AUC were approximately equal to 1. Overall, administration of multiple doses of 100 mg emvododstat b.i.d. for 7 days in combination with a single dose of rosuvastatin was safe and well tolerated. Emvododstat can be safely administered with other BCRP substrate drugs. Hence, pharmacokinetic DDI mediated via BCRP inhibition is not expected when emvododstat and BCRP substrates are coadministered.

Mechanistic in vitro studies indicate that the clinical drug-drug interactions between protease inhibitors and rosuvastatin are driven by inhibition of intestinal BCRP and hepatic OATP1B1 with minimal contribution from OATP1B3, NTCP and OAT3

Previous use of a mechanistic static model to accurately quantify the increased rosuvastatin exposure due to drug-drug interaction (DDI) with coadministered atazanavir underpredicted the magnitude of area under the plasma concentration-time curve ratio (AUCR) based on inhibition of breast cancer resistance protein (BCRP) and organic anion transporting polypeptide (OATP) 1B1. To reconcile the disconnect between predicted and clinical AUCR, atazanavir and other protease inhibitors (darunavir, lopinavir and ritonavir) were evaluated as inhibitors of BCRP, OATP1B1, OATP1B3, sodium taurocholate cotransporting polypeptide (NTCP) and organic anion transporter (OAT) 3. None of the drugs inhibited OAT3, nor did darunavir and ritonavir inhibit OATP1B3 or NTCP. All drugs inhibited BCRP-mediated estrone 3-sulfate transport or OATP1B1-mediated estradiol 17β-D-glucuronide transport with the same rank order of inhibitory potency (lopinavir>ritonavir>atazanavir>>darunavir) and mean IC50 values ranging from 15.5 ± 2.80 μM to 143 ± 14.7 μM or 0.220 ± 0.0655 μM to 9.53 ± 2.50 μM, respectively. Atazanavir and lopinavir also inhibited OATP1B3- or NTCP-mediated transport with a mean IC50 of 1.86 ± 0.500 μM or 65.6 ± 10.7 μM and 5.04 ± 0.0950 μM or 20.3 ± 2.13 μM, respectively. Following integration of a combined hepatic transport component into the previous mechanistic static model using the in vitro inhibitory kinetic parameters determined above for atazanavir, the newly predicted rosuvastatin AUCR reconciled with the clinically observed AUCR confirming additional minor involvement of OATP1B3 and NTCP inhibition in its DDI. The predictions for the other protease inhibitors confirmed inhibition of intestinal BCRP and hepatic OATP1B1 as the principal pathways involved in their clinical DDI with rosuvastatin.

Modulatory Activity of the Copper Chelate, Copper N-(2-Hydroxy Acetophenone) Glycinate, in ABC-transporter-expressing Cell Lines

BACKGROUND/AIM

Metal-containing compounds (e.g., platinum complexes) belong to the standard armamentarium of cancer chemotherapy. Copper N-(2-hydroxy acetophenone) glycinate (CuNG) exerts anticancer activity in vitro and in vivo and modulates drug resistance related to glutathione or P-glycoprotein. The potential of CuNG to interact with ATP-binding cassette (ABC) transporters has not been fully explored yet. This study focused on the modulatory effects of CuNG on four ABC transporters (MRP1, MRP1, BCRP, and P-glycoprotein).

MATERIALS AND METHODS

Cell viability, drug uptake and ABC transporter expression were measured by resazurin assays, flow cytometry, and ELISA in HL60AR, MDCKII-hBCRP, and Caco-2 cells.

RESULTS

CuNG increased doxorubicin sensitivity of MRP1-over-expressing HL60AR with a similar efficacy as the control MRP1 inhibitor MK571. CuNG also increased MRP1's efflux activity. Comparable results were obtained with MDCKII cells over-expressing hBCRP. ELISA assays revealed that the expression of MRP1 in HL60AR cells and BCRP in MDCKII- cells was predominant but other ABC-transporters were also expressed at lower levels. Caco-2 cells expressed high levels of MRP2, but MRP1, BCRP, and P-glycoprotein were also expressed. In contrast to the two former cell lines, CuNG increased doxorubicin resistance and decreased efflux activity in Caco-2 cells.

CONCLUSION

CuNG exerted different modulatory activities towards ABC-transporter-expressing cells. While CuNG-mediated ABC-transporter inhibition may improve tumor chemotherapy (like in HL60AR and MDCKII-hBCRP cells), CuNG-mediated enhanced ABC-transport (like in Caco-2 cells) may be a new strategy to ameliorate inflammatory diseases associated with decreased ABC-transporter expression such as ulcerative colitis.

Co-exposure health risk of benzo[a]pyrene with aromatic VOCs: Monoaromatic hydrocarbons inhibit the glucuronidation of benzo[a]pyrene

Occupational workers and residents near petrochemical industry facilities are exposed to multiple contaminants on a daily basis. However, little is known about the co-exposure effects of different pollutants based on biotransformation. The study examined benzo[a]pyrene (BaP), a representative polycyclic aromatic hydrocarbon related to the petrochemical industry, to investigate changes in toxicity and co-exposure mechanism associated with different monoaromatic hydrocarbons (MAHs). A central composite design method was used to simulate site co-exposure scenarios to reveal biotransformation of BaP when co-exposed with benzene, toluene, chlorobenzene, or nitrobenzene in microsome systems. BaP metabolism depended on MAH concentration, and association of MAH with microsome concentration/incubation time. Particularly, MAH co-exposure negatively affected BaP glucuronidation, an important phase Ⅱ detoxification process. BaP metabolite intensities decreased to 43%-80% for OH-BaP-G, and 32%-71% for diOH-BaP-G in co-exposure system with MAHs, compared with control group. Furthermore, glucuronidation was affected by competitive and time-dependent inhibition. Co-exposure significantly decreased gene expression of UGT 1A10 and BCRP/ABCG2 in HepG2 cells, which are involved in BaP detoxification through metabolism and transmembrane transportation. Therefore, human co-exposure to multiple contaminants may deteriorate toxic effects of these chemicals by disturbing metabolic pathways. This study provides a reference for assessing toxic effects and co-exposure risks of pollutants.

Natural borneol serves as an adjuvant agent to promote the cellular uptake of piperlongumine for improving its antiglioma efficacy

Piperlongumine (PL) can selectively inhibit the proliferation of various cancer cells by increasing reactive oxygen species (ROS) level to cause a redox imbalance in cancer cells rather than in normal cells. However, the clinical application of PL is limited by its poor cellular uptake. Natural borneol (NB) is extracted from the fresh branches and leaves of Cinnamomum camphora (L.) Presl. with the purity of (+)-borneol no less than 96.0%. NB has been often used as an adjuvant agent to promote the cellular uptake of other drugs. This study aims to investigate the effect of NB on the cellular uptake of PL for improving its antiglioma efficacy and underlying mechanism. NB obviously promoted the cellular uptake of PL with a 1.3-fold increase in the maximum peak concentration and an earlier peak time of 30 min in C6 glioma cells. The cellular uptake of PL was enhanced by NB through down-regulating the expression levels of P-glycoprotein (ABCB1) and breast cancer resistance protein (ABCG2). The combination of NB and PL significantly induced higher levels of ROS, which increased apoptosis and enhanced G2/M cycle arrest of C6 glioma cells, compared to PL alone administration. NB-enhanced antiglioma efficacy of PL without side effects was confirmed in tumor-bearing mice, which was attributed to the improved cellular uptake of PL. The distribution of PL in the tumor tissue of combined group increased 2.39 times than that of PL-treated group. We firstly report NB as an adjuvant agent to improve the antiglioma efficacy of PL in a ROS-dependent manner, which is due to the enhanced cellular uptake of PL by NB though down-regulating the expression levels of ABCB1 and ABCG2. This work provides a new strategy to promote the cellular uptake of PL with great potential for the treatment of glioma.

Effects of bacterial and viral pathogen-associated molecular patterns (PAMPs) on multidrug resistance (MDR) transporters in brain endothelial cells of the developing human blood-brain barrier

BACKGROUND

The multidrug resistance (MDR) transporters, P-glycoprotein (P-gp, encoded by ABCB1) and breast cancer resistance protein (BCRP/ABCG2) contribute to the blood-brain barrier (BBB), protecting the brain from drug exposure. The impact of infection on MDR in the developing human BBB remains to be determined. We hypothesized that exposure to bacterial and viral pathogen-associated molecular patterns (PAMPs) modify MDR expression and activity in human fetal brain endothelial cells (hfBECs) isolated from early and mid-gestation brain microvessels.

METHODS

We modelled infection (4 h and 24 h) using the bacterial PAMP, lipopolysaccharide (LPS; a toll-like receptor [TLR]-4 ligand) or the viral PAMPs, polyinosinic polycytidylic acid (Poly I:C; TLR-3 ligand) and single-stranded RNA (ssRNA; TLR-7/8 ligand). mRNA expression was assessed by qPCR, whereas protein expression was assessed by Western blot or immunofluorescence. P-gp and BCRP activity was evaluated by Calcein-AM and Chlorin-6 assays.

RESULTS

TLRs-3,4 and 8 were expressed by the isolated hfBECs. Infection mimics induced specific pro-inflammatory responses as well as changes in P-gp/ABCB1 or BCRP/ABCG2 expression (P < 0.05). LPS and ssRNA significantly decreased P-gp activity at 4 and 24 h in early and mid-gestation (P < 0.03-P < 0.001), but significantly increased BCRP activity in hfBECs in a dose-dependent pattern (P < 0.05-P < 0.002). In contrast, Poly-IC significantly decreased P-gp activity after 4 h in early (P < 0.01) and mid gestation (P < 0.04), but not 24 h, and had no overall effect on BCRP activity, though BCRP activity was increased with the highest dose at 24 h in mid-gestation (P < 0.05).

CONCLUSIONS

Infectious PAMPs significantly modify the expression and function of MDR transporters in hfBECs, though effects are PAMP-, time- and dose-specific. In conclusion, bacterial and viral infections during pregnancy likely have profound effects on exposure of the fetal brain to physiological and pharmacological substrates of P-gp and BCRP, potentially leading to altered trajectories of fetal brain development.

Design, Synthesis and Biological Evaluation of Quinazolinamine Derivatives as Breast Cancer Resistance Protein and P-Glycoprotein Inhibitors with Improved Metabolic Stability

A series of twenty-two quinazolinamine derivatives showing potent inhibitory activities on breast cancer resistance protein (BCRP) and p-glycoprotein (P-gp) were synthesized. A cyclopropyl-containing quinazolinamine 22 was identified as a dual BCRP and P-gp inhibitor, while azide-containing quinazolinamine 33 showed BCRP inhibitory activity. These lead compounds were further investigated in a battery of mechanistic experiments. Compound 22 changed the localization of BCRP and P-gp in cells, thus inhibiting the efflux of anticancer drugs by the two ATP-binding cassette (ABC) transporters. In addition, both 22 and 33 significantly stimulated the ATP hydrolysis of the BCRP transporter, indicating that they can be competitive substrates of the BCRP transporter, and thereby increase the accumulation of mitoxantrone in BCRP-overexpressing H460/MX20 cells. Azide derivative 33, exhibited a greater inhibitory effect on BCRP after UV activation and can serve as a valuable probe for investigating the interactions of quinazolinamine derivatives with BCRP. Notably, the dual BCRP and P-gp inhibitors 4-5, 22-24, 27, and BCRP inhibitor 33 showed improved metabolic stability compared to Ko143.

Cancer Drug Resistance Reduction via Co-treatment with Oxaliplatin and Nitazoxanide: Targeting the ABC Transporters

OBJECTS

Shortly after cancer is diagnosed, a phenomenon develops in cancer cells called multidrug resistance (MDR), in which cell sensitivity against anti-cancer drugs is significantly reduced. The present investigation aimed to assess the effects of nitazoxanide (NTZ), a safe drug, on LS174T/OXP-resistant cells.

METHODS

In the current in vitro research, the effects of NTZ and oxaliplatin (OXP) on the viability of LS174T and LS174T/OXP cell lines were evaluated through MTT assay. Then, the changes in expression levels of MDR1, MRP1, BCRP, and LRP genes and proteins were measured by RT-qPCR and western blotting methods, respectively. Lastly, the apoptosis status was assessed by annexin V-FITC/PI staining flow cytometry assay.

RESULTS

The IC50 values for cells resistant or sensitive to OXP were revealed (11567 nM vs. 1745 nM; p <0.05 for 24 h incubation, and 5161 nM vs. 882.2 nM; p <0.05 for 48 h incubation). Moreover, NTZ plus OXP led to a leftward shift in the cytotoxicity curve (2004 nM; p = 0.007). This co-treatment significantly decreased the expression of all genes and proteins (p <0.05). Finally, the combination of NTZ and OXP induced a significant increase in apoptosis (p <0.001).

CONCLUSION

The data showed that NTZ treatment could increase the sensitivity of LS174T/OXP cell line to the OXP cytotoxic effects. Thus, NTZ may be efficient in reducing drug resistance in clinics by means of the negative regulation of ATP-binding cassette (ABC) transporters. However, further studies are necessary to explain the exact mechanisms of NTZ.

Bromoacetic acid causes oxidative stress and uric acid metabolism dysfunction via disturbing mitochondrial function and Nrf2 pathway in chicken kidney

Since the outbreak of COVID-19, widespread utilization of disinfectants has led to a tremendous increase in the generation of disinfection byproducts worldwide. Bromoacetic acid (BAA), one of the common disinfection byproducts in the environment, has triggered public concern because of its adverse effects on urinary system in mammals. Nevertheless, the BAA-induced nephrotoxicity and potential mechanism in birds still remains obscure. According to the detected content in the Taihu Lake Basin, the model of BAA exposure in chicken was established at doses of 0, 3, 300, 3000 μg/L for 4 weeks. Our results indicated that BAA exposure caused kidney swelling and structural disarrangement. BAA led to disorder in renal function (CRE, BUN, UA) and increased apoptosis (Bax, Bcl-2, caspase3). BAA suppressed the expression of mitochondrial biogenesis genes (PGC-1α, Nrf1, TFAM) and OXPHOS complex I genes (ND1, ND2, ND3, ND4, ND4L, ND5, ND6). Subsequently, BAA destroyed the expression of Nrf2 antioxidant reaction genes (Nrf2, Keap1, HO-1, NQO1, GCLM, GCLC). Furthermore, renal oxidative damage led to disorder in uric acid metabolism genes (Mrp2, Mrp4, Bcrp, OAT1, OAT2, OAT3) and exacerbated destruction in renal function. Overall, our study provided insights into the potential mechanism of BAA-induced nephrotoxicity, which were important for the clinical monitoring and prevention of BAA.

In silico screening of c-Met tyrosine kinase inhibitors targeting nucleotide and drug-substrate binding sites of ABCB1 as potential MDR reversal agents

PURPOSE

Cancer is a significant public health problem and ranks as a leading cause of death globally. Multidrug resistance (MDR) affects the therapeutic potential of conventional chemotherapeutic agents in cancer chemotherapy. Receptor tyrosine kinases (RTKs) are enzymes whose aberrant activation contributes to the tumorigenesis of various types of cancers. The ability of several RTKs, such as c-Met, to reverse ABC transporters mediated MDR was shown before. We aimed to explore the ability of c-Met inhibitors to circumvent MDR in cancer by inhibiting the ABCB1 transporter using in silico studies.

METHODS

Docking virtual screening of several potent and structurally diverse c-Met inhibitors were applied to find repurposed candidates to target the ATP binding sites and drug-substrate binding pockets of the ABCB1 transporter. The selected candidate was subjected to molecular dynamics simulations.

RESULTS

Based on docking findings, among 19 clinical c-Met inhibitors, several drugs, particularly golvatinib, exerted the affinity to both ATP binding sites in the nucleotide-binding domains (NBDs) as well as the drug-substrate binding site in the transmembrane domains (TMDs). Moreover, several non-clinical c-Met inhibitors obtained from the ChEMBL database had strong interactions with TMDs and NBDs, among which CHEMBL1950194 and CHEMBL2385194 compounds showed the highest binding affinity, respectively. Additionally, as a potential repositioning drug, MD simulation studies of golvatinib, corroborated the docking results.

CONCLUSION

We applied docking and molecular dynamics simulations to screen the potential c-Met inhibitors as the MDR reversing agents targeting ATP and drug-substrate binding sites, and the results suggested several repurposed candidate drugs.