Glyceollin Effects on MRP2 and BCRP in Caco-2 Cells, and Implications for Metabolic and Transport Interactions

In Vitro ADME and Preclinical Pharmacokinetics of Ulotaront, a TAAR1/5-HT1A Receptor Agonist for the Treatment of Schizophrenia

Purpose

Ulotaront (SEP-363856) is a TAAR1 agonist with 5-HT_1A agonist activity currently in clinical development for the treatment of schizophrenia. The objectives of the current study were to characterize the in vitro ADME properties, preclinical PK, and to evaluate the DDI potential of ulotaront and its major metabolite SEP-383103.

Methods

Solubility, permeability, plasma protein binding, CYP inhibition and induction, transporter inhibition and uptake studies were conducted in vitro. Phenotyping studies were conducted using recombinant human CYPs and FMOs, human liver microsomes and human liver homogenates. Preclinical plasma and brain pharmacokinetics were determined after a single intraperitoneal, intravenous, and oral administration of ulotaront.

Results

Ulotaront is a compound of high solubility, high permeability, and low binding to plasma proteins. Ulotaront metabolism is mediated via both NADPH-dependent and NADPH-independent pathways, with CYP2D6 as the major metabolizing enzyme. Ulotaront is an inducer of CYP2B6, and an inhibitor of CYP2D6, OCT1 and OCT2, while SEP-383103 is neither a CYP inducer nor a potent inhibitor of CYPs and human transporters. Ulotaront exhibits rapid absorption, greater than 70% bioavailability, approximately 3.5 L/kg volume of distribution, 1.5-4 h half-life, 12-43 ml/min/kg clearance, and good penetration across the blood–brain barrier in preclinical species.

Conclusions

Ulotaront has been designated as a BCS1 compound by US FDA. The ability of ulotaront to penetrate the blood–brain barrier for CNS targeting has been demonstrated in mice and rats. The potential for ulotaront and SEP-383103 to act as perpetrators of CYP and transporter-mediated DDIs is predicted to be remote.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11095-022-03267-1.

Acute regulation of apical ABC transporters in the gut. Potential influence on drug bioavailability

The extensive intestinal surface offers an advantage regarding nutrient, ion and water absorptive capacity but also brings along a high exposition to xenobiotics, including drugs of therapeutic use and food contaminants. After absorption of these compounds by the enterocytes, apical ABC transporters play a key role in secreting them back to the intestinal lumen, hence acting as a transcellular barrier. Rapid and reversible modulation of their activity is a subject of increasing interest for pharmacologists. On the one hand, a decrease in transporter activity may result in increased absorption of therapeutic agents given orally. On the other hand, an increase in transporter activity would decrease their absorption and therapeutic efficacy. Although of less relevance, apical ABC transporters also contribute to disposition of drugs systemically administered. This review article summarizes the present knowledge on the mechanisms aimed to rapidly regulate the activity of the main apical ABC transporters of the gut: multidrug resistance protein 1 (MDR1), multidrug resistance-associated protein 2 (MRP2) and breast cancer resistance protein (BCRP). Regulation of these mechanisms by drugs, drug delivery systems, drug excipients and nutritional components are particularly considered. This information could provide the basis for controlled regulation of bioavailability of therapeutic agents and at the same time would help to prevent potential drug-drug interactions.

Nonclinical safety assessment of PF614: A novel TAAP prodrug of oxycodone for chronic pain indication

PF614, a novel trypsin activated abuse protection (TAAP) prodrug of oxycodone, is being studied as chronic pain analgesic with extended release and abuse resistant properties. A series of nonclinical safety studies were conducted to support PF614 introduction to clinical trials. Ames assays (PF614 and its metabolites), comet assay (PF614 ≤ 50 mg/kg/day oral gavage in rats) and micronucleus assay (PF614 ≤ 175 mg/kg/day oral gavage in rats) were negative. hERG assay IC50 for PF614 was ≥300 μM. PF614 (0.1 and 10 μM) showed a low permeability in Caco-2 cells (≤1.17 x 10-6 cm/s) and was not a P-gp or BCRP substrate or inhibitor. The mean percent unbound PF614 among all concentrations in plasma ranged from 91.2 to 98.4, 79.4 to 100, and 52.9-79.9% in rat, dog, and human, respectively. Also, PF614 was metabolically stable in rat, dog, and human hepatocytes with no metabolites identified. Safety pharmacology study in dog indicated moderately lower heart rate at ≥ 2 mg/kg oral gavage doses. Toxicity studies of PF614 in rat and dog with daily oral doses of 25 and 18 mg/kg, respectively, for 14 Days were well tolerated with favorable safety profile supporting its further clinical evaluation.

Acidity stress for the systemic elicitation of glyceollin phytoalexins in soybean plants

Glyceollins are the major pathogen- and stress-inducible natural products (phytoalexins) of soybean that possess broad-spectrum anticancer and neuroprotective properties. Yet like other phytoalexins, glyceollins are difficult to obtain because they are typically biosynthesized only transiently and in low amounts in plant tissues. We recently identified acidity stress (pH 3.0 growth medium) as an elicitor that exerted prolonged (week-long) inductive effects on glyceollin biosynthesis and identified the NAC family TF gene GmNAC42-1 that activates glyceollin biosynthesis in response to acidity stress or WGE from the soybean pathogen Phytophthora sojae. GmNAC42-1 was annotated as an SAR gene and SAR genes were statistically overrepresented in the transcriptomic response to acidity stress suggesting that acidity stress triggers the systemic elicitation of glyceollin biosynthesis. Here, we demonstrate that acidity stress acts as a systemic elicitor when provided to soybean roots. Acidity stress preferentially elicited specific glyceollins in different soybean organs with exceptionally high yields of glyceollin I in root tissues.

Quercetin and kaempferol increase the intestinal absorption of isorhamnetin coexisting in Elaeagnus rhamnoides (L.) A. Nelson (Elaeagnaceae) extracts via regulating multidrug resistance-associated protein 2

BACKGROUND

Isorhamnetin (IS) is a flavonoid component with many biological activities such as antioxidant, anti-inflammatory, and anticancer, which is also the main active component in total flavones of Elaeagnus rhamnoides (L.) A. Nelson (Elaeagnaceae) (TFH); however, the interaction between IS and other components in TFH is unclear.

PURPOSE

The aim of the present study was to investigate the enhancement of quercetin (QU) or kaempferol (KA) on the intestinal absorption of IS coexisting in TFH, and then preliminarily illuminate the related mechanisms.

METHODS

Firstly, the intestinal absorption of IS in the presence or absence of QU or KA was conducted by in vivo pharmacokinetics model, in situ single-pass intestinal perfusion model (SPIP), and MDCK II-MRP2 monolayer cell model to confirm the enhancement of QU or KA on IS absorption. Secondly, the effects of multidrug resistance-associated protein 2 (MRP2) inhibitors on the IS intestinal absorption were investigated to ascertain the mediation of MRP2 on IS absorption. Finally, the effects of QU or KA on MRP2 activity, protein expression, and mRNA level were performed by SPIP, everted-gut sacs, western blotting, and real-time polymerase chain reaction experiments to elucidate the related mechanisms.

RESULTS

QU or KA increased IS intestinal absorption according to the increased AUC_0-96h, C_max, and P_eff of IS after co-administrated with QU or KA to rats; the oral absorption of IS was mediated by MRP2 based on the facts that the average plasma concentration, AUC_0-96h, and P_eff of IS were increased when co-administrated with PR or MK571 (MRP2 inhibitors) as well as the P_ratio(BL/AP) of IS was decreased by MK571 in MDCK II-MRP2 cell monolayer; the activity, protein expression, and mRNA level of MRP2 were inhibited or down-regulated by QU or KA because of the increased P_eff of MRP2 substrate calcein (CA) and the down-regulated relative protein and mRNA intensity after co-treated with QU or KA.

CONCLUSION

QU and KA increased the intestinal absorption of IS in TFH by regulating the activity and expression of MRP2, which provides useful information for the investigation of the transporter-mediated interaction of flavonoid components in herbal extracts.

An Update on the Effects of Glyceollins on Human Health: Possible Anticancer Effects and Underlying Mechanisms

Biologically active plant-based compounds, commonly referred to as phytochemicals, can influence the expression and function of various receptors and transcription factors or signaling pathways that play vital roles in cellular functions and are then involved in human health and diseases. Thus, phytochemicals may have a great potential to prevent and treat chronic diseases. Glyceollins, a group of phytoalexins that are isolated from soybeans, have attracted attention because they exert numerous effects on human functions and diseases, notably anticancer effects. In this review, we have presented an update on the effects of glyceollins in relation to their potential beneficial roles in human health. Despite a growing number of studies suggesting that this new family of phytochemicals can be involved in critical cellular pathways, such as estrogen receptor, protein kinase, and lipid kinase signaling pathways, future investigations will be needed to better understand their molecular mechanisms and their specific significance in biomedical applications.

Cellular Pharmacokinetic Model-Based Analysis of Genistein, Glyceollin, and MK-571 Effects on 5 (and 6)-Carboxy-2',7'-Dichloroflourescein Disposition in Caco-2 Cells

Pharmacokinetic modeling was used to describe 5 (and 6)-carboxy-2',7'-dichloroflourescein (CDF) disposition in Caco-2 cells following CDF or CDFDA (CDF diacetate) dosing. CDF transcellular flux was modeled by simple passive diffusion. CDFDA dosing models were based on simultaneous fitting of CDF levels in apical, basolateral, and intracellular compartments. Predicted CDF efflux was 50% higher across the apical versus the basolateral membrane. This difference was similar following apical and basolateral CDFDA dosing, despite intracellular levels being 3-fold higher following basolateral dosing, thus supporting nonsaturable CDF efflux kinetics. A 3-compartment catenary model with intracellular CDFDA hydrolysis described CDF disposition. This model predicted that apical CDF efflux was not altered in the presence of MK-571, and that basolateral membrane clearance was enhanced to account for reduced intracellular CDF in the presence of this multidrug resistance-associated protein (MRP) inhibitor. Similar effects were predicted for glyceollin, while genistein exposure had no predicted effects on CDF efflux. These modulator effects are discussed in the context of model predicted intracellular CDF concentrations relative to reports of CDF affinity (measured by Km) for MRP2 and MRP3. This model-based analysis confirms the complexity of efflux kinetics and suggests that other transporters may have contributed to CDF efflux.

Unconjugated bilirubin elevation impairs the function and expression of breast cancer resistance protein (BCRP) at the blood-brain barrier in bile duct-ligated rats

AIM

Liver failure is associated with dyshomeostasis of efflux transporters at the blood-brain barrier (BBB), which contributes to hepatic encephalopathy. In this study we examined whether breast cancer resistance protein (BCRP), a major efflux transporter at the BBB, was altered during liver failure in rats.

METHODS

Rats underwent bile duct ligation (BDL) surgery, and then were sacrificed after intravenous injection of prazosin on d3, d7 and d14. The brains and blood samples were collected. BCRP function at the BBB was assessed by the brain-to-plasma prazosin concentration ratio; Evans Blue extravasation in the brain tissues was used as an indicator of BBB integrity. The protein levels of BCRP in the brain tissues were detected. Human cerebral microvessel endothelial cells (HCMEC/D3) and Madin-Darby canine kidney cells expressing human BCRP (MDCK-BCRP) were tested in vitro. In addition, hyperbilirubinemia (HB) was induced in rats by intravenous injection of unconjugated bilirubin (UCB).

RESULTS

BDL rats exhibited progressive decline of liver function and HB from d3 to d14. In the brain tissues of BDL rats, both the function and protein levels of BCRP were progressively decreased, whereas the BBB integrity was intact. Furthermore, BDL rat serum significantly decreased BCRP function and protein levels in HCMEC/D3 cells. Among the abnormally altered components in BDL rat serum tested, UCB (10, 25 μmol/L) dose-dependently inhibit BCRP function and protein levels in HCMEC/D3 cells, whereas 3 bile acids (CDCA, UDCA and DCA) had no effect. Similar results were obtained in MDCK-BCRP cells and in the brains of HB rats. Correlation analysis revealed that UCB levels were negatively correlated with BCRP expression in the brain tissues of BDL rats and HB rats as well as in two types of cells tested in vitro.

CONCLUSION

UCB elevation in BDL rats impairs the function and expression of BCRP at the BBB, thus contributing to hepatic encephalopathy.