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Journal of Cerebral Blood Flow and... Jan 2020P-glycoprotein (P-gp, ABCB1) is an efflux transporter at the blood-brain barrier (BBB), which mediates clearance of beta-amyloid (Aβ) from brain into blood. We used...
P-glycoprotein (P-gp, ABCB1) is an efflux transporter at the blood-brain barrier (BBB), which mediates clearance of beta-amyloid (Aβ) from brain into blood. We used ()-[C]verapamil PET in combination with partial P-gp inhibition with tariquidar to measure cerebral P-gp function in a beta-amyloidosis mouse model (APPtg) and in control mice at three different ages (50, 200 and 380 days). Following tariquidar pre-treatment (4 mg/kg), whole brain-to-plasma radioactivity concentration ratios () were significantly higher in APPtg than in wild-type mice aged 50 days, pointing to decreased cerebral P-gp function. Moreover, we found an age-dependent decrease in cerebral P-gp function in both wild-type and APPtg mice of up to -50%. Alterations in P-gp function were more pronounced in Aβ-rich brain regions (hippocampus, cortex) than in a control region with negligible Aβ load (cerebellum). PET results were confirmed by immunohistochemical staining of P-gp in brain microvessels. Our results confirm previous findings of reduced P-gp function in Alzheimer's disease mouse models and show that our PET protocol possesses adequate sensitivity to measure these functional changes in vivo. Our PET protocol may find use in clinical studies to test the efficacy of drugs to induce P-gp function at the human BBB to enhance Aβ clearance.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Age Factors; Alzheimer Disease; Amyloidosis; Animals; Biological Transport; Blood-Brain Barrier; Brain Chemistry; Disease Models, Animal; Mice; Positron-Emission Tomography; Quinolines
PubMed: 30354871
DOI: 10.1177/0271678X18806640 -
Medicina (Kaunas, Lithuania) Sep 2019Pain can have a significantly negative impact on the quality of life of patients. Therefore, patients may resort to analgesics to relieve the pain. The struggle to... (Review)
Review
Pain can have a significantly negative impact on the quality of life of patients. Therefore, patients may resort to analgesics to relieve the pain. The struggle to manage pain in cancer patients effectively and safely has long been an issue in medicine. Analgesics are the mainstay treatment for pain management as they act through various methods on the peripheral and central pain pathways. However, the variability in the patient genotypes may influence a drug response and adverse drug effects that follow through. This review summarizes the observed effects of analgesics on UDP-glucuronosyl (UGT) 2B7 isoenzyme, cytochrome P450 (CYP) 2D6, μ-opioid receptor μ 1 (OPRM1), efflux transporter P-glycoprotein (P-gp) and ATP-binding cassette B1 ABCB1/multiple drug resistance 1 (MDR1) polymorphisms on the mechanism of action of these drugs in managing pain in cancer. Furthermore, this review article also discusses the responses and adverse effects caused by analgesic drugs in cancer pain management, due to the inter-individual variability in their genomes.
Topics: ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; Analgesics; Cancer Pain; Cytochrome P-450 CYP2D6; Gene Regulatory Networks; Glucuronosyltransferase; Humans; Pain Management; Pharmacogenomic Variants; Polymorphism, Single Nucleotide; Quality of Life; Receptors, Opioid, mu
PubMed: 31547335
DOI: 10.3390/medicina55090584 -
International Journal of Molecular... Dec 2022The blood-brain barrier (BBB) controls brain homeostasis; it is formed by vascular endothelial cells that are physically connected by tight junctions (TJs). The BBB...
The blood-brain barrier (BBB) controls brain homeostasis; it is formed by vascular endothelial cells that are physically connected by tight junctions (TJs). The BBB expresses efflux transporters such as P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP), which limit the passage of substrate molecules from blood circulation to the brain. Focused ultrasound (FUS) with microbubbles can create a local and reversible detachment of the TJs. However, very little is known about the effect of FUS on the expression of efflux transporters. We investigated the in vivo effects of moderate acoustic pressures on both P-gp and BCRP expression for up to two weeks after sonication. Magnetic resonance-guided FUS was applied in the striatum of 12 rats. P-gp and BCRP expression were determined by immunohistochemistry at 1, 3, 7, and 14 days postFUS. Our results indicate that FUS-induced BBB opening is capable of (i) decreasing P-gp expression up to 3 days after sonication in both the treated and in the contralateral brain regions and is capable of (ii) overexpressing BCRP up to 7 days after FUS in the sonicated regions only. Our findings may help improve FUS-aided drug delivery strategies by considering both the mechanical effect on the TJs and the regulation of P-gp and BCRP.
Topics: Rats; Animals; Blood-Brain Barrier; ATP Binding Cassette Transporter, Subfamily G, Member 2; Pilot Projects; ATP Binding Cassette Transporter, Subfamily B, Member 1; Endothelial Cells; Neoplasm Proteins; Neoplasms; Brain; ATP Binding Cassette Transporter, Subfamily B; Microbubbles
PubMed: 36555129
DOI: 10.3390/ijms232415488 -
Biological & Pharmaceutical Bulletin 2022Dextran is a promising candidate as a nanocarrier of chemotherapeutic drugs due to its biocompatibility, biodegradability, and ability to accumulate in tumors....
Dextran is a promising candidate as a nanocarrier of chemotherapeutic drugs due to its biocompatibility, biodegradability, and ability to accumulate in tumors. Furthermore, dextran derivatives interact with P-glycoprotein (P-gp), so we hypothesized that they may be available as tumor-specific drug delivery systems with the ability to reverse multidrug resistance. Here, to test this idea, we investigated whether dextran and its derivatives inhibit breast cancer resistance protein (BCRP), multidrug resistance associated protein 1 (MRP1), and P-gp in vitro. First, we examined their effect on the uptake of specific fluorescent substrates by inside-out Sf-9 membrane vesicles overexpressing BCRP, MRP1, and P-gp. BCRP and MRP1 were significantly inhibited by 2-hydroxypropyl-trimethylammonium-dextran of 4 and 70 kDa (Q-D4 and Q-D70) at a concentration near the clinically used concentration of dextran; however, P-gp was not inhibited. A structure-activity study showed that Q-D4, Q-D70, and 40 kDa diethylaminoethyl-dextran (DEAE-D40) significantly inhibited BCRP, while 4, 40, and 70 kDa dextrans (D4, D40, and D70), dextran sulfate (Sul-D40), and the individual saccharide components of dextran did not. These results suggest that the cationic side chains, but not the saccharides, are important for BCRP inhibition. Finally, cell-based efflux assay was conducted. Q-D4, Q-D70, and DEAE-D40 did not specifically increase the retention of Hoechst33342 in BCRP-overexpressing KB cells. Similarly, Q-D4 and Q-D70 did not affect the intracellular retention of specific fluorescent substrates in MRP1- and P-gp-overexpressing KB cells. The ineffectiveness in cellular systems is presumably due to inability of the dextran derivatives to access transporters located on the cytoplasmic side of the cell membrane.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP Binding Cassette Transporter, Subfamily G, Member 2; Dextrans; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Humans; Multidrug Resistance-Associated Proteins; Neoplasm Proteins; Neoplasms
PubMed: 35908887
DOI: 10.1248/bpb.b21-01035 -
Molecular Pharmaceutics Aug 2021P-Glycoprotein (P-gp) is an efflux pump located at the blood-brain barrier (BBB) that contributes to the protection of the central nervous system by transporting...
P-Glycoprotein (P-gp) is an efflux pump located at the blood-brain barrier (BBB) that contributes to the protection of the central nervous system by transporting neurotoxic compounds out of the brain. A decline in P-gp function has been related to the pathogenesis of neurodegenerative diseases. P-gp inducers can increase the P-gp function and are considered as potential candidates for the treatment of such disorders. The P-gp inducer MC111 increased P-gp expression and function in SW480 human colon adenocarcinoma and colo-320 cells, respectively. Our study aims to evaluate the P-gp inducing effect of MC111 in the whole brain , using the P-gp tracer [F]MC225 and positron emission tomography (PET). Eighteen Wistar rats were treated with either vehicle solution, 4.5 mg/kg of MC111 (low-dose group), or 6 mg/kg of MC111 (high-dose group). Animals underwent a 60 min dynamic PET scan with arterial-blood sampling, 24 h after treatment with the inducer. Data were analyzed using the 1-tissue-compartment model and metabolite-corrected plasma as the input function. Model parameters such as the influx constant () and volume of distribution () were calculated, which reflect the P-gp function. P-gp and pregnane xenobiotic receptor (PXR) expression levels of the whole brain were assessed using western blot. The administration of MC111 decreased and of [F]MC225 in the whole brain and all of the selected brain regions. In the high-dose group, whole-brain was decreased by 34% (-high-dose = 0.20 ± 0.02 vs -control = 0.30 ± 0.02; < 0.001) and in the low-dose group by 7% (-low-dose = 0.28 ± 0.02 vs -control = 0.30 ± 0.02; = 0.42) compared to controls. Whole-brain was decreased by 25% in the high-dose group (-high-dose = 5.92 ± 0.41 vs -control = 7.82 ± 0.38; < 0.001) and by 6% in the low-dose group (-low-dose = 7.35 ± 0.38 vs -control = 7.82 ± 0.37; = 0.38) compared to controls. values did not vary after treatment. The treatment did not affect the metabolism of [F]MC225. Western blot studies using the whole-brain tissue did not detect changes in the P-gp expression, however, preliminary results using isolated brain capillaries found an increasing trend up to 37% in treated rats. The decrease in and values after treatment with the inducer indicates an increase in the P-gp functionality at the BBB of treated rats. Moreover, preliminary results using brain endothelial cells also sustained the increase in the P-gp expression. In conclusion, the results verify that MC111 induces P-gp expression and function at the BBB in rats. An increasing trend regarding the P-gp expression levels is found using western blot and an increased P-gp function is confirmed with [F]MC225 and PET.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Animals; Biological Transport; Blood-Brain Barrier; Endothelial Cells; Isoquinolines; Kinetics; Male; Positron-Emission Tomography; Radiopharmaceuticals; Rats; Rats, Wistar; Tetrahydronaphthalenes
PubMed: 34228458
DOI: 10.1021/acs.molpharmaceut.1c00302 -
Drug Resistance Updates : Reviews and... Nov 2023Therapy resistance has long been considered to occur through the selection of pre-existing clones equipped to survive and quickly regrow, or through the acquisition of...
Therapy resistance has long been considered to occur through the selection of pre-existing clones equipped to survive and quickly regrow, or through the acquisition of mutations during chemotherapy. Here we show that following in vitro treatment by chemotherapy, epithelial breast cancer cells adopt a transient drug tolerant phenotype characterized by cell cycle arrest, epithelial-to-mesenchymal transition (EMT) and the reversible upregulation of the multidrug resistance (MDR) efflux transporter P-glycoprotein (P-gp). The drug tolerant persister (DTP) state is reversible, as cells eventually resume proliferation, giving rise to a cell population resembling the initial, drug-naïve cell lines. However, recovery after doxorubicin treatment is almost completely eliminated when DTP cells are cultured in the presence of the P-gp inhibitor Tariquidar. Mechanistically, P-gp contributes to the survival of DTP cells by removing reactive oxygen species-induced lipid peroxidation products resulting from doxorubicin exposure. In vivo, prolonged administration of Tariquidar during doxorubicin treatment holidays resulted in a significant increase of the overall survival of Brca1;p53 mammary tumor bearing mice. These results indicate that prolonged administration of a P-gp inhibitor during drug holidays would likely benefit patients without the risk of aggravated side effects related to the concomitantly administered toxic chemotherapy. Effective targeting of DTPs through the inhibition of P-glycoprotein may result in a paradigm shift, changing the focus from countering drug resistance mechanisms to preventing or delaying therapy resistance.
Topics: Humans; Animals; Mice; Female; ATP Binding Cassette Transporter, Subfamily B, Member 1; Lipid Peroxidation; Pharmaceutical Preparations; Breast Neoplasms; ATP Binding Cassette Transporter, Subfamily B; Doxorubicin
PubMed: 37741091
DOI: 10.1016/j.drup.2023.101007 -
Drugs Jul 2020Edoxaban, a direct factor Xa inhibitor, is the latest of the non-vitamin K antagonist oral anticoagulants (NOACs). Despite being marketed later than other NOACs, its use... (Review)
Review
Edoxaban, a direct factor Xa inhibitor, is the latest of the non-vitamin K antagonist oral anticoagulants (NOACs). Despite being marketed later than other NOACs, its use is now spreading in current clinical practice, being indicated for both thromboprophylaxis in patients with non-valvular atrial fibrillation (NVAF) and for the treatment and prevention of venous thromboembolism (VTE). In patients with multiple conditions, the contemporary administration of several drugs can cause relevant drug-drug interactions (DDIs), which can affect drugs' pharmacokinetics and pharmacodynamics. Usually, all the NOACs are considered to have significantly fewer DDIs than vitamin K antagonists; notwithstanding, this is actually not true, all of them are affected by DDIs with drugs that can influence the activity (induction or inhibition) of P-glycoprotein (P-gp) and cytochrome P450 3A4, both responsible for the disposition and metabolism of NOACs to a different extent. In this review/expert opinion, we focused on an extensive report of edoxaban DDIs. All the relevant drugs categories have been examined to report on significant DDIs, discussing the impact on edoxaban pharmacokinetics and pharmacodynamics, and the evidence for dose adjustment. Our analysis found that, despite a restrained number of interactions, some strong inhibitors/inducers of P-gp and drug-metabolising enzymes can affect edoxaban concentration, just as it happens with other NOACs, implying the need for a dose adjustment. However, our analysis of edoxaban DDIs suggests that given the small propensity for interactions of this agent, its use represents an acceptable clinical decision. Still, DDIs can be significant in certain clinical situations and a careful evaluation is always needed when prescribing NOACs.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Cytochrome P-450 CYP3A Inhibitors; Drug Interactions; Factor Xa Inhibitors; Medication Therapy Management; Pyridines; Thiazoles; Thromboembolism
PubMed: 32504376
DOI: 10.1007/s40265-020-01328-6 -
Cells Jul 2022There is little information about the functional expression of the multidrug resistance (MDR) transporters P-glycoprotein (P-gp, encoded by ABCB1) and breast cancer...
There is little information about the functional expression of the multidrug resistance (MDR) transporters P-glycoprotein (P-gp, encoded by ABCB1) and breast cancer resistance protein (BCRP/ABCG2) in the developing blood−brain barrier (BBB). We isolated and cultured primary human fetal brain endothelial cells (hfBECs) from early and mid-gestation brains and assessed P-gp/ABCB1 and BCRP/ABCG2 expression and function, as well as tube formation capability. Immunolocalization of the von Willebrand factor (marker of endothelial cells), zonula occludens-1 and claudin-5 (tight junctions) was detected in early and mid-gestation-derived hfBECs, which also formed capillary-like tube structures, confirming their BEC phenotype. P-gp and BCRP immunostaining was detected in capillary-like tubes and in the cytoplasm and nucleus of hfBECs. P-gp protein levels in the plasma membrane and nuclear protein fractions, as well as P-gp protein/ABCB1 mRNA and BCRP protein levels decreased (p < 0.05) in hfBECs, from early to mid-gestation. No differences in P-gp or BCRP activity in hfBECs were observed between the two age groups. The hfBECs from early and mid-gestation express functionally competent P-gp and BCRP drug transporters and may thus contribute to the BBB protective phenotype in the conceptus from early stages of pregnancy.
Topics: ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP Binding Cassette Transporter, Subfamily G, Member 2; ATP-Binding Cassette Transporters; Brain; Drug Resistance, Multiple; Endothelial Cells; Female; Humans; Neoplasm Proteins; Pregnancy
PubMed: 35883702
DOI: 10.3390/cells11142259 -
International Journal of Pharmaceutics Aug 2022The aim of the present study was to investigate if mucus applied to Caco-2 cell monolayers protects cells from high concentrations of surfactants, while still allowing...
The aim of the present study was to investigate if mucus applied to Caco-2 cell monolayers protects cells from high concentrations of surfactants, while still allowing for an identification of the surfactant's inhibitory effects on P-glycoprotein (P-gp). Two types of porcine mucin and six surfactants (Polysorbate 20 (PS20) and 80 (PS80), Kolliphor EL (Kol. EL) and RH40 (Kol. RH40), Labrafil M 2125 CS (L.fil) and Labrasol (L.sol)) were applied to Caco-2 cells, and TEER, paracellular transport and P-gp mediated digoxin transport was measured. The results showed that 15% porcine mucin type II was incompatible with Caco-2 cell monolayer integrity, resulting in a dramatic drop in monolayer TEER and increased mannitol transport. In contrast, mucin type III was compatible with Caco-2 cell monolayers in the concentration range of 2.5-15% without substantially disturbing barrier properties. The highest concentration of mucin type III impaired the ability of all six surfactants to decrease P-gp mediated digoxin transport. Subsequently lowering the mucin concentration to 5% facilitated adequate protection of cells and enabled e.g., 5% PS20 to inhibit P-gp mediated digoxin transport. Overall, the present work is useful for early-stage permeability investigations on how mucus affects P-gp mediated transport in the presence of formulation excipients.
Topics: ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; Animals; Biological Transport; Caco-2 Cells; Digoxin; Humans; Mucins; Mucus; Polysorbates; Surface-Active Agents; Swine
PubMed: 35690306
DOI: 10.1016/j.ijpharm.2022.121885 -
Clinical Pharmacology and Therapeutics Mar 2021The human blood-brain barrier (BBB) transporter P-gp can efflux amyloid-β (Aβ) out of the central nervous system (CNS). Aβ is thought to be the causative agent for...
The human blood-brain barrier (BBB) transporter P-gp can efflux amyloid-β (Aβ) out of the central nervous system (CNS). Aβ is thought to be the causative agent for Alzheimer's disease (AD). Using positron emission tomography imaging, we have shown that BBB P-gp activity is reduced in AD, as quantified by the in vivo brain distribution of the P-gp probe [ C]-verapamil. Therefore, the aim of this study was to determine whether this reduced BBB P-gp activity in AD was due to decreased P-gp abundance at the BBB. Using targeted proteomics, we quantified the abundance of P-gp and other drug transporters in gray matter brain microvessels isolated from 43 subjects with AD and 38 age-matched controls (AMCs) from regions affected by AD (hippocampus and the parietal lobe of the brain cortex) and not affected by AD (cerebellum). First, P-gp abundance was decreased in the BBB of the hippocampus vs. the cerebellum in both subjects with AD and AMCs, and therefore was not AD-related. In addition, gray matter BBB abundance of P-gp (and of other transporters) in the hippocampus and the parietal lobe was not different between AD and AMC. The gray matter BBB abundance of all drug transporters decreased with age, likely due to age-dependent decrease in the density of brain microvessels. Collectively, the observed reduced in vivo cerebral BBB P-gp activity in AD cannot be explained by reduced abundance of P-gp at the BBB. Nevertheless, the drug transporter abundance at the human gray matter BBB data provided here can be used to predict brain distribution of drugs targeted to treat CNS diseases, including AD.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP Binding Cassette Transporter, Subfamily G, Member 2; Adult; Age Factors; Aged; Aged, 80 and over; Alzheimer Disease; Amyloid beta-Peptides; Biological Transport; Blood-Brain Barrier; Case-Control Studies; Equilibrative Nucleoside Transporter 1; Female; Gray Matter; Humans; Low Density Lipoprotein Receptor-Related Protein-1; Male; Microvessels; Neoplasm Proteins; Organic Anion Transporters; Positron-Emission Tomography; Proteomics; Verapamil; Young Adult
PubMed: 32885413
DOI: 10.1002/cpt.2035