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Food and Chemical Toxicology : An... Dec 2020The drug transporter P-glycoprotein (P-gp) is often investigated in drug-interaction studies because the activity is modulated by a wide variety of xenobiotics including...
The drug transporter P-glycoprotein (P-gp) is often investigated in drug-interaction studies because the activity is modulated by a wide variety of xenobiotics including drugs, herbal products, and food components. In this study, we tested six common arylsulfonate food dyes-allura red, carmoisine, ponceau 4R, quinolone yellow, sunset yellow, and tartrazine-as activators and inhibitors of P-gp activity in vitro. The dyes were studied as P-gp activators by measuring ATPase activity in P-gp-expressing membranes. Compared to verapamil, a known activator of P-gp, the six food dyes showed no stimulatory activity. The potential for these six food dyes to act as P-gp inhibitors was tested in an intracellular efflux assay with P-gp-expressing cells. Compared to GF120918, a known P-gp inhibitor, there was no inhibitory activity for these six food dyes. The six food dyes tested do not interact with P-gp in vitro and, therefore, are unlikely cause clinical drug-food dye interactions. Further investigation is necessary to determine whether these food dyes could interact with other drug transporters.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Adenosine Triphosphatases; Biological Transport; Drug Interactions; Food Coloring Agents; Food-Drug Interactions; Humans; Verapamil
PubMed: 33011351
DOI: 10.1016/j.fct.2020.111785 -
Xenobiotica; the Fate of Foreign... Oct 2020Aspirin (acetyl salicylic acid) is widely used co-medication in patients with cardiovascular and cerebrovascular diseases. Given the prevalence of acetyl salicylic...
Aspirin (acetyl salicylic acid) is widely used co-medication in patients with cardiovascular and cerebrovascular diseases. Given the prevalence of acetyl salicylic acid's use as a co-medication and conflicting reports in the literature on it being a substrate of P-glycoprotein (P-gp). There is a potential risk for its interaction with compounds with P-gp liability, therefore, we have conducted a detailed investigation to determine substrate potential of acetyl salicylic acid towards P-gp. We observed significantly lower cellular uptake of acetyl salicylic acid in MDR1 transfected LLC-PK1 cells compared to LLC-PK1 wild-type (WT) cells, however, the efflux of acetyl salicylic acid in MDR1 transfected LLC-PK1 cells was not inhibited by known inhibitors under various conditions. Acetyl salicylic acid did not show active asymmetrical transport across MDR1 transfected LLC-PK1 cells compared to LLC-PK1-WT cells in transwell assay. Moreover, no difference in plasma and brain exposure of acetyl salicylic acid and its metabolite salicylic acid was observed between FVB-WT and Mdr1a/b knockout (KO) mice. Taken together, our findings indicate that acetyl salicylic acid is not a substrate of P-gp.
Topics: ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; Animals; Aspirin; Biological Transport; Biological Transport, Active; Brain; LLC-PK1 Cells; Swine
PubMed: 32302241
DOI: 10.1080/00498254.2020.1757785 -
Biochimica Et Biophysica Acta.... Jan 2020P-glycoprotein (Pgp) is a biomedically important member of the ABC transporter superfamily that mediates multidrug resistance in various cancer types. Substrate binding...
P-glycoprotein (Pgp) is a biomedically important member of the ABC transporter superfamily that mediates multidrug resistance in various cancer types. Substrate binding and transport in Pgp are modulated by the presence of cholesterol in the membrane. Structural information on cholesterol binding sites and mechanistic details of its redistribution are, however, largely unknown. In this study, a set of 40 independent molecular dynamics (MD) simulations of Pgp embedded in cholesterol-rich lipid bilayers are reported, totaling 8 μs, enabling extensive sampling of cholesterol-protein interactions in Pgp. Clustering analyses of the ensemble of cholesterol molecules (∼5740) sampled around Pgp in these simulations reveal specific and asymmetric cholesterol-binding regions formed by the transmembrane (TM) helices TM1-6 and TM8. Notably, not all the putative cholesterol binding sites identified by MD can be predicted by the primary sequence based cholesterol-recognition amino acid consensus (CRAC) or inverted CRAC (CARC) motifs, an observation that we attribute to inadequacy of these motifs to account for binding sites formed by remote amino acids in the sequence that can still be spatially adjacent to each other. Binding of cholesterol to Pgp occurs more frequently through its rough β-face formed by the two protruding methyl groups, whereas the opposite smooth α-face prefers packing alongside the membrane lipids. One full and two partial cholesterol flipping events between the two leaflets of the bilayer mediated by the surface of Pgp are also captured in these simulations. All flipping events are observed in a region formed by helices TM1, TM2, and TM11, featuring two full and two partial CRAC/CARC motifs, with Tyr49 and Tyr126 identified as key residues interacting with cholesterol during this event. Our study is the first to report direct observation of unconventional cholesterol translocation on the surface of Pgp, providing a secondary transport model for the known flippase activity of ABC exporters of cholesterol. This article is part of a Special Issue entitled: Molecular biophysics of membranes and membrane proteins.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Amino Acid Sequence; Binding Sites; Biological Transport; Cholesterol; Lipid Bilayers; Molecular Dynamics Simulation; Tyrosine
PubMed: 31676371
DOI: 10.1016/j.bbamem.2019.183090 -
International Journal of Molecular... Jun 2023The ABC transporter P-glycoprotein (Pgp) has been found to be involved in multidrug resistance in tumor cells. Lipids and cholesterol have a pivotal role in Pgp's...
The ABC transporter P-glycoprotein (Pgp) has been found to be involved in multidrug resistance in tumor cells. Lipids and cholesterol have a pivotal role in Pgp's conformations; however, it is often difficult to investigate it with conventional structural biology techniques. Here, we applied robust approaches coupled with cross-linking mass spectrometry (XL-MS), where the natural lipid environment remains quasi-intact. Two experimental approaches were carried out using different cross-linkers (i) on living cells, followed by membrane preparation and immunoprecipitation enrichment of Pgp, and (ii) on-bead, subsequent to membrane preparation and immunoprecipitation. Pgp-containing complexes were enriched employing extracellular monoclonal anti-Pgp antibodies on magnetic beads, followed by on-bead enzymatic digestion. The LC-MS/MS results revealed mono-links on Pgp's solvent-accessible residues, while intraprotein cross-links confirmed a complex interplay between extracellular, transmembrane, and intracellular segments of the protein, of which several have been reported to be connected to cholesterol. Harnessing the MS results and those of molecular docking, we suggest an epitope for the 15D3 cholesterol-dependent mouse monoclonal antibody. Additionally, enriched neighbors of Pgp prove the strong connection of Pgp to the cytoskeleton and other cholesterol-regulated proteins. These findings suggest that XL-MS may be utilized for protein structure and network analyses in such convoluted systems as membrane proteins.
Topics: Animals; Mice; ATP Binding Cassette Transporter, Subfamily B, Member 1; Molecular Docking Simulation; Chromatography, Liquid; Tandem Mass Spectrometry; ATP Binding Cassette Transporter, Subfamily B; Cholesterol
PubMed: 37445813
DOI: 10.3390/ijms241310627 -
Journal of Veterinary Pharmacology and... Nov 2023The ATP-binding cassette transporter P-glycoprotein (P-gp) limits the oral bioavailability of many drugs. Although P-gp has been well studied in humans and mice, little...
The ATP-binding cassette transporter P-glycoprotein (P-gp) limits the oral bioavailability of many drugs. Although P-gp has been well studied in humans and mice, little is known about the substrate specificities of many of its species orthologs. To address this, we performed in vitro analysis of P-gp transporter function using HEK293 cells stably expressing human, ovine, porcine, canine, and feline P-gp. We also employed a human physiologically based pharmacokinetic (PBPK) model to assess variations in digoxin exposure resulting from altered P-gp function. Compared to human P-gp, sheep P-gp had significantly less digoxin efflux (2.3-fold ±0.04 vs. 1.8-fold ±0.03, p < .0001) and all species orthologs had significantly less quinidine efflux compared with human P-gp (p < .05). Human P-gp also had significantly greater efflux of talinolol compared to sheep and dog P-gp (1.9-fold ±0.04 vs. 1.6-fold ±0.06, p = .003 and 1.6-fold ±0.05, p = .0002, respectively). P-gp expression protected all lines against paclitaxel-induced toxicity, with sheep P-gp being significantly less protective. The inhibitor verapamil demonstrated dose-dependent inhibition of all P-gp orthologs. Finally, a PBPK model showed digoxin exposure was sensitive to altered P-gp activity. Overall, our study found that species differences in this major drug transporter exist and that the appropriate species ortholog of P-gp should be evaluated during veterinary drug development.
Topics: Humans; Animals; Dogs; Cats; Sheep; Mice; Swine; ATP Binding Cassette Transporter, Subfamily B, Member 1; HEK293 Cells; ATP Binding Cassette Transporter, Subfamily B; Digoxin; Verapamil
PubMed: 37198956
DOI: 10.1111/jvp.13386 -
Clinical Pharmacology and Therapeutics Sep 2022The role of P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) in drug-drug interactions (DDIs) and limiting drug absorption as well as restricting the... (Review)
Review
The role of P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) in drug-drug interactions (DDIs) and limiting drug absorption as well as restricting the brain penetration of drugs with certain physicochemical properties is well known. P-gp/BCRP inhibition by drugs in the gut has been reported to increase the systemic exposure to substrate drugs. A previous International Transporter Consortium (ITC) perspective discussed the feasibility of P-gp/BCRP inhibition at the blood-brain barrier and its implications. This ITC perspective elaborates and discusses specifically the hepatic and renal P-gp/BCRP (referred as systemic) inhibition of drugs and whether there is any consequence for substrate drug disposition. This perspective summarizes the clinical evidence-based recommendations regarding systemic P-gp and BCRP inhibition of drugs with a focus on biliary and active renal excretion pathways. Approaches to assess the clinical relevance of systemic P-gp and BCRP inhibition in the liver and kidneys included (i) curation of DDIs involving intravenously administered substrates or inhibitors; (ii) in vitro-to-in vivo extrapolation of P-gp-mediated DDIs at the systemic level; and (iii) curation of drugs with information available about the contribution of biliary excretion and related DDIs. Based on the totality of evidence reported to date, this perspective supports limited clinical DDI risk upon P-gp or BCRP inhibition in the liver or kidneys.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP Binding Cassette Transporter, Subfamily G, Member 2; Humans; Liver; Membrane Transport Proteins; Neoplasm Proteins
PubMed: 35612761
DOI: 10.1002/cpt.2670 -
Bulletin of Experimental Biology and... Feb 2023The level P-glycoprotein (Pgp) in organs of pregnant rabbits and its content and activity in the placental barrier at different stages of pregnancy were studied. An...
The level P-glycoprotein (Pgp) in organs of pregnant rabbits and its content and activity in the placental barrier at different stages of pregnancy were studied. An increase in Pgp content in the jejunum on days 7, 14, 21, and 28 of pregnancy in comparison with this parameter non-pregnant females was revealed by ELISA; in the liver, Pgp content was higher on day 7 and tended to increase on day 14; in the kidney and cerebral cortex, Pgp content was higher on day 28 of pregnancy in parallel with an increase in serum progesterone concentration. We also observed a decrease in Pgp content in the placenta on days 21 and 28 of pregnancy in comparison with day 14 and a decrease in Pgp activity in the placental barrier, which was confirmed by enhanced penetration of fexofenadine (Pgp substrate) through the barrier.
Topics: Animals; Pregnancy; Rabbits; Female; ATP Binding Cassette Transporter, Subfamily B, Member 1; Placenta; ATP Binding Cassette Transporter, Subfamily B; Progesterone
PubMed: 36881284
DOI: 10.1007/s10517-023-05723-3 -
Life Sciences Dec 2021P-glycoprotein (P-gp) plays a critical role in the excretion of xenobiotics into bile. Previous studies have demonstrated that prolactin (PRL) regulates...
AIM
P-glycoprotein (P-gp) plays a critical role in the excretion of xenobiotics into bile. Previous studies have demonstrated that prolactin (PRL) regulates biotransformation and bile salt transport. Here we investigate whether the capability of the liver to transport xenobiotics into bile is altered in hyperprolactinemic states studying the modulation of hepatic P-gp by PRL.
METHODS
We used lactating post-partum rats (PP), as a model of physiological hyperprolactinemia (15 and 21 days after delivery: PP15 and PP21, respectively), and ovariectomized rats treated with PRL (300 μg/day, 7 days, via osmotic minipumps, OVX + PRL). Hepatic P-gp expression and activity were evaluated by western blotting and using rhodamine 123 as substrate in vivo, respectively. Since P-gp is encoded by Mdr1a and Mdr1b in rodents, we quantified their expression by qPCR in primary hepatocyte cultures exposed to 0.1 μg/ml of PRL after 12 h. To further study the mechanism of hepatic P-gp modulation by PRL, hepatocytes were pretreated with actinomycin D and then exposed to PRL (0.1 μg/ml) for 12 h.
KEY FINDINGS
We found increased hepatic P-gp protein expression and activity in PP15 and OVX + PRL. Also, a significant increase in Mdr1a and Mdr1b mRNA levels was observed in primary hepatocyte cultures exposed to PRL, pointing out the hormone direct action. Actinomycin D prevented these increases, confirming a transcriptional up-regulation of P-gp by PRL.
SIGNIFICANCE
These findings suggest the possibility of an increased biliary excretion of xenobiotics substrates of P-gp, including therapeutic agents, affecting their pharmaco/toxicokinetics in hyperprolactinemic situations.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Animals; Cells, Cultured; Female; Gene Expression Regulation; Hepatocytes; Lactation; Liver; Ovariectomy; Prolactin; Rats; Rats, Wistar; Sheep
PubMed: 34506838
DOI: 10.1016/j.lfs.2021.119936 -
British Journal of Pharmacology Nov 2021P-glycoprotein (P-gp) exhibits a broad substrate specificity and affects pharmacokinetics, especially intestinal absorption. However, prediction, in vivo, of...
BACKGROUND AND PURPOSE
P-glycoprotein (P-gp) exhibits a broad substrate specificity and affects pharmacokinetics, especially intestinal absorption. However, prediction, in vivo, of P-gp-mediated drug-drug interaction (DDI) and non-linear absorption at the preclinical stage, is challenging. Here we evaluate the use of human MDR1 mouse artificial chromosome (hMDR1-MAC) mice carrying human P-gp and lacking their own murine P-gp to quantitatively predict human P-gp-mediated DDI and non-linear absorption.
EXPERIMENTAL APPROACH
The P-gp substrates (aliskiren, betrixaban, celiprolol, digoxin, fexofenadine and talinolol) were administered orally to wild-type, Mdr1a/b-knockout (KO) and hMDR1-MAC mice, and their plasma concentrations were measured. We calculated the ratio of area under the curve (AUCR) in mice (AUC /AUC or AUC /AUC ) estimated as attributable to complete P-gp inhibition and the human AUCR with and without P-gp inhibitor administration. The correlations of AUCR with AUCR and AUCR were investigated. For aliskiren, betrixaban and celiprolol, the K and V values for P-gp in hMDR1-MAC mice and humans were optimized from different dosing studies using GastroPlus. The correlations of K and V for P-gp between human and hMDR1-MAC mice were investigated.
KEY RESULTS
A better correlation between AUCR and AUCR (R = 0.88) was observed. Moreover, good relationships of K (R = 1.00) and V (R = 0.98) for P-gp between humans and hMDR1-MAC mice were observed.
CONCLUSIONS AND IMPLICATIONS
These results suggest that P-gp-mediated DDI and non-linear absorption can be predicted using hMDR1-MAC mice. These mice are a useful in vivo tool for quantitatively predicting P-gp-mediated disposition in drug discovery and development.
Topics: ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; Animals; Drug Interactions; Intestinal Absorption; Mice; Pharmaceutical Preparations
PubMed: 34232502
DOI: 10.1111/bph.15612 -
Nanomedicine : Nanotechnology, Biology,... Feb 2022Multidrug resistance (MDR) in cancer chemotherapy is a growing concern for medical practitioners. P-glycoprotein (P-gp) overexpression is one of the major reasons for... (Review)
Review
Multidrug resistance (MDR) in cancer chemotherapy is a growing concern for medical practitioners. P-glycoprotein (P-gp) overexpression is one of the major reasons for multidrug resistance in cancer chemotherapy. The P-gp overexpression in cancer cells depends on several factors like adenosine triphosphate (ATP) hydrolysis, hypoxia-inducible factor 1 alpha (HIF-1α), and drug physicochemical properties such as lipophilicity, molecular weight, and molecular size. Further multiple exposures of anticancer drugs to the P-gp efflux protein cause acquired P-gp overexpression. Unique structural and functional characteristics of nanotechnology-based drug delivery systems provide opportunities to circumvent P-gp mediated MDR. The primary mechanism behind the nanocarrier systems in P-gp inhibition includes: bypassing or inhibiting the P-gp efflux pump to combat MDR. In this review, we discuss the role of P-gp in MDR and highlight the recent progress in different nanocarriers to overcome P-gp mediated MDR in terms of their limitations and potentials.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Antineoplastic Agents; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Humans; Neoplasms
PubMed: 34775061
DOI: 10.1016/j.nano.2021.102494