scholarly journals Intraluminal Behavior of Various Transporter Substrates in the Rat Gastrointestinal Tract

2021 ◽  
Vol 24 ◽  
pp. 563-570
Author(s):  
Yusuke Tanaka ◽  
Taiki Harada ◽  
Kazuhiro Ito ◽  
Takanori Kurakazu ◽  
Satoshi Kasaoka
Keyword(s):  
Drug Absorption ◽  
Residual Water ◽  
Glycoprotein P ◽  
Transport Studies ◽  
P Glycoprotein ◽  
Drug Concentrations ◽  
Optimal Drug ◽  
Actual Contribution ◽  
Knockout Animals

Purpose: The aim of this study was to evaluate the intraluminal behavior of various transporter substrates in different regions of the gastrointestinal (GI) tract. Methods: Drug solutions containing non-absorbable FITC-dextran 4000 (FD-4), were orally administered to rats. Residual water was sampled from the GI regions to measure the luminal drug concentration. Results: Cephalexin (CEX), a substrate of the proton-coupled oligopeptide transporter, was absorbed rapidly, and no drug was detected in the lower small intestine. Saquinavir (SQV) was primarily absorbed in the upper region. However, unlike CEX, SQV was detected even in the lower segment probably due to the efflux of SQV via P-glycoprotein (P-gp). The concentration of methotrexate (MTX) showed a similar pattern to that of non-absorbable FD-4. The low absorption of MTX was probably due to efflux via several efflux transporters, and the limited expression of proton-coupled folate transporter, an absorptive transporter for MTX, in the upper region. Conclusion: This study revealed that the luminal concentration pattern of each drug differed considerably depending on the site because of the different absorption properties and luminal volumes. Although further investigation using a specific transporter inhibitor or transporter-knockout animals are necessary to clarify the actual contribution of each transporter to the drug absorption, this information will be valuable in evaluating transporter-mediated drug absorption in in vitro transport studies for ensuring optimal drug concentrations.

scholarly journals P-Glycoprotein and Breast Cancer Resistance Protein Restrict Apical-to-Basolateral Permeability of Human Brain Endothelium to Amyloid-β

2009 ◽  
Vol 29 (6) ◽  
pp. 1079-1083 ◽  
Author(s):  
Leon M Tai ◽  
A Jane Loughlin ◽  
David K Male ◽  
Ignacio A Romero
Keyword(s):  
Breast Cancer ◽  
Human Brain ◽  
Breast Cancer Resistance Protein ◽  
Amyloid Β ◽  
Cancer Resistance ◽  
Glycoprotein P ◽  
P Glycoprotein ◽  
Resistance Protein ◽  
The Brain

The clearance of amyloid beta (Aβ) from the brain represents a novel therapeutic target for Alzheimer's disease. Conflicting data exist regarding the contribution of adenosine triphosphatebinding cassette transporters to the clearance of Aβ through the blood-brain barrier. Therefore, we investigated whether Aβ could be a substrate for P-glycoprotein (P-gp) and/or for breast cancer resistance protein (BCRP) using a human brain endothelial cell line, hCMEC/D3. Inhibition of P-gp and BCRP increased apical-to-basolateral, but not basolateral-to-apical, permeability of hCMEC/D3 cells to 125l Aβ 1–40. Our in vitro data suggest that P-gp and BCRP might act to prevent the blood-borne Aβ 1–40 from entering the brain.

scholarly journals Upregulations of Clcn3 and P-Gp Provoked by Lens Osmotic Expansion in Rat Galactosemic Cataract

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Lixia Ji ◽  
Lixia Cheng ◽  
Zhihong Yang
Keyword(s):  
Osmotic Stress ◽  
Early Stage ◽  
Lens Epithelial Cells ◽  
Anterior Capsule ◽  
Glycoprotein P ◽  
Protein Levels ◽  
P Glycoprotein ◽  
Sugar Cataract

Objective.Lens osmotic expansion, provoked by overactivated aldose reductase (AR), is the most essential event of sugar cataract. Chloride channel 3 (Clcn3) is a volume-sensitive channel, mainly participating in the regulation of cell fundamental volume, and P-glycoprotein (P-gp) acts as its modulator. We aim to study whether P-gp and Clcn3 are involved in lens osmotic expansion of galactosemic cataract.Methods and Results.In vitro, lens epithelial cells (LECs) were primarily cultured in gradient galactose medium (10–60 mM), more and more vacuoles appeared in LEC cytoplasm, and mRNA and protein levels of AR, P-gp, and Clcn3 were synchronously upregulated along with the increase of galactose concentration. In vivo, we focused on the early stage of rat galactosemic cataract, amount of vacuoles arose from equatorial area and scattered to the whole anterior capsule of lenses from the 3rd day to the 9th day, and mRNA and protein levels of P-gp and Clcn3 reached the peak around the 9th or 12th day.Conclusion. Galactosemia caused the osmotic stress in lenses; it also markedly leads to the upregulations of AR, P-gp, and Clcn3 in LECs, together resulting in obvious osmotic expansion in vitro and in vivo.

scholarly journals Immuno-oncology agent IPI-549 is a modulator of P-glycoprotein (P-gp, MDR1, ABCB1)-mediated multidrug resistance (MDR) in cancer: In vitro and in vivo

2019 ◽  
Vol 442 ◽  
pp. 91-103 ◽  
Author(s):  
Albert A. De Vera ◽  
Pranav Gupta ◽  
Zining Lei ◽  
Dan Liao ◽  
Silpa Narayanan ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Glycoprotein P ◽  
P Glycoprotein

scholarly journals Transport of Alzheimer’s associated amyloid-β catalyzed by P-glycoprotein

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250371
Author(s):  
James W. McCormick ◽  
Lauren Ammerman ◽  
Gang Chen ◽  
Pia D. Vogel ◽  
John G. Wise
Keyword(s):  
Cell Culture ◽  
Atp Hydrolysis ◽  
Amyloid Β ◽  
Md Simulations ◽  
Membrane Transporter ◽  
Biochemical Activity ◽  
Glycoprotein P ◽  
P Glycoprotein ◽  
Hydrolysis Activity

P-glycoprotein (P-gp) is a critical membrane transporter in the blood brain barrier (BBB) and is implicated in Alzheimer’s disease (AD). However, previous studies on the ability of P-gp to directly transport the Alzheimer’s associated amyloid-β (Aβ) protein have produced contradictory results. Here we use molecular dynamics (MD) simulations, transport substrate accumulation studies in cell culture, and biochemical activity assays to show that P-gp actively transports Aβ. We observed transport of Aβ40 and Aβ42 monomers by P-gp in explicit MD simulations of a putative catalytic cycle. In in vitro assays with P-gp overexpressing cells, we observed enhanced accumulation of fluorescently labeled Aβ42 in the presence of Tariquidar, a potent P-gp inhibitor. We also showed that Aβ42 stimulated the ATP hydrolysis activity of isolated P-gp in nanodiscs. Our findings expand the substrate profile of P-gp, and suggest that P-gp may contribute to the onset and progression of AD.

scholarly journals Pharmacokinetic Alteration of Paclitaxel by Ferulic Acid Derivative

Pharmaceutics ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 593 ◽  
Author(s):  
Jaeok Lee ◽  
Song Wha Chae ◽  
LianJi Ma ◽  
So Yeon Lim ◽  
Sarah Alnajjar ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Ferulic Acid ◽  
Acid Derivative ◽  
Glycoprotein P ◽  
P Glycoprotein ◽  
Substrate Drug

P-glycoprotein (P-gp) is known to be involved in multidrug resistance (MDR) and modulation of pharmacokinetic (PK) profiles of substrate drugs. Here, we studied the effects of synthesized ferulic acid (FA) derivatives on P-gp function in vitro and examined PK alteration of paclitaxel (PTX), a well-known P-gp substrate drug by the derivative. Compound 5c, the FA derivative chosen as a significant P-gp inhibitor among eight FA candidates by in vitro results, increased PTX AUCinf as much as twofold versus the control by reducing PTX elimination in rats. These results suggest that FA derivative can increase PTX bioavailability by inhibiting P-gp existing in eliminating organs.

Reversal of chemoresistance in malignant gliomas by calcium antagonists: correlation with the expression of multidrug-resistant p-glycoprotein

1994 ◽  
Vol 81 (4) ◽  
pp. 587-594 ◽  
Author(s):  
Jurgen Carl Walther Kiwit ◽  
Anja Hertel ◽  
Alexander E. Matuschek
Keyword(s):  
Calcium Antagonists ◽  
Malignant Gliomas ◽  
Multidrug Resistant ◽  
Chemotherapeutic Agents ◽  
Positive Staining ◽  
Glycoprotein P ◽  
Content Type ◽  
P Glycoprotein ◽  
Multiple Drugs

✓ Resistance to multiple drugs is often observed in malignant gliomas. The authors used a microtiter tetrazolium test to analyze primary in vitro chemoresistance and chemosensitivity of 15 early cultures of human malignant glioma exposed to 50 µg/ml (1,4-amino-2-methyl-5-pyrimidinyl)-methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU), 50 µg/ml cisplatin, 1 µg/ml vincristine, or combinations of these chemotherapeutic agents. Primary chemoresistance was observed in 87% of tumors for ACNU, in 87% for cisplatin, and in 83% for vincristine. All tumors were examined for expression of multidrug-resistant p-glycoprotein, a transport protein of 170,000 D, by means of immunohistochemical staining with the JSB-1 antibody on paraffinized tumor sections. Eight of 15 specimens (53%) showed positive staining for the monoclonal antibody. Primary chemoresistance was overcome by addition of the calcium antagonists verapamil or nimodipine to the cultures if the original tumor expressed p-glycoprotein (p < 0.01 for verapamil, p < 0.05 for nimodipine). In tumors not expressing p-glycoprotein, addition of calcium antagonists to the cell cultures did not influence primary chemoresistance. It is concluded from these data that addition of calcium antagonists to the adjuvant chemotherapy of malignant gliomas might overcome primary chemoresistance in tumors expressing the multidrugresistant phenotype.

P-Glycoprotein-Mediated Efflux Using a Rapidly Maturing Caco2 Clone (CLEFF4) in Only 5 Days without Requiring Modified Growth Medium

2020 ◽  
Vol 26 (1) ◽  
pp. 151-160
Author(s):  
Andrew Crowe
Keyword(s):  
Oral Absorption ◽  
Mdck Cells ◽  
Target Cells ◽  
Glycoprotein P ◽  
Caco2 Cells ◽  
P Glycoprotein ◽  
New Chemical Entities ◽  
Bidirectional Transport ◽  
Gp Model

In drug discovery it is essential that one of the parameters tested for any new chemical entity is its affinity for human efflux systems, most notably P-glycoprotein (P-gp). These efflux systems affect not only rates of oral absorption but also rates of excretion through the liver, blood–brain barrier, and accumulation in potential target cells that upregulate efflux systems. Current methods to determine drugs’ P-gp transport potential include in vitro bidirectional transport studies, and the two most common cell lines used are Caco2 and MDR1-transfected MDCK models. Caco2 cells are human but slow growing and require more than 3 weeks to mature, while MDCK cells are canine, but when transfected with human P-gp become a rapid model of P-gp affinity. Our laboratory has generated a Caco2 subclone called CLEFF4 that is fully human, yet now approaches the rapid nature of the MDCK model. No special medium is required. We have shown, in as little as 5 days postseeding, high transepithelial electrical resistance values of more than 1000 Ω·cm2 plus P-gp expression more than threefold higher than that of 21-day-old cells. Currently tested drugs included rhodamine 123 (Rh123), vinblastine, and doxorubicin, and all drugs exhibited P-gp-mediated efflux that was inhibited by PSC833. By day 6, bidirectional transport of Rh123 was as potent as that of mature Caco2 cells, for use in comparative P-gp affinity studies. We now have a human P-gp model that is rapid and works without any need for special accelerating medium. We believe this could be a welcome addition to the testing regime of new chemical entities.

Detection of P-glycoprotein in ovarian cancer: a molecular marker associated with multidrug resistance.

1985 ◽  
Vol 3 (3) ◽  
pp. 311-315 ◽  
Author(s):  
D R Bell ◽  
J H Gerlach ◽  
N Kartner ◽  
R N Buick ◽  
V Ling
Keyword(s):  
Ovarian Cancer ◽  
Multidrug Resistance ◽  
Resistance Mutation ◽  
Advanced Ovarian Cancer ◽  
Surface Glycoprotein ◽  
Glycoprotein P ◽  
Cell Surface Glycoprotein ◽  
P Glycoprotein ◽  
Mutant Lines

A multidrug resistance phenotype is frequently observed in animal and human cell lines selected for in vitro resistance to a single chemotherapeutic agent. Overexpression of a highly conserved cell-surface glycoprotein (P-glycoprotein) is consistently associated with this phenotype in these mutant lines. A monoclonal antibody against P-glycoprotein was used to examine tumor samples from five patients with advanced ovarian cancer for evidence of P-glycoprotein overexpression. High levels of P-glycoprotein were detected in samples from two patients suggesting that a multidrug resistance mutation may also occur in ovarian cancer. This finding has broad implications for the understanding of nonresponse to chemotherapy in a variety of human neoplasms, and may provide a rational explanation for failure of chemotherapy in treatment of advanced ovarian cancer.

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