Cellular Models and In Vitro Assays for the Screening of modulators of P-gp, MRP1 and BCRP

Abstract

Adenosine triphosphate (ATP)-binding cassette (ABC) transporters are highly expressed in tumor cells, as well as in organs involved in absorption and secretion processes, mediating the ATP-dependent efflux of compounds, both endogenous substances and xenobiotics, including drugs. Their expression and activity levels are modulated by the presence of inhibitors, inducers and/or activators. In vitro, ex vivo and in vivo studies with both known and newly synthesized P-glycoprotein (P-gp) inducers and/or activators have shown the usefulness of these transport mechanisms in reducing the systemic exposure and specific tissue access of potentially harmful compounds. This article focuses on the main ABC transporters involved in multidrug resistance [P-gp, multidrug resistance-associated protein 1 (MRP1) and breast cancer resistance protein (BCRP)] expressed in tissues of toxicological relevance, such as the blood-brain barrier, cardiovascular system, liver, kidney and intestine. Moreover, it provides a review of the available cellular models, in vitro and ex vivo assays for the screening and selection of safe and specific inducers and activators of these membrane transporters. The available cellular models and in vitro assays have been proposed as high throughput and low-cost alternatives to excessive animal testing, allowing the evaluation of a large number of compounds.

Elucidation of the Impact of P-glycoprotein and Breast Cancer Resistance Protein on the Brain Distribution of Catechol-O-Methyltransferase Inhibitors

“…In fact, this has also been observed for other high permeability efflux substrates, such as verapamil, meaning that the involved efflux transporter(s) was (or were) unable to cope with compound permeation (Hellinger et al, 2012). This is a limitation of the bidirectional transport assay that may prevent compounds with a P app,AP-BL value close to or higher than 30 Â 10 26 cm/s from being identified as efflux substrates (Polli et al, 2001;Gameiro et al, 2017), emphasizing the importance of performing in vivo studies for such compounds. Even though nebicapone displayed a similarly high passive permeability, the P app values for tolcapone were consistently higher in Pharmacokinetic parameters of BIA 9-1079 and tolcapone in plasma and brain after intravenous administration (10 mg/kg) to Wistar rats…”

Ketone Bodies Promote Amyloid-β1–40 Clearance in a Human in Vitro Blood–Brain Barrier Model

“…The values for [ 3 H]inulin transport did not differ significantly in the presence of KBs ( Figure 4D), confirming that Aβ transport across the BBB is regulated by specific mechanisms. In light of our previous results ( Figure 3A,C) after 48 h of KB treatments (ratio), the transport of Aβ 1-40 Cy5 or [ 3 H]inulin was studied in the presence or in the absence of two standard inhibitors for LRP1 and P-gp [11,[47][48][49], the receptor-associated protein (RAP) (in the basolateral side) or elacridar (in the apical side), respectively. As shown in Figure 5C, the increased basolateral-to-apical of Aβ 1-40 Cy5 peptide transport was abolished in the presence of RAP or elacridar.…”

Ginger Phytochemicals Inhibit Cell Growth and Modulate Drug Resistance Factors in Docetaxel Resistant Prostate Cancer Cell

“…Fraction 1-2 (7.4 g) was subjected to silica gel chromatography by eluting with n -hexane-acetone (40:1), enriched with acetone to furnish four further fractions (1-2-1–1-2-4). Fraction 1-2-1 (2.8 g) was further purified on a silica gel column using n -hexane/acetone mixtures to obtain [ 6 ]-gingerol (42 mg) and [ 10 ]-shogoal (46 mg). Fraction 1-2-2 (3.2 g) was further purified on a silica gel column using n -hexane/acetone mixtures to obtain [ 6 ]-shogoal (26 mg) and [ 10 ]-gingerol (55 mg).…”

“…A lot of studies have been proposed to contribute to drug resistance in tumor cells. Multidrug resistance (MDR) mechanisms are associated with increased expression of the P-gp (P-glycoprotein) or increased cellular metabolism of drug detoxifying proteins, such as glutathione-S-transferase (GST) [ 10 , 11 ]. In particular, elevated P-gp or GST are associated with increased resistance to apoptosis.…”