Global marine pollutants inhibit P-glycoprotein: Environmental levels, inhibitory effects, and cocrystal structure

Nicklisch, Sascha; Rees, Steven D.; McGrath, Aaron P.; Gökirmak, Tufan; Bonito, Lindsay T.; Vermeer, Lydia M.; Cregger, Cristina; Loewen, Greg; Sandin, Stuart A.; Chang, Geoffrey; Hamdoun, Amro

doi:10.1126/sciadv.1600001

Cited by 101 publications

(155 citation statements)

References 92 publications

Supporting

Mentioning

145

Contrasting

Order By: Relevance

“…Additionally, a recent co-crystal structure of mouse P-gp also reported two more conserved phenylalanine residues, F314 and F759, which are important for binding and transport of PBDE-100 pesticide [31]. Our findings suggest that replacing these six key phenylalanines (F303, F314, F336, F732, F759, and F983) with tyrosine has minimal effect on transport of small to medium size substrates.…”

Section: Discussionsupporting

confidence: 58%

“…So far, mutagenesis and molecular docking techniques are among the best approaches to identify the role of residues in substrate binding and transport. Co-crystal structure of mouse P-gp with several QZ-59 cyclopeptide inhibitor derivatives [21], and PBDE-100 pesticide [31] allowed identification of several key amino acids in the substrate or modulator binding pocket of mouse P-gp. We further used published bioinformatic and mutagenesis studies, and generated a list of key amino acids that interact with different substrates or modulators [11, 17, 20, 32–34].…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Global alteration of the drug-binding pocket of human P-glycoprotein (ABCB1) by substitution of fifteen conserved residues reveals a negative correlation between substrate size and transport efficiency

Vahedi

Chufán

Ambudkar

2017

Biochemical Pharmacology

View full text Add to dashboard Cite

P-glycoprotein (P-gp), an ATP-dependent efflux pump, is linked to the development of multidrug resistance in cancer cells. However, the drug-binding sites and translocation pathways of this transporter are not yet well-characterized. We recently demonstrated the important role of tyrosine residues in regulating P-gp ATP hydrolysis via hydrogen bond formations with high affinity modulators. Since tyrosine is both a hydrogen bond donor and acceptor, and non-covalent interactions are key in drug transport, in this study we investigated the global effect of enrichment of tyrosine residues in the drug-binding pocket on the drug binding and transport of P-gp. By employing computational analysis, 15 conserved residues in the drug-binding pocket of human P-gp that interact with substrates were identified and then substituted with tyrosine, including 11 phenylalanine (F72, F303, F314, F336, F732, F759, F770, F938, F942, F983, F994), two leucine (L339, L975), one isoleucine (I306), and one methionine (M949). Characterization of the tyrosine-rich P-gp mutant in HeLa cells demonstrated that this major alteration in the drug-binding pocket by introducing fifteen additional tyrosine residues is well tolerated and has no measurable effect on total or cell surface expression of this mutant. Although the tyrosine-enriched mutant P-gp could transport small to moderate size (<1000 Daltons) fluorescent substrates, its ability to transport large (>1000 Daltons) substrates such as NBD-cyclosporine A, Bodipy-paclitaxel and Bodipy-vinblastine was significantly decreased. This was further supported by the physico-chemical characterization of seventeen tested substrates, which revealed a negative correlation between drug transport and molecular size for the tyrosine-enriched P-gp mutant.

show abstract

Section: Discussionsupporting

confidence: 58%

Section: Resultsmentioning

confidence: 99%

Global alteration of the drug-binding pocket of human P-glycoprotein (ABCB1) by substitution of fifteen conserved residues reveals a negative correlation between substrate size and transport efficiency

Vahedi

Chufán

Ambudkar

2017

Biochemical Pharmacology

View full text Add to dashboard Cite

show abstract

“…Putative consideration of the inhibitory effects of pyrethroids like allethrin and tetramethrin towards drug transporters under a regulatory point of view for pyrethroid risk assessment can therefore be excluded. It should be however kept in mind that humans are likely exposed not only to a single pyrethroid, but to other pesticides and xenobiotics, that may also interact with drug transporters [55], as recently demonstrated for notably organochlorine pesticides [43], polychlorinated biphenyls [72], diesel exhaust particle components [41] and perfluorinated surfactants [73]. Plasma levels of pyrethroids, especially allethrin and tetramethrin, associated with those of other pollutants, may therefore be sufficient to contribute to synergic or additive inhibitory effects towards drug transporters, as already described for pesticide combinations [74].…”

Section: Discussionmentioning

confidence: 99%

Inhibition of Human Drug Transporter Activities by the Pyrethroid Pesticides Allethrin and Tetramethrin

et al. 2017

View full text Add to dashboard Cite

Pyrethroids are widely-used chemical insecticides, to which humans are commonly exposed, and known to alter functional expression of drug metabolizing enzymes. Limited data have additionally suggested that drug transporters, that constitute key-actors of the drug detoxification system, may also be targeted by pyrethroids. The present study was therefore designed to analyze the potential regulatory effects of these pesticides towards activities of main ATP-binding cassette (ABC) and solute carrier (SLC) drug transporters, using transporter-overexpressing cells. The pyrethroids allethrin and tetramethrin were found to inhibit various ABC and SLC drug transporters, including multidrug resistance-associated protein (MRP) 2, breast cancer resistance protein (BCRP), organic anion transporter polypeptide (OATP) 1B1, organic anion transporter (OAT) 3, multidrug and toxin extrusion transporter (MATE) 1, organic cation transporter (OCT) 1 and OCT2, with IC50 values however ranging from 2.6 μM (OCT1 inhibition by allethrin) to 77.6 μM (OAT3 inhibition by tetramethrin) and thus much higher than pyrethroid concentrations (in the nM range) reached in environmentally pyrethroid-exposed humans. By contrast, allethrin and tetramethrin cis-stimulated OATP2B1 activity and failed to alter activities of OATP1B3, OAT1 and MATE2-K, whereas P-glycoprotein activity was additionally moderately inhibited. Twelve other pyrethoids used at 100 μM did not block activities of the various investigated transporters, or only moderately inhibited some of them (inhibition by less than 50%). In silico analysis of structure-activity relationships next revealed that molecular parameters, including molecular weight and lipophilicity, are associated with transporter inhibition by allethrin/tetramethrin and successfully predicted transporter inhibition by the pyrethroids imiprothrin and prallethrin. Taken together, these data fully demonstrated that two pyrethoids, i.e., allethrin and tetramethrin, can act as regulators of the activity of various ABC and SLC drug transporters, but only when used at high and non-relevant concentrations, making unlikely any contribution of these transporter activity alterations to pyrethroid toxicity in environmentally exposed humans.

show abstract

“…A projection of these residues into a homology model of human P‐pg based on the mouse structure (Nicklisch et al. ) is shown in Figure A, B. These residues are exclusively located in TMD2.…”

Section: Resultsmentioning

confidence: 99%

“…The model of human P‐gp is based on the crystal structure of M. musculus P‐gp (PDB ID: 4XWK) (Nicklisch et al. ).…”

Section: Methodsmentioning

confidence: 99%

Folding correction of ABC‐transporter ABCB1 by pharmacological chaperones: a mechanistic concept

Spork

Sohail

Schmid

et al. 2017

Pharmacology Res & Perspec

View full text Add to dashboard Cite

Point mutations of ATP‐binding cassette (ABC) proteins are a common cause of human diseases. Available crystal structures indicate a similarity in the architecture of several members of this protein family. Their molecular architecture makes these proteins vulnerable to mutation, when critical structural elements are affected. The latter preferentially involve the two transmembrane domain (TMD)/nucleotide‐binding domain (NBD) interfaces (transmission interfaces), formation of which requires engagement of coupling helices of intracellular loops with NBDs. Both, formation of the active sites and engagement of the coupling helices, are contingent on correct positioning of ICLs 2 and 4 and thus an important prerequisite for proper folding. Here, we show that active site compounds are capable of rescuing P‐glycoprotein (P‐gp) mutants ∆Y490 and ∆Y1133 in a concentration‐dependent manner. These trafficking deficient mutations are located at the transmission interface in pseudosymmetric position to each other. In addition, the ability of propafenone analogs to correct folding correlates with their ability to inhibit transport of model substrates. This finding indicates that folding correction and transport inhibition by propafenone analogs are brought about by binding to the active sites. Furthermore, this study demonstrates an asymmetry in folding correction with cis‐flupentixol, which reflects the asymmetric binding properties of this modulator to P‐gp. Our results suggest a mechanistic model for corrector action in a model ABC transporter based on insights into the molecular architecture of these transporters.

show abstract

Global marine pollutants inhibit P-glycoprotein: Environmental levels, inhibitory effects, and cocrystal structure

Abstract: Common seafood pollutants inhibit a crucial cellular defense protein.

Cited by 101 publications

References 92 publications

Global alteration of the drug-binding pocket of human P-glycoprotein (ABCB1) by substitution of fifteen conserved residues reveals a negative correlation between substrate size and transport efficiency

Global alteration of the drug-binding pocket of human P-glycoprotein (ABCB1) by substitution of fifteen conserved residues reveals a negative correlation between substrate size and transport efficiency

Inhibition of Human Drug Transporter Activities by the Pyrethroid Pesticides Allethrin and Tetramethrin

Folding correction of ABC‐transporter ABCB1 by pharmacological chaperones: a mechanistic concept

Contact Info

Product

Resources

About