Active transport of fluorescent P-glycoprotein substrates: evaluation as markers and interaction with inhibitors.

Article Details

Citation

Wang EJ, Casciano CN, Clement RP, Johnson WW

Active transport of fluorescent P-glycoprotein substrates: evaluation as markers and interaction with inhibitors.

Biochem Biophys Res Commun. 2001 Nov 30;289(2):580-5.

PubMed ID
11716514 [ View in PubMed
]
Abstract

With P-glycoprotein (P-gp) continuing to have prominence among the ABC transporters for its ability to remove various xenobiotics from many cell types, accurate and robust methods for estimating the exposure of drug, carcinogen, toxicant, pesticide, and even some endobiotics to tissues and cells affected by P-gp are valuable. The inhibition of P-gp active transport of molecules, therefore, has often been quantified by concentration dependence of inhibitor effect on fluorescent substrate marker efflux mediated by this enzyme, with much evidence indicating two asymmetric yet interdependent substrate binding sites on P-gp. A uniqueness in the pair of binding sites could result in distinct effects of an inhibitor on the transport of certain substrates, thus leading to differences in fluorescent substrate responsiveness or sensitivity. Seven different fluorescent substrates of P-gp were quantitatively tested for their responsiveness to inhibition by a wide range of P-gp substrates/inhibitors. Interesting differences were observed in the IC(50) values caused by each of the inhibitors employed, in part exemplified by DNR and LDS being generally more sensitive to inhibition effects than any other fluorescent marker. However, no clear trend emerged to designate any fluorochrome marker as the most or least responsive to inhibition. Furthermore, LDS is more sensitive to some P-gp inhibitors than the substrate marker DNR, generally the most responsive. These results support the assertion of two unequal substrate binding sites that are allosterically dependent on each other. Therefore, an inhibitor that favors binding to the site opposite from that favored by a particular marker may have significant transduced effects through the protein between the two binding sites. Nevertheless, although either DNR or LDS is generally the fluorescent substrate most responsive to inhibition, there may be other substrates yet even more sensitive.

DrugBank Data that Cites this Article

Drug Transporters
DrugTransporterKindOrganismPharmacological ActionActions
CarvedilolP-glycoprotein 1ProteinHumans
Unknown
Inhibitor
Details
ClarithromycinP-glycoprotein 1ProteinHumans
Unknown
Substrate
Inhibitor
Details
ColforsinP-glycoprotein 1ProteinHumans
Unknown
Inhibitor
Details
DipyridamoleP-glycoprotein 1ProteinHumans
Unknown
Substrate
Inhibitor
Details
FelodipineP-glycoprotein 1ProteinHumans
Unknown
Inhibitor
Details
FluphenazineP-glycoprotein 1ProteinHumans
Unknown
Inhibitor
Details
IndomethacinP-glycoprotein 1ProteinHumans
Unknown
Substrate
Inhibitor
Details
ItraconazoleP-glycoprotein 1ProteinHumans
Unknown
Inhibitor
Details
KetoconazoleP-glycoprotein 1ProteinHumans
Unknown
Inhibitor
Details
LovastatinP-glycoprotein 1ProteinHumans
Unknown
Inhibitor
Details
NicardipineP-glycoprotein 1ProteinHumans
Unknown
Substrate
Inhibitor
Details
PaclitaxelP-glycoprotein 1ProteinHumans
Unknown
Substrate
Inhibitor
Details
ProgesteroneP-glycoprotein 1ProteinHumans
Unknown
Substrate
Inhibitor
Inducer
Details
QuinidineP-glycoprotein 1ProteinHumans
Unknown
Substrate
Inhibitor
Details
QuinineP-glycoprotein 1ProteinHumans
Unknown
Substrate
Inhibitor
Details
ReserpineP-glycoprotein 1ProteinHumans
Unknown
Substrate
Inhibitor
Inducer
Details
SimvastatinP-glycoprotein 1ProteinHumans
Unknown
Inhibitor
Details
TerfenadineP-glycoprotein 1ProteinHumans
Unknown
Inhibitor
Details
TrifluoperazineP-glycoprotein 1ProteinHumans
Unknown
Inhibitor
Details
TroleandomycinP-glycoprotein 1ProteinHumans
Unknown
Inhibitor
Details
VinblastineP-glycoprotein 1ProteinHumans
Unknown
Substrate
Inhibitor
Inducer
Details
Binding Properties
DrugTargetPropertyMeasurementpHTemperature (°C)
CarvedilolP-glycoprotein 1IC 50 (nM)4600N/AN/ADetails
CarvedilolP-glycoprotein 1IC 50 (nM)6600N/AN/ADetails
CarvedilolP-glycoprotein 1IC 50 (nM)6000N/AN/ADetails
ClarithromycinP-glycoprotein 1IC 50 (nM)3800N/AN/ADetails
ClarithromycinP-glycoprotein 1IC 50 (nM)15100N/AN/ADetails
ClarithromycinP-glycoprotein 1IC 50 (nM)50200N/AN/ADetails
ClarithromycinP-glycoprotein 1IC 50 (nM)56100N/AN/ADetails
ClarithromycinP-glycoprotein 1IC 50 (nM)7200N/AN/ADetails
ClarithromycinP-glycoprotein 1IC 50 (nM)86700N/AN/ADetails
ClarithromycinP-glycoprotein 1IC 50 (nM)23800N/AN/ADetails
ColforsinP-glycoprotein 1IC 50 (nM)188200N/AN/ADetails
ColforsinP-glycoprotein 1IC 50 (nM)80200N/AN/ADetails
CyclosporineP-glycoprotein 1IC 50 (nM)4300N/AN/ADetails
CyclosporineP-glycoprotein 1IC 50 (nM)1400N/AN/ADetails
CyclosporineP-glycoprotein 1IC 50 (nM)1700N/AN/ADetails
CyclosporineP-glycoprotein 1IC 50 (nM)1800N/AN/ADetails
CyclosporineP-glycoprotein 1IC 50 (nM)2100N/AN/ADetails
CyclosporineP-glycoprotein 1IC 50 (nM)2400N/AN/ADetails
DipyridamoleP-glycoprotein 1IC 50 (nM)34300N/AN/ADetails
DipyridamoleP-glycoprotein 1IC 50 (nM)22700N/AN/ADetails
DipyridamoleP-glycoprotein 1IC 50 (nM)23700N/AN/ADetails
FelodipineP-glycoprotein 1IC 50 (nM)>60000N/AN/ADetails
FelodipineP-glycoprotein 1IC 50 (nM)32300N/AN/ADetails
FelodipineP-glycoprotein 1IC 50 (nM)26300N/AN/ADetails
FluphenazineP-glycoprotein 1IC 50 (nM)5700N/AN/ADetails
FluphenazineP-glycoprotein 1IC 50 (nM)10400N/AN/ADetails
FluphenazineP-glycoprotein 1IC 50 (nM)6500N/AN/ADetails
ItraconazoleP-glycoprotein 1IC 50 (nM)2400N/AN/ADetails
KetoconazoleP-glycoprotein 1IC 50 (nM)5600N/AN/ADetails
KetoconazoleP-glycoprotein 1IC 50 (nM)53400N/AN/ADetails
KetoconazoleP-glycoprotein 1IC 50 (nM)23400N/AN/ADetails
LovastatinP-glycoprotein 1IC 50 (nM)32700N/AN/ADetails
LovastatinP-glycoprotein 1IC 50 (nM)114400N/AN/ADetails
NicardipineP-glycoprotein 1IC 50 (nM)3200N/AN/ADetails
NicardipineP-glycoprotein 1IC 50 (nM)14600N/AN/ADetails
NicardipineP-glycoprotein 1IC 50 (nM)5600N/AN/ADetails
NicardipineP-glycoprotein 1IC 50 (nM)11700N/AN/ADetails
NicardipineP-glycoprotein 1IC 50 (nM)6600N/AN/ADetails
NicardipineP-glycoprotein 1IC 50 (nM)7100N/AN/ADetails
NicardipineP-glycoprotein 1IC 50 (nM)>25800N/AN/ADetails
PaclitaxelP-glycoprotein 1IC 50 (nM)53900N/AN/ADetails
PaclitaxelP-glycoprotein 1IC 50 (nM)54000N/AN/ADetails
PaclitaxelP-glycoprotein 1IC 50 (nM)70200N/AN/ADetails
ProgesteroneP-glycoprotein 1IC 50 (nM)192200N/AN/ADetails
ProgesteroneP-glycoprotein 1IC 50 (nM)88100N/AN/ADetails
ProgesteroneP-glycoprotein 1IC 50 (nM)96200N/AN/ADetails
QuinineP-glycoprotein 1IC 50 (nM)159300N/AN/ADetails
QuinineP-glycoprotein 1IC 50 (nM)112400N/AN/ADetails
QuinineP-glycoprotein 1IC 50 (nM)184900N/AN/ADetails
QuinineP-glycoprotein 1IC 50 (nM)74400N/AN/ADetails
QuinineP-glycoprotein 1IC 50 (nM)87600N/AN/ADetails
QuinineP-glycoprotein 1IC 50 (nM)167800N/AN/ADetails
QuinineP-glycoprotein 1IC 50 (nM)22600N/AN/ADetails
ReserpineP-glycoprotein 1IC 50 (nM)3900N/AN/ADetails
ReserpineP-glycoprotein 1IC 50 (nM)5300N/AN/ADetails
ReserpineP-glycoprotein 1IC 50 (nM)500N/AN/ADetails
ReserpineP-glycoprotein 1IC 50 (nM)2100N/AN/ADetails
ReserpineP-glycoprotein 1IC 50 (nM)6100N/AN/ADetails
ReserpineP-glycoprotein 1IC 50 (nM)2600N/AN/ADetails
SimvastatinP-glycoprotein 1IC 50 (nM)26100N/AN/ADetails
SimvastatinP-glycoprotein 1IC 50 (nM)56800N/AN/ADetails
TamoxifenP-glycoprotein 1IC 50 (nM)31400N/AN/ADetails
TamoxifenP-glycoprotein 1IC 50 (nM)12100N/AN/ADetails
TamoxifenP-glycoprotein 1IC 50 (nM)6400N/AN/ADetails
TerfenadineP-glycoprotein 1IC 50 (nM)1800N/AN/ADetails
TerfenadineP-glycoprotein 1IC 50 (nM)2500N/AN/ADetails
TerfenadineP-glycoprotein 1IC 50 (nM)2700N/AN/ADetails
TrifluoperazineP-glycoprotein 1IC 50 (nM)10900N/AN/ADetails
TrifluoperazineP-glycoprotein 1IC 50 (nM)6300N/AN/ADetails
TrifluoperazineP-glycoprotein 1IC 50 (nM)7200N/AN/ADetails
TroleandomycinP-glycoprotein 1IC 50 (nM)68300N/AN/ADetails
TroleandomycinP-glycoprotein 1IC 50 (nM)78200N/AN/ADetails
TroleandomycinP-glycoprotein 1IC 50 (nM)86300N/AN/ADetails
VerapamilP-glycoprotein 1IC 50 (nM)4200N/AN/ADetails
VerapamilP-glycoprotein 1IC 50 (nM)4700N/AN/ADetails
VerapamilP-glycoprotein 1IC 50 (nM)28900N/AN/ADetails
VerapamilP-glycoprotein 1IC 50 (nM)446500N/AN/ADetails
VerapamilP-glycoprotein 1IC 50 (nM)6500N/AN/ADetails
VerapamilP-glycoprotein 1IC 50 (nM)42000N/AN/ADetails
VerapamilP-glycoprotein 1IC 50 (nM)38200N/AN/ADetails
VinblastineP-glycoprotein 1IC 50 (nM)29500N/AN/ADetails
VinblastineP-glycoprotein 1IC 50 (nM)17700N/AN/ADetails
VinblastineP-glycoprotein 1IC 50 (nM)19900N/AN/ADetails