RT Journal Article
SR Electronic
T1 Effect of Multidrug Resistance-Reversing Agents on Transporting Activity of Human Canalicular Multispecific Organic Anion Transporter
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP 1219
OP 1228
DO 10.1124/mol.56.6.1219
VO 56
IS 6
A1 Chen, Zhe-Sheng
A1 Kawabe, Takeshi
A1 Ono, Mayumi
A1 Aoki, Shunji
A1 Sumizawa, Tomoyuki
A1 Furukawa, Tatsuhiko
A1 Uchiumi, Takeshi
A1 Wada, Morimasa
A1 Kuwano, Michihiko
A1 Akiyama, Shin-Ichi
YR 1999
UL http://molpharm.aspetjournals.org/content/56/6/1219.abstract
AB The canalicular multispecific organic anion transporter (cMOAT), also termed MRP2, is a recently identified ATP-binding cassette transporter. We previously established stable human cMOAT cDNA-transfected cells, LLC/cMOAT-1 from LLC-PK1 cells, and LLC/CMV cells that were transfected with an empty vector. We found that LLC/cMOAT-1 cells have increased resistance to vincristine (VCR), 7-ethyl-10-hydroxy-camptothecin, and cisplatin but not to etoposide. The multidrug resistance-reversing agents cyclosporin A (CsA) and 2-[4-(diphenylmethyl)-1-piperazinyl]-5-(trans-4,6-dimethyl-1,3,2-dioxaphosphorinan-2-yl)-2,6-dimethyl-4-(3-nitrophenyl)-3-pyridinecarboxylate P-oxide (PAK-104P) almost completely reversed the resistance to VCR, 7-ethyl-10-hydroxy-camptothecin, and cisplatin of LLC/cMOAT-1 cells; anddl-buthionine-(S,R)-sulfoximine, (3′-oxo-4-butenyl-4-methyl-threonine1, (valine2) cyclosporin (PSC833), and 3-([{3-(2-[7-chloro-2-quinolinyl]ethenyl)phenyl}-{(3-dimethylamino-3-oxopropyl)-thio}-methyl]thio)propanoic acid (MK571) partially reversed the resistance to these drugs. CsA and PAK-104P at 10 μM enhanced the accumulation of VCR in LLC/cMOAT-1 cells almost to the level in LLC/CMV cells without the agents. The efflux of VCR from LLC/cMOAT-1 cells was enhanced compared with LLC/CMV cells and inhibited by CsA and PAK-104P. Transport of leukotriene C4 (LTC4) and S-(2, 4-dinitrophenyl)glutathione also was studied with membrane vesicles prepared from these cells. LTC4 and S-(2, 4-dinitrophenyl)glutathione were actively transported into membrane vesicles prepared from LLC/cMOAT-1 cells. TheK m and V maxvalues for the uptake of LTC4 by the LLC/cMOAT-1 membrane vesicles were 0.26 ± 0.05 μM and 7.48 ± 0.67 pmol/min/mg protein, respectively. LTC4 transport was competitively inhibited by PAK-104P, CsA, MK571, and PSC833, withK i values of 3.7, 4.7, 13.1, and 28.9 μM, respectively. These findings demonstrate that cMOAT confers a novel drug-resistance phenotype. CsA and PAK-104P may be useful for reversing cMOAT-mediated drug resistance in tumors.