Interactions of the Human Multidrug Resistance Proteins MRP1 and MRP2 with Organic Anions

Abstract

The human multidrug resistance protein MRP1 and its homolog, MRP2, are both suggested as being involved in cancer drug resistance and the transport of organic anions. We expressed MRP1 and MRP2 in Spodoptera frugiperda ovarian cells and compared their ATP-dependent transport properties and vanadate-sensitive ATPase activities in isolated membrane vesicles. Both MRP1 and MRP2 actively transported leukotriene C 4 and N-ethylmaleimide glutathione (NEM-GS), although the relative affinity of MRP2 for these substrates was found to be significantly lower than that of MRP1. Methotrexate was actively transported by both proteins, although more efficiently by MRP2. ATP-dependent NEM-GS transport by MRP1 and MRP2 was variably modulated by organic anions. Probenecid and furosemide inhibited, whereas under certain conditions sulfinpyrazone, penicillin G, and indomethacin greatly stimulated, MRP2-mediated NEM-GS uptake. Vanadate-sensitive ATPase activity in isolated membranes containing MRP1 or MRP2 was significantly stimulated by NEM-GS and reduced GS, although these compounds acted only at higher concentrations in MRP2. ATP hydrolysis by MRP2 was also effectively stimulated by methotrexate. Probenecid, sulfinpyrazone, indomethacin, furosemide, and penicillin G all significantly increased MRP2-ATPase activity, whereas these compounds acted more as ATPase inhibitors on MRP1. These results indicate that MRP1 is a more efficient transporter of glutathione conjugates and free glutathione than MRP2, whereas several anions are preferred substrates for MRP2. Our data suggest that MRP2 may be responsible for the active secretion of pharmacologically relevant organic anions, such as diuretics and antibiotics, and indicate different modulation possibilities for MRP1 or MRP2 in drug-resistant tumor cells.

Vinblastine and sulfinpyrazone export by the multidrug resistance protein MRP2 is associated with glutathione export

“…We propose a working model in which MRP2 has two drug-binding sites: one with a relatively high affinity for GSH (G-site) and a low affinity for drug, and one with a relatively high affinity for drug and a low affinity for GSH (D-site). The presence of a GSH-binding site is not unlikely as Taguchi et al (1997) have shown by vanadate trapping experiments that GSH can bind to MRP1, and Bakos et al (2000) have found GSH-induced ATP-ase activity in MRP1-and MRP2-containing membrane vesicles. We think that both binding sites are occupied by GSH in the absence of drugs, resulting in a slow export of GSH (Paulusma et al, 1999).…”

Oxidative and electrophilic stress induces multidrug resistance-associated protein transporters via the nuclear factor-E2-related factor-2 transcriptional pathway

“…Several studies have demonstrated that Mrp-dependent transport is inhibited when GSH is depleted, 16,[32][33][34] but no studies have examined whether Mrp expression is altered after GSH loss. Thus, this study is the first to examine the effects of GSH deficiency on the expression of Mrp transporters.…”

Intestinal transporters for endogenic and pharmaceutical organic anions: the challenges of deriving in-vitro kinetic parameters for the prediction of clinically relevant drug–drug interactions

“…p-Aminohippuric acid [92] 372 Bilirubin biglucuronide [93] 0.8 a Daunorubicin [94,95] 1.4 Atazanavir [59] Bilirubin bisglucuronide [93] Bilirubin monoglucuronide [93] 0.4 a Grepafloxacin [96] Benzbromarone [97,98] Bilirubin monoglucuronide [93] E217bG [99] 22 Irinotecan [100] Benzylpenicillin [98] DHEAS [101] 5 Estradiol sulfate [102] 0.4 Methotrexate [98,103,104] 930/2150 Daunorubicin [99]~8a DNP-GS [105] 3.6 E23SO417bG [99] 1.7 Doxorubicin [99]~5 0 a E217bG [99,[105][106][107] 1.5-4.8 E316bG [99] 45 Mitoxantrone [108] Flurbiprofen [109] Estrone-3-sulfate [102] 0.7/4.2 E317bG [99] 1.4 Saquinavir [110] Furosemide [98] Folic acid [103] Estrone-3-sulfate [102] 0.5 Vinblastine [111] Glibenclamide [77] Glutathione [97,112] Glycholate [99] Vincristine [95,113] Indinavir [114] Leucovorin [103] Glycolithocholate-3-sulfate [99] 1.4 Indometacin …”