Oerlemans R, van der Heijden J, Vink J, Dijkmans BAC, Kaspers GJL, Lems WF, Scheffer GL, Ifergan I, Scheper RJ, Cloos J, Assaraf YG, Jansen G. Acquired resistance to chloroquine in human CEM T cells is mediated by multidrug resistance–associated protein 1 and provokes high levels of cross-resistance to glucocorticoids.
ACTA ACUST UNITED AC 2006;
54:557-68. [PMID:
16447232 DOI:
10.1002/art.21569]
[Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE
To explore the onset and molecular mechanism of resistance to the antimalarial disease-modifying antirheumatic drug (DMARD) chloroquine (CQ) in human CEM T cells.
METHODS
Human CEM cells were used as an in vitro model system to study the development of CQ resistance by growing cells in stepwise increasing concentrations of CQ.
RESULTS
Over a period of 6 months, CEM cell lines developed 4-5-fold resistance to CQ. CQ resistance was associated with the specific overexpression of multidrug resistance-associated protein 1 (MRP-1), an ATP-driven drug efflux pump. This was illustrated by 1) overexpression of MRP-1 by Western blotting and 2) the complete reversal of CQ resistance by the MRP-1 transport inhibitors MK571 and probenecid. Importantly, CQ-resistant CEM cells retained full sensitivity to other DMARDs, including methotrexate, leflunomide, cyclosporin A, and sulfasalazine, but exhibited a high level of cross-resistance (>1,000-fold) to the glucocorticoid dexamethasone. The mechanistic basis for the latter was associated with aberrant signaling via the cAMP-protein kinase A pathway, since the cAMP-inducing agent forskolin reversed dexamethasone resistance. Finally, CQ-resistant CEM cells displayed a markedly reduced capacity to release proinflammatory cytokines (tumor necrosis factor alpha) and chemokines (interleukin-8).
CONCLUSION
Induction of overexpression of the multidrug resistance efflux transporter MRP-1 can emerge after long-term exposure to CQ and results in CQ resistance and collateral resistance to dexamethasone. These findings warrant further detailed investigations into the possible role of MRP-1 and other members of the superfamily of drug efflux pumps in diminishing the efficacy of DMARDs in rheumatoid arthritis treatment.
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