Efflux of Chloroquine from
            <i>Plasmodium falciparum</i>
            : Mechanism of Chloroquine Resistance

Krogstad, Donald J.; Gluzman, Ilya Y.; Kyle, Dennis E.; Oduola, A. M. J.; Martin, Samuel K.; Milhous, Wilbur K.; Schlesinger, Paul H.

doi:10.1126/science.3317830

Cited by 510 publications

(358 citation statements)

References 22 publications

(37 reference statements)

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“…Possibly, PfCRT mutations affect accumulation by altering drug flux across the digestive vacuole membrane. Our data also document a key role for pfcrt point mutations in the mode of action of verapamil, a known CQR reversal agent (22,25,37,38) that also chemosensitized the pfcrt-modified lines to quinine and quinidine (Fig. 1, C and D).…”

mentioning

confidence: 79%

Chloroquine Resistance in Plasmodium falciparum Malaria Parasites Conferred by pfcrt Mutations

Sidhu

Verdier-Pinard

Fidock

2002

Science

637

663

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Plasmodium falciparum chloroquine resistance is a major cause of worldwide increases in malaria mortality and morbidity. Recent laboratory and clinical studies have associated chloroquine resistance with point mutations in the gene pfcrt. However, direct proof of a causal relationship has remained elusive and most models have posited a multigenic basis of resistance. Here, we provide conclusive evidence that mutant haplotypes of the pfcrt gene product of Asian, African, or South American origin confer chloroquine resistance with characteristic verapamil reversibility and reduced chloroquine accumulation. pfcrt mutations increased susceptibility to artemisinin and quinine and minimally affected amodiaquine activity; hence, these antimalarials warrant further investigation as agents to control chloroquine-resistant falciparum malaria.Chloroquine has for decades been the primary chemotherapeutic means of malaria treatment and control (1). This safe and inexpensive 4-aminoquinoline compound accumulates inside the digestive vacuole of the infected red blood cell, where it is believed to form complexes with toxic heme moieties and interfere with detoxification mechanisms that include heme sequestration into an inert pigment called hemozoin (2-4). Chloroquine resistance (CQR) was first reported in Southeast Asia and South America and has now spread to the vast majority of malaria-endemic countries (1). pfcrt was recently identified as a candidate gene for CQR after the analysis of a genetic cross between a chloroquine-resistant clone (Dd2, Indochina) and a chloroquine-sensitive clone (HB3, Honduras) (5-7). The PfCRT protein localizes to the digestive vacuole membrane and contains 10 putative transmembrane domains (7,8). Point mutations in PfCRT, including the Lys 76 → Thr (K76T) mutation in the first predicted transmembrane domain, show an association with CQR in field isolates and clinical studies (7,9,10). Episomal complementation assays demonstrated a low-level, atypical CQR phenotype in chloroquine-selected, transformed, pseudo-diploid parasite lines that coexpressed the Dd2 form of pfcrt (containing eight point mutations; Table 1), under the control of a heterologous promoter, with the wild-type endogenous allele (7).To address whether mutations in pfcrt are sufficient to confer CQR, we implemented an allelic exchange approach to replace the endogenous pfcrt allele of a chloroquine-sensitive line (GC03) with pfcrt alleles from chloroquine-resistant lines of Asian, African, or South American origin (Table 1) (fig. S1) (11). This approach maintained the endogenous promoter and terminator regulatory elements for correct stage-specific expression and did not use chloroquine during the selection procedure. As a result of this gene's highly interrupted nature * To whom correspondence should be addressed. dfidock@aecom.yu.edu. Wootton et al. (39) recently presented compelling evidence for rapid evolutionary sweeps of mutant pfcrt sequences throughout malaria-endemic areas, starting from a limited number of initi...

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mentioning

confidence: 79%

Chloroquine Resistance in Plasmodium falciparum Malaria Parasites Conferred by pfcrt Mutations

Sidhu

Verdier-Pinard

Fidock

2002

Science

637

663

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“…P. falciparum resistance to CQ has been associated with lower drug accumulation in infected erythrocytes [11] or mainly to a mutation at position 76 (K76T) in the Plasmodium falciparum chloroquine resistance transporter (pfcrt) gene [12,13 ]. Several other studies have suggested the implication of multidrug resistance-1 (mdr1) gene family in resistance to quinoline containing compounds in P. falciparum [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Chloroquine Resistant Plasmodium falciparum in Nigeria: Relationship between pfcrt and pfmdr1 Polymorphisms, In-Vitro Resistance and Treatment Outcome

Folarin

Gbotosho²,

Sowunmi³

et al. 2008

TOTMJ

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This study was designed to evaluate the association between polymorphisms in pfcrt and pfmdr1 genes and in-vitro chloroquine (CQ) sensitivity in fresh isolates of P. falciparum and patients' treatment outcome. The modified schizont inhibition assay was used to determine in-vitro sensitivity of P. falciparum. Polymorphisms in pfcrt and pfmdr1 genes were detected using nested PCR and RFLP techniques in 84 P. falciparum isolates obtained from patients with acute uncomplicated malaria.Eighty five percent (71/84) and 15% (13/84) of the parasites were resistant and sensitive in-vitro to CQ respectively. Molecular analysis showed presence of mutant pfcrtT76, pfmdr1Y86 and pfmdr1F184 alleles in 60%, 33% and 14% of the isolates respectively. There was a significant association between in-vitro and in-vivo CQ resistance (p=0.029) and also between the presence of mutant pfcrtT76+pfmdr1 Y86-Y184 haplotype and in-vitro (p=0.013) or in-vivo CQ resistance (p=0.024).Overall results from this study demonstrates that the presence of pfcrtT76+ pfmdr1 Y86-Y184 haplotype in Nigerian isolates of Plasmodium falciparum is predictive of in-vitro and in-vivo CQ resistance and therefore may be useful for monitoring resistance to this drug.

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“…Entre los primeros moduladores de Pgp que se evaluaron están algunos bloqueadores de los canales de calcio como el verapamilo, la nifedipina, la imipramina y la azidopina (114-117); se ha encontrado que los inhibidores de los canales de calcio como el verapamilo (118,119), la eritromicina (120) y los derivados de las fenotiazinas (121) son capaces de revertir el fenotipo MDR en P. falciparum.…”

Section: Posibles Estrategias Para Revertir El Fenotipo Mdrunclassified

Leishmania: papel de la glicoproteína P en la mediación de resistencia a medicamentos y estrategias de reversión.

et al. 2005

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Actualmente, los parásitos protozoarios son uno de los principales agentes causantes de morbilidad y mortalidad en el mundo, un problema complicado, además, por la aparición de resistencia a medicamentos en estos organismos. La resistencia a medicamentos observada en parásitos protozoarios se debe a diferentes mecanismos como la disminución de la entrada del medicamento a la célula por cambios en el transportador requerido, la pérdida de la activación del medicamento por parte del hospedero, las alteraciones en el blanco del medicamento y la expresión exagerada del transportador múltiple de medicamentos o glicoproteína P (Pgp). En esta revisión, nos centramos en: 1) el papel de las glicoproteínas P (Pgp) de la familia de proteínas ABC (ATP binding cassette) como los transportadores de múltiples medicamentos en la mediación de resistencia en protozoarios, especialmente en Leishmania, y en el desarrollo de resistencia cruzada para medicamentos estructural y funcionalmente no relacionados, y 2) en algunos conceptos relacionados con los mecanismos moduladores que podrían revertir la resistencia a medicamentos por fármacos y productos naturales. Numerosos moduladores o quimiosensibilizadores son conocidos por alterar la capacidad de las glicoproteínas P para mantener concentraciones intracelulares subtóxicas del medicamento; algunos ejemplos incluyen los bloqueadores de los canales de calcio como el verapamilo; sin embargo, se requieren altas concentraciones para una inhibición eficiente y duradera, las cuales producen efectos adversos indeseables. Por tanto, se necesitan más investigaciones relacionadas con los moduladores naturales para Pgp, los cuales podrían presentar menor toxicidad para el hospedero.Palabras clave: Leishmania, protozoos, multirresistencia, glicoproteína P, productos naturales. Leishmania: role of P glycoprotein in drug resistance and reversion strategiesProtozoan parasites are important causative agents of morbidity and mortality throughout the world -a problem further complicated by the emergence of drug resistance in these parasites. Mechanisms of drug resistance include the following: decreased uptake of the drug into the cell, loss of drug activation, alterations in the drug target, and over-expression of a well-known multiple drug transporter proteins. In this review, two critical components of resistance are stressed: (1) the role of ATP binding cassette proteins, such as P-glycoproteins, in mediating drug resistance in Leishmania and other protozoans, followed by development of cross-resistance to many structurally and functionally unrelated drugs, and (2) some concepts concerning the reversal mechanism of multidrug resistance by drugs and natural products. Several modulators or chemosensitizers alter the capacity of P-glycoproteins to maintain subtoxic intracellular drug concentrations. Calcium channel blockers such as verapamil act in this mode; however, high concentrations are required for an efficient and effective inhibition and, in addition, produce undesirable side effects. The di...

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Efflux of Chloroquine from Plasmodium falciparum : Mechanism of Chloroquine Resistance

Cited by 510 publications

References 22 publications

Chloroquine Resistance in Plasmodium falciparum Malaria Parasites Conferred by pfcrt Mutations

Chloroquine Resistance in Plasmodium falciparum Malaria Parasites Conferred by pfcrt Mutations

Chloroquine Resistant Plasmodium falciparum in Nigeria: Relationship between pfcrt and pfmdr1 Polymorphisms, In-Vitro Resistance and Treatment Outcome

Leishmania: papel de la glicoproteína P en la mediación de resistencia a medicamentos y estrategias de reversión.

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