title: Balancing drug resistance and growth rates via compensatory mutations in the Plasmodium falciparum chloroquine resistance transporter.
abstract: The widespread use of chloroquine to treat Plasmodium falciparum infections has resulted in the selection and dissemination of variant haplotypes of the primary resistance determinant PfCRT. These haplotypes have encountered drug pressure and within-host competition with wild-type drug-sensitive parasites. To examine these selective forces in vitro, we genetically engineered P. falciparum to express geographically diverse PfCRT haplotypes. Variant alleles from the Philippines (PH1 and PH2, which differ solely by the C72S mutation) both conferred a moderate gain of chloroquine resistance and a reduction in growth rates in vitro. Of the two, PH2 showed higher IC50 values, contrasting with reduced growth. Furthermore, a highly mutated pfcrt allele from Cambodia (Cam734) conferred moderate chloroquine resistance and enhanced growth rates, when tested against wild-type pfcrt in co-culture competition assays. These three alleles mediated cross-resistance to amodiaquine, an antimalarial drug widely used in Africa. Each allele, along with the globally prevalent Dd2 and 7G8 alleles, rendered parasites more susceptible to lumefantrine, the partner drug used in the leading first-line artemisinin-based combination therapy. These data reveal ongoing region-specific evolution of PfCRT that impacts drug susceptibility and relative fitness in settings of mixed infections, and raise important considerations about optimal agents to treat chloroquine-resistant malaria.
authors.affiliation: Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.|Hygiene Institut, Abteilung Parasitologie, Universitätsklinikum Heidelberg, 69120, Heidelberg, Germany.
authors.forename: Ines
authors.initials: I
authors.lastname: Petersen
authors.affiliation: Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.
authors.forename: Stanislaw J
authors.initials: SJ
authors.lastname: Gabryszewski
authors.affiliation: Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.|School of International and Public Affairs, Columbia University, New York, NY, 10027, USA.
authors.forename: Geoffrey L
authors.initials: GL
authors.lastname: Johnston
authors.affiliation: Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.|Department of Biological Sciences, Binghamton University, Binghamton, NY, 13902, USA.
authors.forename: Satish K
authors.initials: SK
authors.lastname: Dhingra
authors.affiliation: Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.
authors.forename: Andrea
authors.initials: A
authors.lastname: Ecker
authors.affiliation: Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.
authors.forename: Rebecca E
authors.initials: RE
authors.lastname: Lewis
authors.affiliation: Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.
authors.forename: Mariana Justino
authors.initials: MJ
authors.lastname: de Almeida
authors.affiliation: Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.
authors.forename: Judith
authors.initials: J
authors.lastname: Straimer
authors.affiliation: Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.
authors.forename: Philipp P
authors.initials: PP
authors.lastname: Henrich
authors.affiliation: Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.
authors.forename: Eugene
authors.initials: E
authors.lastname: Palatulan
authors.affiliation: Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Johnson
authors.affiliation: Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.
authors.forename: Olivia
authors.initials: O
authors.lastname: Coburn-Flynn
authors.affiliation: Hygiene Institut, Abteilung Parasitologie, Universitätsklinikum Heidelberg, 69120, Heidelberg, Germany.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Sanchez
authors.affiliation: Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.
authors.forename: Adele M
authors.initials: AM
authors.lastname: Lehane
authors.affiliation: Hygiene Institut, Abteilung Parasitologie, Universitätsklinikum Heidelberg, 69120, Heidelberg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Lanzer
authors.affiliation: Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.|Division of Infectious Diseases, Department of Medicine, Columbia University Medical Center, New York, NY, 10032, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Fidock
mesh_terms: D002738:Chloroquine; D004351:Drug Resistance; D004912:Erythrocytes / Q000469:parasitology; D005787:Gene Frequency; D006239:Haplotypes; D006801:Humans; D016778:Malaria, Falciparum / Q000469:parasitology; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000235:genetics* / Q000378:metabolism; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D026901:Membrane Transport Proteins; C416369:PfCRT protein, Plasmodium falciparum; D015800:Protozoan Proteins; D002738:Chloroquine