Sosa, Yvett Egbo, Deborah Akabas, Myles H. Impact of Field Isolate Identified Nonsynonymous Single Nucleotide Polymorphisms on <i>Plasmodium falciparum</i> Equilibrative Nucleoside Transporter 1 Inhibitor Efficacy <i>Plasmodium falciparum</i> causes the most severe form of malaria and causes approximately 500 000 deaths per year. <i>P</i>. <i>falciparum</i> parasites resistant to current antimalarial treatments are spreading. Therefore, it is imperative to develop new antimalarial drugs. Malaria parasites are purine auxotrophic. They rely on purine import from the host erythrocyte via Equilibrative Nucleoside Transporters (ENTs). Recently, inhibitors of the <i>P. falciparum</i> ENT1 (PfENT1) that inhibit proliferation of malaria parasites in culture have been identified as promising starting points for antimalarial drug development. Genome sequencing of <i>P. falciparum</i> field isolates has identified nonsynonymous single nucleotide polymorphisms (SNPs) in the gene encoding PfENT1. Here we evaluate the impact of these PfENT1 SNPs on purine substrate affinity and inhibitor efficacy. We expressed each PfENT1-SNP in <i>Saccharomyces cerevisiae</i>. Using PfENT1-SNP-expressing yeast, we characterized the PfENT1 purine substrate affinity using radiolabeled substrate uptake inhibition experiments. Four of the 13 SNPs altered affinity for one or more purines by up to 7-fold. Three of the SNPs reduced the potency of a subset of the inhibitors by up to 7-fold. One SNP, Q284E, reduced the potency of all six inhibitor chemotypes. We tested drug efficacy in available parasite strains containing PfENT1 SNPs. While PfENT1-SNP-expressing yeast had decreased sensitivity to PfENT1 inhibitors, parasite strains containing SNPs showed similar or more potent inhibition of proliferation with all PfENT1 inhibitors. Thus, parasite strains bearing PfENT1 SNPs are not resistant to these PfENT1 inhibitors. This supports PfENT1 as a promising target for further development of novel antimalarial drugs. Equilibrative Nucleoside Transporters;Field Isolate Identified Nonsynonymous Single Nucleotide Polymorphisms;500 000 deaths;PfENT 1 purine substrate affinity;PfENT 1 SNPs;PfENT 1 inhibitors;parasite strains;novel antimalarial drugs;falciparum ENT 1;284E;Plasmodium falciparum Equilibrative Nucleoside Transporter 1 Inhibitor Efficacy Plasmodium falciparum causes;radiolabeled substrate uptake inhibition experiments;antimalarial drug development;gene encoding PfENT 1.;PfENT 1-SNP yeast;purine substrate affinity 2020-01-13
    https://acs.figshare.com/articles/journal_contribution/Impact_of_Field_Isolate_Identified_Nonsynonymous_Single_Nucleotide_Polymorphisms_on_i_Plasmodium_falciparum_i_Equilibrative_Nucleoside_Transporter_1_Inhibitor_Efficacy/11591127
10.1021/acsinfecdis.9b00203.s001