Introduction of Scaffold Nitrogen Atoms Renders Inhibitors of the Malarial l-Lactate Transporter, PfFNT, Effective against the Gly107Ser Resistance Mutation

J Med Chem. 2020 Sep 10;63(17):9731-9741. doi: 10.1021/acs.jmedchem.0c00852. Epub 2020 Aug 28.

Abstract

The spreading of malaria parasites, Plasmodium falciparum, with resistance to all known drugs calls for novel classes of inhibitors with new modes of action. Recently, we discovered and validated the plasmodial l-lactate transporter, PfFNT, as a novel antimalarial drug target. However, treatment of parasites with a screening hit from the malaria box compound collection, MMV007839, gave rise to a PfFNT Gly107Ser resistance mutation decreasing inhibitor affinity by 2 orders of magnitude. Here, we show that newly introduced nitrogen atoms into the inhibitor scaffold can act as hydrogen bond acceptor sites to the serine hydroxyl. The gain in affinity led to almost equal inhibition of wildtype PfFNT and the Gly107Ser mutation. The most potent inhibitor of this work, BH267.meta, killed cultured P. falciparum parasites with nanomolar efficacy and did not give rise to new resistance formation in vitro. Its deduced pharmacokinetic properties appear suitable for further drug development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antimalarials / chemistry*
  • Antimalarials / pharmacology*
  • Models, Molecular
  • Monocarboxylic Acid Transporters / antagonists & inhibitors*
  • Monocarboxylic Acid Transporters / chemistry
  • Monocarboxylic Acid Transporters / genetics*
  • Mutation*
  • Nitrogen / chemistry*
  • Plasmodium falciparum / drug effects
  • Plasmodium falciparum / genetics
  • Protein Conformation
  • Protozoan Proteins / antagonists & inhibitors
  • Protozoan Proteins / chemistry
  • Protozoan Proteins / genetics
  • Structure-Activity Relationship

Substances

  • Antimalarials
  • Monocarboxylic Acid Transporters
  • Protozoan Proteins
  • Nitrogen