Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, United States
Madeline R Luth
Division of Host Pathogen Systems and Therapeutics, Department of Pediatrics, University of California, San Diego, San Diego, United States
Mark A Tye
Center for Systems Biology, Massachusetts General Hospital, Boston, United States; Harvard Graduate School of Arts and Sciences, Cambridge, United States
Ralph Mazitschek
Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, United States; Center for Systems Biology, Massachusetts General Hospital, Boston, United States
Sabine Ottilie
Division of Host Pathogen Systems and Therapeutics, Department of Pediatrics, University of California, San Diego, San Diego, United States
Division of Host Pathogen Systems and Therapeutics, Department of Pediatrics, University of California, San Diego, San Diego, United States; Skaggs School of Pharmaceutical Sciences, University of California, San Diego, La Jolla, United States
Maria Jose Lafuente-Monasterio
Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Madrid, Spain
Francisco Javier Gamo
Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Madrid, Spain
Dyann F Wirth
Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, United States; Infectious Disease and Microbiome Program, The Broad Institute, Cambridge, United States
Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, United States; Infectious Disease and Microbiome Program, The Broad Institute, Cambridge, United States
Drug resistance remains a major obstacle to malaria control and eradication efforts, necessitating the development of novel therapeutic strategies to treat this disease. Drug combinations based on collateral sensitivity, wherein resistance to one drug causes increased sensitivity to the partner drug, have been proposed as an evolutionary strategy to suppress the emergence of resistance in pathogen populations. In this study, we explore collateral sensitivity between compounds targeting the Plasmodium dihydroorotate dehydrogenase (DHODH). We profiled the cross-resistance and collateral sensitivity phenotypes of several DHODH mutant lines to a diverse panel of DHODH inhibitors. We focus on one compound, TCMDC-125334, which was active against all mutant lines tested, including the DHODH C276Y line, which arose in selections with the clinical candidate DSM265. In six selections with TCMDC-125334, the most common mechanism of resistance to this compound was copy number variation of the dhodh locus, although we did identify one mutation, DHODH I263S, which conferred resistance to TCMDC-125334 but not DSM265. We found that selection of the DHODH C276Y mutant with TCMDC-125334 yielded additional genetic changes in the dhodh locus. These double mutant parasites exhibited decreased sensitivity to TCMDC-125334 and were highly resistant to DSM265. Finally, we tested whether collateral sensitivity could be exploited to suppress the emergence of resistance in the context of combination treatment by exposing wildtype parasites to both DSM265 and TCMDC-125334 simultaneously. This selected for parasites with a DHODH V532A mutation which were cross-resistant to both compounds and were as fit as the wildtype parent in vitro. The emergence of these cross-resistant, evolutionarily fit parasites highlights the mutational flexibility of the DHODH enzyme.
