ECR Oral Presentation (ECR Day Dec 4) 11th Annual Conference of the International Chemical Biology Society 2022

Investigating the antimalarial activity of novel heterospirocyclic compounds in drug-resistant malaria parasites (#7)

Liana Theodoridis 1 , Carlo Giannangelo 2 , Farrah El-Saafin 3 4 , MR Ranga Prabhath 5 , Pallavi Sharma 5 6 , Delphine Merino 3 4 7 8 , Darren Creek 2 , Teresa G Carvalho 1
  1. Department of Microbiology, Anatomy, Physiology and Pharmacology, La Trobe University, Bundoora, VIC, Australia
  2. Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Science, Monash University, Parkville, VIC, Australia
  3. Olivia Newton-John Cancer Research Institute, Heidelberg, VIC, Australia
  4. School of Cancer Medicine, La Trobe University, Bundoora, VIC, Australia
  5. School of Chemistry, University of Lincoln, Lincoln, LN6 7TS, United Kingdom
  6. Cold Spring Harbor Laboratory, New York, United States of America
  7. Department of Medical Biology, The Faculty of Medicine, Dentistry and Health Science, The University of Melbourne, Melbourne, VIC, Australia
  8. Molecular Medicine Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia

Malaria remains a significant global health burden and a leading contributor to global mortality rates, particularly in Africa and South-East Asia. Although the first ever malaria vaccine has been approved (in 2021) by the World Health Organisation, it is only 36% effective highlighting the importance of antimalarial drugs as key tools of malaria control. However, the spread of drug resistance against all treatment options, including artemisinin, the current frontline malaria treatment, creates an urgent need for novel treatments. Due to the lack of chemical diversity amongst existing antimalarials, a focus on novel compounds with underrepresented chemical scaffolds is vital to combat drug resistance. We have designed and synthesised a new class of 3D-spiroheterocyclic compounds with chemical connectivities never previously explored as drug leads. We hypothesise that the unique 3D architecture of these molecules may allow them to reach and interact with biological domains otherwise inaccessible to relatively flat structures, leading to increased efficiency. We have previously shown that two spirocyclic compounds (C25 and C26) induce death of the most lethal human malaria parasite P. falciparum within 48hrs and present IC50 values in the low micromolar range. Recently, we have shown both compounds to be non-toxic in kidney- (HEK293) and hepatic- (HepG2 and Huh-7) derived humans cell lines. Further, both compounds have a killing effect on multiple drug-resistant P. falciparum strains, including artemisinin-sensitive Cam3.IIrev, artemisinin-resistant Cam3.IIR539T and Cam3.IIC580Y, and multi-drug resistant W2mef parasite lines. Untargeted metabolomics indicates that C25 perturbs pyrimidine biosynthesis, with further analysis ongoing to identify the specific target(s). Parasites resistant to C25 and C26 have been generated in 3D7 and Dd2 genetic backgrounds and whole genome sequencing will be performed on the resistant clones. This biological information will allow the synthesis of refined derivatives with more potent antimalarial activity.