The anticancer human mTOR inhibitor sapanisertib potently inhibits multiple Plasmodium kinases and life cycle stages

Abstract

Compounds acting on multiple targets are critical to combating antimalarial drug resistance. Here, we report that the human “mammalian target of rapamycin” (mTOR) inhibitor sapanisertib has potent prophylactic liver stage activity, in vitro and in vivo asexual blood stage (ABS) activity, and transmission-blocking activity against the protozoan parasite Plasmodium spp. Chemoproteomics studies revealed multiple potential Plasmodium kinase targets, and potent inhibition of Plasmodium phosphatidylinositol 4-kinase type III beta (PI4Kβ) and cyclic guanosine monophosphate–dependent protein kinase (PKG) was confirmed in vitro. Conditional knockdown of PI4Kβ in ABS cultures modulated parasite sensitivity to sapanisertib, and laboratory-generated P. falciparum sapanisertib resistance was mediated by mutations in PI4Kβ. Parasite metabolomic perturbation profiles associated with sapanisertib and other known PI4Kβ and/or PKG inhibitors revealed similarities and differences between chemotypes, potentially caused by sapanisertib targeting multiple parasite kinases. The multistage activity of sapanisertib and its in vivo antimalarial efficacy, coupled with potent inhibition of at least two promising drug targets, provides an opportunity to reposition this pyrazolopyrimidine for malaria.

A Pyridyl-Furan Series Developed from the Open Global Health Library Block Red Blood Cell Invasion and Protein Trafficking in Plasmodium falciparum through Potential Inhibition of the Parasite’s PI4KIIIB Enzyme

“…During preparation of this manuscript, we became aware that human mTOR inhibitor sapanisertib also inhibits parasite PfPI4KIIIB and PfPKG (Figure S4). Parasites selected for resistance to sapanisertib were found to contain the same E1316D mutation as our M-797 resistant parasites, supporting our finding that PfPI4KIIIB is very likely the main target of M-797. Unlike sapanisertib, M-797 is unlikely to be a major inhibitory target for PfPKG as M-797 did not inhibit egress like known PfPKG inhibitor compound 1 , which was used here as a positive control in our egress inhibition experiments (Figure ).…”

“…The compounds used here were assayed against recombinant PvPI4Kβ (PVX_098050) kinase with inhibitory activity detected using the ADP-Glo kinase assay kit (Promega). 44 Transmission blocking assay. The transmission blocking activity of M-797, WEHI-518, and C3 was evaluated by incubating the compounds against stage V gametocytes and evaluating their transition to male gametes by counting exflagellation centers and female gametes by counting anti-Pfs25 IgG parasites as per.…”

First fully-automated AI/ML virtual screening cascade implemented at a drug discovery centre in Africa

“…In the longer term, it is envisaged that scientists will be able to run predictions on their own. We also anticipate expanding the array of available models and building models on demand, especially for target-based projects such as those based on the clinically-validated Pf phosphatidylinositol 4-kinase (PI4K) enzyme (Arendse et al 2022; Paquet et al 2017). Continued revision and maintenance of the models ensure that they are updated with the latest data being generated at H3D.…”

Advances in malaria pharmacology and the online guide to MALARIA PHARMACOLOGY: IUPHAR review 38

“…However, clinical development was stopped due to teratoxicity concerns based on data emerging from studies in rats (Demarta‐Gatsi et al, 2022). A number of other scaffolds potently inhibiting this kinase have also been reported, including the quinoxaline BQR695 (McNamara et al, 2013), BRD73842 (Kato et al, 2016), imidazopyridazines (Cheuka et al, 2021; McNamara et al, 2013), naphthyridines (MMV024101) (Kandepedu et al, 2018), bipyridine‐sulfonamides (CHMFL‐PI4K‐127) (Liang et al, 2020), Torin 2 derivatives (NCATS‐SM3710) (Krishnan et al, 2020) and the anticancer mTOR inhibitor sapanisertib (Arendse et al, 2022). PI4Kβ inhibition leads to a moderately slow rate of parasite kill in vitro (Paquet et al, 2017), although it should be noted that MMV390048 displayed fast killing kinetics in the clinic (Mohammed et al, 2023; Sinxadi et al, 2020).…”

“…MMV390048 and other PI4Kβ ATP‐competitive inhibitors show a moderate propensity to generate de novo resistance as demonstrated in vitro , where a higher number of parasites in culture is needed to raise resistance compared to other drugs known to be highly mutable such as atovaquone (Brunschwig et al, 2018; Paquet et al, 2017). In vitro resistant selections carried out with different PI4Kβ inhibitors have resulted in resistant lines showing low to moderate EC 50 shifts between 3‐ and 22‐fold, with single point mutations in the PI4Kβ kinase domain, Rab11a and/or PI4Kβ copy number variations (Arendse et al, 2022; Brunschwig et al, 2018; Kato et al, 2016; Krishnan et al, 2020; McNamara et al, 2013; Paquet et al, 2017). The success of Plasmodium PI4Kβ inhibitors has led to an interest in targeting Plasmodium phosphatidylinositol 3‐kinase (PfPI3K, PF3D7_0515300).…”