New Amidated 3,6-Diphenylated Imidazopyridazines with Potent Antiplasmodium Activity Are Dual Inhibitors of Plasmodium Phosphatidylinositol-4-kinase and cGMP-Dependent Protein Kinase. Cheuka, P., Centani, L., Arendse, L., Fienberg, S., Wambua, L., Renga, S., Dziwornu, G., Kumar, M., Lawrence, N., Taylor, D., Birkholtz, L., & Chibale, K. ACS Infectious Diseases, 7(1):34–46, 2021.
doi  abstract   bibtex   
Recent studies on 3,6-diphenylated imidazopyridazines have demonstrated impressive in vitro activity and in vivo efficacy in mouse models of malaria infection. Herein, we report the synthesis and antiplasmodium evaluation of a new series of amidated analogues and demonstrate that these compounds potently inhibit Plasmodium phosphatidylinositol-4-kinase (PI4K) type III$β$ while moderately inhibiting cyclic guanidine monophosphate (cGMP)-dependent protein kinase (PKG) activity in vitro. Using in silico docking, we predict key binding interactions for these analogues within the adenosine triphosphate (ATP)-binding site of PI4K and PKG, paving the way for structure-based optimization of imidazopyridazines targeting both Plasmodium PI4K and PKG. While several derivatives showed low nanomolar antiplasmodium activity (IC50 \textless 100 nM), some compounds, including piperazine analogue 28, resulted in strong dual PI4K and PKG inhibition. The compounds also demonstrated transmission-blocking potential, evident from their potent inhibition of early- A nd late-stage gametocytes. Finally, the current compounds generally showed improved aqueous solubility and reduced hERG (human ether-a-go-go-related gene) channel inhibition.
@article{Cheuka2021a,
abstract = {Recent studies on 3,6-diphenylated imidazopyridazines have demonstrated impressive in vitro activity and in vivo efficacy in mouse models of malaria infection. Herein, we report the synthesis and antiplasmodium evaluation of a new series of amidated analogues and demonstrate that these compounds potently inhibit Plasmodium phosphatidylinositol-4-kinase (PI4K) type III$\beta$ while moderately inhibiting cyclic guanidine monophosphate (cGMP)-dependent protein kinase (PKG) activity in vitro. Using in silico docking, we predict key binding interactions for these analogues within the adenosine triphosphate (ATP)-binding site of PI4K and PKG, paving the way for structure-based optimization of imidazopyridazines targeting both Plasmodium PI4K and PKG. While several derivatives showed low nanomolar antiplasmodium activity (IC50 {\textless} 100 nM), some compounds, including piperazine analogue 28, resulted in strong dual PI4K and PKG inhibition. The compounds also demonstrated transmission-blocking potential, evident from their potent inhibition of early- A nd late-stage gametocytes. Finally, the current compounds generally showed improved aqueous solubility and reduced hERG (human ether-a-go-go-related gene) channel inhibition.},
author = {Cheuka, P.M. and Centani, L. and Arendse, L.B. and Fienberg, S. and Wambua, L. and Renga, S.S. and Dziwornu, G.A. and Kumar, M. and Lawrence, N. and Taylor, D. and Birkholtz, L.-M. and Chibale, K.},
doi = {10.1021/acsinfecdis.0c00481},
journal = {ACS Infectious Diseases},
number = {1},
pages = {34--46},
title = {{New Amidated 3,6-Diphenylated Imidazopyridazines with Potent Antiplasmodium Activity Are Dual Inhibitors of Plasmodium Phosphatidylinositol-4-kinase and cGMP-Dependent Protein Kinase}},
volume = {7},
year = {2021}
}

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