Novel anthraquinone amino-derivatives as anticancer targeting human serine/threonine kinase PAK4

Abstract

<title>Abstract</title> Anthraquinone scaffold has attracted increasing attention recently as a source for effective drug synthesis targeting various diseases. Here we demonstrate the potential of nine anthraquinone amino-derivatives (AAD) as anticancer agents. We synthesized nine Schiff bases (1–9) using anthraquinone scaffold and amino acids. We performed molecular docking against the anticancer drug target human serine/threonine p21-activated kinase 4 (PAK4) and compared it with the recently developed PAK4 inhibitor PF-3758309. Compounds <bold>5</bold> and <bold>8</bold> showed comparable docking properties to that of the PF-3758309 at two binding sites located at the c-terminal domain of PAK4. Compound <bold>5</bold> , a tryptophan-based anthraquinone derivative, exerts a docking score of -9.3 and − 8.7 kcal/mol at two different identified cavities, cav-1 and cav-4, respectively, exceeding that of the control PF-3758309 for both cavities. Additional optimization on the indole moiety of <bold>5</bold> gave rise to <bold>5b</bold> , resulting in high drug likeness (0.74) and comparable binding properties to cav-1 with − 8.6 kcal/mol and the highest achievable binding affinity to cav-4 with an average of -9.7 kcal/mol, indicating a potential allosteric inhibitory effect via cav-4. Our molecular dynamics simulation analysis on the top hits and the control compound provides important insights into the mechanism of action of these drug candidates. Additionally, all compounds exhibited promising pharmacokinetics and toxicity properties as revealed by the ADMET profiles, urging the need for comprehensive <italic>in vitro</italic> and <italic>in vivo</italic> antitumor characterization. Our results also indicate that cav-4 may serve as a target for designing specific allosteric inhibitors against PAK4-overexpressed cancer cells, suggesting a potential application in adjuvant cancer treatment.