Dual Inhibition of IDO1 and TDO: A Unified Therapeutic Strategy to Combat Alzheimer’s Disease and Cancer

The kynurenine pathway, regulated by the enzymes indoleamine 2,3-dioxygenase 1 (IDO1) and tryptophan 2,3-dioxygenase (TDO), plays a pivotal role in immune regulation and neuroinflammation in human. Dysregulation of this pathway has been strongly associated with the pathogenesis of Alzheimer's disease and various cancers. In this study, we present a comprehensive computational investigation to identify potential dual inhibitors of IDO1 and TDO, aiming to simultaneously target the molecular mechanisms underlying these two devastating conditions. A natural compound library was subjected to an integrated screening approach involving virtual screening, ADMET profiling, and molecular dynamics simulations. Our analysis identifies hydroxy sanguinarine, chelirubine, 17-decarboxy-neobitanin, and epicatechin-5-O-glucuronide as the potent leads that exhibited strong binding affinity, favorable pharmacokinetic properties, and stable protein-ligand interactions with both the enzymes. Dual inhibition of IDO1 and TDO is proposed to restore immune surveillance in cancer while mitigating neurodegenerative processes in Alzheimer's disease via modulation of the kynurenine pathway. To the best of our knowledge, this is the first attempt exploring the dual targeting of IDO1 and TDO as a unified therapeutic strategy for combating both Alzheimer's disease and cancer. These findings would provide information for future experimental validation and the development of innovative multitarget therapeutics.