Searching for Novel Anaplastic Lymphoma Kinase Inhibitors: Structure-Guided Screening of Natural Compounds for a Tyrosine Kinase Therapeutic Target in Cancers

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase molecular target with broad importance for drug discovery, especially in the field of cancer therapeutics. ALK belongs to the insulin receptor superfamily that is involved in various malignancies, including non-small cell lung cancer, anaplastic large cell lymphoma, and neuroblastoma. ALK has been shown to play a role in cancer progression and metastasis, making it one of the prime targets to develop novel anticancer therapeutics. In this context, natural compounds can be an important resource to unravel novel ALK inhibitors. In this study, we report a structure-based virtual screening of natural compounds from the ZINC database, with an eye to potential inhibitors of ALK. Molecular docking was performed on a natural compound library, and top hits holding good binding affinity, docking score, and specificity toward ALK were selected. The hits were further evaluated based on the PAINS (pan-assay interference compounds) filter, ADMET (absorption, distribution, metabolism, excretion, toxicity) properties, PASS (prediction of activity spectra for substances) analysis, and two-dimensional interaction of protein–ligand complexes. Importantly, two natural compounds (ZINC03845566 and ZINC03999625) were identified as potential candidates for ALK, having appreciable affinity and specificity toward the ALK binding pocket and depicting drug-like properties as predicted from ADMET analysis and their physicochemical parameters. An all-atom molecular dynamics simulation for 100 ns on ALK promised stable ALK-ligand complexes. Hence, we conclude that ZINC03845566 and ZINC03999625 can act as potential ALK inhibitors against cancers where ALK plays a role, for example, in lung cancer, among others. All in all, these findings inform future discovery and translational research for ALK inhibitors as anticancer drugs.