Apigenin-mediated MARK4 inhibition: a novel approach in advancing Alzheimer's disease therapeutics

Apigenin, a dietary flavonoid with notable anti-cancer properties, has emerged as a promising candidate for the treatment of neurodegenerative disorders, particularly Alzheimer's disease (AD). While extensively studied for its ability to modulate key molecular pathways in cancers, apigenin also exerts neuroprotective effects by reducing neuroinflammation, protecting neurons from oxidative stress, and enhancing neuronal survival and synaptic plasticity. This dual functionality makes apigenin an intriguing therapeutic option for diseases like AD, where kinase dysregulation plays a central role. In this study, we focus on Microtubule Affinity-Regulating Kinase 4 (MARK4), a key enzyme implicated in tauopathies associated with AD, as well as in cancer progression. Through in silico analysis, we explore the interaction between apigenin and MARK4, revealing significant structural changes within the kinase domain upon ligand binding. These computational findings were confirmed via experimental assays using purified recombinant MARK4, where apigenin demonstrated potent inhibition with an IC₅₀ value of 2.39 µM. Fluorescence binding assays further confirmed a strong binding affinity (Ka = 10⁸ M^-1), indicating that apigenin efficiently occupies the MARK4 active site, thereby suppressing its enzymatic activity. These results position apigenin as a potent inhibitor of MARK4, offering a dual therapeutic advantage-both as an anti-cancer agent and as a neuroprotective compound for the potential treatment of AD. This study opens new avenues for the development of apigenin-based therapeutics targeting kinase dysregulation in cancer and neurodegeneration.