Targeting v-ATPase to Inhibit Lysosomal Acidification: A Study on the Anticancer Mechanism of Phenolic Small Molecules

Introduction: Vacuolar-type Adenosine Triphosphatases (v-ATPases) are essential for maintaining lysosomal acidification, a process critical for cancer cell survival and proliferation, making them a promising therapeutic target. This study aims to identify novel phenolic compounds that inhibit v-ATPase, disrupt lysosomal pH homeostasis, and exert anticancer effects. Methods: The anti-proliferative effects of four phenolic compounds (Daidzin, Quercetin, Gossypol, and Gossypol acetic acid) were evaluated in human cervical (HeLa) and ovarian (SKOV3) cancer cell lines using CCK-8 assays. Their impact on lysosomal acidification was assessed using LysoTracker Red staining. Molecular docking simulations were performed to characterize their binding interactions with v-ATPase. Results: All four compounds demonstrated significant, dose-dependent anticancer activity, effectively suppressing cancer cell proliferation. Treatment with these compounds markedly disrupted lysosomal acidification, as indicated by loss of LysoTracker Red signal. Molecular docking revealed that these phenolic compounds specifically bind to key residues (e.g., Glu-813 and Lys-99) at the interface of the a and c subunits within the v-ATPase V0 domain, with Daidzin showing the strongest binding affinity. Discussion: Molecular docking simulations further corroborated these phenotypic findings, demonstrating that the phenolic compounds, particularly Daidzin, bind with high affinity to key residues (e.g., Glu-813, Lys-99) at the a-c subunit interface of the v-ATPase V0 domain. This interaction is proposed to sterically hinder proton translocation, providing a structural rationale for the observed lysosomal acidification dysfunction and the consequent anticancer effects. Conclusion: This study identifies specific phenolic compounds as effective inhibitors of v-ATPase, proposing a mechanism by which they disrupt lysosomal acidification and inhibit cancer cell growth. These findings provide a theoretical foundation for developing novel anticancer therapeutics targeting v-ATPase.