Cytotoxic Activity of Aplykurodin A Isolated From Aplysia kurodai against AXIN1-Mutated Hepatocellular Carcinoma Cells by Promoting Oncogenic β-Catenin Degradation

Dysregulation of the Wnt/β-catenin signaling pathway is involved in the development of human hepatocellular carcinoma and has thus emerged as a therapeutic target for this malignant tumor. In this study, we employed sensitive cell-based assays to identify aplykurodin A isolated from Aplysia kurodai as an antagonist of Wnt/β-catenin signaling. Aplykurodin A inhibited β-catenin responsive transcription, which was stimulated by a Wnt3a-conditioned medium or a glycogen synthase kinase 3β inhibitor by accelerating intracellular β-catenin degradation. Aplykurodin A downregulated the level of oncogenic β-catenin and decreased the expression of β-catenin-dependent gene, leading to inhibition of human hepatoma Hep3B and SNU475 cell proliferation. Moreover, apoptosis and autophagy were elicited by aplykurodin A, as indicated by an increase the number of Annexin V-FITC-stained cells and the formation of microtubule-associated protein 1 light chain 3 puncta, respectively, in Hep3B and SNU475 cells. Our findings suggest that aplykurodin A provides a novel therapeutic strategy for human hepatocellular carcinoma via stimulation of oncogenic β-catenin degradation.