Regulation of Autophagy and Metabolism in Hepatocellular Carcinoma: Involvement of Wnt-β-Catenin Pathway.

Most cancer cells rely on aerobic glycolysis to support uncontrolled proliferation and evade apoptosis and switch to glutamine metabolism to survive under hypoxic conditions. In hepatocellular carcinoma (HCC), the Wnt/β-catenin pathway acts as a critical driver of metabolic reprogramming and stemness, primarily by enhancing aerobic glycolysis and altering the tumour microenvironment. The Wnt/β-catenin pathway induces activation of enzymes required for glucose metabolism and regulates the expression of glutamate transporter and glutamine synthetase. The objective of this study is to examine the mechanism by which riluzole inhibits HCC growth and induces autophagy. The results indicate that riluzole inhibits cell viability and colony formation of HCC cells and cancer stem cells (CSCs) and induces apoptosis, while sparing human normal hepatocytes. Riluzole induces autophagic cell death by inducing Beclin1 and Atg5. Riluzole inhibits β-catenin, Wnt3a, Wnt5a, Axin1, TCF, LEF and GSK3β expression, and TCF/LEF activity in HCC cells. Inhibition of the Wnt-β-catenin/TCF-LEF pathway by riluzole suppresses the expression of Cyclin D1, Axin2, cMyc, MCT1 and DNMT1. Riluzole inhibits the expression of Glut1 and Glut3, PDK1, LDHA and PKM2, glucose uptake and NAD+ levels. Furthermore, riluzole inhibits glutamate release, which reduces the antioxidant glutathione, leading to increased reactive oxygen species (ROS). Riluzole disrupts mitochondrial homeostasis by increasing Bax/Bcl-2 ratio, resulting in a drop of mitochondrial membrane potential. In conclusion, riluzole inhibits HCC growth by regulating glucose and glutamine metabolism and inducing autophagic cell death, thereby highlighting its therapeutic potential for HCC treatment.