Coenzyme Q inhibited the NLRP3 inflammasome, metastasis/EMT, and Warburg effect by suppressing hypoxia-induced HIF-1α expression in HNSCC cells.

Coenzyme Q (CoQ), a quinone derivative from , has antitumor capabilities. This study investigated the antitumor effect of noncytotoxic CoQ, which included NLRP3 inflammasome inhibition, anti-EMT/metastasis, and metabolic reprogramming via HIF-1α inhibition, in HNSCC cells under normoxia and hypoxia. CoQ suppressed hypoxia-induced ROS-mediated HIF-1α expression in OECM-1 and SAS cells. Under normoxia and hypoxia, the inflammatory NLRP3, ASCcaspase-1, NFκB, and IL-1β expression was reduced by CoQ. CoQ reduced migration/invasion by enhancing epithelial marker E-cadherin and suppressing mesenchymal markers Twist, N-cadherin, Snail, and MMP-9, and MMP-2 expression. CoQ inhibited glucose uptake, lactate accumulation, GLUT1 levels, and HIF-1α-target gene (HK-2, PFK-1, and LDH-A) expressions that are involved in aerobic glycolysis. Notably, CoQ reduced ECAR as well as glycolysis, glycolytic capability, and glycolytic reserve and enhanced OCR, basal respiration, ATP generation, maximal respiration, and spare capacity in OECM-1 cells. Metabolomic analysis using LC-ESI-MS showed that CoQ treatment decreased the levels of glycolytic intermediates, including lactate, 2/3-phosphoglycerate, fructose 1,6-bisphosphate, and phosphoenolpyruvate, and increased the levels of TCA cycle metabolites, including citrate, isocitrate, and succinate. HIF-1α silencing reversed CoQ-mediated anti-metastasis (N-Cadherin, Snail, and MMP-9) and metabolic reprogramming (GLUT1, HK-2, and PKM-2) under hypoxia. CoQ prevents cancer stem-like characteristics (upregulated CD24 expression and downregulated CD44, ALDH1, and OCT4) under normoxia and/or hypoxia. Further, in IL-6-treated SG cells, CoQ attenuated fibrosis by inhibiting TGF-β and Collagen I expression and suppressed EMT by downregulating Slug and upregulating E-cadherin expression. Interesting, CoQ inhibited the growth of OECM-1 tumors in xenografted mice. Our results advocate CoQ for the therapeutic application against HNSCC.