In addition, HIF-1α knockdown exerted a combinatorial effect with CoQ0, which enhanced the inhibition of N-Cadherin, Snail, and MMP-9 expression under hypoxia, confirming the hypothesis that CoQ0 exerted anti-metastasis/EMT effects via HIF-1α inhibition in HNSCC cells. Here, MMP9 is linked to head and neck squamous cell carcinoma.