MMP9 and head and neck squamous cell carcinoma: In addition to MT1-MMP, tumor necrosis factor-α (TNF-α), an inducer of MMP-9 secretion in hypopharyngeal and OSCC cell lines [30], was synergistically suppressed by a combination of ACY-241 and JQ1 in both HNSCC cells (Figure 4C,D and Figure S1G).