EMMPRIN expression in oral SCC is regulated by FYN kinase

This study shows that the expression of the extracellular matrix metalloproteinase inducer (EMMPRIN) in oral squamous cell carcinoma cells (SCC) depends upon activation of the Src Family kinaseFyn; and that EMMPRIN and β6 form a complex that requires active Fyn and the full length β6 integrin cytoplasmic domain. Fyn is also important for matrix remodeling as it regulates both matrix type 1 metalloproteinase (MT1-MMP) and tissue inhibitor of metalloproteinase-1 and -2 (TIMP1/2). The tumor promoter/suppressor caveolin-1, which associates with MT1-MMP, also requires FYN activation for expression. Lastly, EMMPRIN expression can act as a readout for the mitogen-activated protein kinase (MAPK) pathway, since when MAPK is blocked, so is the expression of EMMPRIN. In oral cancer, the activation of FYN occurs post β6 integrin ligand binding. That the activation of FYN drives EMMPRIN expression and several important pathways associated with invasive oral SCC is now demonstrated.