Expression of Fyn kinase modulates EMT in oral cancer cells.

Oral squamous cell carcinoma (SCC) is an aggressive tumor with a poor 5-year survival rate. Oral SCC can undergo epithelial to mesenchymal transition (EMT). We previously showed that the epithelial integrin alphavbeta6 complexes with Fyn kinase in oral SCC to promote EMT. Using immunofluorescence microscopy and Western blotting, we evaluated whether the expression of specific markers of EMT were influenced by modulating serum concentration (ie. growth factors). The SCC cultures were grown under contrasting levels of serum. In low serum (1%), Fyn promoted EMT; whereas suppression of Fyn kinase promoted the epithelial phenotype. However, when the SCC cells were grown in 10% serum, activation of Fyn had the reverse effect. Lastly, cell migration was evaluated under low serum conditions (1% FBS). Activation of Fyn promoted SCC cell migration and its suppression thwarted SCC migration toward FN. These results indicate that the activation of Fyn kinase as well as local growth factor concentration modulate EMT in oral SCC.