The role of the integrin alpha v beta6 in regulating the epithelial to mesenchymal transition in oral cancer.

In this study, we evaluated whether the forced expression of beta6 integrin would modulate the epithelial to mesenchymal transition (EMT). When the full length beta6 integrin was expressed in poorly invasive squamous cell carcinoma SCC9 cells, the resulting SCC9/6 cells acquired a fibroblast-like morphology, increased expression of the mesenchymal marker vimentin and reduced expression of the epithelial markers keratin and E-cadherin. SCC9beta6D1 cells, which express a truncated form of beta6 subunit lacking the C-terminal 11 amino acids (AA), retained their epithelial morphology and did not alter vimentin or E-cadherin expression. This suggests that the full-length beta6 subunit can induce EMT in oral SCC cells. We previously showed that expression of beta6 increases both MMP-3 activation and tenascin-C expression and we now show that both molecules are MEK dependent. These results also demonstrate that the terminal 11 AA of beta6 contain information important for establishing an epithelial to mesenchymal transition.