The integrin alphavbeta6 is a fibronectin receptor whose expression is not detectable on normal oral epithelium but is increased significantly in healing and in oral epithelial dysplasia and oral squamous cell carcinoma, suggesting it may promote changes associated with tumor development. To study whether alphavbeta6 may drive invasive behavior we have used transfection and retroviral infection to create a panel of epithelial cell lines expressing various levels of alphavbeta6. We report that increased expression of alphavbeta6 in malignant keratinocytes promotes invasion and leads to an increased capacity for migration towards fibronectin. alphavbeta6 expression may have a significant role in contributing to the malignant behavior of epithelial cells.

a b s t r a c tAlterations in the levels of molecules which interact with the extracellular matrix, such as integrins, are associated with invasion of oral squamous cell carcinomas (OSCC). The molecular mechanisms underlying dysregulation of integrin expression in OSCC, however, remain unclear. Here, we show that microRNA-124, a small non-coding RNA down-regulated in OSCC, is able to downregulate expression of integrin beta-1 (ITGB1) by interacting with its 3 0 untranslated region. Over-expression of miR-124 attenuates endogenous ITGB1 expression and reduces the adherence and motility of OSCC cells, suggesting disruption of miR-124-mediated repression of ITGB1 may be a key factor in OSCC progression.

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