Paxillin modulates squamous cancer cell adhesion and is important in pressure-augmented adhesion

Paxillin is an adapter protein regulating signaling and focal adhesion assembly that has been linked to malignant potential in many malignancies. Overexpression of paxillin has been noted in aggressive tumors. Integrin‐mediated binding through the focal adhesion complex is important in metastatic adhesion and is upregulated by extracellular pressure in malignant colonocytes through FAK and Src activation. Neither head and neck cancers nor paxillin have been studied in this regard. We hypothesized that paxillin would play a role in modulating squamous cancer adhesion both at baseline and under conditions of increased extracellular pressure. Using SCC25 tongue squamous cancer cells stably transfected with either an empty selection vector or paxillin expression and selection vectors, we studied adhesion to collagen, paxillin, FAK, and Src expression and phosphorylation in cells maintained for 30 min under ambient or 15 mmHg increased pressure conditions. Paxillin‐overexpressing cells exhibited adhesion 121 ± 2.9% of that observed in vector‐only cells (n = 6, P