Integrin β1 is required for the invasive behaviour but not proliferation of squamous cell carcinoma cells in vivo

Integrin beta1 is both overexpressed and in an 'active' conformation in vulval squamous cell carcinomas (VSCCs) compared to matched normal skin. To investigate the significance of integrin beta1 deregulation we stably knocked-down integrin beta1 expression in the VSCC cell line A431. In vitro analysis revealed that integrin beta1 is required for cell adhesion, cell spreading and invasion. However, integrin beta1 is not required for cell growth or activation of FAK and ERK signalling in vitro or in vivo. Strikingly, while control tumours were able to invade the dermis, integrin beta1 knockdown tumours were significantly more encapsulated and less invasive.