Notch-mediated induction of N-cadherin and α9-integrin confers higher invasive phenotype on rhabdomyosarcoma cells

BACKGROUND: Rhabdomyosarcoma (RMS) is the commonest type of soft-tissue sarcoma in children. Patients with metastatic RMS continue to have very poor prognosis. Recently, several works have demonstrated a connection between Notch pathway activation and the regulation of cell motility and invasiveness. However, the molecular mechanisms of this possible relationship remain unclear. METHODS: The Notch pathway was manipulated pharmacologically and genetically. The mRNA changes were analysed by quantitative PCR and protein variations by western blot and immunofluorescence. Finally, the capabilities of RMS cells to adhere, heal a wound and invade were assessed in the presence of neuronal cadherin (N-cadherin)- and alpha 9-integrin-blocking antibodies. RESULTS: Cells treated with gamma-secretase inhibitor showed lower adhesion capability and downregulation of N-cadherin and alpha 9-integrin. Genetic manipulation of the Notch pathway led to concomitant variations in N-cadherin and alpha 9-integrin. Treatment with anti-N-cadherin-blocking antibody rendered marked inhibition of cell adhesion and motility, while anti-alpha 9-integrin-blocking antibody exerted a remarkable effect on cell adhesion and invasiveness. CONCLUSION: Neuronal cadherin and alpha 9-integrin are postulated as leading actors in the association between the Notch pathway and promotion of cell adhesion, motility and invasion, pointing to these proteins and the Notch pathway itself as interesting putative targets for new molecular therapies against metastases in RMS. British Journal of Cancer (2012) 107, 1374-1383. doi:10.1038/bjc.2012.411 www.bjcancer.com Published online 13 September 2012 (C) 2012 Cancer Research UK