Receptor Activator Of Nf-Kappa B Ligand Induces Cell Adhesion And Integrin Alpha 2 Expression Via Nf-Kappa B In Head And Neck Cancers

Cellular interactions with the extracellular matrix play critical roles in tumor progression. We previously reported that receptor activator of NF-kappa B ligand (RANKL) specifically facilitates head and neck squamous cell carcinoma (HNSCC) progression in vivo. Here, we report a novel role for RANKL in the regulation of cell adhesion. Among the major type I collagen receptors, integrin alpha 2 was significantly upregulated in RANKL-expressing cells, and its knockdown suppressed cell adhesion. The mRNA abundance of integrin alpha 2 positively correlated with that of RANKL in human HNSCC tissues. We also revealed that RANK-NF-kappa B signaling mediated integrin alpha 2 expression in an autocrine/paracrine manner. Interestingly, the amount of active integrin beta 1 on the cell surface was increased in RANKL-expressing cells through the upregulation of integrin alpha 2 and endocytosis. Moreover, the RANK-integrin alpha 2 pathway contributed to RANKL-dependent enhanced survival in a collagen gel and inhibited apoptosis in a xenograft model, demonstrating an important role for RANKL-mediated cell adhesion in three-dimensional environments.