Laminin Interactions with Head and Neck Cancer Cells under Low Fluid Shear Conditions Lead to Integrin Activation and Binding

Lymphatic metastasis of cancer cells involves movement from the primary tumor site to the lymph node, where the cells must be able to productively lodge and grow. It is there that tumor cells encounter cellular and non-cellular constituent elements that make up the lymph node parenchyma. Our work shows that head and neck squamous cell carcinoma (HNSCC) cell lines are able to bind to laminin, fibronectin, vitronectin, and hyaluronic acid, which are extracellular matrix elements within the lymph node parenchyma. HNSCC cell lines bound to laminin under lymphodynamic low shear stress (0.07 dynes/cm2), consistent with lymph flow via β1 integrins, including α2β1, α3β1, and α6β1. Binding occurred in the presence of shear stress and not in the absence of flow. Additionally, tumor cell binding to laminin under flow did result in calcium signaling. Our data indicate a novel role for β1 integrin-mediated binding of HNSCC cells to laminin under conditions of lymphodynamic flow that results in intracellular calcium signaling within the cancer cell.