Intravascular arrest of circulating tumor cells is a two-step process exploiting their adhesion repertoire.

Abstract

Cancer metastasis is a process whereby a primary tumor spreads to distant organs. We have previously demonstrated that blood flow controls the intravascular arrest of circulating tumor cells (CTCs), through stable adhesion to endothelial cells. We now aim at defining the contribution of cell adhesive potential and at identifying adhesion receptors at play. Early arrest is mediated by the formation of weak adhesion depending on CD44 and integrin v{beta}3. Stabilization of this arrest uses integrin 5{beta}1-dependent adhesions with higher adhesion strength, which allows CTCs to stop in vascular regions with lower shear forces. Moreover, blood flow favors luminal deposition of fibronectin on endothelial cells, an integrin 5{beta}1 ligand. Finally, we show that only receptors involved in stable adhesion are required for subsequent extravasation and metastasis. In conclusion, we identified the molecular partners that are sequentially exploited by CTCs to arrest and extravasate in vascular regions with permissive flow regimes.