Impairing flow-mediated endothelial remodeling reduces extravasation of tumor cells

Tumor progression and metastatic dissemination are driven by cell-intrinsic and biomechanical cues that favor the growth of life-threatening secondary tumors. We recently identified prometastatic vascular regions with blood flow profiles that are permissive for the arrest of circulating tumor cells. We have further established that such flow profiles also control endothelial remodeling, which favors extravasation of arrested CTCs. Yet, how shear forces control endothelial remodeling is unknown. In the present work, we aimed at dissecting the cellular and molecular mechanisms driving blood flow-dependent endothelial remodeling. Transcriptomic analysis revealed that blood flow modulated several signaling pathways in endothelial cells. More specifically, we observed that VEGFR signaling was significantly enhanced. Using a combination of in vitro microfluidics and intravital imaging in zebrafish embryos, we now demonstrate that the early flow-driven endothelial response can be prevented with sunitinib, a pan-inhibitor of VEGFR signaling. Embryos treated with sunitinib displayed reduced endothelial remodeling and subsequent metastatic extravasation. These results confirm the importance of endothelial remodeling as a driving force of CTC extravasation and metastatic dissemination. Furthermore, the present work suggests that therapies targeting endothelial remodeling might be a relevant clinical strategy in order to impede metastatic progression. Highlights - Flow profiles that are permissive for metastasis stimulate the VEGFR pathway - Flow-dependent VEGFR signaling favors extravasation of CTCs through endothelial remodeling - Inhibition of VEGFR signaling suppresses early flow-driven endothelial response