VEGFD/VEGFR2 axis induces the dedifferentiation of high endothelial venules and impairs lymphocyte homing
High endothelial venules (HEVs) are important structures in lymph nodes (LNs) that mediate lymphocyte homing, and their dedifferentiation is a necessary step before LN metastasis. Whether vascular endothelial growth factor (VEGF)-related signaling, which plays an important role in LN metastasis, is involved in the dedifferentiation of HEVs remains unclear. Here, we confirmed increased expression of VEGFA, VEGFC, and VEGFD; HEV dedifferentiation; and impaired lymphocyte homing function in tumor-draining lymph nodes (TDLNs). Furthermore, we demonstrated that tumor-secreted VEGFA induced lymphangiogenesis in TDLNs to promote premetastatic niche (PMN) formation; VEGFC promoted HEV proliferation but did not affect its lymphocyte homing function. Notably, we showed that VEGFD induced the dedifferentiation of HEVs by binding to VEGFR2 on the endothelial surface of HEVs and further impaired the lymphocyte homing function of TDLNs. Overall, we revealed that tumor-secreted VEGFD interacted with VEGFR2, induced HEV dedifferentiation, and reduced lymphocyte homing, providing potential insights for the prevention and treatment of LN metastasis.