The high incidence of
lymphatic metastasis is closely related to poor prognosis and mortality in
cancers. Potent inhibitors to prevent pathological lymphangiogenesis and lymphatic spread are urgently needed. The VEGF-C-VEGFR3 pathway plays a vital role in driving lymphangiogenesis and
lymph node metastasis. In addition, COX2 in
tumor cells and tumor-associated macrophages (TAMs) facilitates lymphangiogenesis. We recently reported that
aiphanol, a natural stilbenolignan, attenuates
tumor angiogenesis by repressing VEGFR2 and COX2. In this study, we evaluated the antilymphangiogenic and antimetastatic potency of
aiphanol using in vitro, ex vivo and in vivo systems. We first demonstrated that
aiphanol directly bound to VEGFR3 and blocked its
kinase activity with an half-maximal inhibitory concentration (IC50) value of 0.29 μM in an in vitro
ADP-GloTM
kinase assay. Furthermore, we showed that
aiphanol (7.5-30 μM) dose-dependently counteracted
VEGF-C-induced proliferation, migration and tubular formation of lymphatic endothelial cells (LECs), which was further verified in vivo. VEGFR3 knockdown markedly mitigated the inhibitory potency of
aiphanol on lymphangiogenesis. In 4T1-luc
breast tumor-bearing mice,
oral administration of
aiphanol (5 and 30 mg· kg-1 ·d-1) dose-dependently decreased
lymphatic metastasis and prolonged survival time, which was associated with impaired lymphangiogenesis, angiogenesis and, interestingly, macrophage infiltration. In addition, we found that
aiphanol decreased the COX2-dependent secretion of
PGE2 and
VEGF-C from
tumor cells and macrophages. These results demonstrate that
aiphanol is an appealing agent for preventing lymphangiogenesis and lymphatic dissemination by synergistically targeting VEGFR3 and inhibiting the COX2-PGE2-VEGF-C signaling axis.