Epstein-Barr Virus Induces Lymphangiogenesis and Lympth Node Metastasis via Upregulation of VEGF-C in Nasopharyngeal Carcinoma

Lymphatic metastasis is a common clinical symptom in nasopharyngeal carcinoma (NPC), the most common EBV-associated head and neck malignancy. However, the effect of EBV on NPC LN metastasis is still unclear. In this study, we demonstrated that EBV infection is strongly associated with advanced clinical N stage and lymphangiogenesis of NPC. We found that NPC cells infected with EBV promote LN metastasis by inducing cancer-associated lymphangiogenesis, whereas these changes were abolished upon clearance of EBV genomes. Mechanistically, EBV-induced VEGF-C contributed to lymphangiogenesis and LN metastasis, and PHLPP1, a target of miR-BART15, partially contributed to AKT/HIF-1a hyperactivity and subsequent VEGF-C transcriptional activation. Additionally, administration of anti-VEGF-C antibody or HIF-1α inhibitors attenuated the lymphangiogenesis and LN metastasis induced by EBV. Finally, we verified the clinical significance of this prometastatic EBV/VEGF-C axis by determining the expression of PHLPP1, AKT, HIF-1a and VEGF-C in NPC specimens with and without EBV. These results uncover a reasonable mechanism for the EBV-modulated LN metastasis microenvironment in NPC, indicating that EBV is a potential therapeutic target for NPC with lymphatic metastasis.