TNF-α promotes tumor lymph angiogenesis in head and neck squamous cell carcinoma through regulation of ERK3

BACKGROUND: Squamous cell carcinoma of the head and neck (HNSCC) is the sixth most common cancer worldwide. The poor prognosis of HNSCC patients is largely due to its early lymph node metastasis. Tumor necrosis factor (TNF)-α has been reported to be involved in lymph angiogenesis in several cancers whereas its relationship with HNSCC was still largely unknown. METHODS: In this work, mice xenograft model was constructed and treated with extra TNF-α, Hep-2 conditioned medium was constructed for human lymphatic endothelial cells (hLECs) culture. qRT-PCR, Western blot analysis and immunohistochemical (IHC) staining were utilized to detect the expression levels of lymph angiogenesis markers as well as ERK3 and its downstream. CCK8 assay was performed to evaluate cell proliferation. Wound healing assay was used for measuring cell migration. Tube formation assay was used to estimate the tube formation ability of hLECs. RESULTS: The results indicated that TNF-α could up-regulated the expression levels of VEGF-C, VEGFR-3 and LYVE-1 in cell or animal level, change the cell morphology, accelerate cell proliferation, enhance cell migration and tube formation ability of hLECs. Moreover, ERK3 was up-regulated by TNF-α in both cell and animal levels and the over-expression of ERK3 in hLECs could also up-regulate VEGF-C and promote cell proliferation. CONCLUSIONS: In conclusion, this study indicated the promotion effect of TNF-α on tumor lymph angiogenesis in HNSCC and demonstrated that ERK3 may be involved in the underlying molecular mechanism. This work provides new diagnostic and therapeutic targets, which are of great significance to improve the prognosis of HNSCC patients.