Background
Lymphatic metastasis is a common phenomenon of cervical cancer. Tumor necrosis factor-α (TNF-α) was found to be closely associated with lymphatic cancer metastasis. However, the mechanism through which TNF-α regulates lymphatic metastasis in cervical cancer remains unclear.
Conclusion
Collectively, TNF-α could promote tumorigenesis, lymphangiogenesis, and lymphatic metastasis in vitro and in vivo in cervical cancer via activating VEGFC-mediated AKT and ERK pathways. These results may provide new directions for the treatment of cervical cancer.
Methods
In this study, cervical cancer cells were cultured in Dulbecco's modified Eagle's medium (DMEM) with or without TNF-α for 48 h, and then the corresponding conditional medium (CM-TNF-α or CM) was collected. The level of vascular endothelial growth factor (VEGFC) in the corresponding CM was then detected using an enzyme-linked immunosorbent assay (ELISA). Next, human lymphatic endothelial cells (HLECs) were cultured in CM-TNF-α or CM for 48 h. Cell viability was measured using the cell counting kit-8 (CCK-8) assay, and angiogenesis was detected using a tube formation assay. Subsequently, the expressions of AKT, p-AKT, ERK, and p-ERK in HLECs were detected using western blotting. In addition, to further investigate the effect of TNF-α on the progression of cervical cancer, a C33A subcutaneous xenograft model was established in vivo.
Results
We found that TNF-α significantly stimulated cervical cancer cells to secrete VEGFC. Additionally, the CM collected from the TNF-α-treated cervical cancer cells notably promoted the proliferation, migration, and angiogenesis of HLECs; however, these changes were reversed by MAZ51, a VEGFR3 inhibitor. Moreover, TNF-α obviously elevated D2-40 and VEGFC protein expressions in tumor tissues, promoting lymphangiogenesis and lymphatic metastasis in vivo. Meanwhile, TNF-α markedly upregulated p-AKT and p-ERK expressions in tumor tissues, whereas these changes were reversed by MAZ51.