Epidermal growth factor and tumor necrosis factor alpha cooperatively promote the motility of hepatocellular carcinoma cell lines via synergistic induction of fibronectin by NF-kappaB/p65

摘要

Background: The interaction between hepatocellular carcinoma (HCC) cells and their microenvironment plays a fundamental role in tumor metastasis. The HCC microenvironment is rich in epidermal growth factor (EGF) and tumor necrosis factor alpha (TNFalpha), which may cooperatively, rather than individually, interact with tumor cells to influence their biological behavior. Methods: Immunohistochemistry was performed to study the expression of EGF and TNFalpha in HCCs. Western blotting, immunofluorescence, qRT-PCR, wound healing scratch and invasion assay, and chromatin immunoprecipitation assays were used to study the combined roles of EGF and TNFalpha in the motility of HCC cells in vitro. Results: We demonstrated that both EGF and TNFalpha were highly expressed in HCCs, and HCCs with higher expression of both EGF and TNFalpha were more frequently rated as high-grade tumors. In vitro, EGF and TNFalpha cooperatively promoted the motility of HCC cells mainly via synergistic induction of an extracellular matrix glycoprotein fibronectin (FN). Mechanistically, EGF and TNFalpha jointly increased the nuclear translocation and PKC mediated phosphorylation of NF-kappaB/p65 which could bind to the ?356 bp to ?259 bp fragment of the FN promoter, leading to a markedly increased activity of the FN promoter in HCC cells. Conclusions: HCCs with higher expression of both EGF and TNFalpha were more frequently rated as high-grade tumors. EGF and TNFalpha cooperatively promoted the motility of HCC cells mainly through NF-kappaB/p65 mediated synergistic induction of FN in vitro. General Significance: These findings highlight the crosstalk between EGF and TNFalpha in promoting HCC, and provide potential targets for HCC prevention and treatment.