Background: Upregulation of matrix metalloproteinase-9 (MMP-9) induced by tumour necrosis factor-α (TNF-α) is reportedly involved in a variety of non-neoplastic and neoplastic diseases. In this study, we examined which signalling pathways are involved in TNF-α-induced MMP-9 upregulation in cholangiocarcinoma (CC).
Methods: We used two CC cell lines: HuCCT-1 and CCKS-1.
Results: In an ex vivo study using HuCCT-1 and CCKS-1 cells, TNF-α treatment induced MMP-9 production and activation via interaction with TNF receptor-1 (TNF-R1) but not with TNF receptor-2 (TNF-R2), shown by zymography, and increased MMP-9 promoter activity (luciferase assay). As for the signalling pathway, TNF-α stimulation led to the phosphorylation of extracellular signal-regulated kinase 1/2 (Erk1/2) and p38 mitogen-activated protein kinase (p38MAPK) and translocation of nuclear factor κB (NF-κB) (p65) into the nuclei. Inhibition studies using SB203580 (inhibitor of p38MAPK), U0126 (inhibitor of mitogen-activated or extracellular signal-regulated protein kinase 1/2) and MG132 (inhibitor of NF-κB) showed that the phosphorylation of Erk1/2 and p38MAPK with activation of NF-κB was closely related to MMP-9 upregulation in both cell lines.
Conclusion: These data suggest that TNF-α/TNF-R1 interaction leads to the phosphorylation of Erk1/2 and p38MAPK and nuclear translocation of NF-κB, which is closely associated with the production and activation of MMP-9 in cultured CC cells of HuCTT-1 and CCKS-1. Upregulation of MMP-9 with NF-κB activation may be involved in the tumour invasion of CC.