[TNF-α activates Wnt signaling pathway to promote the invasion of human colon cancer stem cells].

Objective To explore the effect of Wnt/β-catenin signal pathway on the invasion of human colon cancer stem cells in the inflammatory environment. Methods The CD44CD133 human colon cancer stem cells were sorted from HT29 human colon cancer cell line by fluorescence-activating cell sorting (FACS), and these stem cells were identified by flow cytometry and single cell cloning formation assay. The inflammatory cell model was established by tumor necrosis factor-α (TNF-α) treating CD44CD133 HT29 cells and the optimal dose and reaction time of TNF-α were confirmed by MTT assay. DKK1 as an inhibitor of the Wnt signaling pathway was used in the inflammatory cell model. The experiment cells were divided into control group, TNF-α treatment group and TNF-α combined with DKK1 group. The cell proliferation was determined by MTT assay, and the expression of Wnt signaling pathway-related proteins including β-catenin, cyclin D1, c-Myc and epithelial mesenchymal transition (EMT)-related proteins (E-cadherin, vimentin) were detected by Western blot analysis. The invasive ability of cancer stem cells was detected by Transwell assay. Results The CD44CD133 human colon cancer stem cells were successfully obtained from HT29 cells. Compared with the control group, the relative survival rate and invasive ability of CD44CD133 HT29 cells increased after treated with 10 ng/mL TNF-α for 48 hours, and the expression of E-cadherin was downregulated and vimentin was upregulated after CD44CD133 HT29 cells were treated with TNF-α. Compared with the TNF-α treatment group, the relative survival rate of CD44CD133 HT29 cells was reduced after DKK1 treatment. The number of transmembrane cells and the expression of Wnt signaling pathway-related proteins including β-catenin, cyclin D1 and c-Myc decreased after DKK1 treatment, and E-cadherin expression was upregulated and vimentin expression was reduced after CD44CD133 HT29 cells were treated with DKK1. Conclusion TNF-α promotes the invasion of colon cancer stem cells by activating the Wnt signaling pathway.