Effects of inflammatory microenvironment on the epithelial to mesenchymal transition of colon cancer cells

Objective To explore the effects of tumor necrosis factor α (TNF-α) and transforming growth factor β1 (TGF-β1) in the inflammatory microenvironment on the epithelial to mesenchymal transition (EMT) of colon cancer cells.Methods SW480,HCT116 and SW480 interfered with transforming growth factor beta receptor 2 (TGFBR2) cells were treated with TGF-β1 (10 μg/L),TNF-α (20 μg/L),or a combination of both.Untreated SW480 and HCT116 cells were set as blank controls.The morphologic changes of cells of each group were observed at 24,48 and 72 hour.The expressions of E-cadherin,N-cadherin and vimentin of each group were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot.The cell migration ability of cells interfered with TGFBR2 was tested by cell migration assay.The data were analyzed by one way analysis of variance.Results There were no obvious morphologic changes in SW480 cells,HCT116 cells and SW480 interfered with TGFBR2 at different time point.Among the three groups of cells treated with TNF-α and TGF-β1 combination,the morphologic changes to fibroblast were observed in the SW480 cells and SW480 interfered with TGFBR2.Compared with the group of SW480 cells treated with TNF-α and TGF-、β、and the group of SW480 blank controls,the expression of E cadherin at mRNA level of the group of SW480interfered with TGFBR2 significantly decreased (0.58 ± 0.23 vs 0.80 ± 0.12 vs 0.23 ± 0.03) and the expression of N-cadherin at mRNA level remarkably increased (1.10± 0.10 vs 0.60 ± 0.11 vs 1.34 ±0.20),the differences were statistically significant (F =46.92,47.93,bofh P ＜0.05).There was no statistically significant differences in the expression of vimintin (P＞0.05).Compared with HCT116 blank control group,the expression of E-cadherin at mRNA level of HCT116 treated with TNF-α and TGF-β1combination significantly decreased (0.92 ± 0.14 vs 0.22 ± 0.03),the expression of N-eadherin (0.46 ±0.02 vs 1.40±0.05) and vimintin(0.78±0.11 vs 1.60±0.12)at mRNA level obviously increased,and the differences were statistically significant (F=72.59,23.67,45.19,all P＜0.05).The expressions of E-cadherin,N-cadherin and vimintin at protein level were consistent with those at mRNA level.Cell migration assay showed the A570 of the group of SW480 interfered with TGFBR2 was 102.7 ±8.5,and that of the SW480 cells treated with TNF-α and TGF-、β1 combination and SW480 cells blank control group were 20.1 ± 7.6 and 18.3 ± 11.2,respectively,and the difference was statistically significant (F=108.92,P＜0.05).The ability of cell migration was significantly enhanced after treated with TNF-α and TGF-β1 combination in those colon cancer cells with TGFBR2 mutant.Conclusion The rich of TNF-α and TGF-β1 in the inflammation microenvironment may facilitate the early metastasis of colon cancer cells,especially the cells with TGFBR2 mutant. Key words: Colonic neoplasms;  Epithelial to mesenchymal transition;  Transforming growth factor beta1 ;  Tumor necrosis factor-alpha