A mediator of phosphorylated Smad2/3, evodiamine, in the reversion of TAF-induced EMT in normal colonic epithelial cells.

Purpose Transdifferentiation exists within stromal cells in the tumour microenvironment. Transforming growth factor-β (TGF-β) secreted by tumour-associated fibroblasts (TAFs) affects the differentiation states of epithelial cells, including epithelial-mesenchymal transition (EMT). Evodiamine, a natural drug, can regulate differentiation. However, the specific effects and relative mechanisms of evodiamine remain unknown. Design We used four models to observe the influence of TAF-like CCD-18Co cells on the colon epithelial cell line HCoEpiC: the 3D- and 2D-mono-culture system, Transwell and direct co-culture model. Additionally, we established conditioned medium from CCD-18Co cells. The TGF-β pathway inhibitor LY364947 and evodiamine were added. Morphological changes and classical EMT markers were observed and detected using phase contrast microscopy and immunofluorescence. Cell migration was measured by the wound-healing assay. Western blotting was performed to detect the TGF-β/Smad signalling pathway. Results CCD-18Co cells induced EMT-like changes in the 2D- and 3D-cultured epithelial cell line HCoEpiC, accompanied by high expression of ZEB1 and Snail and the enhancement of migration. Moreover, CCD-18Co-derived conditioned medium caused dysfunction of TGF-β/Smad signalling in EMT. Evodiamine inhibited these EMT-like HCoEpiC and their migration. Additionally, evodiamine down-regulated the expression of ZEB1/Snail and up-regulated the expression of phosphorylated Smad2/3 (pSmad2/3). Evodiamine also increased the ratios of pSmad2/Smad2 and pSmad3/Smad3. Conclusion Based on our observations, evodiamine can reverse the TAF-induced EMT-like phenotype in colon epithelial cells, which may be associated with its mediation of phosphorylated Smad2 and Smad3 expression.