Effect of iridoid glycosides from Boschniakia rossica on epithelial-mesenchymal transition of HepG2 cells induced by transforming growth factor-beta 1
Objective To investigate the effect of iridoid glycosides from Boschniakia rossica(IGBR)on epithelial-mesenchymal transition(EMT)of HepG2 hepatoma cells induced by transforming growth factor-beta 1(TGF-β1).Methods HepG2 hepatoma cells were induced by 10 μg/L TGF-β1 to construct an EMT model of hepatoma cells.The cells were divided into control group(treated with serum-free DMEM),model group(treated with 10 μg/L TGF-β1),and IGBR group(treated with 10 μg/L TGF-β1 and 500 mg/L IGBR),and all cells were cultured for 48 hours.Cell adhesion assay,wound healing assay,and Transwell chamber assay were used to observe the migration and invasion abilities of cells.RT-PCR and Western blot were used to measure the mRNA and protein expression levels of E-cadherin,N-cadherin,and vimentin in cells,and Western blot was used to measure the protein expression levels of Slug,Twist1,ZEB1,p-STAT3,and STAT3.A one-way analysis of variance was used for comparison of continuous data between multiple groups,and the least significant difference t-test was used for further comparison between two groups;the independent-samples t test was used for comparison between two groups.Results After TGF-β1 induction,HepG2 cells in the model group showed long spindle-shape changes,while those in the control group showed polygonal epithelia-like changes.Compared with the model group,the IGBR group had a significant reduction in cell adhesion rate and significant inhibition of cell migration and invasion abilities(all P<0.05),as well as significant increases in the mRNA and protein expression levels of E-cadherin(P<0.05),significant reductions in the mRNA and protein expression levels of N-cadherin and vimentin(all P<0.05),and significant reductions in the protein expression levels of Slug,Twist1,ZEB1,and p-STAT3(all P<0.05).Conclusion IGBR can inhibit TGF-β1-induced EMT process in HepG2 cells,thereby attenuating cell adhesion,migration,and invasion abilities,and it can also upregulate E-cadherin,downregulate N-cadherin and vimentin,and upregulate the protein expression of Slug,Twist1,ZEB1,and STAT3,possibly by inhibiting the STAT3 pathway to downregulate the EMT transcription factors such as Slug,Twist1,and ZEB1.