Fig. 5

Overexpression of circPTK2 enhances TIF1γ expression and inhibits TGF-β-induced EMT and invasion of NSCLC cells in vitro. a TIF1γ mRNA and protein levels in A549 and H226 cells transiently overexpressing circPTK2. Relative TIF1γ expression was determined with normalization against β-actin. b After being serum-starved for 24 h, A549 and H226 cells transiently overexpressing circPTK2 were treated with or without TGF-β1 (5 ng/ml) for 1 h and 0.5 h, respectively. Snail mRNA expression was quantified by qRT-PCR analysis. Snail mRNA level of the unstimulated cells was assigned the value 1, and the relative Snail mRNA expression in TGF-β1-stimulated cells was recalculated accordingly. c A549 and H226 cells transiently overexpressing circPTK2 were serum-starved for 24 h and then treated with or without TGF-β1 (5 ng/ml) for 24 h and 48 h, respectively. Snail and N-cadherin protein levels were determined by western blot. β-actin was used as internal control. d, e A549 and H226 cells transiently overexpressing circPTK2 were treated as above and subjected to the transwell migration and invasion assays. Migrated and invasive cells were stained and counted in at least three light microscopic fields. Scale bar, 100 μm. *P < 0.05; **P < 0.01; ***P < 0.001