OBJECTIVE: To investigate the effect of Tatarinan O（TO）

a lignans monomeric compound in Acorus calamus

on transforming growth factor-β1（TGF-β1）-induced epithelial mesenchymal transition（EMT） and its migration of non-small cell lung cancer A459 cells. METHODS: The onset of EMT in A549 cells was induced by TGF-β1. The expression of E-cadherin

Vimentin

SMAD2 protein and phosphorylated SMAD2（p-SMAD2） protein

and the nuclear translocation behavior of SMAD2 were detected by using Western blotting and immunofluorescence assay; the cell migration ability was detected by scratch assay. RESULTS: TO was able to inhibit TGF-β1-induced phosphorylation of SMAD2 on A549 cells

which presented a dose-dependent（P<0.05） and prevented its nuclear translocation. The Vimentin expression was significantly reduced and the E-cadherin expression was significantly increased under the action of TO at 25 and 50 μmol/L

with statistically significant differences（P<0.05） compared with TO at 0 μmol/L

which further inhibited the migratory behavior of A549 cells. CONCLUSIONS: TO can inhibit TGF-β1-induced EMT in non-small cell lung cancer A549 cells through SMAD2 signaling pathway

and reduce its migratory ability.