OBJECTIVETo detect the expression of epithelial-to-mesenchymal transition (EMT) biomarkers in nasal polyposis (NP) and to determine the effect of transforming growth factor β1 (TGF-β1) on EMT in cultured nasal epithelial cells.

METHODSThe specimens were obtained from sinus mucosa of 10 NP patients and inferior turbinate mucosa of 10 nasal septum deviation patients. The difference of mRNA expression of E-cadherin, β-catenin , zonula occludens 1 (ZO-1), vimentin and α-smooth muscle actin (α-SMA) in tissue and cultured nasal epithelial cells was detected by real-time PCR. The difference of protein exprssion of E-cadherin and vimentin in cultured nasal epithelial cells was detected by Western blot.SPSS 16.0 software was used to analyze the data.

RESULTSThe relative expression of E-cadherin and ZO-1 in NP tissues (0.012±0.007; 0.006±0.003) was higher than in normal nasal mucosa (0.041±0.024; 0.011±0.005), the difference was significant (t=3.675, P<0.01; t=2.956, P<0.05). However, there was no significant difference in the relative expression of β-catenin, vimentin and α-SMA between two groups (t value was 0.990, 0.429, 0.326, all P>0.05). In cultured nasal epithelial cells both from two groups, TGF-β1 induced the decreased E-cadherin, ZO-1 (tcontrol value was 3.639, 3.430, both P<0.05; tNP value was 3.279, 2.864, both P<0.05) and increased α-SMA, vimentin mRNA expression (tcontrol value was -6.393, -3.085, all P<0.05; tNP value was -2.981, -3.087, both P<0.05). Also, TGF-β1 induced the decreased E-cadherin and increased vimentin protein expression (tcontrol value was 3.583, -3.844, both P<0.05; tNP value was 5.113, -3.642, both P<0.05).

CONCLUSIONEMT is likely to contribute to nasal polyposis and TGF-β1 is involved in this process.