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Objective:Squamous cell carcinoma of head and neck (SCCHN) is the sixth most common cancer in the world, and its five-year survival rate for patients are not improving, mainly due to the early occurrence of cancer metastasis. Epithelial-mesenchymal transition (EMT) is considered to be closely ralated to metastasis of SCCHN, and TGF-βpathway plays an important role in this process. EGCG, a major component of polyphenols in green tea, its antitumor activity involves many aspects, including the inhibition of tumor growth, progression, migration, invasion, and metas-tasis, etc. Results show that, EGCG can reverse the occurrence of EMT in tumor cells, and regulate TGF-βmediated pathway through controlling with Smad7. Currently, there are few reports about the impaction on how EGCG regulates EMT in SCCHN. Therefore, our study will illustrate that EGCG can inhibit the occurrence of EMT in SCCHN, and explore the changes of Smad7 in this process.Methods:(1) In order to develop EMT model, Tu686 cells were treated with 5ng/ml TGF-β1;(2) Following EGCG (0、10、20、30μM) treament in Tu686 cells, mRNA and protien level of E-cadherin and Vimentin, respectively epithelial cell marker and mesenchymal cell marker, were detected by RT-PCR and Western-blot. Simultaneously, expression of Smad7, one member of TGF-βmediated pathway, was detected in the same way. (3) Cells were treated with 20μM EGCG before collected at different time points (6、12、24h), then detect E-cadherin and Vimentin expression. (4)Tu686 cells was treated by 5ng/ml TGF-β1 for 24h before 20μM EGCG was added, morphology and cell changes was observed after 24h.Results:(1) After treatment with TGF-β1, expression of E-cadherin was decreased, while increased expression of Vimentin was observed, corresponding changes in cell morphogenesis, TGF-β1-mediated EMT model in Tu686 cells was successfully constructed; (2) In this model, EGCG can inhibit the occurrence of EMT, and increase the expression of E-cadherin and decrease expression of Vimentin;(3) EGCG can increase Smad7 mRNA and protein levels in EMT model.Conclusions:(1) EGCG can inhibit TGF-β1-mediated EMT inTu686 cell lines of SCCHN; (2) Smad7 plays an important role in TGF-β1-mediated EMT in Tu686 cell lines of SCCHN.
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