Objective To investigate the effect and mechanism of RNAi-mediated STAT3 gene silencing on epithelial-to-mesenchymal transition (EMT) of human pancreatic cancer cells.Methods Lentivirus vector mediating RNA interference targeting STAT3 was constructed in SW1990 cell line.The invasion ability of SW1990 cells was determined by cell invasion assay in vitro.Cell proliferation and cell cycle of SW1990 cells were also detected.The expression of EMT related genes such as STAT3,P-STAT3,Twist,Snail and E-cadherin were analyzed by reverse transcription-PCR,real-time PCR,and Western blotting.Results Silencing of STAT3 with RNAi not only markedly reduced proliferation but also greatly decreased the invasion ability of SW1990 cells.The mRNA level and protein expression of Snail decreased significantly (P ＜ 0.05),but those of E-cadherin increased significantly (P ＜ 0.05),compared to parental cells.However,no difference was on the expression of Twist in SW1990 cell line.Conclusions STAT3 signaling pathway plays an important role in the process of EMT.Silencing of STAT3 with RNAi can significantly inhibit EMT by downregulating expression of Snail and E-cadherin in pancreatic cancer cells.

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