[Effects of inhibition of Hedgehog signaling pathway for transforming growth factor-ß-induced epithelial-mesenchymal transition].

OBJECTIVE: To elucidate the mechanism of Hedgehog pathway in the metastasis of gastric cancer and examine particularly the effect on epithelial-mesenchymal transition (EMT). METHODS: Using pharmacological and siRNA knockdown approach, the Hedgehog pathway was inhibited. The cellular morphology, protein level, invasion and metastatic abilities were measured by microscope, Western blot, Transwell invasion assay and Transwell migration assay. RESULTS: Under the inhibition of Hedgehog pathway, the invasive and migration abilities of gastric cancer decreased. The transforming growth factor (TGF) -ß could induce spindle-like-shaped morphological changes with a down-regulation of epithelial characteristic (decreased E-cadherin protein level) and an up-regulation of mesenchymal characteristics (increased Vimentin protein level). There were concurrent increases of invasive and migration potentials by 3 and 4 folds respectively.However, under the continuous stimulation of TGF-ß, the inhibition of Hedgehog pathway could reverse the EMT changes, lower the expression of vimentin and reduce the invasion and metastatic abilities by 3 and 2 folds respectively. CONCLUSIONS: The inhibition of Hedgehog pathway can decrease the TGF-ß-inducing EMT.It suggests that Hedgehog pathway may play a critical role in the metastasis of gastric cancer.