Regulatory mechanisms of Hedgehog signaling pathway for epithelial-mesenchymal transition in pancreatic cancer cells

Abstract

To explore the blocking effects of hedgehog signaling pathway on the processes of cell migration, invasion and epithelial-mesenchymal transition (EMT) in human pancreatic cancer cells and elucidate its possible mechanisms. The lentiviral expression vector for RNA interference of human Smoothened (SMO) gene was constructed to silence the expression of SMO. And RNAi against SMO was used to suppress the hedgehog signaling pathway in human pancreatic cancer Panc-1 cells. The in vitro invasion capacity in Panc-1 cells was assessed by Matrigel/Transwell chamber assay. Real-time PCR (polymerase chain reaction) and Western blot were used to detect the expressions of such EMT markers as E-cadherin, N-cadherin, β-catenin, vimentin and fibronectin and such transcription factors as Snail, Slug, Twist1 and Sip1. The stable interference of SMO could suppress the hedgehog signaling activity in Panc-1 cells. The inhibition of hedgehog signaling reduced the in vitro invasion capacity significantly in Panc-1 cells. The expression of E-cadherin significantly increased while N-cadherin, vimentin and fibronectin were significantly down-regulated in the RNAi group. Compared to the control group, the expressions of Snail and Slug were significantly reduced in the SMO knock-down group. The inhibition of hedgehog signaling pathway reduces the in vitro invasion capacity in human pancreatic cancer cells. And the EMT process is significantly suppressed. The mechanism is partially correlated with the down-regulations of Snail and Slug.