SDF-1/CXCR4 signaling induces pancreatic cancer cell invasion and epithelial–mesenchymal transition in vitro through non-canonical activation of Hedgehog pathway

In our previous study, we found that blockade of SDF-1/CXCR4 signaling inhibits pancreatic cancer cell migration and invasion in vitro. However, the mechanism governing the downstream regulation of SDF-1/CXCR4-mediated invasion remains unclear. Here we report the role of SDF-1/CXCR4 in pancreatic cancer and the possible mechanism of SDF-1/CXCR4-mediated pancreatic cancer invasion. We show that there is a cross-talk between SDF-1/CXCR4 axis and non-canonical Hedgehog (Hh) pathway in pancreatic cancer. Furthermore, our data demonstrate that the ligand of CXCR4, SDF-1 induces CXCR4-positive pancreatic cancer invasion, epithelial–mesenchymal transition (EMT) process and activates the non-canonical Hh pathway. Moreover, we also demonstrate that the invasion of a pancreatic cancer and EMT resulting from the activation of SDF-1/CXCR4 axis is effectively inhibited by Smoothened (SMO) inhibitor cyclopamine and siRNA specific to Gli-1. Collectively, these data demonstrate that SDF-1/CXCR4 modulates the non-canonical Hh pathway by increasing the transcription of SMO in a ligand-independent manner. Taken together, SDF-1/CXCR4 axis may represent a promising therapeutic target to prevent pancreatic cancer progression.