Background: Earlier results from our group have shown that in pancreatic ductal adenocarcinoma
(PDAC)-derived cells transforming growth factor (TGF)-β1-dependent epithelial-mesenchymal transition (EMT)
and cell motility was inhibited by the Src inhibitors PP2 and PP1 both of which targeted the TGF-β receptors for
Objective: In this study we evaluated the impact of another Src inhibitor, AZM475271, on various TGF-β
responses in PDAC cells.
Method: The effect of AZM475271 on TGF-β1-induced random cell migration (chemokinesis), the expression of
EMT and migration/invasion-associated genes, TGF-β-induced luciferase activity, and C-terminal phosphorylation of
Smad2 and Smad3 was measured in the PDAC-derived Panc-1 and Colo357 cell lines using real-time cell migration
assays, quantitative real-time PCR, luciferase reporter gene assays and phosphoimmunoblotting, respectively.
Results: AZM475271 effectively blocked TGF-β1-induced chemokinesis of Panc-1 cells in a dose-dependent
fashion and inhibited the high chemokinetic activity of Panc-1 cells with ectopic expression of a constitutively
active ALK5T204D mutant. AZM475271 but not another Src inhibitor, SU6656, partially relieved the suppressive
effect of TGF-β1 on E-cadherin and inhibited TGF-β1-induced upregulation of the MMP2, MMP9, N-cadherin
and vimentin genes, activity of a TGF-β1-dependent reporter gene, and activation of Smad2 and Smad3.
Conclusion: Our data suggest that AZM475271 cross-inhibits tumor-promoting TGF-β signaling and may thus
function as an inhibitor of both TGF-β and Src in both experimental and clinical therapies against metastatic
dissemination in late-stage PDAC.