Fyn mediates transforming growth factor-beta1-induced down-regulation of E-cadherin in human A549 lung cancer cells

Transforming growth factor-beta (TGF-β) signaling positively contributes to the regulation of tumor metastasis. However, the underlying molecular mechanisms are less well defined. We here show that Fyn, a member of Src family tyrosine kinases, plays a critical role in mediating TGF-β1-induced down-regulation of E-cadherin in human A549 lung cancer cells. Blockade of Fyn with siRNA knockdown or ligand-binding defective mutant significantly lowered the ability of TGF-β1 to repress E-cadherin expression. Furthermore, our results demonstrated that Fyn facilitates TGF-β1-mediated suppression of E-cadherin through p38 kinase-dependent induction of Snail. Collectively, our findings identify a Fyn-p38-Snail cascade as a new signaling pathway mediating oncogenic TGF-β function.

► Fyn is involved in the down-regulation of E-cadherin by TGF-β1.
► p38 Kinase is required for TGF-β1-induced suppression of E-cadherin.
► Snail is involved in the repression of TGF-β1-mediated E-cadherin expression as a downstream target of Fyn-p38-linked signaling.