Type I collagen promotes epithelial-mesenchymal transition through ILK-dependent activation of NF-kappaB and LEF-1.

Collagen I has been shown to promote epithelial-mesenchymal transition (EMT), a critical process of embryonic development and disease progression. However, little is known about the signaling mechanisms by which collagen I induces this cellular transformation. Here we show that collagen I causes ILK-dependent phosphorylation of IkappaB and subsequent nuclear translocation of active NF-kappaB, which in turn promotes increased expression of the Snail and LEF-1 transcription factors. ILK also causes inhibitory phosphorylation of GSK-3beta, a kinase that prevents functional activation of both Snail and LEF-1. These transcription factors alter expression of epithelial and mesenchymal markers to initiate EMT and stimulate cell migration. These data provide a foundation for understanding the mechanisms by which collagen I stimulates EMT and identify potential therapeutic targets for suppressing this transition in pathological conditions.