C-kit induces epithelial-mesenchymal transition and contributes to salivary adenoid cystic cancer progression.

Epithelial-mesenchymal transition (EMT) is associated with salivary adenoid cystic cancer (ACC) progression and metastasis. Here, we report that ectopic overexpression of c-kit in ACC cell lines is sufficient for acquisition of mesenchymal traits, enhanced cell invasion, along with stem cell properties defined by the presence of a CD133(+)/CD44(+) cell subpopulation. c-kit positively regulated expression of known EMT inducers, also activating TGF-beta to contribute to EMT. c-kit itself was induced by TGF-beta in ACC cell lines and required for TGF-beta-induced EMT. Xenograft experiments showed that c-kit cooperated with oncogenic Ras to promote tumorigenesis in vivo. Finally, in human specimens of ACC, we found that c-kit was abnormally overexpressed and correlated with the prognosis of ACC. Our findings define an important function for c-kit in ACC progression by orchestrating EMT, and they implicate this gene product as a marker of poor prognosis in this disease.