Ras induces NBT-II epithelial cell scattering through the coordinate activities of Rac and MAPK pathways.

摘要: Cell dissociation and cell migration are the two main components of epithelium-mesenchyme transitions (EMT). We previously demonstrated that Ras is required for accomplishment both these processes during EGF-induced EMT NBT-II rat carcinoma line in vitro. In this study, we examined downstream targets responsible motility cells. Overexpression activated forms c-Raf MEK1 (a component mitogen-activated protein kinase pathway, MAPK) led to dissociation, as inferred by loss desmosomes from periphery. By contrast, active PI3K, RalA RalB did not induce desmosome breakdown. The inhibitor PD098059 inhibited EGF- Ras-induced dispersion, whereas PI3K LY294002 had no effect. Accordingly, among partial loss-of-function mutants (RasV12) were used distinguish between Ras, found Raf-specific RasV12S35 RasV12E38 induced dissociation. PI3K- RalGDS-activating had, effect on dispersion. However, was unable promote motility, migration, suggesting another effector motility. small GTPase Rac necessary EGF-mediated dispersion since overexpression a dominant-negative mutant Rac1 (Rac1N17) migration. All stimuli promoted also activation. Finally, coexpression cells, mediates scattering through coordinate activation Raf/MAPK pathway.