title: Rac1 modulates TGF-beta1-mediated epithelial cell plasticity and MMP9 production in transformed keratinocytes.
abstract: Transforming growth factor-beta1 (TGF-beta1) activates Rac1 GTPase in mouse transformed keratinocytes. Expression of a constitutively active Q61LRac1 mutant induced an epithelial to mesenchymal transition (EMT) linked to stimulation of cell migration and invasion. On the contrary, expression of a dominant-negative N17TRac1 abolished TGF-beta1-induced cell scattering, migration and invasion. Moreover, Q61LRac1 enhanced metalloproteinase-9 (MMP9) production to levels comparable to those induced by TGF-beta1, while N17TRac1 was inhibitory. TGF-beta1-mediated EMT involves the expression of the E-cadherin repressor Snail1, regulated by the Rac1 and mitogen-activated protein kinase (MAPK) pathways. Furthermore, MMP9 production was MAPK-dependent, as the MEK inhibitor PD98059 decreased TGF-beta1-induced MMP9 expression and secretion in Q61LRac1 expressing cells. We propose that regulation of TGF-beta1-mediated plasticity of transformed keratinocytes requires the cooperation between the Rac1 and MAPK signalling pathways.
authors.affiliation: Laboratorio de Biología Celular, Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile, Santiago, Chile. jfsantibanez@imi.bg.ac.rs
authors.forename: Juan F
authors.initials: JF
authors.lastname: Santibáñez
authors.forename: Jelena
authors.initials: J
authors.lastname: Kocić
authors.forename: Angels
authors.initials: A
authors.lastname: Fabra
authors.forename: Amparo
authors.initials: A
authors.lastname: Cano
authors.forename: Miguel
authors.initials: M
authors.lastname: Quintanilla
mesh_terms: D000818:Animals; D015820:Cadherins / Q000378:metabolism; D054337:Cell Dedifferentiation; D002465:Cell Movement; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000378:metabolism*; D005419:Flavonoids / Q000494:pharmacology; D015603:Keratinocytes / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D015398:Signal Transduction; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*
chemical_list: D015820:Cadherins; D004791:Enzyme Inhibitors; D005419:Flavonoids; D053773:Transforming Growth Factor beta1; D020928:Mitogen-Activated Protein Kinases; D020780:Matrix Metalloproteinase 9; C501830:Mmp9 protein, mouse; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one