EGF-receptor-mediated mammary epithelial cell migration is driven by sustained ERK signaling from autocrine stimulation.
J Cell Sci
; 120(Pt 20): 3688-99, 2007 Oct 15.
Article
em En
| MEDLINE
| ID: mdl-17895366
ABSTRACT
EGF family ligands are synthesized as membrane-anchored precursors whose proteolytic release yields mature diffusible factors that can activate cell surface receptors in autocrine or paracrine mode. Expression of these ligands is altered in pathological states and in physiological processes, such as development and tissue regeneration. Despite the widely documented biological importance of autocrine EGF signaling, quantitative relationships between protease-mediated ligand release and consequent cell behavior have not been rigorously investigated. We thus explored the relationship between autocrine EGF release rates and cell behavioral responses along with activation of ERK, a key downstream signal, by expressing chimeric ligand precursors and modulating their proteolytic shedding using a metalloprotease inhibitor in human mammary epithelial cells. We found that ERK activation increased monotonically with increasing ligand release rate despite concomitant downregulation of EGF receptor levels. Cell migration speed was directly related to ligand release rate and proportional to steady-state phospho-ERK levels. Moreover, migration speed was significantly greater for autocrine stimulation compared with exogenous stimulation, even at comparable phospho-ERK levels. By contrast, cell proliferation rates were approximately equivalent at all ligand release rates and were similar regardless of whether the ligand was presented endogenously or exogenously. Thus, in our mammary epithelial cell system, migration and proliferation are differentially sensitive to the mode of EGF ligand presentation.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Movimento Celular
/
Comunicação Autócrina
/
Glândulas Mamárias Humanas
/
MAP Quinases Reguladas por Sinal Extracelular
/
Células Epiteliais
/
Receptores ErbB
Limite:
Humans
Idioma:
En
Ano de publicação:
2007
Tipo de documento:
Article