EGF-receptor-mediated mammary epithelial cell migration is driven by sustained ERK signaling from autocrine stimulation.

TitleEGF-receptor-mediated mammary epithelial cell migration is driven by sustained ERK signaling from autocrine stimulation.
Publication TypeJournal Article
Year of Publication2007
AuthorsJoslin, EJ, Opresko, LK, Wells, A, Wiley, HS, Lauffenburger, DA
JournalJ Cell Sci
IssuePt 20
Date Published2007 Oct 15
KeywordsADAM Proteins, Autocrine Communication, Cell Line, Cell Movement, Epithelial Cells, Extracellular Signal-Regulated MAP Kinases, Humans, Ligands, Mammary Glands, Human, MAP Kinase Signaling System, Phosphorylation, Receptor, Epidermal Growth Factor

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.

Alternate JournalJ. Cell. Sci.
PubMed ID17895366
Grant ListR01-CA096504 / CA / NCI NIH HHS / United States
R01-GM069668 / GM / NIGMS NIH HHS / United States
U54-CA112967 / CA / NCI NIH HHS / United States

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