Keratinocytes to Epidermal Growth Factor and Transforming Growth Factor-Alpha

Experiments were performed to quantitatively characterize the differential migratory response of human keratinocytes to the polypeptide growth factors EGF and TGF-a. Videomicroscopic tracking of single cells, on collagen IV surfaces, was used to examine the migratory response of cells to a range of growth factor concentrations, as well as to the EGF receptor blocking antibody 225. Results indicate that both EGF and TGF-0a increase the random motility coefficient of human keratinocytes, relative to control experiments and those in which EGFR blocking antibody is used. This increase in motility appears to occur in a dose-dependent manner, with TGF-a performing as a stronger motogen than EGF. Results also suggest that the addition of exogenous growth factor or receptor blocking antibody lowers cellular persistence times relative to the control state. This finding supports a model of autocrine pathways as cellular environmental sensing systems, a model that has been termed "cell sonar"