c-Met overexpression promotes cell rounding. c-Met overexpression promotes cell rounding. (A) Representative images from time-lapse series of HEK 293 cells growing in the absence or presence of tetracycline (Tet). (B) Shown on the left are representative images from time-lapse movies of HEK 293 cells embedded into 50% Matrigel and stimulated as indicated with Tet in the presence or absence of the c-Met kinase inhibitor SU11274 (2 µM). The quantification of cell-cluster granularity from three independent experiments is shown on the right (mean±s.d., 18 clusters per condition, ***P<0.005). (C) Immunofluorescent staining of Matrigel-embedded HEK 293 cells with or without Tet-induction using the antibodies indicated. The squares indicate regions that are shown at higher magnification to the right as single channel-images of Tet-induced cells. (D) Migration analysis of HEK 293 cells that were embedded into collagen (2 mg/ml) and either induced with Tet or not induced. The location of cells (n = 8 cells per treatment) was tracked over time, and both the distance migrated (in 14.5 h) and the migration speed (distance migrated per minute) were measured. (E) Migration analysis of HEK 293 cells that were embedded into 50% Matrigel and induced with Tet in the presence or absence of 80 µg/ml Mab13 (to block β1-integrin function) or 10 µM MMP-inhibitor III. Migration distance and speed were measured as described for D. (F) Representative transmission electron microscopy images of thin sections (70 nm) of Matrigel-embedded HEK 293 cells with or without Tet-mediated induction. The black squares indicate regions that are shown at higher magnification, either depicting the cell surface (a) or cell–cell contact sites (b). (G) Cells plated as a monolayer were overlaid with Matrigel and were either induced with Tet or left uninduced in the presence or absence of 2 µM SU11274. The invasiveness of cells over 4 days was analysed. Shown are confocal stacks of Syto®60-stained cells (z-axis) as well as the quantification of three independent experiments (mean±s.d., ***P<0.005). Anja Mai et al. J Cell Sci 2014;127:1938-1952 © 2014. Published by The Company of Biologists Ltd