Figure 5.
EpICD provides target gene and proliferation induction independently of cell-to-cell contact. (A) Human embryonic kidney HEK293 cells were stably transfected with empty vector, EpCAM, EpICD, or EpICD-HA expression vectors. EpICD was stained with specific antibodies (red) and nuclear DNA was stained with DAPI (blue). Shown are representative sections recorded with a laser scanning confocal microscope. (B) The indicated HEK293 transfectants were seeded at initial densities of 3 × 105 and 3 × 106 cells and c-Myc expression was assessed upon immunoblotting with specific antibodies. For a control, actin expression levels were assessed in parallel. Shown are representative results from three independent experiments. (C) The indicated HEK293 transfectants were seeded at initial densities of 3 × 105 and 3 × 106 cells. Cell numbers were assessed at day three and seven after seeding. Levels of c-Myc expression were assessed by image densitometry, normalised for the amount of actin, and values for D1 set to one for a reference. Target gene levels are given n-fold of D1. Shown are the mean cell numbers with standard deviation from three independent experiments. Significant differences are marked (* p < 0.05; ** p < 0.005).