Snail and Notch1 intracellular domain regulate invasion. Mouse embryonic fibroblast (MEFs) (A), Huh7 cells (B) and Hep3B cells (C) were infected with murine stem cell virus-Notch1 intracellular domain (MSCV-NICD) and/or MSCV-Snail, selected in puromycin, and assayed for cell invasion using the Oris Cell Invasion and Detection Kit. (D) Hep3B cells were transfected with Notch1 and/or Snail siRNA, then assayed for cell invasion. (E) Hep3B cells were transfected with Myc-NICD and/or Snail siRNA, treated with 300 μM H2O2 for 72 hours and assayed for cell invasion. Bar graphs show the means ± SD of three independent experiments. *P < 0.05 statistical significance of the three experiments was determined using Student's t-test.