SNAI2 /Slug overexpression increases glioblastoma growth and proliferation. A) Phase and fluorescence micrographs showing human U251 glioblastoma cells transduced with a Slug-IRES-EGFP lentivirus. B) Western blot analysis demonstrating increased Slug protein expression in U251 glioblastoma cells transduced with the Slug-IRES-GFP lentivirus. C) Colorimetric growth assay demonstrating growth curves for human U251 glioblastoma cells overexpressing a vector containing SNAI2/Slug (solid line) or an empty control vector (dashed line). Data shown are mean ± SEM. Slug-expressing glioblastoma cells grew at a significantly faster rate than control cells (P < 0.03, t-test). D) BrdU incorporation into DNA for human U251 glioblastoma cells overexpressing an SNAI2/Slug vector or an empty control vector. Data shown are mean ± SEM. SNAI2/Slug-expressing glioblastoma cells synthesized new DNA at a significantly faster rate than control cells (asterisk indicates P < 0.00001, t-test).