SOX2 and glioblastoma: Initially, SK-N-BE (2) (Figure 5A) and SH-SY5Y (Figure 5B) neuroblastoma cells and U87-MG (Figure 5C), A172 (Figure 5D), and T98G (Figure 5E) GBM cells were either transfected with constitutively active Elk-1-VP16 and/or dominant-negative Elk-1-EN fusion protein expression vectors for overexpression (i), or with siElk-1 or scrRNA vectors for silencing (ii) experiments to study the regulation of SOX2 promoter by Elk-1 protein (Figure 5).