SOX2 and glioblastoma: To determine whether exogenous SOX2 expression could impair the long-term growth of other brain tumors types, we stably engineered U87 glioblastoma cells for Dox-inducible expression of SOX2 (i-SOX2-U87, Figure S5) using the same lentiviral vectors used to engineer i-SOX2-DAOY cells.