Methods and compositions capable of modulating activity of TLX (NR2E1), a nuclear receptor essential for neural stem cell self-renewal are provided. The modulation may comprise downregulating TLX expression and/or modulating TET3. In addition, methods of delivering shRNAs using dendrimer nanoparticles into glioblastoma stem cells are provided. The methods and compositions are useful for treating and preventing the progression of brain cancer, e.g., glioblastoma.