Small animal stereotactic apparatus

Athymic nude mice (nu/nu, female; National Cancer Institute Animal Production, Frederick, MD, USA) aged 10–12 weeks were used. To implant tumor cells, the mice were anesthetized using isoflurane gas then placed in a small animal stereotactic apparatus (Stoelting, Wood Dale, IL, USA). To generate NSC11 and GBMJ1 tumors, neurospheres were dissociated into single‐cell suspensions; 1 x 10⁵ cells were then injected in a total volume of 2.5 μL at 1.0 mm anterior and 2.0 mm lateral to the bregma to a depth of 3.5 mm at a rate of approximately 1 μL/minute as previously described.¹⁶, ¹⁸ To generate a U251 tumor, 2.5 x 10⁵ cells were injected in a total volume of 2.5 μL. The mice were observed daily until the onset of neurologic symptoms (morbidity). All experiments were performed as approved by the Institutional Animal Care and Use Committee.