Micro drill

Cell lines for use in vivo were transduced with pHIV-Luc-ZsGreen (a gift from Bryan Welm, Addgene plasmid #39196). Labeled cells were sorted for ZsGreen expression. Cells were implanted into the brains of 6-to-8-week-old female NOD-scid IL2Rγ^null mice (Jackson Laboratory), using a fixed stereotactic apparatus (Stoelting). A 1-mm burr hole was drilled into the skull using a microdrill (Harvard Apparatus) at 1.5 mm lateral and 1 mm caudal to bregma, and injections were made at a depth of 2 mm. Mice receiving injections of cells harboring inducible shCD24 or shNTC were fed dox-containing chow (doxycycline hyclate diet formulated at 625 mg/kg; Envigo) to induce expression of the hairpin.
All mouse experiments were approved by the Institutional Animal Care and Use Committee at MSKCC. Tumor-bearing mice were monitored for symptoms such as hunching, deteriorating body condition, hydrocephaly, lethargy, and neurological symptoms such as head tilt, rolling, and seizures. Symptomatic animals were sacrificed, and tissues were obtained at this time. Animals that died of unrelated causes were excluded from the study. Pathologists aided in the examination and scoring of slides: Dr. Sebastien Monette (general assessment), Dr. Tejus Bale (tumor scoring).