Intracranial xenograft

The method for establishing the intracranial xenograft model was previously described [30]. Briefly, 2 weeks after lentiviral transfection, 2 × 10⁵ U87-luc cells were injected stereotactically into the right hemicerebrum of 4- to 6- week-old female nude mice (n = 4, BALB/c-nu, Guangdong Medical Laboratory Animal Center, China). Tumor growth was monitored using an in vivo imaging system (IVIS Lumina II, Caliper, USA) after an intraperitoneal injection of luciferase substrate-D-luciferin (YEASEN, Shanghai, China). The tumors were excised on day 15 after the injection. A similar intracranial xenograft was established for evaluating survival time of nude mice. The observations continued past day 15 until the last mouse died naturally.