Xenograft studies

The GSC suspension (1 × 10⁴ cells for GSC 83 and 1123, and 5 × 10⁵ cells for GSC 23 and 528) was intracranially injected into the brains of mice as described previously [⁷,²⁴]. Intracranial tumor xenograft-bearing mice received radiation at 2 Gy directed at the cranium for five consecutive days. The radiation treatment was started one week after transplantation. TMZ-treated mice received TMZ through gavage at 20 mg/kg daily for 15 d. TMZ treatments were started at day 3 post-implantation. The mice were monitored every day for the neurological symptoms relative to tumor burden. The tumor growth was monitored using an in vivo imaging system (IVIS) Lumina imaging station. For the animal survival analysis, mice were maintained until pathological symptoms developed resulting from tumor burden and combined with IVIS signal intensity indicative of tumor burden [⁷].

In all experiments, the mice were monitored every day for the development of neurological symptoms indicative of substantial tumor growth. The mice were humanely euthanized 15–28 d after GSC 83 and 1123 implantation, or 30–58 d after GSC 23 and 528 implantation based on tumor burden. Mouse brains were collected for analysis as previously described [⁷,²⁴].