Radiation cooperates with PLX4720 to reduce clonogenic survival in BRAF V600E-mutant but not BRAF WT glioma cells. (A) BRAF V600E glioma cell lines; (B) BRAF WT glioma cell line; (C) Dose Enhancement Ratio (DER) for each cell line calculated at 90% survival level. PLX4720 (500 nM) was administered 24 hour before radiation (0, 2, 4, 6 Gy). Surviving fractions, shown as mean + SE (quadruplicate samples), were normalized to plating efficiency for each cell line. Radiation alone: solid line. Radiation + PLX4720: dashed line. XRT: radiation therapy. Clonogenic survival data points were fitted to a linear quadratic mathematical model.