Changes in ATP production from respiration (blue bars) and glycolysis (red bars) following the introduction of TART and 5-ALA, respectively, in U87 (A), T98G (B), M059K (C), and Ln18 (D) human GBM cells. Error bars represent one SD; * p < 0.05, ** p < 0.01, *** p < 0.001.