In order to study the possible mechanisms of action of NGF, LL-37, PG-1, and TMZ on the proliferative activity of U251 glioma cells, we measured of the oxygen consumption rate (OCR) and the respiratory capacity of mitochondria of these cells under the 2 h effect of NGF (7.55 × 10−3 μM), PG-1 (16 μM), LL-37 (4 μM) and temozolomide (155 μM) by XF Cell MitoStress test kit and Extracellular Flux Analyzer as previously described (Figure 2). The gene discussed is NGF; the disease is central nervous system cancer.