TRPM8 and glioblastoma: Ionizing radiation (4 Gy) had no or only minor additive effect on ΔΨm dissipation and caspase activation in nt siRNA-transfected or TRPM8 knockdown glioblastoma cells (compare 1st with 2nd bar and 3rd with 4th bar in Figure 4B, 4C, 4E, 4F) indicating pivotal anti-apoptotic survival signaling by TRPM8 in unirradiated cells.