ATF4 and glioma: Further apoptosis mechanisms were described with CB2 receptor-dependent induced apoptosis of glioma cells associated with an increase in the stress-associated transcriptional coactivator p8 as an upstream regulator of the endoplasmic reticulum (ER) stress-related proteins activating transcription factor (ATF)-4 and tribbles pseudokinase 3 (TRB3) [64].