ATF4 and neuroblastoma: A derivative of 4-hydroperoxy-2-decenoic acid known as 4-hydroperoxy-2-decenoic acid ethyl ester (HPO-DAEE) prevents 6-hydroxydopamine-induced cell death in human neuroblastoma SH-SY5Y cells through triggering slight emission of reactive oxygen species (ROS), which stimulates the production of antioxidants via activation of antioxidant pathways: nuclear factor erythroid 2 (NRF2)-antioxidant response element (ARE) and eukaryotic initiation factor 2 (eIF2α), an upstream effector of the activating transcription factor-4 (ATF4) [37].