DDIT3 and glioblastoma: In malignant glioblastoma cells, Pyrko et al. discovered a nelfinavir-mediated increase in the expression of GRP78, CHOP, and ER stress-related death mediator caspase-4; the importance of ER stress in nelfinavir-derived cytotoxicity was further underscored when siRNA-mediated silencing of GRP78 reduced the clonogenic survival [58].