Induction of cell death by a N-acetylalaninate QM producing prodrug. A) The prodrug (S-NPAA) has been shown to cross the plasma membrane and be cleaved by the esterase activity of OPH. B) A quinone methide (QM) is generated which rapidly reacts with GSH causing a reduction in GSH levels. C) Cancer cells are known to typically have a pro-oxidant state due to activated Akt, which promotes the production of reactive oxygen species (ROS) and reduces some antioxidant defense mechanisms. The reduction in GSH levels by QM induces further oxidative stress that D) causes mitochondrial damage and activation of the caspase cascade, followed by E) DNA fragmentation and apoptosis.