Effects of DJ-1-binding compound-23 on oxidative stress-induced cell death. (A-D) SH-SY5Y cells were pretreated with 1 μM of comp-23 for 20 hours and then treated with 250 μM H2O2 for 24 hours (A) and 450 μM H2O2 for 3 hours or with 50 μM 6-OHDA for 24 hours (C) and 125 μM 6-OHDA for 1 hour, and cell viability was measured by an MTT assay. "-'' indicates cells not treated with comp-23. Significance: ** P < 0.01 versus vehicle (DMSO) control without compound. (E) SH-SY5Y cells were pretreated with 1 μM of comp-23 for 20 hours, treated with 5 μM DCFH-DA for 10 min at 37°C, and then treated with 40 μM 6-OHDA for 10 min. The amounts of ROS in cells were measured using a fluorescence spectrophotometer.