Figure 6.

Obtusaquinone (OBT) tumor specificity. A) A panel of 12 different cancer cell lines and normal control cells were transduced to stably express Gluc then treated with OBT. Aliquots of the conditioned medium were assayed for Gluc activity after 24 hours. Human cortical neuron (HCN) and human hepatocyte (HH) viability was measured using CellTiter-Glo assay. The experiment was performed in triplicates. Error bars represent the SD. B) HF27 and HF29 normal fibroblast cells and U251 glioma cells were treated with OBT, and caspase 3/7 activity was measured after 24 hours. C) Reactive oxygen species (ROS) quantification in HF27. Cells were preincubated with CM-H₂DCFDA (5 µM) for 30 minutes, then treated for 1 hour with OBT before analysis by flow cytometry. Data are presented as the mean of fluorescence intensity. Tumor cells are represented with solid lines; normal cells are represented with dashed lines. Ctrl = control.