β-Lapachone Significantly Increases the Effect of Ionizing Radiation to Cause Mitochondrial Apoptosis via JNK Activation in Cancer Cells
Figure 2
β-lap in combination with IR enhances ROS generation and leads to apoptotic cell death.
(A) and (B) Cells were treated with IR alone, β-lap alone or combination of IR and β-lap for the indicated times. After 3 h, the cells were incubated with 10 µM H2DCF-DA and 4 µM DHE, respectively, for 30 min and then analyzed by flow cytometry. Results from three independent experiments are expressed as means ± SEMs. (C) NQO1+-MDA-MB-231 cells were treated with IR alone, β-lap alone or combination of IR and β-lap for 24 h in the presence or absence of NAC (10 mM). After 24 h, the percentage of cells with sub-G1 DNA content was determined by flow cytometry. Results from three independent experiments are expressed as means ± SEMs. (D) NQO1+-MDA-MB-231 cells were treated with combination of IR (2 Gy) and β-lap (2 µM) in the presence or absence of NAC (10 mM). Cells were allowed to grow for 10 to 14 days and were stained with 0.5% crystal violet and scored for colony formation. Results from three independent experiments are expressed as means ± SEM. *Significant difference between cells in the presence or absence of NAC after combined treatment with IR and β-lap, at p<0.05.