This study was designed to investigate the effect of
juglone on the apoptosis of human
gastric cancer SGC-7901 cells. The cytotoxic activity of
juglone on SGC-7901 cells was tested by the
sulforhodamine B (SRB) assay. The morphological changes in the cells were observed by transmission electron microscopy (TEM). The apoptotic rate, the level of
reactive oxygen species (ROS), mitochondrial transmembrane potential and the expression of
cytochrome c protein were detected by flow cytometry (FCM). The expression of Bcl-2 and Bax
proteins were examined by Western blot.
Caspase 3 activity was determined with a microplate reader. Our results were as follows: the GI(50) values for SGC-7901 cells were 36.51 ± 1.05 μmol/L (24h) and 25.37 ± 1.19 μmol/L (48 h). After 24h of exposure to
juglone (5, 10, 15 and 20 μmol/L), the cells presented the typical morphological changes of apoptosis, and the rate of apoptosis was found to increase in a dose-dependent manner. After cells were treated with
juglone at the same dose for 24h, the level of ROS was significantly higher, the expression of Bcl-2 was significantly down-regulated and the expression of Bax was significantly up-regulated compared to the control. The mitochondrial transmembrane potential was significantly lower, and the expression of the
cytochrome c protein was significantly higher relative to the control.
Caspase 3 was activated in a concentration-dependent manner. In conclusion,
juglone can induce apoptosis in SGC-7901 cells through a mitochondrial pathway that seems to be mediated by the generation of ROS and a reduction in the Bcl-2/Bax ratio.