Molecular mechanisms of oridonin-induced apoptosis and autophagy in murine fibrosarcoma L929 cells

Abstract

Apoptosis and autophagy are genetically regulated, evolutionarily conserved processes that can jointly seal the fate of cancer cells. However, substantial gaps remain in our understanding of the molecular mechanisms that mediate the two cellular processes. In the present study, the exposure of murine fibrosarcoma L929 cells to oridonin led to the generation of intracellular reactive oxygen species (ROS) and, subsequently, the ROS triggered apoptosis by Bax translocation, cytochrome c release and ERK activations. In addition, oridonin induced autophagy in L929 cells, and the inhibition of autophagy by 3-MA or siRNA against LC3 and beclin 1 promoted oridonin-induced apoptosis. Furthermore, p38 and NFκB were confirmed to have roles in inhibiting apoptosis but promoting autophagy. Moreover, the inhibition of autophagy could reduce oridonin-induced activation of p38. Finally, NFkB activation was inhibited by blocking the p38 pathway. In conclusion, these findings indicate that oridonin-induced apoptosis can be regulated by ROS-mediated signaling pathways, and oridonin-induced autophagy may block apoptosis by upregulating p38 and NFkB activation. © 2009 Landes Bioscience.