Emodin targets mitochondrial cyclophilin D to induce apoptosis in HepG2 cells

- Emodin localized in mitochondria analyzed by its inherent fluorescence.
- CypD was involved in the apoptosis induced by emodin.
- ROS and ERK played a role in the regulation of CypD.
- Molecule docking disclosed three hydrogen bonds existed in the emodin-CypD complex.

Emodin has demonstrated potent anticancer activity in human hepatocarcinoma cells and animal models, however, the cellular targets of emodin have not been fully defined. Here we report that emodin induces the dysfunction of mitochondria and the apoptosis in HepG2 cells through an enrichment in mitochondria. Specifically, A mitochondrial matrix protein (cyclophilin D, CyPD) is involved in emodin-induced apoptosis, and the inhibitor of CyPD (cyclosporin A) could almost completely suppressing the apoptosis; Moreover, as the expression of CyPD could be effectively inhibited by antioxidant N-acetyl-l-cysteine and epidermal growth factor (the activator of ERK), reactive oxygen species and ERK might be involved in the relevant role of CyPD. A further molecule-docking discloses the existence of three hydrogen-bonds in CyPD-emodin complex. Thus, target localization and CyPD in mitochondria provides an insight into the action of emodin in the treatment of liver cancer.

103