Abstract
Peperomin E was first isolated from Peperomia dindygulensis, an anticarcinogenic herb, and exhibited anticancer activity in many cancer cell
lines. To date, it is unknown whether peperomin E has an effect on human prostate
cancer DU145 cells in vitro and in vivo. In this study, we used MTT to assess the proliferation inhibition activity of peperomin
E in DU145 cells in vitro and observed the cell morphological changes by a phase contrast microscope. A DU145
cell xenograft tumor mouse model was used to evaluate the efficacy of peperomin E
in vivo. Apoptosis rates were measured by flow cytometry, and protein expression levels were
analyzed by western blot. The results showed that peperomin E significantly inhibited
the proliferation of DU145 cells in vitro and reduced the weight and volume of tumors in vivo. Peperomin E also significantly induced the apoptosis and autophagic response of
DU145 cells. The autophagic inhibitors
LY294002 and chloroquine enhanced peperomin E-mediated inhibition of DU145 cell
proliferation and induction of DU145 cell apoptosis. The results also showed that
the Akt/mTOR pathway participated in peperomin E-induced autophagy in DU145 cells.
In summary, our finding showed that peperomin E had an effect on DU145 cells in vitro and in a nude mouse DU145 cell xenograft model in vivo, demonstrated that peperomin E could significantly induce apoptosis and the autophagic
response in DU145 cells and that autophagy played a cytoprotective role in peperomin
E-treated DU145 cells. These results suggest that the combination of peperomin E treatment
and autophagic inhibition has potential for the treatment of prostate cancer.
Key words
Peperomia dindygulensis
- Piperaceae - peperomin E - DU145 cell line - apoptosis - autophagy
