Abstract
Hellebrigenin is a natural product found in the toad skin secretions and plants of Urginea, including Hellebores and Kalanchoe genera. It has been shown to be active against Leishmania chagasi promastigotes and Trypanosoma cruzi trypomastigotes and also reported to play an anti-tumor effect on several cancer cell lines in vitro, including pancreatic cancer. This study is aimed to investigate the effects of Hellebrigenin on pancreatic carcinoma cells, SW1990 and BxPC-3 in vitro and its molecular mechanism involved in antitumor activities. Our results showed that Hellebrigenin effectively inhibited the proliferation of SW1990 and BxPC-3 cells in dose- and time-dependent manner. Flow cytometry results showed that Hellebrigenin induced the G0/G1 arrest in both of SW1990 and BxPC-3 cells and promoted cell early apoptosis and autophagy according to morphological observation. Immunofluorescence staining results further confirmed that cell apoptosis and autophagy also increased upon the Hellebrigenin treatment. Moreover, higher dose of Hellebrigenin further increased the cell apoptosis rate while decrease the mitochondrial membrane potential 24 h after treatment. The autophagy rate increased 48 h after treatment with significant difference (P < 0.05). Western blot analysis showed that the expression of caspase 3, 7, cleaved caspase 7, Atg 12, LC3 proteins were increased in SW1990 cell after treatment with Hellebrigenin. In addition, increasing expression of caspase 3, 7, 9, PARP, cleaved caspase 3, 7, 9, PARP, the sub basic protein of the PI3K family, Beclin-1, LC 3, Atg 3, 5, 12, 16 L were also observed after BxPC-3 cells treated with Hellebrigenin. In summary, this study reported for the first time that Hellebrigenin effectively induced autophagy and apoptosis especially the early apoptosis in SW1990 and BxPC-3 cells.