Mitochondrial dysfunction is involved in the cellular activity inhibition by eleutheroside B in SMMC-7721 and HeLa cells

Eleutheroside B, also known as syringin, has been shown to have various pharmacological activities such as anti-inflammatory, anti-irradiation and antidepressant, but there are few studies on its anti-cancer activity. Its anti-tumor effect on SMMC-7721 cells has not been revealed. Moreover, whether it induces autophagy is still unclear. Thus, the present study investigated whether Eleutheroside B induces apoptosis, autophagy and cellular motility in SMMC-7721 cells and HeLa cells, and explored the underlying molecular mechanisms. SMMC-7721 cells and HeLa cells treated with Eleutheroside B and cell viability measured by MTT assay and trypan blue dye exclusion assay. Apoptosis checked by flow cytometry combined, fluorescent staining. Apoptotic signal proteins and autophagy proteins were checked by Western blot. This study showed that Eleutheroside B inhibited the cell proliferation and blocked cell cycle, migration and invasion as well. Moreover, Eleutheroside B induced apoptosis in SMMC-7721 cells and HeLa cells. It upregulated Bax expression, while simultaneously decreasing Bcl-2 expression. Further elucidation of the mechanism revealed that Eleutheroside B induced mitochondrial dysfunction, with mitochondrial membrane potential collapse and cytochrome c release, suggesting that Eleutheroside B induced apoptosis by triggering mitochondrial pathway. Most importantly, Eleutheroside B could induce autophagy in SMMC-7721 cells and HeLa cells. Taken together, these results suggested Eleutheroside B is a potential therapeutic candidate for HCC and Human cervical cancer.