Antitumor activity of physcion 8-o-β-glucopyranoside against cervical cancer by induction of apoptosis

Purpose: To investigate the antitumor activity of physcion8-O-β-glucopyranoside (PSG) against cervical cancer, as well as its mechanisms.
Methods: The anti-proliferative effects of PSG on HeLa cells were determined by CCK-8 assay and the half maximal inhibitory concentration (IC₅₀) values were calculated. Subsequently, a mouse xenograft model of HeLa cell line was established to investigate the antitumor effect of PSG in vivo. Furthermore, cell apoptosis was investigated by ﬂuorescence microscopy via DAPI staining, and other mechanisms were determined by Western blot assay.
Results: In vitro, PSG exhibited significant anti-proliferative effect on HeLa cells (p <0.05) in concentration-and time-dependent manners, with an IC₅₀ value of 41.34 μg/mL. In vivo, PSG also had significant anti-tumor activity in nude mouse xenograft model (p < 0.05), inhibiting tumor growth. Furthermore, the results showed that treatment with PSG (20, 40 and 60 μg/mL) for 24 h resulted in significantly increased apoptosis in HeLa cells (p < 0.05). Additionally, Western blot analysis revealed that after exposure to 20, 40 and 60 μg/mL of PSG for 24 h, protein expressions of C-caspase-3, Ccaspase-9 and Bax were markedly up-regulated (p < 0.05) while Bcl-2 was significantly down-regulated (p < 0.05). These results confirmed that PSG inhibited HeLa cell growth by inducing mitochondriamediated apoptosis via up-regulation of caspase-3 and caspase-9 and Bax, and down-regulation of Bcl2.
Conclusion: The results demonstrate that PSG possesses notable anti-tumor activity against cervical cancer and that the mechanisms involve induction of apoptosis by mitochondria-mediated signaling pathway.

Keywords
Physcion 8-O-β-glucopyranoside; Cervical cancer; Apoptosis; HeLa cells; Caspase; Antitumour; Mouse xenograft