Induction of Cytotoxicity and Apoptosis in Human Gastric Cancer Cell SGC-7901 by Isovaltrate Acetoxyhydrin Isolated from Patrinia heterophylla Bunge Involves a Mitochondrial Pathway and G2/M Phase Cell Cycle Arrest

Background: Our previous study demonstrated cytotoxicity of a crude extract from Patrinia heterophylla Bunge(PHEB). In the present study, we aimed to investigate the effects of isovaltrate acetoxyhydrin (IA) isolated fromPHEB on the gastric cancer cell SGC-7901, in order to explore a potential treatment for gastric cancer.
Methods:MTT assays were employed to determine the effects of IA on cell vitality and proliferation, with monitoring ofcell morphology changes and examination of apoptosis with Annexin V-PI staining. Flow cytometry was used toassess cell cycle progression and mitochondrial membrane potential. The activity of caspase 3, 9 was evaluatedby spectrophotometry, and the protein levels of Bax, Bcl2 and Cyclin B1 were analyzed with Western blottingof total proteins extracted from cultured cells.
Results: The results demonstrated direct toxicity of IA towardsSGC-7901 cells. Evidence of apoptosis included blebbing and chromatin condensation. Annexin V-PI assaysrevealed early apoptosis, involving rapid depolarization of mitochondrial membranes and activity of caspase3, 9 signaling pathways. Western blotting showed that Bcl2 and Bax proteins was down- and up-regulated,respectively, and cyclin B1 was up-regulated. Cell cycle analysis further indicated that IA could induce G2/Mphase arrest in SGC-7901 cells.
Conclusions: In conclusion, we believe that IA induces apoptosis of SGC-7901cells, therefore providing a potential therapeutic agent for treatment of gastric cancer.