Astragalus saponins affect proliferation, invasion and apoptosis of gastric cancer BGC-823 cells

Abstract

Background: Astragalus memebranaceus is a traditional Chinese herbal medicine used in treatment of common cold, diarrhea, fatigue, anorexia and cardiac diseases. Recently, there are growing evidences that Astragalus extract may be a potential anti-tumorigenic agent. Some research showed that the total saponins obtained from Astragalus membranaceus possess significant antitumorigenic activity. Gastric cancer is one of the most frequent cancers in the world, almost two-thirds of gastric cancer cases and deaths occur in less developed regions. But the effect of Astragalus membranaceus on proliferation, invasion and apoptosis of gastric cancer BGC-823 cells remains unclear.

Methods: Astragalus saponins were extracted. Cells proliferation was determined by CCK-8 assay. Cell cycle and apoptosis were detected by the flow cytometry. Boyden chamber was used to evaluate the invasion and metastasis capabilities of BGC-823 cells. Tumor growth was assessed by subcutaneous inoculation of cells into BALB/c nude mice.

Results: The results demonstrated that total Astragalus saponins could inhibit human gastric cancer cell growth both in vitro and in vivo, in additional, Astragalus saponins deceased the invasion ability and induced the apoptosis of gastric cancer BGC-823 cells.

Conclusions: Total Astragalus saponins inhibited human gastric cancer cell growth, decreased the invasion ability and induced the apoptosis. This suggested the possibility of further developing Astragalus as an alternative treatment option, or perhaps using it as adjuvant chemotherapeutic agent in gastric cancer therapy.

Figure 1

Effect of Astragalus saponins on proliferation and cell cycle of BGC-823 cells. A. Astragalus saponins inhibited proliferation of BGC-823 cells. Cells were treated with, 20 μg/ml, 40 μg/ml, and 80 μg/ml Astragalus saponins, 0 μg/ml as a control, and cell proliferation was assessed using the CCK8 assay. Data are presented as the mean of triplicate experiments. The growth inhibitory effect of the Astragalus saponins was time and dose dependent, with the maximum inhibition detected 72 h after treatment. *Significant difference (p < 0.05). B. Astragalus saponins impaired cell cycle progression in BGC-823 cells. Cell cycle distribution was analyzed by flow cytometry. Data are presented as the mean of triplicate experiments. Administration of Astragalus saponins significantly increased the percentage of cells in the G0/G1 phase, and significantly decreased the S and G2/M phase fractions.

Figure 2

Astragalus saponins decreased the invasion and migration ability of BGC-823 cells. A. BGC-823 cell invasion was determined using the transwell invasion assay, which measures the number of cells that migrate through the matrigel into the lower surface of the polycarbonic membrane (100×). Data are presented as the mean of triplicate experiments. B. Cell invasion decreased significantly (*p < 0.05) in a dose-dependent manner in Astragalus saponins -treated cells compared with the control group.

Figure 3

BGC-823 cell apoptosis and xenograft tumor experiment. A. Astragalus saponins induced apoptosis in BGC-823 cells. Cell apoptosis was analyzed by flow cytometry. Statistically significant (*p < 0.05)increases in annexin V + apoptotic cells were observed in Astragalus saponins–treated BGC-823 cells compared to controls. Data are presented as the mean of triplicate experiments. B. BGC-823 cell xenograft tumor experiment. Injection of Astragalus saponins inhibited tumor growth in a BGC-823 xenograft model compared with the blank control group. *Significant difference (p < 0.05).