20(S)-ginsenoside Rg3 Inhibits Human Glioma Cell Growth Through the Suppression of Voltage-gated K+ Channels

摘要

Previous studies demonstrated that 20(S)-ginsenoside Rg3 (20S-Rg3) could effectively inhibit tumor cell proliferation as well as K+ channel currents expressed in xenopus oocytes. However, the effect of 20S-Rg3 on the growth of human glioma cells and the ion channels expressed in tumor cells was rarely reported in the literature. In the present study, we investigated the effect and the underlying mechanism of 20S-Rg3 on cell proliferation and apoptosis of human glioma U87-MG cells. In vitro results exhibited that 20S-Rg3 had potent cytotoxic effect and significantly inhibited the proliferation of U87-MG cells in a dose- and time-dependent manner. Typical arrest at G_2/M phase was induced, and the apoptosis rate of U87-MG cells was significantly higher in the 20S-Rg3 treatment group than in the control group. Electrophysiological results showed that 80 umol/L 20S-Rg3 substantially inhibited voltage-gated K+ currents of U87-MG cells. Together, these results suggest that the suppression of voltage-gated K+ currents might play an important role in the 20S-Rg3-induced cell death, and these new findings provide useful data for further study of the antitumor effect of 20S-Rg3.