Research on the antitumor effect of ginsenoside Rg3 in B16 melanoma cells.

Ginsenoside Rg3 is an effective chemical component extracted from the red Panix. The experiment demonstrated that it might effectively inhibit proliferation and metastasis of tumor cells. The exact molecular mechanism of Rg3 remains unclear so far. To further explore the antitumor function of Rg3, we investigated the in-vitro and in-vivo activity of Rg3 in the treatment of B16 melanoma cells, derived from C57BL/6 mouse, capable of forming tumor colonies in the lungs following intravenous injection. Cell proliferation was measured by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide assay. Morphological changes of cells were observed by staining with Giesma and Hoechst 33258. Cell cycle and apoptosis rate were analyzed by flow cytometry. The expression of caspase-3 and bcl-2 in cells was detected by immunocytochemistry and western blot analysis. We found that Rg3 could inhibit cell proliferation, regulate cell cycle, and induce cell apoptosis in vitro. B16 melanoma-bearing mice were used to evaluate in vivo the antitumor activity of Rg3. Mice that were injected with Rg3 showed significant inhibition of the tumor metastasis with lighter lung weight, lower density of microvessels, fewer metastasis nodules, and longer survival time than those in the control group (P<0.001). In conclusion, the results reveal that antitumor metastasis of Rg3 is also associated with inducing apoptosis, regulating cell cycle, and blocking angiogenesis in addition to inhibiting proliferation. This research might supply valuable data for chemotherapy with Rg3 in melanoma. Rg3 would turn out to be an anticancer drug with promising prospects. Melanoma Res 18:322-329 (C) 2008 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.