Effects of Lipid Soluble Components of Korean Red Ginseng on Proliferation and Cell Cycle Regulation Factors in Human Melanoma Cell Lines / 대한암학회지

ABSTRACT

PURPOSE: Growth inhibitory effects of lipid soluble components of the Korean red ginseng and the antineoplastic mechanism against human melanoma cell lines were investigated. To examine molecular mechanism of growth inhibitory effects of GX-PE, we analyzed the effect of GX-PE on cell cycle progression and expression of cell cycle regulatory factors such as retinoblastoma gene product (Rb), p27 (Kip1), p21 (WAF1), cdk2, cdk4 and cyclin D1 which are known to regulate cell cycle progression. MATERIALS AND METHODS: Petroleum ether extract of the Korean red ginseng (GX-PE) was added to cultures of three human melanoma cell lines, SK-MEL-1, SK-MEL-2, and SK-MEL-5. Proliferation was measured by 3H-thymidine incorporation assay. Cell cycle and expression of cell cycle regulatory factors were analyzed by flow cytometry and Western blotting, respectively. RESULTS: Growth of melanoma cells was inhibited by GX-PE in proportion to the concentration. GX-PE significantly inhibited cell cycle progression at G1 phase. GX-PE increased expression of negative cell cycle regulators, i.e., p27 (Kip1) in SK-MEL-2 and p21 (WAF1) and Rb in SK-MEL-1. CONCLUSION: These results suggest that GX-PE inhibits proliferation of melanoma cells at a G1-S transition point of the cell cycle. The effect of GX-PE is most likely due to induction of negative cell cycle regulatory factors.