The Signal Transduction Mechanisms Of Apoptosis Induced By Ginsenoside-rh2 In Hl-60 Cells

Ginsenoside-Rh2 is an effective component extracted from ginseng. Researches have confirmed that G-Rh2 has a potent antitumor activity. In the early studys, we found G-Rh2 can induce apoptosis in HL-60 cells, in a dose-dependent manner. The expression of the tumor necrosis factor (TNFa) was up-regulated in the G-Rh2 treated HL-60 cells.Estrogen receptors play an important role in the physiology actions of cells and changes of the expression level of estrogen receptors have a complicated influence in tumor's occurring and developing process. The experiment has proved that, G-Rh2 is a compound with an estrogen-like effect. It can bind to and activate estrogen receptors.In order to explore the mechanisms underlying the apoptotic effects of HL-60 cells induced by G-Rh2, we treated HL-60 cells with IC50 dosage of G-Rh2 (25μM), and combined with antagonists of estrogen receptors:MPP, PHTPP and ICI 182,780. Flow cytometry assay was used to detect the changes of apoptosis. We chose ERa, ERβand TNFαas the target proteins, and used Western blotting to analyze the action of estrogen receptors in the process of TNFa expression up-regulation of HL-60 cells induced by G-Rh2.The results showed, the up-regulation of TNFa induced by G-Rh2 plays a decisive role in the apoptosis of HL-60 cells. In HL-60 cells induced by G-Rh2, accompanied with the up-regulation of the TNFa protein level, the ERβover expressed remarkably. When PHTPP has antagonized ERβ, the apoptotic effect was weakened. This indicates that, ERβplays an important role in the signal transduction pathway of the apoptosis in HL-60 cells induced by G-Rh2.