[Primary Mechanisms of CD34+CD38---KG1a Leukemia Stem Cells Apoptosis Induced by FA-2-b-β Extracted from Qinba Selenium- Mushroo].

OBJECTIVE: To investigate the apoptosis of CD34(+)CD38(-)-KG1a leukemia stem cells induced by Qinba selenium-mushroom extract(FA-2-b-beta), and its related mechanism. METHODS: CD34(+)CD38(-)--KG1a cells were isolated from KG1a cell line by magnetic activated cell sorting. The proliferation ability of KG1a stem cells treatd by various concentration of FA-2-b-beta(1.2-2.4 mg/ml) in vitro for 24 and 48 hours were tested by cell counting Kit-8(CCK8). Flow cytometry was used to detect the apoptosis rate of KG1a stem cells in each group after treated by FA-2-b-beta in vitro. Expression of BAX,BCL-2,Casepase-3 and Cyclin D1 protein were detected by Western blot. RESULTS: The proportion of CD34(+)CD38(-)--KG1a stem cells was (95.35+/-2.63% after immunomagnetic isolation. The proliferation of KG1a stem cells was inhibited significantly by FA-2-b-beta, which shows a time- and dose-dependent manner (24 h,r=0.943; 48 h,r=0.976). Flow cytometry shows that with the increasing of drug concentration, the apoptosis was also increased, when KG1a stem cells was treated by FA-2-b-beta for 24 h. Western blot indicated that the expression of apoptosis-related protein BAX and Casepase-3 were up-regulated, the expression of BCL-2 and Cyclin D1 were down-regulated. CONCLUSION: FA-2-b-beta can regulate proliferation and apoptosis KG1a stem cells, the involved mechanism may be related with the activation of mitochondrial-mediated apoptotic pathway.