Glycogen synthase kinase-3β inhibition induces nuclear factor-κB-mediated apoptosis in pediatric acute lymphocyte leukemia cells

Background: Molecular therapies that target genetic abnormalities in leukemic cells and their affected signaling pathways have been emerging in pediatric acute lymphoblastic leukemia (ALL). Glycogen synthase kinase-3 beta (GSK-3 beta) has recently been found to positively regulate the activity of nuclear factor-kappa B (NF-kappa B). Here, we investigated the relationship between GSK-3 beta inhibition and NF-kappa B in apoptosis of pediatric primary leukemia cells obtained from 39 newly diagnosed ALL children in China. Methods: Bone marrow mononuclear cells (BMMC) were isolated by density gradient centrifugation from the heparinized aspirates of children with ALL. We used immunofluorescence staining to detect nuclear GSK-3 beta in these cells. After treatment with chemically distinct GSK-3 beta inhibitors in vitro, NF-kappa B transcriptional activity was identified by means of western blotting and electrophoretic mobility shift assay (EMSA). NF-kappa B-mediated apoptosis was detected by Annexin V-PE/7-AAD double-staining flow cytometry. The expression level of the survivin gene was detected by reverse-transcriptase polymerase chain reaction (RT-PCR). Results: GSK-3 beta significantly accumulates in the nuclei of ALL cells than in the nuclei of control cells. Cell death induced by GSK-3 beta inhibition in ALL cells was mediated by a downregulation of NF-kappa B p65 transcriptional activity. GSK-3 beta inhibition significantly decreased the expression of the NF-kappa B target gene survivin. Conclusions: These results indicate that inhibition of GSK-3 beta downregulates the NF-kappa B activation pathway, leading to suppression of the expression of an NF-kappa B-regulated gene and promotion of apoptosis in ALL cells in vitro. Furthermore, our findings suggest that GSK-3 beta or NF-kappa B is a potential therapeutic target in the treatment of pediatric ALL.