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-3beta (GSK-3beta) has recently been found to positively regulate the activity of nuclear factor-kappaB (NF-kappaB). Here, we investigated the relationship between GSK-3beta inhibition and NF-kappaB in apoptosis of pediatric primary leukemia cells obtained from 39 newly diagnosed ALL children in China.

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-3beta in these cells. After treatment with chemically distinct GSK-3beta inhibitors in vitro, NF-kappaB transcriptional activity was identified by means of western blotting and electrophoretic mobility shift assay (EMSA). NF-kappaB-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).

GSK-3beta significantly accumulates in the nuclei of ALL cells than in the nuclei of control cells. Cell death induced by GSK-3beta inhibition in ALL cells was mediated by a downregulation of NF-kappaB p65 transcriptional activity. GSK-3beta inhibition significantly decreased the expression of the NF-kappaB target gene survivin.

These results indicate that inhibition of GSK-3beta downregulates the NF-kappaB activation pathway, leading to suppression of the expression of an NF-kappaB-regulated gene and promotion of apoptosis in ALL cells in vitro. Furthermore, our findings suggest that GSK-3beta or NF-kappaB is a potential therapeutic target in the treatment of pediatric ALL.

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