Glycogen synthase kinase−3β inhibitors suppress leukemia cell growth

• Published in: Experimental hematology 2010-10, Vol.38 (10), p.908-921.e1
• Main Authors: Song, Emma Y, Palladinetti, Patricia, Klamer, Guy, Ko, Kap-Hyoun, Lindeman, Robert, O'Brien, Tracey A, Dolnikov, Alla
• Format: Article
• Language: English
• Subjects: Advanced Basic Science; Animals; Apoptosis - drug effects; Blotting, Western; Cell Line; Cell Line, Tumor; Cell Proliferation - drug effects; Cells, Cultured; Dose-Response Relationship, Drug; Enzyme Inhibitors - pharmacology; Female; Gene Expression Regulation, Leukemic - drug effects; Glycogen Synthase Kinase 3 - antagonists & inhibitors; Glycogen Synthase Kinase 3 - metabolism; Glycogen Synthase Kinase 3 beta; Hematology, Oncology and Palliative Medicine; HL-60 Cells; Humans; Indoles - pharmacology; Jurkat Cells; K562 Cells; Leukemia - metabolism; Leukemia - pathology; Leukemia - prevention & control; Mice; Mice, Inbred BALB C; Mice, Inbred NOD; Mice, Nude; Mice, SCID; Oximes - pharmacology; Reverse Transcriptase Polymerase Chain Reaction; U937 Cells; Xenograft Model Antitumor Assays
• ISSN: 0301-472X; 1873-2399
• DOI: 10.1016/j.exphem.2010.06.001

Objective The objective of this study was to investigate the effect of small molecule inhibitors of glycogen synthase kinase−3β (GSK-3β) on leukemia cell growth and survival. Materials and Methods Analysis of cytotoxicity and cell proliferation was conducted using the MTS assay, cell-cycle analysis, and division tracking. Apoptosis was investigated by Annexin-V/7-aminoactinomycin D and caspase-3 expression. The effect of GSK-3β inhibitors was also tested in vivo in an animal model of leukemia. Gene expression analysis was performed to identify the genes modulated by GSK-3β inhibition in leukemia cells. Results GSK-3β inhibitors suppress cell growth and induce apoptosis in seven leukemia cell lines of diverse origin, four acute myeloid leukemia, one myelodysplastic syndrome, and one acute lymphoblastic leukemia samples. GSK-3β inhibitors are cytotoxic for rapidly dividing clonogenic leukemia blasts, and higher doses of the inhibitors are needed to eliminate primitive leukemia progenitor/stem cells. Slow cell-division rate, low drug uptake, and interaction with bone marrow stroma make leukemia cells more resistant to apoptosis induced by GSK-3β inhibitors. Global gene expression analysis combined with functional approaches identified multiple genes and specific signaling pathways modulated by GSK-3β inhibition. An important role for Bcl2 in the regulation of apoptosis induced by GSK-3β inhibitors was defined by expression analysis and confirmed by using pharmacological inhibitors of the protein. In vivo administration of GSK-3β inhibitors delayed tumor formation in a mouse leukemia model. GSK-3β inhibitors did not affect hematopoietic recovery following irradiation. Conclusions Our data support further evaluation of GSK-3β inhibitors as promising novel agents for therapeutic intervention in leukemia and warrant clinical investigation in leukemia patients.