Inhibition of phosphatidylinositol 3-kinase dephosphorylates BAD and promotes apoptosis in myeloid leukemias

S. Zhao, M. Konopleva, M. Cabreira-Hansen, Z. Xie, W. Hu, M. Milella, Z. Estrov, G. B. Mills, M. Andreeff

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    131 Scopus citations

    Abstract

    The phosphatidylinositol 3-kinase (PI3K)/AKT protein kinase pathways is involved in cell growth, proliferation, and apoptosis. The functional activation of PI3K/AKT provides survival signals and blockade of this pathway may facilitate cell death. Down-stream targets of PI3K-AKT include the proapoptotic protein BAD, caspase-9, NFκB, and Forkhead. We have previously reported that BAD is constitutively phosphorylated in primary acute myeloid leukemia (AML) cells, a post-transcriptional modification, which inactivates its proapoptotic function. In this study, we tested the hypothesis that the inhibition of PI3K by LY294002 results in the dephosphorylation of AKT and BAD, and thus promote leukemia cell apoptosis. We investigated the effects of LY294002 in megakaryocytic leukemia-derived MO7E cells, primary AML and normal bone marrow progenitor cells. In MO7E cells. LY294002 reduced AKT kinase activity, induced dephosphorylation of AKT and BAD, and increased apoptosis. Concomitant inhibition of mitogen-activated protein kinase signaling or combination with all-trans retinoic acid further enhanced apoptosis of leukemic cells. In primary AML samples, clonogenic cell growth was significantly reduced. Normal hematopoietic progenitors were less affected, suggesting preferential targeting of leukemia cells. In conclusion, the data suggest that the inhibition of the PI3K/AKT signaling pathway restores apoptosis in AML and may be explored as a novel target for molecular therapeutic in AML.

    Original languageEnglish (US)
    Pages (from-to)267-275
    Number of pages9
    JournalLeukemia
    Volume18
    Issue number2
    DOIs
    StatePublished - Feb 2004

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    Keywords

    • AML and apoptosis
    • BAD phosphorylation
    • LY294002
    • MO7E
    • PI3K-AKT

    ASJC Scopus subject areas

    • Hematology
    • Oncology
    • Cancer Research

    Cite this

    Zhao, S., Konopleva, M., Cabreira-Hansen, M., Xie, Z., Hu, W., Milella, M., Estrov, Z., Mills, G. B., & Andreeff, M. (2004). Inhibition of phosphatidylinositol 3-kinase dephosphorylates BAD and promotes apoptosis in myeloid leukemias. Leukemia, 18(2), 267-275. https://doi.org/10.1038/sj.leu.2403220