Abstract
More than half of anaplastic large-cell lymphomas (ALCLs) have a chromosomal translocation t(2;5) that leads to the expression of a hybrid protein composed of the nucleolar phosphoprotein nucleophosmin (NPM) and the anaplastic lymphoma kinase (ALK) that exhibits an unregulated tyrosine kinase activity. We have previously identified PLC-gamma as a crucial downstream signaling molecule of NPM-ALK that contributes to its mitogenic potential. Here, we show that NPM-ALK recruits the C-terminal SH2 domain of the phosphatidylinositol 3-kinase (PI 3kinase) p85 subunit. PI 3-kinase assays revealed that the kinase is activated by NPM-ALK in vivo, in turn activating PKB/Akt in NPM-ALK-expressing cells. The use of 2 specific PI 3-kinase inhibitors, wortmannin and LY294002, demonstrated the requirement of PI 3-kinase for the growth of NPM-ALK-transformed cell lines, as well as a cell line established from a patient with ALCL. Primary murine bone marrow retrovirally transduced with NPM-ALK showed a transformed phenotype that was reversible on treatment with PI 3-kinase inhibitors. Flow cytometric analysis revealed that wortmannin-treated NPM-ALK-transformed cell lines underwent apoptosis. Furthermore, apoptosis induced by overexpression of the proapoptotic molecule Bad could be partially blocked by the overexpression of NPM-ALK. Thus, NPM-ALK activates the antiapoptotic PI 3-kinase/Akt pathway, which likely contributes to the molecular pathogenesis of ALCL. (Blood. 2000;96:4319-4327)
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Substitution
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Androstadienes / pharmacology
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Animals
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Apoptosis / drug effects
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Binding Sites
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Binding, Competitive
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Carrier Proteins / physiology
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Cell Line, Transformed / drug effects
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Cell Line, Transformed / enzymology
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Cell Line, Transformed / pathology
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Cell Survival / physiology*
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Cell Transformation, Neoplastic / genetics
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Chromones / pharmacology
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Coculture Techniques
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Enzyme Activation
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Enzyme Inhibitors / pharmacology
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Fibroblasts / drug effects
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Hematopoietic Stem Cells / drug effects
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Hematopoietic Stem Cells / enzymology
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Hematopoietic Stem Cells / pathology
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Humans
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Interleukin-3 / pharmacology
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Lymphoma, Large B-Cell, Diffuse / enzymology*
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Lymphoma, Large B-Cell, Diffuse / genetics
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Lymphoma, Large B-Cell, Diffuse / pathology
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Mice
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Mice, Inbred BALB C
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Morpholines / pharmacology
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Mutagenesis, Site-Directed
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Neoplasm Proteins / antagonists & inhibitors
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Neoplasm Proteins / genetics
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Neoplasm Proteins / physiology*
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Phosphatidylinositol 3-Kinases / metabolism*
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Phosphoinositide-3 Kinase Inhibitors
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Phosphorylation
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Point Mutation
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Protein Processing, Post-Translational
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Protein Serine-Threonine Kinases*
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Protein Subunits
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Protein-Tyrosine Kinases / genetics
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Protein-Tyrosine Kinases / physiology*
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Proto-Oncogene Proteins / metabolism
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Proto-Oncogene Proteins c-akt
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Rats
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Recombinant Fusion Proteins / physiology
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Signal Transduction / physiology*
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Stromal Cells
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Transfection
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Wortmannin
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bcl-Associated Death Protein
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src Homology Domains
Substances
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Androstadienes
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BAD protein, human
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Bad protein, mouse
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Bad protein, rat
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Carrier Proteins
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Chromones
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Enzyme Inhibitors
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Interleukin-3
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Morpholines
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Neoplasm Proteins
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Phosphoinositide-3 Kinase Inhibitors
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Protein Subunits
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Proto-Oncogene Proteins
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Recombinant Fusion Proteins
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bcl-Associated Death Protein
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2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
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p80(NPM-ALK) protein
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Protein-Tyrosine Kinases
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AKT1 protein, human
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Akt1 protein, rat
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Protein Serine-Threonine Kinases
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Proto-Oncogene Proteins c-akt
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Wortmannin