Abstract
Shp2 has been known to mediate growth factor-stimulated cell proliferation, but its role in cell survival is less clear. Gain-of-function Shp2 mutants such as Shp2E76K are associated with myeloid leukemias. We found that Shp2E76K could transform cytokine-dependent human TF-1 myeloid cells into cytokine independence and further characterized the Shp2E76K-induced cell survival mechanism in this study. Expression of Shp2E76K suppressed the cytokine withdrawal-induced intrinsic/mitochondrial apoptosis pathway, which is controlled by the Bcl-2 family proteins. Analysis of Bcl-2 family proteins showed that Bcl-XL and Mcl-1 were up-regulated in Shp2E76K-transformed TF-1 (TF-1/Shp2E76K) cells. Knockdown of Bcl-XL but not Mcl-1 with short hairpin RNAs prevented Shp2E76K-induced cytokine-independent survival. Roscovitine, which down-regulated Mcl-1, also did not prevent cytokine-independent survival of TF-1/Shp2E76K cells, whereas the Bcl-XL inhibitor HA14-1 did. Ras and mitogen-activated protein kinases Erk1 and Erk2 (Erk1/2) were constitutively activated in TF-1/Shp2E76K cells, whereas little active Akt was detected under cytokine-free conditions. Shp2E76K-induced Bcl-XL expression was suppressed by Mek inhibitors and by a dominant-negative Mek1 mutant but not by the phosphoinositide 3-phosphate inhibitor LY294002 and the Akt inhibitor API-2. Inhibition of Erk1/2 blocked cytokine-independent survival of TF-1/Shp2E76K cells, whereas inhibition of Akt had a minimal effect on cytokine-independent survival of TF-1/Shp2E76K cells. These results show that Shp2E76K can evoke constitutive Erk1/2 activation in TF-1 cells. Furthermore, Shp2E76K induces cytokine-independent survival of TF-1 cells by a novel mechanism involving up-regulation of Bcl-XL through the Erk1/2 pathway.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Substitution
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Apoptosis / genetics
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Apoptosis / physiology
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Benzopyrans / pharmacology
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Cell Line
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Cell Survival / drug effects
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Cell Survival / genetics
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Chlorpropamide / analogs & derivatives
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Chlorpropamide / pharmacology
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Chromones / pharmacology
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Down-Regulation / drug effects
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Down-Regulation / genetics
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Elafin / antagonists & inhibitors
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Elafin / genetics
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Elafin / metabolism
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Enzyme Activation / drug effects
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Enzyme Activation / genetics
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Granulocyte-Macrophage Colony-Stimulating Factor / metabolism*
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Granulocyte-Macrophage Colony-Stimulating Factor / pharmacology
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Humans
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Interleukin-3 / metabolism*
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Interleukin-3 / pharmacology
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Leukemia, Myeloid / enzymology
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Leukemia, Myeloid / genetics
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MAP Kinase Signaling System / drug effects
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MAP Kinase Signaling System / genetics
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Mitochondria / genetics
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Mitochondria / metabolism
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Mitogen-Activated Protein Kinase 1 / antagonists & inhibitors
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Mitogen-Activated Protein Kinase 1 / genetics
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Mitogen-Activated Protein Kinase 1 / metabolism
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Mitogen-Activated Protein Kinase 3 / antagonists & inhibitors
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Mitogen-Activated Protein Kinase 3 / genetics
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Mitogen-Activated Protein Kinase 3 / metabolism
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Morpholines / pharmacology
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Mutation, Missense
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Myeloid Cell Leukemia Sequence 1 Protein
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Myeloid Progenitor Cells / enzymology*
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Neoplasm Proteins / biosynthesis
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Neoplasm Proteins / genetics
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Nitriles / pharmacology
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Oncogene Protein p21(ras) / antagonists & inhibitors
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Oncogene Protein p21(ras) / genetics
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Oncogene Protein p21(ras) / metabolism
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Protein Kinase Inhibitors / pharmacology
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Protein Tyrosine Phosphatase, Non-Receptor Type 11 / genetics
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Protein Tyrosine Phosphatase, Non-Receptor Type 11 / metabolism*
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Proto-Oncogene Proteins c-akt / antagonists & inhibitors
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Proto-Oncogene Proteins c-akt / genetics
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Proto-Oncogene Proteins c-akt / metabolism
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Proto-Oncogene Proteins c-bcl-2 / biosynthesis
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Proto-Oncogene Proteins c-bcl-2 / genetics
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Purines / pharmacology
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Roscovitine
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Up-Regulation* / drug effects
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Up-Regulation* / genetics
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bcl-X Protein / biosynthesis*
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bcl-X Protein / genetics
Substances
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API 2
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BCL2L1 protein, human
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Benzopyrans
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Chromones
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Elafin
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IL3 protein, human
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Interleukin-3
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Morpholines
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Myeloid Cell Leukemia Sequence 1 Protein
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Neoplasm Proteins
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Nitriles
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PI3 protein, human
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Protein Kinase Inhibitors
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Proto-Oncogene Proteins c-bcl-2
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Purines
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bcl-X Protein
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ethyl 2-amino-6-bromo-4-(1-cyano-2-ethoxy-2-oxoethyl)-4H-chromene-3-carboxylate
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Roscovitine
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2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
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Granulocyte-Macrophage Colony-Stimulating Factor
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Proto-Oncogene Proteins c-akt
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Mitogen-Activated Protein Kinase 1
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Mitogen-Activated Protein Kinase 3
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Protein Tyrosine Phosphatase, Non-Receptor Type 11
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Oncogene Protein p21(ras)
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Chlorpropamide