Abstract
It is generally believed that shutting down the kinase activity of BCR-ABL by imatinib will completely inhibit its functions, leading to inactivation of its downstream signaling pathways and cure of the disease. Imatinib is highly effective at treating human Philadelphia chromosome-positive (Ph(+)) chronic myeloid leukemia (CML) in chronic phase but not Ph(+) B cell acute lymphoblastic leukemia (B-ALL) and CML blast crisis. We find that SRC kinases activated by BCR-ABL remain fully active in imatinib-treated mouse leukemic cells, suggesting that imatinib does not inactivate all BCR-ABL-activated signaling pathways. This SRC pathway is essential for leukemic cells to survive imatinib treatment and for CML transition to lymphoid blast crisis. Inhibition of both SRC and BCR-ABL kinase activities by dasatinib affords complete B-ALL remission. However, curing B-ALL and CML mice requires killing leukemic stem cells insensitive to both imatinib and dasatinib. Besides BCR-ABL and SRC kinases, stem cell pathways must be targeted for curative therapy of Ph(+) leukemia.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Animals
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Antineoplastic Agents / therapeutic use
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B-Lymphocytes / enzymology
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Benzamides
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Blast Crisis / enzymology
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Burkitt Lymphoma / drug therapy
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Burkitt Lymphoma / enzymology
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Cell Line, Tumor
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Cell Transformation, Neoplastic / metabolism
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Dasatinib
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Fusion Proteins, bcr-abl / antagonists & inhibitors
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Humans
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Imatinib Mesylate
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Leukemia, Myelogenous, Chronic, BCR-ABL Positive / drug therapy*
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Leukemia, Myelogenous, Chronic, BCR-ABL Positive / enzymology*
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Leukemia, Myelogenous, Chronic, BCR-ABL Positive / genetics
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Leukemia, Myelogenous, Chronic, BCR-ABL Positive / pathology
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Mice
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Mice, Inbred BALB C
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Mice, Inbred C57BL
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Mice, Knockout
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Neoplastic Stem Cells / drug effects*
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Neoplastic Stem Cells / enzymology*
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Piperazines / therapeutic use
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Protein Kinase Inhibitors / therapeutic use
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Pyrimidines / therapeutic use
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Thiazoles / therapeutic use
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src-Family Kinases / deficiency
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src-Family Kinases / genetics
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src-Family Kinases / metabolism
Substances
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Antineoplastic Agents
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Benzamides
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Piperazines
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Protein Kinase Inhibitors
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Pyrimidines
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Thiazoles
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Imatinib Mesylate
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Fusion Proteins, bcr-abl
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src-Family Kinases
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Dasatinib