Abstract
Treatment with LAQ824 (Novartis Pharmaceutical, Inc.), a cinnamyl hydroxamic acid analogue inhibitor of histone deacetylases, depleted the mRNA and protein expression of Bcr-Abl in human chronic myeloid leukemia blast crisis (CML-BC) cells. Exposure to LAQ824 induced the expression of the cell cycle-dependent kinase inhibitors p21 and p27 and caused cell cycle G(1)-phase accumulation and apoptosis of CML-BC cells. LAQ824 also induced acetylation of heat shock protein 90. This inhibited the chaperone association of Bcr-Abl with heat shock protein 90, thereby promoting the proteasomal degradation of Bcr-Abl. Cotreatment with LAQ824 increased imatinib mesylate-induced apoptosis of CML-BC cells. Additionally, LAQ824 down-regulated the levels of mutant Bcr-Abl possessing the T315I point mutation, as well as induced apoptosis of imatinib-refractory primary CML-BC cells. Therefore, LAQ824 may be a promising therapeutic agent in the treatment of imatinib-sensitive or -refractory human leukemia.
MeSH terms
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Acetylation
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Antineoplastic Agents / pharmacology*
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Apoptosis / drug effects*
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Benzamides
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Blast Crisis / drug therapy*
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Cyclin-Dependent Kinase Inhibitor p21
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Cyclins / biosynthesis
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Cysteine Endopeptidases / physiology*
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Drug Resistance, Neoplasm
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Enzyme Inhibitors / pharmacology*
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Fusion Proteins, bcr-abl / genetics
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Fusion Proteins, bcr-abl / metabolism*
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G1 Phase / drug effects
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Histone Deacetylase Inhibitors*
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Humans
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Hydroxamic Acids / pharmacology*
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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 / metabolism
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Leukemia, Myelogenous, Chronic, BCR-ABL Positive / pathology
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Microfilament Proteins / biosynthesis
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Multienzyme Complexes / physiology*
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Muscle Proteins*
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Piperazines / pharmacology*
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Promoter Regions, Genetic
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Proteasome Endopeptidase Complex
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Pyridones / pharmacology
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Pyrimidines / pharmacology*
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Tumor Cells, Cultured
Substances
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Antineoplastic Agents
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Benzamides
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CDKN1A protein, human
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Cyclin-Dependent Kinase Inhibitor p21
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Cyclins
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Enzyme Inhibitors
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Histone Deacetylase Inhibitors
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Hydroxamic Acids
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LAQ824
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Microfilament Proteins
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Multienzyme Complexes
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Muscle Proteins
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Piperazines
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Pyridones
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Pyrimidines
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Tagln protein, mouse
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Imatinib Mesylate
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Fusion Proteins, bcr-abl
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Cysteine Endopeptidases
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Proteasome Endopeptidase Complex
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PD 180970