Abstract
AZD1775 targets the cell cycle checkpoint kinase Wee1 and potentiates genotoxic agent cytotoxicity through p53-dependent or -independent mechanisms. Here, we report that AZD1775 interacted synergistically with histone deacetylase inhibitors (HDACIs, for example, Vorinostat), which interrupt the DNA damage response, to kill p53-wild type (wt) or -deficient as well as FLT3-ITD leukemia cells in association with pronounced Wee1 inhibition and diminished cdc2/Cdk1 Y15 phosphorylation. Similarly, Wee1 shRNA knockdown significantly sensitized cells to HDACIs. Although AZD1775 induced Chk1 activation, reflected by markedly increased Chk1 S296/S317/S345 phosphorylation leading to inhibitory T14 phosphorylation of cdc2/Cdk1, these compensatory responses were sharply abrogated by HDACIs. This was accompanied by premature mitotic entry, multiple mitotic abnormalities and accumulation of early S-phase cells displaying increased newly replicated DNA, culminating in robust DNA damage and apoptosis. The regimen was active against patient-derived acute myelogenous leukemia (AML) cells harboring either wt or mutant p53 and various next-generation sequencing-defined mutations. Primitive CD34(+)/CD123(+)/CD38(-) populations enriched for leukemia-initiating progenitors, but not normal CD34(+) hematopoietic cells, were highly susceptible to this regimen. Finally, combining AZD1775 with Vorinostat in AML murine xenografts significantly reduced tumor burden and prolonged animal survival. A strategy combining Wee1 with HDACI inhibition warrants further investigation in AML with poor prognostic genetic aberrations.
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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Animals
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Apoptosis / drug effects
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CDC2 Protein Kinase
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Cell Cycle Checkpoints / drug effects
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Cell Cycle Proteins / antagonists & inhibitors*
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism
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Checkpoint Kinase 1
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Cyclin-Dependent Kinases / antagonists & inhibitors
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Cyclin-Dependent Kinases / genetics
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Cyclin-Dependent Kinases / metabolism
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DNA Fragmentation / drug effects
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Drug Synergism
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Drug Therapy, Combination
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Gene Expression Regulation, Leukemic*
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Histone Deacetylase Inhibitors / pharmacology*
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Humans
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Hydroxamic Acids / pharmacology*
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Leukemia, Myeloid, Acute / drug therapy*
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Leukemia, Myeloid, Acute / genetics
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Leukemia, Myeloid, Acute / mortality
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Leukemia, Myeloid, Acute / pathology
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Mice
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Myeloid Cells / metabolism
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Myeloid Cells / pathology
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Nuclear Proteins / antagonists & inhibitors*
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism
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Phosphorylation
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Primary Cell Culture
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Protein Kinase Inhibitors / pharmacology*
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Protein Kinases / genetics
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Protein Kinases / metabolism
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Protein-Tyrosine Kinases / antagonists & inhibitors*
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Protein-Tyrosine Kinases / genetics
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Protein-Tyrosine Kinases / metabolism
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Signal Transduction
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Survival Analysis
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Tumor Suppressor Protein p53 / genetics
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Tumor Suppressor Protein p53 / metabolism
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Vorinostat
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Xenograft Model Antitumor Assays
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fms-Like Tyrosine Kinase 3 / genetics
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fms-Like Tyrosine Kinase 3 / metabolism
Substances
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Cell Cycle Proteins
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Histone Deacetylase Inhibitors
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Hydroxamic Acids
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Nuclear Proteins
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Protein Kinase Inhibitors
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Tumor Suppressor Protein p53
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Vorinostat
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Protein Kinases
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FLT3 protein, human
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Protein-Tyrosine Kinases
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fms-Like Tyrosine Kinase 3
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WEE1 protein, human
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CHEK1 protein, human
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Checkpoint Kinase 1
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Chek1 protein, mouse
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CDC2 Protein Kinase
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CDK1 protein, human
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Cyclin-Dependent Kinases