Abstract
Cyclin-dependent kinases (cdks) represent potentially promising molecular targets for cancer therapeutic strategies. To evaluate the antitumor activity of selective cyclin/cdk inhibition, we constructed a chimeric protein composed of a F-box protein (TrCP) fused to a peptide comprising the cyclin/cdk2 binding motif in p21-like cdk inhibitors (TrCP-LFG). We now demonstrate that endogenous cyclin A and its binding substrate, cdk2, can be tethered to beta-TrCP, ubiquitinated, and effectively degraded. Degradation of cdk2 and cyclin A together, but not cdk2 alone, results in massive tumor cell apoptosis in vitro and in vivo in a proteasome-dependent manner with no toxicity to normal tissue. These data demonstrate that cyclin A and/or the cyclin A/cdk2 complex is a promising anticancer target with a high therapeutic index.
MeSH terms
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Animals
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Apoptosis / genetics
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Apoptosis Regulatory Proteins
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CDC2-CDC28 Kinases / antagonists & inhibitors*
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CDC2-CDC28 Kinases / metabolism
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Carrier Proteins / genetics
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Carrier Proteins / metabolism
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Carrier Proteins / pharmacology*
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Cell Division / drug effects
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Cell Division / physiology
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Cell Line, Tumor
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Cyclin A / antagonists & inhibitors*
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Cyclin A / metabolism
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Cyclin-Dependent Kinase 2
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Cysteine Endopeptidases / metabolism*
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Female
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Glioma / drug therapy
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Glioma / pathology
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HeLa Cells
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Humans
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Membrane Proteins
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Mice
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Mice, Nude
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Multienzyme Complexes / metabolism*
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Proteasome Endopeptidase Complex
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Protein Engineering
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Recombinant Fusion Proteins / pharmacology
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Transduction, Genetic
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Xenograft Model Antitumor Assays
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beta-Transducin Repeat-Containing Proteins / genetics
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beta-Transducin Repeat-Containing Proteins / metabolism
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beta-Transducin Repeat-Containing Proteins / pharmacology*
Substances
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Apoptosis Regulatory Proteins
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Carrier Proteins
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Cyclin A
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FAIM2 protein, human
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Membrane Proteins
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Multienzyme Complexes
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Recombinant Fusion Proteins
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beta-Transducin Repeat-Containing Proteins
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CDC2-CDC28 Kinases
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CDK2 protein, human
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Cdk2 protein, mouse
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Cyclin-Dependent Kinase 2
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Cysteine Endopeptidases
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Proteasome Endopeptidase Complex