Abstract
High expression of the epidermal growth factor receptor (EGFR) has been implicated in the development of squamous-cell carcinomas of head and neck (SCCHN). ZD1839 ('Iressa') is an orally active, selective EGFR-TKI (EGFR-tyrosine kinase inhibitor) that blocks signal transduction pathways implicated in proliferation and survival of cancer cells, and other host-dependent processes promoting cancer growth. We have demonstrated that ZD1839 induces growth arrest in SCCHN cell lines by inhibiting EGFR-mediated signaling. Cell cycle kinetic analysis demonstrated that ZD1839 induces a delay in cell cycle progression and a G1 arrest together with a partial G2/M block; this was associated with increased expression of both p27(KIP1) and p21(CIP1/WAF1) cyclin-dependent kinase (CDK) inhibitors. The activity of CDK2, the main target of CIP/KIP CDK inhibitors, was reduced in a dose-dependent fashion after 24 h of ZD1839 treatment and this effect correlated to the increased amount of p27(KIP1) and p21(CIP1/WAF1) proteins associated with CDK2-cyclin-E and CDK2-cyclin-A complexes. In addition, ZD1839-induced growth inhibition was significantly reduced in cell transfectants expressing p27(KIP1) or p21(CIP1/WAF1) antisense constructs. Overall, these results as well as the timing of the effect of ZD1839 on G1 arrest and p27(KIP1) and p21(CIP1/WAF1) upregulation, suggest a mechanistic connection between these events.
Copyright 2003 Wiley-Liss, Inc.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Antineoplastic Agents / pharmacology*
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CDC2-CDC28 Kinases*
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Carcinoma, Squamous Cell / drug therapy*
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Carcinoma, Squamous Cell / metabolism
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Carcinoma, Squamous Cell / pathology
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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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Cell Division / drug effects
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Cyclin-Dependent Kinase 2
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Cyclin-Dependent Kinase Inhibitor p21
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Cyclin-Dependent Kinase Inhibitor p27
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Cyclin-Dependent Kinases / metabolism
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Cyclins / antagonists & inhibitors
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Cyclins / genetics
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Cyclins / metabolism*
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Dose-Response Relationship, Drug
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Drug Screening Assays, Antitumor
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ErbB Receptors / antagonists & inhibitors*
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ErbB Receptors / biosynthesis
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G1 Phase / drug effects
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Gefitinib
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Head and Neck Neoplasms / drug therapy*
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Head and Neck Neoplasms / metabolism
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Head and Neck Neoplasms / pathology
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Humans
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Macromolecular Substances
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Oligonucleotides, Antisense / genetics
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Oligonucleotides, Antisense / pharmacology
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Protein Serine-Threonine Kinases / metabolism
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Quinazolines / pharmacology*
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Signal Transduction / drug effects
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Transfection
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Tumor Cells, Cultured
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Tumor Suppressor Proteins / antagonists & inhibitors
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Tumor Suppressor Proteins / genetics
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Tumor Suppressor Proteins / metabolism*
Substances
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Antineoplastic Agents
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CDKN1A protein, human
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Cell Cycle Proteins
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Cyclin-Dependent Kinase Inhibitor p21
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Cyclins
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Macromolecular Substances
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Oligonucleotides, Antisense
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Quinazolines
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Tumor Suppressor Proteins
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Cyclin-Dependent Kinase Inhibitor p27
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ErbB Receptors
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Protein Serine-Threonine Kinases
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CDC2-CDC28 Kinases
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CDK2 protein, human
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Cyclin-Dependent Kinase 2
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Cyclin-Dependent Kinases
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Gefitinib