Differential regulation of cell cycle machinery by various antiproliferative agents is linked to macrophage arrest at distinct G1 checkpoints.
There is currently much interest in the mechanisms of action of antiproliferative agents and their effects on cell cycle machinery. In the present study we examined the mechanisms of action of four unrelated agents known to inhibit proliferation of CSF-1-stimulated bone marrow-derived macrophages (BMM). We report that 8-bromo-cAMP (8Br-cAMP) and lipopolysaccharide (LPS) potently reduced CSF-1-stimulated cyclin D1 protein, and cyclin-dependent kinase (cdk) 4 mRNA and protein levels, while the inhibitory effects of the Na+/ H+ antiport inhibitor 5-(N',N'-dimethyl) amiloride (DMA) and interferon gamma (IFN gamma ) were only weak. All agents repressed CSF-1-stimulated retinoblastoma protein phosphorylation. Furthermore, 8Br-cAMP and to a lesser extent IFN gamma, also reduced CSF-1-stimulated levels of E2F DNA binding activity in a macrophage cell line, BAC1.2F5. An explanation for the different effects of the agents is that 8Br-cAMP and LPS were found to arrest BMM in early/mid-G1, while IFN gamma and DMA arrested cells in late G1 or early S phase. These data indicate that (1) different antiproliferative agents can arrest the same cell type at distinct checkpoints in G1 and (2) effects of antiproliferative agents on cell cycle machinery is linked to the position at which they arrest cells in G1.
Vadiveloo
P K
PK
Department of Medicine, University of Melbourne, Royal Melbourne Hospital, Parkville, Australia.
Vairo
G
G
Novak
U
U
Royston
A K
AK
Whitty
G
G
Filonzi
E L
EL
Cragoe
E J
EJ
Hamilton
J A
JA
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001483:Base Sequence; D002352:Carrier Proteins; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology; D018797:Cell Cycle Proteins; D002455:Cell Division / Q000187:drug effects; D019938:Cyclin D1; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases / Q000494:pharmacology; D016213:Cyclins / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D016193:G1 Phase / Q000187:drug effects* / Q000502:physiology; D007371:Interferon-gamma / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D015513:Oncogene Proteins / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011518:Proto-Oncogene Proteins; D016160:Retinoblastoma Protein / Q000378:metabolism; D056465:Retinoblastoma-Binding Protein 1; D050680:Transcription Factor DP1; D014157:Transcription Factors / Q000378:metabolism
D000970:Antineoplastic Agents; C533431:Arid4a protein, mouse; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D016213:Cyclins; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D008070:Lipopolysaccharides; D015513:Oncogene Proteins; D011518:Proto-Oncogene Proteins; D016160:Retinoblastoma Protein; D056465:Retinoblastoma-Binding Protein 1; D050680:Transcription Factor DP1; D014157:Transcription Factors; D019938:Cyclin D1; D015124:8-Bromo Cyclic Adenosine Monophosphate; C039465:5-dimethylamiloride; D000584:Amiloride; D007371:Interferon-gamma; D004247:DNA; C495902:Cdk4 protein, mouse; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases