Cellular effects of purvalanol A: a specific inhibitor of cyclin-dependent kinase activities.
We have studied the effects of purvalanol A on the cell cycle progression, proliferation and viability. In synchronized cells, purvalanol A induced a reversible arrest the progression in G1 and G2 phase of the cell cycle, but did not prevent the completion of DNA synthesis in S-phase cells. The specificity of action of the drug was supported by the selective inhibition of the phosphorylation of cyclin-dependent kinase (cdk) substrates such as Rb and cyclin E. The cell contents of cyclins D1 and E were lower in cells incubated with purvalanol A compared to controls, but the level of the cdk inhibitory protein p21(WAF1/CIP1) was increased, indicating that the drug did not cause a general inhibition of gene expression. Purvalanol A did not inhibit transcription under cell-free conditions. This compound, however, caused an inhibition of the estradiol-induced expression of an integrated luciferase gene, suggesting that cdk or related enzymes may participate in the regulation of the activity of certain promoters. When exponentially growing cells, both mouse fibroblasts and human cancer cell lines, were incubated with purvalanol A for prolonged periods of time (24 hr), a lasting inhibition of cell proliferation as well as cell death were observed. In contrast, a 24 hr incubation of quiescent (non-transformed) cells with purvalanol A did not prevent their resumption of cell cycle after removal of the drug.
Villerbu
Nathalie
N
INSERM U482, Paris, France.
Gaben
Anne-Marie
AM
Redeuilh
Gérard
G
Mester
Jan
J
D001943:Breast Neoplasms / Q000188:drug therapy / Q000473:pathology; D002453:Cell Cycle / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects*; D003110:Colonic Neoplasms / Q000378:metabolism*; D019938:Cyclin D1 / Q000378:metabolism; D019927:Cyclin E / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors*; D016213:Cyclins / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D019073:HT29 Cells / Q000187:drug effects; D006367:HeLa Cells / Q000187:drug effects; D006801:Humans; D008715:Methionine / Q000378:metabolism; D008840:Microfilament Proteins / Q000378:metabolism; D009124:Muscle Proteins; D010766:Phosphorylation; D016160:Retinoblastoma Protein / Q000378:metabolism; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured / Q000187:drug effects; D002583:Uterine Cervical Neoplasms / Q000188:drug therapy / Q000473:pathology
C493956:CDKN1A protein, human; D019927:Cyclin E; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004791:Enzyme Inhibitors; D008840:Microfilament Proteins; D009124:Muscle Proteins; D016160:Retinoblastoma Protein; C058992:Tagln protein, mouse; D019938:Cyclin D1; D008715:Methionine; D018844:Cyclin-Dependent Kinases