Unscheduled activation of cyclin B1/Cdc2 kinase in human promyelocytic leukemia cell line HL60 cells undergoing apoptosis induced by DNA damage.
We have studied changes in cyclin A- and B1-dependent kinases during apoptosis induced in human promyelocytic leukemia (HL60) cells treated with the topoisomerase I inhibitor camptothecin. We found that cyclin B1/Cdc2 kinase activity transiently increases within 30 min after camptothecin treatment. This increase is followed by a rapid inactivation of the cyclin B1/Cdc2 kinase that is associated with Cdc2 tyrosine phosphorylation without any change in Cdc2 or cyclin B1 protein levels. The DNA polymerase inhibitor aphidicolin abrogates camptothecin-induced changes in cyclin B1/Cdc2 kinase activity, indicating that DNA replication-induced DNA damage is essential for both Cdc2 alterations and apoptosis activation. Apoptosis and the initial cyclin B1/Cdc2 kinase activation were amplified using synchronized S-phase cells, and cyclin A/cdk2 kinase did not change under these conditions. The same transient activation and subsequent inactivation of cyclin B1/Cdc2 kinase were observed after DNA damage by etoposide or bis-(2-chloroethyl)methylamine hydrochloride. These observations suggest that DNA damage promotes the transient and unscheduled stimulation of cyclin B1/Cdc2 kinase activity in HL60 cells prior to apoptosis.
Shimizu
T
T
Laboratory of Molecular Pharmacology, National Cancer Institute, NIH, Bethesda, Maryland 20892-4255.
O'Connor
P M
PM
Kohn
K W
KW
Pommier
Y
Y
D016590:Aphidicolin / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D016203:CDC2 Protein Kinase / Q000378:metabolism*; D002166:Camptothecin / Q000494:pharmacology; D016213:Cyclins / Q000378:metabolism*; D004249:DNA Damage; D004789:Enzyme Activation / Q000187:drug effects; D005047:Etoposide / Q000494:pharmacology; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D008466:Mechlorethamine / Q000494:pharmacology; D010766:Phosphorylation; D016196:S Phase; D014407:Tumor Cells, Cultured
D016213:Cyclins; D016590:Aphidicolin; D008466:Mechlorethamine; D005047:Etoposide; D016203:CDC2 Protein Kinase; D002166:Camptothecin