A brief staurosporine treatment of mitotic cells triggers premature exit from mitosis and polyploid cell formation
Hall, L.L.; Th'ng, J.P.; Guo, X.W.; Teplitz, R.L.; Bradbury, E.M.
Cancer Research 56(15): 3551-3559
1996
ISSN/ISBN: 0008-5472 PMID: 8758926 Document Number: 458654
At any point during the progression of many tumor types, cells can develop a hyperploid DNA content. Hyperploid tumors are significantly more aggressive, with a higher growth rate and a poor patient prognosis. Yeast genetics have implicated three important genes involved in DNA ploidy changes: cdc2, cyclin b, and a specific inhibitor of the p34-cdc2/cyclin B kinase, rum1. Mutations in these genes uncoupled the dependence of mitosis on DNA replication in the fission yeast, Saccharomyces pombe. It was proposed that the inactivation of the mitotic kinase complex, p34-cdc2/cyclin B, induces a G-1 state wherein the cells re-replicate their DNA without an intervening mitosis. We show in this report that treatment of only M phase-arrested mouse cells, with the protein kinase inhibitor staurosporine, induced polyploidy. Nocodazole-arrested metaphase FT210 cells were pulsed with 100 ng/ml of staurosporine for 1 h. This 1-h treatment results in the inhibition of the mitotic p34-cdc2 kinase. The inhibition of the mitotic kinases leads to a reduction in the histone H1 and H3 mitotic-associated phosphorylations, chromosome decondensation, and nuclear membrane reformation. When released into normal growth medium, these cells are reset to a G-1 state, re-replicate their DNA without completing mitosis, and become octaploid.