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Up-regulation of cdc2 protein during paclitaxel-induced apoptosis

Abstract : Microtubule damages induced by paclitaxel inhibit proteasome-dependent degradation of cyclin B, resulting in a sustained activation of cyclin B/cdc2 kinase and a cell cycle arrest in mitosis. It has been previously shown that this kinase activity is also required for paclitaxel-induced apoptosis. We found here that paclitaxel increased cdc2 mRNA and protein levels and led to an accumulation of cdc2 in the active dephosphorylated form in NIH-OVCAR-3 cells. The addition of cycloheximide inhibited the paclitaxel-induced increase in cdc2 protein level, further indicating that paclitaxel stimulates cdc2 synthesis. This increase in cdc2 synthesis is a consequence of paclitaxel-induced arrest in mitosis. Indeed, dual analysis of DNA and cdc2 protein contents indicated that cdc2 up-regulation occurred in cells arrested with a G2/M DNA content. Furthermore, no up-regulation of cdc2 protein was observed when paclitaxel-treated cells were prevented from entering mitosis by treatment with purvalanol A, a cyclin-dependent kinase (CDK) inhibitor, or stimulated to exit mitosis with 2-AP, a non-specific kinase inhibitor. In addition, when paclitaxel-induced apoptosis was inhibited by Bcl-2 over-expression, cdc2 up-regulation did not occur, leading to a lower level of activation of the cyclin B/cdc2 complex. Taken together, these results indicated that paclitaxel-induced cdc2 protein synthesis participates in a positive feedback loop designed to increase the activity of cyclin B/cdc2 kinase and thus may play a role in paclitaxel-induced apoptosis.
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https://www.hal.inserm.fr/inserm-03253482
Contributor : Philippe Chadebech <>
Submitted on : Tuesday, June 8, 2021 - 12:14:12 PM
Last modification on : Thursday, June 10, 2021 - 3:32:13 AM

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Philippe Chadebech, Isabelle Truchet, Laetitia Brichese, Annie Valette. Up-regulation of cdc2 protein during paclitaxel-induced apoptosis. International Journal of Cancer, Wiley, 2000, 87 (6), pp.779-786. ⟨10.1002/1097-0215(20000915)87:6<779::AID-IJC3>3.0.CO;2-4⟩. ⟨inserm-03253482⟩

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