title: Inhibitors of cyclin-dependent kinases promote survival of post-mitotic neuronally differentiated PC12 cells and sympathetic neurons.
abstract: Previous studies have demonstrated that multiple agents that promote survival of PC12 cells and sympathetic neurons deprived of trophic support also block cell cycle progression. Presently, we address whether inhibition of cell cycle-related cyclin-dependent kinases (CDKs) prevents neuronal cell death. We show that two distinct CDK inhibitors, flavopiridol and olomoucine, suppress the death of neuronal PC12 cells and sympathetic neurons. In addition, we demonstrate that inhibitor concentrations required to promote survival correlate with their ability to inhibit proliferation. Promotion of survival, however, does not correlate with inhibition of extracellular signal-regulated kinase or c-Jun kinase activities or with interference with the activation of c-Jun kinase that accompanies serum/nerve growth factor deprivation. In contrast to their actions on nerve growth factor-differentiated PC12 cells, the CDK inhibitors do not prevent the death of proliferation-competent PC12 cells and, in fact, promote their cell death. These findings support the hypothesis that post-mitotic neuronal cells die after removal of trophic support due to an attempt to re-enter the cell cycle in an uncoordinated and inappropriate manner. We speculate that cycling PC12 cells are not saved by these agents due to a signaling conflict between an inherent oncogenic signal and the inhibition of CDK activity.
authors.affiliation: Department of Pathology, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA.
authors.forename: D S
authors.initials: DS
authors.lastname: Park
authors.forename: S E
authors.initials: SE
authors.lastname: Farinelli
authors.forename: L A
authors.initials: LA
authors.lastname: Greene
mesh_terms: D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002453:Cell Cycle; D002454:Cell Differentiation; D002470:Cell Survival; D002478:Cells, Cultured; D003470:Culture Media; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases; D007701:Kinetin; D020928:Mitogen-Activated Protein Kinases; D009414:Nerve Growth Factors / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000096:biosynthesis; D016716:PC12 Cells; D010880:Piperidines / Q000494:pharmacology*; D011687:Purines / Q000494:pharmacology*; D051381:Rats; D013564:Sympathetic Nervous System / Q000166:cytology*
chemical_list: D003470:Culture Media; D004791:Enzyme Inhibitors; D005419:Flavonoids; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D010880:Piperidines; D011687:Purines; C077990:alvocidib; C090046:olomoucine; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D018844:Cyclin-Dependent Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D007701:Kinetin