Inhibition of cell cycle pathway by flavopiridol promotes survival of cerebellar granule cells after an excitotoxic treatment.
Kainic acid (KA)-induced neuronal damage and the protective effects of flavopiridol were studied in primary cultures of rat cerebellar granule cells (CGNs). When neurons were treated with 500 microM KA, the percentage of cells with condensed nuclei measured by nuclear counting increased by up to 55%. After flavopiridol treatment, an antitumoral drug that is a broad inhibitor of cyclin-dependent kinases, the percentage of condensed nuclei decreased by up to 26%. Furthermore, this KA-mediated cell death was only partially dependent on the activation of the initiator caspase-9 and the effector caspases-3 and -6. This argues for a minor role of caspases in the intracellular pathway leading to KA-induced programmed cell death in CGNs. We examined the possible implication of cell cycle proteins in KA-induced neurotoxicity. We found an increase in the expression of proliferating cell nuclear antigen and E2F-1, two proteins implicated in S-phase, by Western blot. KA increased bromodeoxyuridine incorporation in CGNs, a marker of cell proliferation, and flavopiridol attenuated this effect. These results indicated that flavopiridol decreased the expression of cell cycle markers in CGNs after KA treatment. Flavopiridol might thus be used as a preventive agent against neurodegenerative diseases associated with cell cycle activation.
Verdaguer
Ester
E
Unitat de Farmacologia i Farmacognòsia, Facultat de Farmàcia, Universitat de Barcelona, Nucli Universitari de Pedralbes, Barcelona, Spain. camins@ub.edu
Jiménez
Andrés
A
Canudas
Anna M
AM
Jordà
Elvira G
EG
Sureda
F Xavier
FX
Pallàs
Mercè
M
Camins
Antoni
A
D000818:Animals; D001973:Bromodeoxyuridine; D020169:Caspases / Q000378:metabolism; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D002467:Cell Nucleus / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology; D004268:DNA-Binding Proteins; D004347:Drug Interactions; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018690:Excitatory Amino Acid Agonists; D005419:Flavonoids / Q000494:pharmacology*; D007608:Kainic Acid / Q000494:pharmacology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D010880:Piperidines / Q000494:pharmacology*; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D015854:Up-Regulation
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; C493755:E2f1 protein, rat; D004791:Enzyme Inhibitors; D018690:Excitatory Amino Acid Agonists; D005419:Flavonoids; D018696:Neuroprotective Agents; D010880:Piperidines; D018809:Proliferating Cell Nuclear Antigen; D018091:Receptors, AMPA; D014157:Transcription Factors; C077990:alvocidib; D020169:Caspases; D001973:Bromodeoxyuridine; D007608:Kainic Acid