title: Simultaneous suppression of cdc2 and cdk2 activities induces neuronal differentiation of PC12 cells.
abstract: The involvement of cdc2 and cdk2 during neuronal differentiation in rat pheochromocytoma PC12 cells was examined. When PC12 cells were cultured with nerve growth factor (NGF), expression of cdc2 decreased significantly after day 5, while expression of cdk2 decreased gradually after day 7. Cells overexpressing cdc2 or cdk2 were resistant to NGF-induced differentiation and growth suppression, and maintained high cdc2 or cdk2 kinase activity, respectively, during NGF treatment. In contrast, the NGF-treated parental cells showed a marked decline in these kinase activities after day 3. When PC12 cells were treated with specific inhibitors of cdc2/cdk2 (butyrolactone-I, olomoucin), they showed marked neurite extension and up-regulation of microtubule-associated protein 2 expression. In addition, treatment with mixtures of antisense oligonucleotides for cdc2 and cdk2 resulted in down-regulation of both cdc2 and cdk2 kinase activities as well as significant neurite outgrowth and up-regulation of microtubule-associated protein 2 expression. However, neurite outgrowth was not observed in cells treated with either single antisense oligonucleotide, or antisense cdc2 + cdk4 or cdk2 + cdk4 oligonucleotide mixtures. These results suggest that simultaneous down-regulation of cdc2 and cdk2 activity is sufficient and necessary for neuronal differentiation in PC12 cells.
authors.affiliation: Department of Pathology, Kitasato University School of Medicine, 1-15-1, Kitasato, Sagamihara, Kanagawa 228-8555, Japan. ydobashi@med.kitasato-u.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Dobashi
authors.forename: M
authors.initials: M
authors.lastname: Shoji
authors.forename: M
authors.initials: M
authors.lastname: Kitagawa
authors.forename: T
authors.initials: T
authors.lastname: Noguchi
authors.forename: T
authors.initials: T
authors.lastname: Kameya
mesh_terms: D000818:Animals; D016203:CDC2 Protein Kinase / Q000037:antagonists & inhibitors / Q000502:physiology*; D042846:CDC2-CDC28 Kinases; D002454:Cell Differentiation; D002455:Cell Division; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D003720:Densitometry; D015151:Immunoblotting; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D020932:Nerve Growth Factor / Q000378:metabolism; D009474:Neurons / Q000166:cytology*; D016376:Oligonucleotides, Antisense / Q000378:metabolism; D016716:PC12 Cells; D010766:Phosphorylation; D010957:Plasmids; D011233:Precipitin Tests; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D011518:Proto-Oncogene Proteins; D051381:Rats; D013997:Time Factors; D014162:Transfection
chemical_list: D008869:Microtubule-Associated Proteins; D016376:Oligonucleotides, Antisense; D011518:Proto-Oncogene Proteins; D020932:Nerve Growth Factor; D017346:Protein Serine-Threonine Kinases; D016203:CDC2 Protein Kinase; D042846:CDC2-CDC28 Kinases; C495892:Cdk2 protein, rat; C495903:Cdk4 protein, rat; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases