title: Roles of cyclin-dependent kinase 4 and p53 in neuronal cell death induced by doxorubicin on cerebellar granule neurons in mouse.
abstract: Cell cycle regulators such as cyclin-dependent kinases (Cdks) and their inhibitors (Ckis) have been reported to be involved in neuronal cell death (NCD) induced by a variety of insults such as ischemia, UV-irradiation, nerve growth factor (NGF)-withdrawal, and anticancer therapeutics. But their precise interactive regulation has still to be unveiled. In the present study, we focused on cell cycle regulators such as Cdk4, p21(WAF1) and p53 to clarify their regulatory mechanisms, using NCD induced by doxorubicin (D-NCD) in mouse cerebellar granule neurons as a model. Doxorubicin induced NCD in a dose-dependent manner, a typical feature of apoptosis as determined by TUNEL assay. Doxorubicin increased the protein expression of p53 in time- and dose-dependent manners. The protein expression of p21(WAF1), a Cki of Cdk4, was stimulated by doxorubicin at low concentrations, but it disappeared at high concentrations. Doxorubicin activated the kinase activity of Cdk4 without the enhancement of Cdk4 protein. 3-Amino-9-thio(10H)-acridone (3-ATA), the specific inhibitor of Cdk4, prevented D-NCD in a dose-dependent manner. Wortmannin, an inhibitor of ATM (ataxia telangiectasia, mutated) that has high homology with the phosphatidyl-inositol-3-kinase (PI3K) family and has protein kinase activity for the induction of p53 with specificity for serine and threonine residues, inhibited the activation of Cdk4 without the induction of p53 in D-NCD. These data suggest that (1) Cdk4 is one of the essential components for inducing NCD, that (2) p53 may prevent D-NCD through the induction of p21(WAF1) at low concentrations of doxorubicin, and that (3) Cdk4 might be activated by the same signal-molecules, like ATM, that are necessary for the activation of p53 in D-NCD.
authors.affiliation: Department of Clinical Cell Biology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Otsuka
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Tanaka
authors.forename: Daigaku
authors.initials: D
authors.lastname: Uchida
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Noguchi
authors.forename: Naokatsu
authors.initials: N
authors.lastname: Saeki
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Saito
authors.forename: Ichiro
authors.initials: I
authors.lastname: Tatsuno
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D051358:Cyclin-Dependent Kinase 4; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D016213:Cyclins / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D004317:Doxorubicin / Q000008:administration & dosage / Q000494:pharmacology*; D020287:In Situ Nick-End Labeling; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D011518:Proto-Oncogene Proteins; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis*
chemical_list: C493957:Cdkn1a protein, mouse; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D011518:Proto-Oncogene Proteins; D016159:Tumor Suppressor Protein p53; D004317:Doxorubicin; C495902:Cdk4 protein, mouse; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases