title: Roscovitine, olomoucine, purvalanol: inducers of apoptosis in maturing cerebellar granule neurons.
abstract: Cyclin-dependent kinases (CDKs) mediate proliferation and neuronal development, while aberrant CDK activity is associated with cancer and neurodegeneration. Consequently, pharmacologic inhibitors, such as 2,6,9-trisubstituted purines, which potently inhibit CDKs 1, 2, and 5, were developed to combat these pathologies. One agent, R-roscovitine (CYC202), has advanced to clinical trials as a potential cancer therapy. In primary neuronal cultures, these agents have been used to delineate the physiologic and pathologic functions of CDKs, and associated signaling pathways. Herein we demonstrate that three 2,6,9-trisubstituted purines: olomoucine, roscovitine, and purvalanol, used at concentrations ascribed by others to potently inhibit CDKs 1, 2, and 5, are powerful triggers of death in maturing cerebellar granule neurons, assessed by loss of mitochondrial reductive capacity and differential staining with fluorescent indicators of living/dead neurons. Based on several criteria, including delayed time course and establishment of an irreversible commitment point of death, pyknotic cell and nuclear morphology, and caspase-3 cleavage, the death process is apoptotic. However, pharmacological and biochemical data indicate that apoptosis is independent of CDK 1, 2, or 5 inhibition. This is based on the pattern of changes in c-jun mRNA, c-Jun protein, and Ca(2+)/cAMP response element binding protein (CREB) phosphorylation, and also, the ineffectiveness of structurally distinct CDK 1, 2, and 5 inhibitors butyrolactone-1 and PNU112445A to induce apoptosis. Collectively, our results, and those of others, indicate that the CDK regulation of transcription (CDKs 7 and 9) should be examined as a target of these agents, and as an indirect mediator of neuronal fate.
authors.affiliation: Department of Neuroscience & Physiology, SUNY Upstate Medical University, Syracuse, NY 13210, USA.
authors.forename: Edward A
authors.initials: EA
authors.lastname: Monaco
authors.forename: Carol M
authors.initials: CM
authors.lastname: Beaman-Hall
authors.forename: Anjili
authors.initials: A
authors.lastname: Mathur
authors.forename: Mary Lou
authors.initials: ML
authors.lastname: Vallano
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis; D016203:CDC2 Protein Kinase / Q000378:metabolism; D042846:CDC2-CDC28 Kinases / Q000378:metabolism; D002531:Cerebellum / Q000166:cytology*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D051360:Cyclin-Dependent Kinase 5; D042863:Cyclin-Dependent Kinase 9 / Q000378:metabolism; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases; D007701:Kinetin; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects*; D010766:Phosphorylation; D011518:Proto-Oncogene Proteins; D011687:Purines / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D000077546:Roscovitine; D015398:Signal Transduction / Q000187:drug effects; D013449:Sulfonamides / Q000494:pharmacology
chemical_list: C471843:6-((3-chloro)anilino)-2-(isopropyl-2-hydroxyethylamino)-9-isopropylpurine; D017362:Cyclic AMP Response Element-Binding Protein; D004791:Enzyme Inhibitors; C445326:PNU 112455A; D011518:Proto-Oncogene Proteins; D011687:Purines; D011743:Pyrimidines; D013449:Sulfonamides; D000077546:Roscovitine; C090046:olomoucine; C082868:butyrolactone I; D051360:Cyclin-Dependent Kinase 5; D016203:CDC2 Protein Kinase; D042846:CDC2-CDC28 Kinases; C495892:Cdk2 protein, rat; C495903:Cdk4 protein, rat; C495907:Cdk5 protein, rat; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D042863:Cyclin-Dependent Kinase 9; D018844:Cyclin-Dependent Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D015107:4-Butyrolactone; D007701:Kinetin