title: Etoposide-induced PC12 cell death: apoptotic morphology without oligonucleosomal DNA fragmentation or dependency upon de novo protein synthesis.
abstract: Etoposide, a topoisomerase II inhibitor used in cancer therapy, has been shown to induce apoptosis in vitro in a variety of cell types. In the present study, we have characterized the effects of etoposide on undifferentiated rat pheochromocytoma PC12 cells. Etoposide killed PC12 cells in a time- and concentration-dependent manner. 20-24 h incubation with 10 micrograms/ml etoposide induced 25-50% cell death. Hoechst 33258 staining revealed apoptotic morphology in dying cells. No evidence was found of either oligonucleosomal DNA fragmentation, as shown by agarose gel electrophoresis, or endonuclease involvement, as shown by the inability of aurintricarboxylic acid to prevent cell death. Cycloheximide and actinomycin-D were unable to prevent etoposide cytotoxicity indicating that the process is not dependent upon de novo protein or mRNA synthesis. NGF (5 ng/ml) prevented etoposide-induced PC12 cell death. These results offer an example of how the morphological features of apoptosis are not necessarily associated with oligonucleosomal DNA fragmentation or with de novo macromolecule synthesis.
authors.affiliation: Department of Pharmacology and Clinical Pharmacology, School of Medicine, University of Auckland, New Zealand.
authors.forename: J
authors.initials: J
authors.lastname: Saura
authors.forename: G
authors.initials: G
authors.lastname: MacGibbon
authors.forename: M
authors.initials: M
authors.lastname: Dragunow
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects*; D003513:Cycloheximide / Q000494:pharmacology; D053938:DNA Fragmentation; D003609:Dactinomycin / Q000494:pharmacology; D005047:Etoposide / Q000633:toxicity*; D007150:Immunohistochemistry; D009414:Nerve Growth Factors / Q000494:pharmacology; D009707:Nucleosomes / Q000378:metabolism; D016716:PC12 Cells; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis*; D016755:Proto-Oncogene Proteins c-jun / Q000096:biosynthesis*; D051381:Rats
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D009414:Nerve Growth Factors; D009707:Nucleosomes; D011500:Protein Synthesis Inhibitors; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D003609:Dactinomycin; D005047:Etoposide; D003513:Cycloheximide