Oxygen-induced apoptosis in PC12 cells with special reference to the role of Bcl-2.
We previously reported that PC12h cells are killed by a high oxygen atmosphere. In this study, we further characterized this oxygen-induced cell death and found apoptotic features, as follows. Firstly, chromatin condensation was observed in cells cultured in a 50% O2 atmosphere. Secondly, cycloheximide and cordycepin, protein and RNA synthesis inhibitors, respectively, prevented the oxygen-induced cell death in PC12h cells, suggesting that it is mediated by an intracellular death program. Thirdly, NGF, CPT-cAMP and depolarization by high potassium medium also effectively inhibited this apoptotic cell death in PC12h cells. The effect of high K+ is thought to be mediated by the influx of Ca2+ into cells through voltage-dependent Ca2+ channels, because nifedipine, an L-type Ca2+ channel blocker, inhibited the effect of high K+. In addition, since the oxygen-induced apoptosis was blocked by the antioxidant vitamin E, this oxygen toxicity is suggested to be mediated by reactive oxygen species. To further characterize this oxygen-induced apoptosis at the molecular level, we used PC12 cells overexpressing the proto-oncogene bcl-2. Although a large number of PC12 cells transfected with the control vector died in a 50% O2 atmosphere within 6 days, bcl-2-transfected PC12 cells survived and proliferated. These findings suggested that our system using PC12 cells will be a useful model with which to analyze the molecular mechanisms of apoptosis induced by oxidative stress in neuronal cells.
Kubo
T
T
Division of Protein Biosynthesis, Osaka University, Japan.
Enokido
Y
Y
Yamada
M
M
Oka
T
T
Uchiyama
Y
Y
Hatanaka
H
H
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003513:Cycloheximide / Q000494:pharmacology; D003839:Deoxyadenosines / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D051379:Mice; D009414:Nerve Growth Factors / Q000302:isolation & purification / Q000494:pharmacology; D009543:Nifedipine / Q000494:pharmacology; D009994:Osmolar Concentration; D010100:Oxygen / Q000633:toxicity*; D016716:PC12 Cells; D011188:Potassium / Q000494:pharmacology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D051381:Rats; D013997:Time Factors
D003839:Deoxyadenosines; D009414:Nerve Growth Factors; D019253:Proto-Oncogene Proteins c-bcl-2; D003513:Cycloheximide; C058120:cordycepin; D009543:Nifedipine; D011188:Potassium; D010100:Oxygen