Apoptosis in RAW 264.7 cells exposed to 4-hydroxy-2-nonenal: dependence on cytochrome C release but not p53 accumulation.
The toxic reactive aldehyde lipid peroxidation byproduct 4-hydroxy-2-nonenal (HNE) is thought to be a major contributor to oxidant stress-mediated cell injury. HNE induced apoptosis in RAW 264.7 murine macrophage cells in a dose-dependent manner within 6-8 h after exposure. Expression of the antiapoptotic protein Bcl-2 in stably transfected RAW 264.7 cells prevented HNE-induced internucleosomal DNA fragmentation and apoptosis, and these cells resume growth after a temporary (24-48 h) growth delay. While parental RAW 264.7 cells released mitochondrial cytochrome c within 3 h after HNE exposure, expression of Bcl-2 prevented cytochrome c release. In control cells, p53 protein levels peaked at 6-9 h after HNE exposure and then declined, while in Bcl-2 expressing cells, p53 levels were maximal at 6-9 h and remained elevated up to 96 h. Expression of SV40 large T-antigen, which forms a stable complex with p53 protein, via stable transfection-blocked transactivation of the p53-regulated gene p21(WAF1/CIP1), but did not affect induction of apoptosis by HNE, suggesting that p53 function is not important in HNE-induced apoptosis. These results suggest that cytochrome c release, but not p53 accumulation, plays an essential role in HNE-induced apoptosis in RAW 264.7 cells.
Haynes
R L
RL
Department of Biochemistry, Wake Forest University, School of Medicine and Comprehensive Cancer Center, Winston Salem, NC 27157, USA.
Brune
B
B
Townsend
A J
AJ
D000447:Aldehydes / Q000494:pharmacology*; D000818:Animals; D000957:Antigens, Viral, Tumor / Q000235:genetics / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D003574:Cytochrome c Group / Q000378:metabolism*; D053938:DNA Fragmentation / Q000187:drug effects; D016676:Macrophages, Alveolar / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D013539:Simian virus 40; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
D000447:Aldehydes; D000957:Antigens, Viral, Tumor; D003574:Cytochrome c Group; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; C027576:4-hydroxy-2-nonenal