Effect of overexpression of BCL-2 on cellular oxidative damage, nitric oxide production, antioxidant defenses, and the proteasome.
Bcl-2 is a gene family involved in the suppression of apoptosis in response to a wide range of cellular insults. Multiple papers have suggested a link between Bcl-2 and oxidative damage/antioxidant protection. We therefore examined parameters of antioxidant defense and oxidative damage in two different cell lines, NT-2/D1 (NT-2) and SK-N-MC, overexpressing Bcl-2 as compared with vector-only controls. Bcl-2 transfectants of both cell lines were more resistant to H(2)O(2) and showed increases in GSH level and Cu/Zn-superoxide dismutase (SOD1) activity, but not in Mn-superoxide dismutase, glutathione peroxidase, or glutathione reductase activities. Catalase activity was increased in SK-N-MC cells. Overexpression of Bcl-2 did not significantly decrease levels of oxidative DNA damage (measured as 8-hydroxyguanine) or lipid peroxidation, but it decreased levels of 3-nitrotyrosine in both cell lines and protein carbonyls in SK-N-MC cells only. It also increased proteasome activity in both cell lines. We conclude that Bcl-2 raises cellular antioxidant defense status, but this is not necessarily reflected in decreased levels of oxidative damage to DNA and lipids. The ability of Bcl-2 overexpression to decrease 3-nitrotyrosine levels suggests that it may decrease formation of peroxynitrite or other reactive nitrogen species; this was confirmed as decreased production of NO(2)(-)/NO(3)(-) in the transfected cells and a fall in the level of nNOS protein.
Lee
M
M
Wolfson Centre for Age-Related Diseases, Guy's, King's and St. Thomas' School of Biomedical Sciences, King's College London, London, UK.
Hyun
D H
DH
Marshall
K A
KA
Ellerby
L M
LM
Bredesen
D E
DE
Jenner
P
P
Halliwell
B
B
D000975:Antioxidants / Q000378:metabolism*; D002470:Cell Survival / Q000502:physiology; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004789:Enzyme Activation; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D008297:Male; D009097:Multienzyme Complexes / Q000378:metabolism*; D009380:Neoplasms, Nerve Tissue; D009447:Neuroblastoma; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology; D046988:Proteasome Endopeptidase Complex; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis / Q000378:metabolism*; D026361:Reactive Nitrogen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D000072105:Superoxide Dismutase-1; D018243:Teratocarcinoma; D013736:Testicular Neoplasms; D014162:Transfection; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
D000975:Antioxidants; D009097:Multienzyme Complexes; D019253:Proto-Oncogene Proteins c-bcl-2; D026361:Reactive Nitrogen Species; C000606290:SOD1 protein, human; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D005978:Glutathione