Role of NF-kappaB and DNA repair protein Ku on apoptosis in pancreatic acinar cells.
Reactive oxygen species have been known to cause DNA damage and induce apoptosis. During DNA damage, DNA repair proteins Ku70 and Ku80 prevent cell death, but severe DNA damage beyond the repair capacity of the DNA repair proteins triggers necrosis or apoptosis. Recent reports have shown that NF-kappaB plays a critical role in protecting the cells from apoptosis. We investigated whether glucose oxidase acting on beta-D-glucose (G/GO), which continuously produces H(2)O(2), induces apoptosis, and whether NF-kappaB and Ku are involved in G/GO-induced apoptosis in pancreatic acinar AR42J cells. Electron microscopic observation showed that apoptotic cells with characteristic nuclear condensation and shrinkage as well as large vacuoles were detected after G/GO treatment. G/GO treatment induced apoptotic cell death, as determined by viable cell count and DNA fragmentation. G/GO-induced apoptosis was increased in the cells transfected with the Ku-dominant negative mutant (Ku D/N) and mutated IkappaBalpha gene (IkappaB mt) as compared to the wild-type cells (Wild) and the cells transfected with the control pcDNA3 vector (pcN-3). G/GO treatment caused nuclear loss of both Ku70 and Ku80 in Wild cells and pcN-3 cells. Even without G/GO treatment, nuclear loss of Ku proteins was observed in IkappaB mt cells. These results suggest that oxidative stress-induced reduction of nuclear Ku proteins may cause loss of defense against DNA damage and thus induce apoptosis in pancreatic acinar cells. The novel finding is that nuclear translocation of Ku proteins may be mediated by NF-kappaB.
Song
Ji Yeon
JY
Department of Pharmacology and Institute of Gastroenterology, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752, Korea.
Lim
Joo Weon
JW
Kim
Hyeyoung
H
Kim
Kyung Hwan
KH
D000818:Animals; D034961:Antigens, Nuclear / Q000378:metabolism*; D017209:Apoptosis / Q000502:physiology*; D001324:Autoantigens / Q000378:metabolism; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005949:Glucose Oxidase / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D000072200:Ku Autoantigen; D016328:NF-kappa B / Q000378:metabolism*; D010179:Pancreas; D021381:Protein Transport; D051381:Rats
D034961:Antigens, Nuclear; D001324:Autoantigens; D004268:DNA-Binding Proteins; D016328:NF-kappa B; D006861:Hydrogen Peroxide; D005949:Glucose Oxidase; C000606511:Xrcc6 protein, rat; D000072200:Ku Autoantigen