The pancreatitis-associated protein is induced by free radicals in AR4-2J cells and confers cell resistance to apoptosis.
OBJECTIVE
Free radicals are involved in the pathogenesis of acute pancreatitis, during which pancreatitis-associated protein (PAP)-I is overexpressed. We explored whether PAP-I expression could be induced by oxidative stress and whether it could affect apoptosis.


METHODS
AR4-2J cells were exposed to H2O2 or menadione, and PAP-I messenger RNA (mRNA) expression was analyzed by Northern blotting.


RESULTS
Maximal expression was observed with 0.1 mmol/L H2O2 or with 0.05 mmol/L menadione. Induction was detectable after 12 hours, reached a climax at 18 hours, and then decreased. Pretreatment of the cells with pyrrolidine dithiocarbamate completely abolished PAP-I mRNA induction, suggesting involvement of NFkappaB in the signaling pathway. These findings were confirmed in transient transfection assays using a plasmid containing the PAP-I promoter linked to the chloramphenicol acetyltransferase reporter gene. Then the relationship between PAP-I induction and protection against cell damage during oxidative stress was considered. Constitutive PAP-I expression in AR4-2J cells after transfection with PAP-I complementary DNA conferred significant resistance to apoptosis induced by low doses of H2O2 but not to necrosis induced by high doses of H2O2.


CONCLUSIONS
These results suggest that during oxidative stress, PAP-I might be part of a mechanism of pancreatic cell protection against apoptosis.
Ortiz
E M
EM
Unité de Recherches de Physiologie et Pathologie Digestives, INSERM Unité 315, Marseille, France.
Dusetti
N J
NJ
Vasseur
S
S
Malka
D
D
Bödeker
H
H
Dagorn
J C
JC
Iovanna
J L
JL
D000209:Acute-Phase Proteins / Q000096:biosynthesis* / Q000235:genetics; D000951:Antigens, Neoplasm; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis; D014408:Biomarkers, Tumor; D002460:Cell Line; D005609:Free Radicals; D006861:Hydrogen Peroxide / Q000633:toxicity; D037181:Lectins, C-Type; D018384:Oxidative Stress; D010179:Pancreas / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D000073718:Pancreatitis-Associated Proteins; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000032:analysis
D000209:Acute-Phase Proteins; D000951:Antigens, Neoplasm; D000975:Antioxidants; D014408:Biomarkers, Tumor; D005609:Free Radicals; D037181:Lectins, C-Type; D000073718:Pancreatitis-Associated Proteins; C000612141:REG3A protein, human; D012333:RNA, Messenger; D006861:Hydrogen Peroxide