Supraphysiologic concentrations of cerulein induce apoptosis in the rat pancreatic acinar cell line AR4-2J

Little is known as yet about the role of apoptosis in pancreatic damage. Th is study evaluated the effects of supraphysiologic concentrations of the ch olecystokinin (CCK) analog, cerulein, which causes cell damage in vitro and acute pancreatitis in vivo, on cell proliferation and DNA fragmentation in the rat pancreatic acinar cell line AR4-2J. Cerulein inhibited the cell pr oliferation of AR4-2J time- and dose-dependently to similar to 60% of the c ontrol level at 10(-6) M after 72 h. DNA fragmentation, as assessed by both electrophoresis and enzyme-linked immunosorbent assay (ELISA), occurred at cerulein concentrations greater than or equal to 10(-8) M. The maximal DNA fragmentation as measured by ELISA was reached after 24 h. Cerulein at con centrations greater than or equal to 10(-9) M induced wild-type p53. Glutat hione (1 mM) diminished the effects of cerulein on both cell proliferation and DNA fragmentation, whereas spermine (100 mu M), which partially attenua ted DNA fragmentation, did not have an effect on cell proliferation. The CC K-A-receptor antagonist loxiglumide completely abolished the effect of ceru lein on DNA fragmentation. The serine-protease inhibitor FUT-175 (10 mu M), the cysteine-protease inhibitor NCO-700 (5 mM), and ethylene glycol tetraa cetic acid (EGTA; 500 mu M) all had no effects on the changes in cell proli feration and DNA fragmentation induced by cerulein, The elate suggest that supraphysiologic concentrations of cerulein rapidly induce apoptosis in AR4 -2J cells and only later inhibit cell proliferation. These effects are medi ated by CCK-A receptors, Cerulein-induced apoptosis may involve the inducti on of wild-type p53 or glutathione depletion or both.