MENADIONE INDUCES BOTH NECROSIS AND APOPTOSIS IN RAT PANCREATIC ACINAR AR4-2J CELLS

This study evaluated the action of menadione on cell proliferation and integrity of the rot pancreatic acinar cell line, AR4-2J. Menadione a t 1-20 mu M dose-and time-dependently inhibited cell proliferation of AR4-2J cells. In contrast, a high concentration of menadione (100 mu M ) caused rapid cell death (> 90% of cells took up trypan blue within 4 -h). While the high concentration of menadione (100 mu M) induced DNA smear in electrophoresis indicative of necrosis, lower concentrations (10-20 mu M) induced a DNA ladder indicative of apoptosis, Similar res ults were obtained using a DNA fragmentation ELISA. Glutathione (1 mM) , the calcium chelator EGTA (500 mu M), and the cystein protease inhib itor NCO-700 (5 mM) partly inhibited the effect of 1-10 mu M menadione on cell proliferation and DNA fragmentation. Menadione at 1-20 mu M i nduced wild-type P53, whereas the 100 mu M menadione had a minor effec t on wild-type P53. It is concluded that menadione induced necrosis at high concentrations and apoptosis at low concentrations in AR4-2J cel ls. Apoptosis induced by lower concentrations of menadione may be medi ated by wild-type P53, intracellular calcium, and mechanisms which dec rease the intracellular concentration of reduced glutathione. (C) 1997 Elsevier Science Inc.