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 rat pancreatic acinar cell line, AR4-2J. Menadione at 1-20 microM dose- and time-dependently inhibited cell proliferation of AR4-2J cells. In contrast, a high concentration of menadione (100 microM) caused rapid cell death (> 90% of cells took up trypan blue within 4-h). While the high concentration of menadione (100 microM) induced DNA smear in electrophoresis indicative of necrosis, lower concentrations (10-20 microM) induced a DNA ladder indicative of Apoptosis. Similar results were obtained using a DNA fragmentation ELISA. Glutathione (1 mM), the calcium chelator EGTA (500 microM), and the cysteine Protease inhibitor NCO-700 (5 mM) partly inhibited the effect of 1-10 microM menadione on cell proliferation and DNA fragmentation. Menadione at 1-20 microM induced wild-type P53, whereas the 100 microM menadione had a minor effect on wild-type P53. It is concluded that menadione induced necrosis at high concentrations and Apoptosis at low concentrations in AR4-2J cells. Apoptosis induced by lower concentrations of menadione may be mediated by wild-type P53, intracellular calcium, and mechanisms which decrease the intracellular concentration of reduced glutathione.