Induction of apoptotic cell death in a neuroblastoma cell line by dibucaine

Dibucaine, a local anesthetic known to intersect with cell membranes, induced apoptosis in SK-N-MC human neuroblastoma cells in a dose-dependent manner. Apoptosis was demonstrated by direct visualization of morphological nuclear changes using a DAPI staining technique and confirmed by the production of characteristic ladder patterns of DNA fragmentation on gel electrophoresis. At concentrations which induced apoptosis, dibucaine significantly altered membrane fluidity, indicating that fluidity may be a major target for the cytotoxic action of dibucaine, Also, dibucaine increased intracellular calcium levels more effectively in calcium-containing Krebs-Ringer buffer than in calcium-free Krebs-Ringer buffer, Removal of extracellular calcium or addition of antioxidants or protein synthesis inhibitor effectively blocked dibucaine-induced apoptosis, These results suggest that membrane damage, intracellular calcium levels, and oxygen free radicals may be involved in the apoptosis induced by dibucaine. (C) 1997 Academic Press.