Thapsigargin induces apoptosis in SH-SY5Y neuroblastoma cells and cerebrocortical cultures.

Thapsigargin, a specific inhibitor of the endoplasmic reticular Ca(2+)-ATPase, has been used previously to mobilize calcium release from intracellular calcium stores. We now show that thapsigargin (1-10 microM) induces apoptosis in a neuroblastoma cell line (SH-SY5Y) and in fetal rat cerebrocortical cultures. Cell death measured by lactate dehydrogenase release was observed 24-48 hours after treatment with thapsigargin. In both cases, DNA extracts from thapsigargin treated cells showed laddering, typical of endonuclease-mediated internucleosomal cleavages. The presence of DNA fragments was also confirmed by an ELISA designed for detecting nucleosomes in apoptotic cells. Cycloheximide reduced the extent of DNA fragmentation and injury in thapsigargin-treated cells. Dantrolene, an inhibitor of calcium release from intracellular stores partially abolished the effect of thapsigargin, suggesting that the initial Ca2+ rise may be the signalling event in this apoptotic cell death pathway. We propose that thapsigargin-induced cell death in cultured neuronal cells may be a useful system to study the molecular and genetic events involved in apoptosis.