Acetaminophen potentiates staurosporine‐induced death in a human neuroblastoma cell line

Background and purpose:Neuroblastoma is the most common solid tumour in infants characterized by a high resistance to apoptosis. Recently, the cyclo‐oxygenase pathway has been considered a potential target in the treatment of different kinds of tumours. The aim of the present work was to investigate a possible relationship between cyclo‐oxygenase pathway and stauroporine‐induced apoptosis in the neuroblastoma cell line SH‐SY5Y.Experimental approach:Cellular viability was measured by release of LDH. DNA fragmentation was visualized by electrophoresis on agarose gel containing ethidium bromide. Cyclo‐oxygenase activity was measured in microsomal fractions obtained from cells by quantification of its final product PGE2by RIA. Caspase‐3 activity was measured fluorimetrically and Western blot analysis was performed to assess cytochrome c expression.Key results:We have found that staurosporine (500 nM) induced cellular death in a time‐dependent manner in SH‐SY5Y human neuroblastoma cells. Cyclo‐oxygenase enzymatic activity was present in SH‐SY5Y human neuroblastoma cells under basal conditions and pharmacological experiments using COX inhibitors indicate that cyclo‐oxygenase‐1 and cyclo‐oxygenase‐3 are the active isoforms in these cells. Co‐incubation of SH‐SY5Y cells with staurosporine (500 nM) and acetaminophen for 24 h potentiated staurosporine‐mediated cellular death in a concentration‐dependent manner. This process is mediated by an increase in cytochrome c release and caspase 3 activation and is prevented by N‐acetylcysteine or the superoxide dismutase mimetic, MnTBAP.Conclusions and implications:Acetaminophen potentiates staurosporine‐mediated neuroblastoma cell death. The mechanism of action of acetaminophen seems to be related to production of reactive oxygen species and decreased intracellular glutathione levels.British Journal of Pharmacology(2007)150, 577–585. doi:10.1038/sj.bjp.0706993