The Sarin-like Organophosphorus Agent bis(isopropyl methyl)phosphonate Induces Apoptotic Cell Death and COX-2 Expression in SK-N-SH Cells

: Organophosphorus compounds, such as sarin, are highly toxic nerve agents that inhibit acetylcholinesterase (AChE), but not cholinesterase, via multiple mechanisms. Recent studies have shown that organophosphorus compounds increase cyclooxygenase-2 (COX-2) expression and induce neurotoxicity. In this study, we examined the toxicity of the sarin-like organophosphorus agent bis(isopropyl methyl)phosphonate (BIMP) and the effects of BIMP on COX-2 expression in SK-N-SH human neuroblastoma cells. Exposure to BIMP changed cell morphology and induced caspase-dependent apoptotic cell death accompanied by cleavage of caspase 3, caspase 9, and poly (ADP-ribose) polymerase (PARP). It also increased COX-2 expression, while pretreatment with a COX inhibitor, ibuprofen, decreased BIMP-dependent cell death and COX-2 expression in SK-N-SH cells. Thus, our findings suggest that BIMP induces apoptotic cell death and upregulates COX-2 expression.