Investigation of 2,6-diisopropylphenol (propofol)-evoked Ca2+ movement and cell death in human glioblastoma cells.

This study examined whether propofol altered Ca(2+) and caused cell death in DBTRG-05MG cells. Propofol at 400-1000μM increased Ca(2+) in a concentration-dependent manner. The signal was decreased partially by removal of extracellular Ca(2+). Propofol-induced Ca(2+) influx was not altered by nifedipine, econazole, SK&F96365, and protein kinase C (PKC) activators; but was inhibited by PKC inhibitor. In Ca(2+)-free medium, pretreatment with the endoplasmic reticulum Ca(2+) pump inhibitors thapsigargin or 2,5-di-tert-butylhydroquinone (BHQ) nearly abolished propofol-induced Ca(2+) rise. Incubation with propofol inhibited thapsigargin or BHQ-induced Ca(2+) rise. Inhibition of phospholipase C (PLC) with U73122 abolished propofol-induced Ca(2+) rise. At 300-700μM, propofol killed cells in a concentration-dependent manner. The cytotoxic effect of propofol was partly reversed by prechelating cytosolic Ca(2+) with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA). Annexin V/PI staining further showed that 300-500μM propofol evoked apoptosis. Propofol also increased reactive oxygen species (ROS) production. Overall, propofol induced a Ca(2+) rise by inducing PLC- and PKC-dependent Ca(2+) release from the endoplasmic reticulum and Ca(2+) entry via non store-operated Ca(2+) channels. Propofol induced cell death that might involve ROS-mediated apoptosis.