Tetraethylammonium Inhibits Glioma Cells via Increasing Production of Intracellular Reactive Oxygen Species

Background: Potassium channel blockers have been shown to possess antitumor properties, but the role of apoptosis remains to be clarified. In this study, we investigated the antiproliferative effect of tetraethylammonium ( TEA), a nonspecific potassium channel blocker, in rat C6 and 9L glioma cells. Methods: Cytotoxicity was evaluated by MTT assay. Apoptosis was detected by TUNEL and annexin V-FITC/propidium iodide assays. Protein levels were determined by Western blot analysis. Intracellular reactive oxygen species (ROS) levels were assessed flow cytometrically. Results: TEA (2-60 m M) significantly inhibited the proliferation of C6 and 9L glioma cells. In addition, increased cell apoptosis was confirmed after treatment with 40 m M TEA. Apoptosis was associated with a dramatic increase in ROS levels and altered Bcl-2/Bax protein balance. Conclusion: TEA can inhibit proliferation and induce apoptosis in both cell lines; therefore, it might be associated with the increase in intracellular ROS production. Copyright (C) 2009 S. Karger AG, Basel