ROS activate KCl cotransport in nonadherent Ehrlich ascites cells but K+ and Cl- channels in adherent Ehrlich Lettre and NIH3T3 cells

• Published in: American Journal of Physiology: Cell Physiology Vol. 297; no. 1; pp. C198 - C206
• Main Authors: Lambert, Ian Henry, Klausen, Thomas Kjaer, Bergdahl, Andreas, Hougaard, Charlotte, Hoffmann, Else Kay
• Format: Journal Article
• Language: English
• Published: United States American Physiological Society 01.07.2009
• Subjects: Animals; Calcium; Carboxylic Acids - pharmacology; Carcinoma, Ehrlich Tumor - metabolism; Cell Adhesion; Cell Line, Tumor; Cell Size; Cells; Chloride Channels - metabolism; Chlorine; Enzyme Inhibitors - pharmacology; Female; Fibroblasts - metabolism; Hydrogen Peroxide - metabolism; Hypotonic Solutions; Indenes - pharmacology; Ion Transport; K Cl- Cotransporters; Marine Toxins; Mice; NIH 3T3 Cells; Nitrates - metabolism; Osmotic Pressure; Oxazoles - pharmacology; Oxidative Stress; Oxygen; Phosphoprotein Phosphatases - metabolism; Phosphorylation; Potassium; Potassium Channels - metabolism; Reactive Oxygen Species - metabolism; Symporters - metabolism; Time Factors; Tumors
• ISSN: 0363-6143; 1522-1563
• DOI: 10.1152/ajpcell.00613.2008

1 NeuroSearch A/S, Ballerup, Denmark; 2 Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada; 3 Department of Biology, The August Krogh Building, University of Copenhagen, Copenhagen, Denmark Submitted 26 November 2008 ; accepted in final form 4 May 2009 Addition of H 2 O 2 (0.5 mM) to Ehrlich ascites tumor cells under isotonic conditions results in a substantial (22 ± 1%) reduction in cell volume within 25 min. The cell shrinkage is paralleled by net loss of K + , which was significant within 8 min, whereas no concomitant increase in the K + or Cl – conductances could be observed. The H 2 O 2 -induced cell shrinkage was unaffected by the presence of clofilium and clotrimazole, which blocks volume-sensitive and Ca 2+ -activated K + channels, respectively, and is unaffected by a raise in extracellular K + concentration to a value that eliminates the electrochemical driving force for K + . On the other hand, the H 2 O 2 -induced cell shrinkage was impaired in the presence of the KCl cotransport inhibitor (dihydro-indenyl)oxyalkanoic acid (DIOA), following substitution of NO 3 – for Cl – , and when the driving force for KCl cotransport was omitted. It is suggested that H 2 O 2 activates electroneutral KCl cotransport in Ehrlich ascites tumor cells and not K + and Cl – channels. Addition of H 2 O 2 to hypotonically exposed cells accelerates the regulatory volume decrease and the concomitant net loss of K + , whereas no additional increase in the K + and Cl – conductance was observed. The effect of H 2 O 2 on cell volume was blocked by the serine-threonine phosphatase inhibitor calyculin A, indicating an important role of serine-threonine phosphorylation in the H 2 O 2 -mediated activation of KCl cotransport in Ehrlich cells. In contrast, addition of H 2 O 2 to adherent cells, e.g., Ehrlich Lettré ascites cells, a subtype of the Ehrlich ascites tumor cells, and NIH3T3 mouse fibroblasts increased the K + and Cl – conductances after hypotonic cell swelling. Hence, H 2 O 2 induces KCl cotransport or K + and Cl – channels in nonadherent and adherent cells, respectively. regulatory volume decrease; taurine; reactive oxygen species Address for reprint requests and other correspondence: I. H. Lambert, Dept. of Biology, The August Krogh Building, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark (E-mail: ihlambert{at}bio.ku.dk )