Leukotriene-D4 induced cell shrinkage in Ehrlich ascites tumor cells

1989 ◽  
Vol 108 (2) ◽  
pp. 165-176 ◽  
Author(s):  
Ian Henry Lambert
2009 ◽  
Vol 297 (1) ◽  
pp. C198-C206 ◽  
Author(s):  
Ian Henry Lambert ◽  
Thomas Kjær Klausen ◽  
Andreas Bergdahl ◽  
Charlotte Hougaard ◽  
Else Kay Hoffmann

Addition of H2O2 (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 H2O2-induced cell shrinkage was unaffected by the presence of clofilium and clotrimazole, which blocks volume-sensitive and Ca2+-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 H2O2-induced cell shrinkage was impaired in the presence of the KCl cotransport inhibitor (dihydro-indenyl)oxyalkanoic acid (DIOA), following substitution of NO3− for Cl−, and when the driving force for KCl cotransport was omitted. It is suggested that H2O2 activates electroneutral KCl cotransport in Ehrlich ascites tumor cells and not K+ and Cl− channels. Addition of H2O2 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 H2O2 on cell volume was blocked by the serine-threonine phosphatase inhibitor calyculin A, indicating an important role of serine-threonine phosphorylation in the H2O2-mediated activation of KCl cotransport in Ehrlich cells. In contrast, addition of H2O2 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, H2O2 induces KCl cotransport or K+ and Cl− channels in nonadherent and adherent cells, respectively.


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