Volume-sensitive chloride channels (ICl,vol) mediate doxorubicin-induced apoptosis through apoptotic volume decrease in cardiomyocytes.
Apoptosis is associated with early changes in cell volume through a mechanism called apoptotic volume decrease (AVD). As volume-sensitive chloride channels (I(Cl,vol)) are known to play a key role in the regulation of cell volume, this study investigated the role of I(Cl,vol) and AVD in doxorubicin-induced apoptotic cell death in adult rabbit ventricular cardiomyocytes. Exposure of cardiomyocytes to 1 microm doxorubicin induced a rapid and significant reduction in cell volume of cardiomyocytes (average of 15%), i.e. AVD as well as increases in the early markers of apoptosis, annexin V labeling and caspase-3 activity. Doxorubicin also induced the activation of a current characterized as I(Cl,vol) on the basis of the external chloride sensitivity and pharmacological properties with the patch clamp technique. Doxorubicin-induced AVD and apoptosis were both abolished when cardiomyocytes were exposed to the I(Cl,vol) inhibitors 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) (0.1 mM) or indanyloxyacetic acid 94 (IAA-94) (10 microM). The crucial role of I(Cl,vol) during AVD and apoptosis was confirmed using C(2)-ceramide, another pro-apoptotic compound. These results demonstrate that activation of I(Cl,vol) plays a major role in the mechanism leading to cell shrinkage and apoptosis-induced AVD by agents such as doxorubicin or C(2)-ceramide in adult cardiomyocytes.
Laboratoire de Pharmacologie, Faculté de Médecine de Créteil, Université Paris XII, France and Laboratoire de Pharmacologie, INSERM E00.01, Faculté de Médecine Paris-Sud, 94270 Le Kremlin-Bicêtre, France.
Alexandra
A
d'Anglemont de Tassigny
Rachid
R
Souktani
Patrick
P
Henry
Bijan
B
Ghaleh
Alain
A
Berdeaux
D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D048429:Cell Size / Q000187:drug effects; D002478:Cells, Cultured; D018118:Chloride Channels / Q000502:physiology*; D004317:Doxorubicin / Q000494:pharmacology*; D006352:Heart Ventricles / Q000166:cytology; D008297:Male; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000502:physiology; D009997:Osmotic Pressure; D018408:Patch-Clamp Techniques; D011817:Rabbits; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D013997:Time Factors
D017304:Annexin A5; D000970:Antineoplastic Agents; D018118:Chloride Channels; C064769:N-acetylsphingosine; D004317:Doxorubicin; D053148:Caspase 3; D020169:Caspases; D013110:Sphingosine