Cisplatin-induced apoptosis is enhanced by hypoxia and by inhibition of mitochondria in renal collecting duct cells.
Cisplatin is a widely used chemotherapeutic agent. Here we show that cisplatin induces apoptosis in renal collecting duct-derived cells (MDCK-C7 cells, resembling principal cells) in a dose-dependent manner. Additionally, we studied the role of mitochondria in this process by inhibition of the mitochondrial respiratory chain, the F1F(o)-ATP synthase or by uncoupling. The role of intra- and extracellular pH in apoptosis induction was investigated. Activation of caspase-3 and DNA ladder formation were used to monitor the apoptotic response. When cells were incubated with inhibitors of the mitochondrial respiratory chain or an inhibitor of the ATP-synthase, cisplatin-induced apoptosis was markedly enhanced. Mitochondrial blockade led to enhanced production of lactic acid. Also, anoxia potentiated the cisplatin-induced caspase-3 activation. Neither intra- nor extracellular pH had an influence on caspase-3 activation at low cisplatin concentrations. Acidic conditions (pH 6.8) potentiated the caspase-3 activation when high (100 microM) cisplatin concentrations were used. We demonstrate that intact mitochondria are important to prevent cisplatin-induced apoptosis in MDCK-C7 cells and that acidic conditions can aggravate the toxic effects of cisplatin.
Schwerdt
Gerald
G
Physiologisches Institut, Universität Würzburg, Röntgenring 9, D-97070 Würzburg, Germany. gerald.schwerdt@mail.uni-wuerzburg.de
Freudinger
Ruth
R
Schuster
Claudia
C
Weber
Florian
F
Thews
Oliver
O
Gekle
Michael
M
D000818:Animals; D000970:Antineoplastic Agents / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D015687:Cell Hypoxia; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002945:Cisplatin / Q000633:toxicity*; D004285:Dogs; D006863:Hydrogen-Ion Concentration; D007685:Kidney Tubules, Collecting / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects* / Q000201:enzymology
D000970:Antineoplastic Agents; D053148:Caspase 3; D020169:Caspases; D002945:Cisplatin