Role of ERK activation in cisplatin-induced apoptosis in A172 human glioma cells.
Cisplatin activates multiple signal transduction pathways associated with cell survival and apoptosis in various cell types. The present study was undertaken to determine the role of extracellular signal-regulated protein kinase (ERK), a member of the mitogen-activated protein kinase family, in cisplatin-induced apoptosis in human glioma cells. Cisplatin resulted in apoptosis in a dose- and time-dependent manner. Cisplatin-induced apoptosis was prevented by the hydrogen peroxide scavenger pyruvate and the antioxidant N-acetylcysteine, but not by the superoxide scavenger tiron. Western blot analysis demonstrated that cisplatin treatment induced time-dependent activation of ERK, which was inhibited by chemical inhibitors of the MEK signaling pathway (PD98059 and U0126) and N-acetylcysteine. These inhibitors prevented cisplatin-induced cell death. Transient transfection of constitutive active MEK1 increased cisplatin-induced apoptosis. Cisplatin resulted in a reduction in mitochondrial membrane potential and its effect was prevented by N-acetylcysteine and PD98059. Caspase inhibitors (Boc-D-FMK and zDEVD-FMK) protected against cisplatin-induced cell death. Cisplatin-induced activation of caspase-3 was inhibited by N-acetylcysteine and PD98059. Taken together, these findings suggest that the ERK activation plays an active role in mediating cisplatin-induced apoptosis of human glioma cells and functions upstream of mitochondrial dysfunction and caspase activation to the initiate the apoptotic signal.
Choi
Byung Kwan
BK
Department of Neurosurgery, College of Medicine, Pusan National University & Medical Research Institute, Pusan National University, Pusan 602-739, South Korea.
Choi
Chang Hwa
CH
Oh
Hyun Lim
HL
Kim
Yong Keun
YK
D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002945:Cisplatin / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D005910:Glioma / Q000201:enzymology*; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology
D048049:Extracellular Signal-Regulated MAP Kinases; D002945:Cisplatin