RESUMO
Activation of the c-Jun N-terminal kinase (JNK) pathway is suggested to be required for neuronal apoptosis. We investigated the role of JNK on phosphorylation of c-Jun, Bcl-2, and apoptotic translocation of cytochrome c (cyt c) in UV-induced apoptosis in human neuroblastoma SH-SY5Y cells. We confirm that UV irradiation induces both apoptosis and necrosis in SH-SY5Y cells and that phosphorylation of JNK at Thr183/Tyr185 in SH-SY5Y cells treated with UV is an early event preceding apoptosis. We also demonstrate that phosphorylation of c-Jun at Ser63 is an early event coinciding with JNK activation, and that the phosphorylation of c-Jun is partially prevented by the JNK inhibitor SP600125. Despite the use of SP600125, the amount of cyt c released into the cytoplasm is not diminished and SP600125 is also unable to decrease the extent of UV-induced apoptosis. These data support the hypothesis that in this system, UV-induced apoptosis is not dependent exclusively on JNK activation. Possible involvement of cyclin-dependent kinases (CDKs) in c-Jun phosphorylation at Ser63 was excluded by pretreating UV-irradiated SH-SY5Y cells with the CDK1/2/5 inhibitor roscovitine.
Assuntos
Apoptose/efeitos da radiação , Citocromos c/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Raios Ultravioleta/efeitos adversos , Antracenos/farmacologia , Apoptose/fisiologia , Western Blotting/métodos , Caspase 3 , Caspases/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular , Interações Medicamentosas , Ativação Enzimática , Inibidores Enzimáticos/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos da radiação , Humanos , L-Lactato Desidrogenase/metabolismo , Mitocôndrias/metabolismo , Mitocôndrias/efeitos da radiação , Neuroblastoma/patologia , Proteínas Proto-Oncogênicas c-jun/metabolismo , Fatores de TempoRESUMO
Abstract Glycogen synthase kinase3 (GSK3) is emerging as a prominent drug target in the CNS. The most exciting of the possibilities of GSK3 lies within the treatment of Alzheimer's disease (AD) where abnormal increases in GSK3 levels and activity have been associated with neuronal death, paired helical filament tau formation and neurite retraction as well as a decline in cognitive performance. Abnormal activity of GSK3 is also implicated in stroke. Lithium, a widely used drug for affective disorders, inhibits GSK3 at therapeutically relevant concentrations. Thus while the rationale remains testable, pharmaceutical companies are investing in finding a selective inhibitor of GSK3. In the present review, we summarize the properties of GSK3, and discuss the potential for such a therapy in AD, and other CNS disorders.
