Diphenyl Diselenide Modulates Protein Kinases Phosphorylation And Induces Apoptotic Cell Death In Human Neuroblastoma Cells Sh-sy5y

Thaís Posser, Jeferson Luis Franco, João B. Teixeira Rocha, Rodrigo B. Leal, Peter Dunkley

Resumo


Introdução: Synthetic organoselenium compounds including ebselen and diphenyl diselenide (PhSe)2 are recognized by their antioxidant properties associated with a glutathione peroxidase like activity. The biological potential of selenium compounds was demonstrated in a range of studies and includes antidepressant, anti-inflammatory and neuroprotective effects. These compounds presented a low toxicity when administrated in in vivo and in vitro models, emphasizing the importance of studies addressing the biological effects of organoselenium compounds. An antitumoral effect associated with selenium supplementation in human was previously demonstrated. In this regard, some works pointed to cytotoxic effects of selenium compounds in cell cultures associated with modulation of several protein kinases. Considering the importance of biological effects and very low toxicity already demonstrated for (PhSe)2, in this study we analyzed the effects of prolonged treatment with (PhSe)2 on cell viability and modulation of signaling pathways, including MAPKs and PKC phosphorylation human neuroblastoma lineage SH-SY5Y. Material e Métodos: Cultures of SH-SY5Y cells were maintained for 24 hours in serum free media in the presence of crescent concentrations of (PhSe)2 (0.3-30 µM). For some experiments, U0126, a pharmacological ERK1/2 inhibitor was added toward the diselenide in the media. Finished the treatments, cells were used for analysis of cell viability and presence of apoptotic nucleus. The study of PARP cleavage, ERK1/2, p38 and PKC substrates phosphorylation was performed by technique of western blotting, through specific antibodies. Resultados e Discussão: Prolonged treatment of SH-SY5Y lineage with (PhSe)2 (from 10 µM) decreased cell viability. This effect was followed by PARP cleavage associated with presence of apoptotic nuclei and inhibition of p38, ERK1/2 and PKC substrates phosphorylation. At 3 µM the diselenide increased ERK1/2 phosphorylation without affecting cell viability. However, in the presence of U0126, an ERK1/2 inhibitor, the selenium compound (3 µM) caused a decrease in cell viability and improved PARP cleavage. Conclusões: The treatment with (PhSe)2 caused cytotoxic effects in human neuroblastoma cell lineage SH-SY5Y characterized by apoptotic cell death and inhibition of protein kinases phosphorylation. The results pointed to a cytoprotective role for ERK1/2, since the inhibition of this enzyme improved apoptotic effects of the compound. Our data contributed to clarify molecular targets of (PhSe)2 in neuronal cells and pointed to a potential antitumoral effect for this selenium compound. Orgão de Fomento: CNPq

Palavras-chave


diphenyl diselenide, neuroblastoma, Mapk, apoptose, Erk1/2

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