Regular Article: Centrosome overduplication induced by rotenone treatment affects the cellular distribution of p53 tumor suppressor protein in the neuroblastoma B65 cell line

Recently, the formation of inclusion bodies in several neurodegenerative diseases, including Parkinson's disease, has been associated with the aggregation of unfolded proteins recruited in the centrosome. We have reported previously that rotenone, an insecticide that is used to produce experimental models of Parkinsonism, induced the aggregation of the alpha -synuclein protein in the centrosome, and it notably affected the structure and function of this organelle in primary cultures of mesencephalic neurons and astrocytes. However, it is still obscure the mechanisms through which the disorganization and centrosomal dysfunction could induce cell death. In this study the rat neuroblastoma B65 cell line was chronically exposed to rotenone, and then the distribution of the centrosomal protein gamma -tubulin was studied by immunocytochemistry and Western blot analyses. Finally, the configuration of mitotic spindles and distribution of the p53 protein was observed in the control and rotenone-treated groups. Rotenone treatment increased the number of cells having centrosome overduplication and multipolar mitotic spindles. In contrast, rotenone induced redistribution of the p53 protein, which was colocalized with the gamma -tubulin protein in the perinuclear region of cells having overduplicated centrosomes. In addition, the p53 positive signal was markedly intense in cells containing aberrant chromosome segregation and micronuclei. Our results suggest that centrosome overduplication may play an important role in the redistribution of the p53 protein in rotenone-treated cells, and this could represent an alternative mechanism of rotenone to induce apoptosis in neuronal cells.