Differential effects of staurosporine and retinoic acid on the vulnerability of the SH-SY5Y neuroblastoma cells: involvement of bcl-2 and p53 proteins.

Human catecholaminergic neuroblastoma cells (SH-SY5Y) have been widely used in different neurochemical investigations. Quite often these cells are induced to differentiation by various agents, such as staurosporine and retinoic acid. Interestingly, even though both staurosporine and retinoic acid induce similar morphological differentiation in SH-SY5Y cells, we found that these two groups of differentiated cells exhibited opposite vulnerability to harmful chemicals and physical insults. In the present study, cisplatin, 5-fluorouracil (5-FU), N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4), 6-hydroxydopamine (6-OHDA), and gamma-radiation were used to assess the tolerance of the differentiated cells. Cell viability was determined by 3-(4,5-dimethylthiazol-2yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Staurosporine-treated SH-SY5Y cells were more sensitive to these toxic insults than the untreated controls. In contrast, retinoic acid-treated cells became more resistant to the same treatments. The expression of the proteins of the protooncogene Bcl-2 and the tumor suppressor gene p53 following staurosporine or retinoic acid treatment was assessed by Western blot and immunocytochemistry. Retinoic acid increased Bcl-2 and decreased p53 levels, whereas staurosporine decreased Bcl-2 and increased p53 levels. The opposite alteration of Bcl-2 (anti-apoptotic) and p53 (apoptotic) contents in SH-SY5Y cells with retinoic acid and staurosporine are attributed to the changes in cell vulnerability. These observations also indicate that caution should be taken when chemically induced differentiated neuroblastoma cells are to be used as an in vitro model for studying neuronal survival. Copyright 1999 Wiley-Liss, Inc.