Staurosporine- and H-7-induced cell death in SH-SY5Y neuroblastoma cells is associated with caspase-2 and caspase-3 activation, but not with activation of the FAS/FAS-L-caspase-8 signaling pathway

Apoptotic cell death is induced in SH-SY5Y neuroblastoma cells following ex posure to the protein kinase inhibitors staurosporine (100 nM) and 1-(5-Iso quinolinesulfonyl)-2-methylpipe K-7 (100 muM). This is associated with redu ced levels of PARP 117 kDa and with the concomitant formation of PARP-cleav ed products of 89 kDa that result from caspase-3 activation. The process is inhibited with DEVD-fmk, a potent caspase-3 (and caspase-8) inhibitor, thu s indicating that staurosporine- and H-7-induced cell death in SH-SY5Y is m ediated by caspase activation. Increased caspase-2- and caspase-3-like acti vities, but not caspase-9-like activity, were demonstrated by monitoring pr oteolysis of the corresponding colorimetric substrates. Caspase-2 activity peaked at 6 h, whereas caspase-3 peaked at 12 h in parallel with the maxima l loss of cell viability. No modifications in the expression levels of Fas and Fas-L were observed by Western blotting. Furthermore, no activation of caspase-8 was elicited by colorimetric assays through the process of apopto sis of neuroblastoma cells. These findings indicate that the Fas/Fas-L-casp ase-8 pathway of cell death signaling is not involved in staurosporine- and H-7-induced apoptosis in SH-SY5Y neuroblastoma cells. (C) 2000 Elsevier Sc ience BN. All rights reserved.