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Cell Death Differ. 1998 Oct;5(10):894-900.

Crm-A, bcl-2 and NDGA inhibit CD95L-induced apoptosis of malignant glioma cells at the level of caspase 8 processing.

Author information

1
Laboratory of Molecular Neuro-Oncology, Department of Neurology, University of Tübingen, School of Medicine, Tübingen, Germany.

Abstract

Susceptibility to CD95 (Fas/APO-1)-mediated apoptosis in human glioma cells depends on CD95 expression and unknown factors that regulate signal transduction. Thus, LN-18 cells are highly sensitive to CD95 ligand (CD95L) whereas LN-229 cells require coexposure to inhibitors of RNA or protein synthesis for induction of apoptosis. Here, we report that caspase 8 and 3 activation, poly(ADP-ribose)polymerase cleavage and apoptosis are inhibited by the lipoxygenase inhibitor, nordihydroguaretic acid (NDGA), or ectopic expression of crm-A or bcl-2. CD95L-induced glioma cell apoptosis does not involve ceramide generation. Apoptosis induced by exogenous ceramide resembles CD95-mediated apoptosis in that bcl-2 is protective but differs in that NDGA and crm-A have no effect and in that cycloheximide (CHX) inhibits rather than potentiates ceramide-induced cell death. We conclude that caspase 8 and caspase 3 activation, but not ceramide generation, are required for CD95 ligand-induced apoptosis of glioma cells and that bcl-2, crm-A and NDGA all act upstream of caspases to inhibit apoptosis.

PMID:
10203695
DOI:
10.1038/sj.cdd.4400435
[Indexed for MEDLINE]
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