title: Chemotherapy-induced apoptosis of S-type neuroblastoma cells requires caspase-9 and is augmented by CD95/Fas stimulation.
abstract: Stromal or S-type tumor cells are a distinct lineage found in neuroblastoma tumors and have an important role in the biology of this disease. Anticancer agents induce apoptosis through death receptor- and mitochondria-initiated pathways. The object of this work was to determine the involvement of these pathways in the response to doxorubicin (Dox) and cisplatin (CDDP) in S-type neuroblastoma cells. Both drugs activated caspase-9 and caspase-3 but not caspase-8. Caspase-9-specific inhibition blocked S-type cell death induced by Dox. SH-EP1 cells transfected to express dominant negative mutant caspase-9, but not those expressing DN caspase-8, were resistant to Dox- and CDDP-induced apoptosis. The lack of caspase-8 involvement in chemotherapy-induced death was not the result of an intrinsic inability of these cells to activate this enzyme because when they were treated with tumor necrosis factor-related apoptosis-inducing ligand, caspase-8 was activated. We also found that both drugs up-regulated CD95/Fas expression but that CD95/Fas signaling was not necessary for cell killing. Experiments testing the response of chemotherapy-treated cells to agonists of the CD95/Fas receptor established that Dox and CDDP treatment sensitizes cells to CD95/Fas killing. Together, these results are consistent with a model in which caspase-9 is of central importance in the death mechanism utilized by these drugs in S-type cells. Although the death response is not dependent on CD95/Fas, concomitant stimulation of this receptor amplifies the death response in drug-treated cells.
authors: Department of Pediatrics, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA.
authors: Xin
authors: X
authors: Bian
authors: Thomas D
authors: TD
authors: Giordano
authors: Huey-Jen
authors: HJ
authors: Lin
authors: Gabriel
authors: G
authors: Solomon
authors: Valerie P
authors: VP
authors: Castle
authors: Anthony W
authors: AW
authors: Opipari
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D053453:Caspase 9; D020169:Caspases / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology; D004317:Doxorubicin / Q000494:pharmacology; D053222:Fas Ligand Protein; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism; D008954:Models, Biological; D009154:Mutation; D009447:Neuroblastoma / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014162:Transfection; D019014:fas Receptor / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D011994:Recombinant Proteins; D019014:fas Receptor; D004317:Doxorubicin; C506433:CASP9 protein, human; D053453:Caspase 9; D020169:Caspases; D002945:Cisplatin