title: Caspase-3 is essential for procaspase-9 processing and cisplatin-induced apoptosis of MCF-7 breast cancer cells.
abstract: In this study, we sought to investigate in more detail the role of caspase-3 in apoptotic processes in cultured cells and in cell-free extracts of breast cancer cells. We present evidence that apoptosis of caspase-3-deficient MCF-7 breast cancer cells is defective in response to cisplatin treatment, as determined by chromatin condensation, nuclear fragmentation, DNA fragmentation, and release of cytochrome c from the mitochondria. Reconstitution of MCF-7 cells by stable transfection of CASP-3 cDNA restores all these defects and results in an extensive apoptosis after cisplatin treatment. We further show that in extracts from caspase-3-deficient MCF-7 cells, procaspase-9 processing is strongly impaired after stimulation with either cytochrome c or recombinant caspase-8. Reconstitution of MCF-7 cell extracts with procaspase-3 corrects this defect, resulting in an efficient and complete processing of procaspase-9. Together, our data define caspase-3 as an important integrator of the apoptotic process in MCF-7 breast cancer cells and reveal an essential function of caspase-3 for procaspase-9 processing.
authors.affiliation: Department of Clinical Research, University of Bern, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Blanc
authors.forename: Q L
authors.initials: QL
authors.lastname: Deveraux
authors.forename: S
authors.initials: S
authors.lastname: Krajewski
authors.forename: R U
authors.initials: RU
authors.lastname: Jänicke
authors.forename: A G
authors.initials: AG
authors.lastname: Porter
authors.forename: J C
authors.initials: JC
authors.lastname: Reed
authors.forename: R
authors.initials: R
authors.lastname: Jaggi
authors.forename: A
authors.initials: A
authors.lastname: Marti
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D001943:Breast Neoplasms / Q000188:drug therapy / Q000201:enzymology* / Q000473:pathology*; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism* / Q000502:physiology*; D002457:Cell Extracts; D002945:Cisplatin / Q000494:pharmacology*; D003574:Cytochrome c Group / Q000502:physiology; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000378:metabolism*; D006801:Humans; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D002457:Cell Extracts; D003574:Cytochrome c Group; D004792:Enzyme Precursors; C505407:CASP3 protein, human; C505530:CASP8 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases; D002945:Cisplatin