Evidence for a novel, caspase-8-independent, Fas death domain-mediated apoptotic pathway

Hanping Feng, Yi Zeng, Michael W. Graner, Luke Whitesell, Emmanuel Katsanis

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


Certain caspase-8 null cell lines demonstrate resistance to Fas-induced apoptosis, indicating that the Fas/FasL apoptotic pathway may be caspase-8-dependent. Some reports, however, have shown that Fas induces cell death independent of caspase-8. Here we provide evidence for an alternative, caspase-8-independent, Fas death domain-mediated apoptotic pathway. Murine 12B1-D1 cells express procaspase-3, -8, and -9, which were activated upon the dimerization of Fas death domain. Bid was cleaved and mitochondrial transmembrane potential was disrupted in this apoptotic process. All apoptotic events were completely blocked by the broad-spectrum caspase inhibitor Z-VAD-FMK, but not by other peptide caspase inhibitors. Cyclosporin A (CsA), which inhibits mitochondrial transition pore permeability, blocked neither pore permeability disruption nor caspase activation. However, CsA plus caspase-8 inhibitor blocked all apoptotic events of 12B1-D1 induced by Fas death domain dimerization. Our data therefore suggest that there is a novel, caspase-8-independent, Z-VAD-FMK-inhibitable, apoptotic pathway in 12B1-D1 cells that targets mitochondria directly.

Original languageEnglish (US)
Pages (from-to)41-51
Number of pages11
JournalJournal of Biomedicine and Biotechnology
Issue number1
StatePublished - Apr 27 2004

ASJC Scopus subject areas

  • Biotechnology
  • Molecular Medicine
  • Molecular Biology
  • Genetics
  • Health, Toxicology and Mutagenesis


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