A role for caspase-8 and c-FLIPL in proliferation and cell-cycle progression of primary hepatocytes
| Autor: | Anne Corlu, Christiane Guguen-Guillouzo, Pascal Loyer, G. P. Ilyin, David Gilot, Anne Laure Serandour, Marcus E. Peter, Alexandre Coutant, Dominique Lagadic-Gossmann, Georges Baffet, Olivier Fardel |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
DNA Replication
Male Cancer Research Programmed cell death Fas-Associated Death Domain Protein CASP8 and FADD-Like Apoptosis Regulating Protein MAP Kinase Kinase 1 Biology Caspase 8 S Phase Rats Sprague-Dawley Epidermal growth factor Animals Humans Immunoprecipitation FADD fas Receptor Enzyme Inhibitors RNA Small Interfering Cells Cultured Death domain Adaptor Proteins Signal Transducing Cell Proliferation Epidermal Growth Factor Cell growth G1 Phase Intracellular Signaling Peptides and Proteins General Medicine Cell cycle Molecular biology Cell biology Rats ErbB Receptors Apoptosis Caspases biology.protein Hepatocytes Signal Transduction |
| Zdroj: | Carcinogenesis. 26(12) |
| ISSN: | 0143-3334 |
| Popis: | Growth factors are known to favor both proliferation and survival of hepatocytes. In the present study, we investigated if c-FLIP(L) (cellular FLICE-inhibitory protein, long isoform) could be involved in epidermal growth factor (EGF)-stimulated proliferation of rat hepatocytes since c-FLIP(L) regulates both cell proliferation and procaspase-8 maturation. Treatment with MEK inhibitors prevented induction of c-FLIP(L) by EGF along with total inhibition of DNA replication. However, EGF failed to inhibit processing of procaspase-8 in the presence of EGF suggesting that c-FLIP(L) does not play its canonical anti-apoptotic role in this model. Downregulation of c-FLIP expression using siRNA oligonucleotides strongly reduced DNA replication but did not result in enhanced apoptosis. Moreover, intermediate cleavage products of c-FLIP(L) and caspase-8 were found in EGF-treated hepatocytes in the absence of caspase-3 maturation and cell death. To determine whether the Fas/FADD/caspase-8/c-FLIP(L) complex was required for this activity, Fas, procaspase-8 and Fas-associated death domain protein (FADD) expression or function was inhibited using siRNA or constructs encoding dominant negative mutant proteins. Inhibition of any of these components of the Fas/FADD/caspase-8 pathway decreased DNA replication suggesting a function of these proteins in cell-cycle arrest. Similar results were obtained when the IETD-like caspase activity detectable in EGF-treated hepatocytes was inhibited by the pan-caspase inhibitor, z-ASP. Finally, we demonstrated co-immunoprecipitation between EGFR and Fas within 15 min following EGF stimulation. In conclusion, our results indicate that the Fas/FADD/c-FLIP(L)/caspase-8 pathway positively controls the G(1)/S transition in EGF-stimulated hepatocytes. Our data provide new insights into the mechanisms by which apoptotic proteins participate to mitogenic signals during the G(1) phase. |
| Databáze: | OpenAIRE |
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