The tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) has gained much attention as a possible therapeutic reagent for the treatment of tumors, as TRAIL was originally described to induce apoptosis specifically in cancer cells, but not in normal cells. Fibroblast-like synoviocytes (FLS) in rheumatoid arthritis (RA) patients exhibit tumor-like features and we have described earlier that TRAIL induces apoptosis only in a subset of RA FLS, but an induction of proliferation in the surviving cells. This observation corresponds to the pleiotropic effects of TRAIL observed on primary human tumor cells. Here, we describe that the PI3 kinase/Akt-signaling pathway, but not that of the MAP kinases ERK and p38, protects RA FLS from TRAIL-induced apoptosis by modulating the expression of the cell survival regulators p21, XIAP, Mcl-1 and RIP. Moreover, we found that not only TRAIL-induced apoptosis, but also TRAIL-triggered proliferation in RA FLS is mediated by caspases with a crucial role for caspase 8. TRAIL was found to induce degradation of p21 and p27 that was caspase-dependent, but independent of the ERK, p38 and PI3 kinase/Akt-signaling pathways. The finding that TRAIL-triggered proliferation and apoptosis share intracellular routes has to be taken in consideration in defining therapeutic strategies on the basis of the administration of TRAIL.
The pleiotropic effect of TRAIL on tumor-like synovial fibroblasts from rheumatoid arthritis patients is mediated by caspases
Audo, R.; Combe, B.; Coulet, B.; Morel, J.; Hahne, M.
Cell Death Differ
2009-09 / vol 16 / pages 1227-37
cdd200938 [pii] 10.1038/cdd.2009.38
1476-5403 (Electronic) 1350-9047 (Linking)
IGMM team(s) involved in this publication
Inflammation and Cancer
Humans; Cell Proliferation; Cells, Cultured; Signal Transduction; Apoptosis; RNA, Small Interfering/metabolism; Cyclin-Dependent Kinase Inhibitor p21/metabolism; Cyclin-Dependent Kinase Inhibitor p27/metabolism; Extracellular Signal-Regulated MAP Kinases/metabolism; p38 Mitogen-Activated Protein Kinases/metabolism; Antineoplastic Agents/*pharmacology; Arthritis, Rheumatoid/enzymology/metabolism; Caspase 3/genetics/*metabolism; Caspase 8/genetics/*metabolism; Fibroblasts/drug effects/enzymology/metabolism; Phosphatidylinositol 3-Kinases/metabolism; Recombinant Proteins/pharmacology; Synovial Membrane/cytology; TNF-Related Apoptosis-Inducing Ligand/*pharmacology