Dominant-negative Fas mutation is reversed by down-expression of c-FLIP
Authors: Patrick Legembre
Sophie Daburon
Jean-François Moreau
Jean-Luc Taupin
Marie Bénéteau
Journal: Cancer Research (2007)
Discipline: CLINICAL MEDICINE
Keywords: Fas; apoptosis; Jurkat cell line; agonistic antibodies; FasL
Affiliations: Laboratoire Composantes Innées de la Réponse Immunitaire et Différenciation, Centre National de la Recherche Scientifique UMR 5164, University of Bordeaux 2, 146 rue Léo Saignat, 33076 Bordeaux, France.

Abstract:  Fas triggering by agonistic antibodies or by its cognate ligand, FasL, induces apoptotic cell death, whereas mutation in the Fas death domain is associated with lymphoma progression. On prolonged culture in the presence of an agonistic anti-Fas antibody, we raised a Jurkat cell line resistant to agonistic antibodies but still sensitive to soluble FasL, which carried at the heterozygous state, a point mutation into the Fas death domain. Down-modulation of c-FLIP expression reversed the blockade of the Fas pathway. We show that the activation threshold for the Fas receptor is more easily overcome by multimeric FasL than by agonistic antibodies and that the increase of this threshold due to mutation in the Fas death domain can be overcome by acting on a downstream effector of the Fas signal, c-FLIP. These findings put forward a new approach to eradicate Fas-resistant tumor cells. 

Retracted: No

PubPeer comments:
 Two blots in Figure 4A look identical to two blots from a previously published article (Legembre et al, J Immunol, 2003) : https: www.ncbi.nlm.nih.gov pubmed 14634070 DOI: 10.4049 jimmunol.171.11.5659 Even more puzzling, the labelling is different when comparing the two figures: - No mention of control antibody 10C9 that became a 0-time point - The Jurkat 77 parental cell line became the Jurkat-R resistant cell line ![file] , 
 At least 2 cuts are visible in Figure 6C (Red arrows). ![file] , 
 The whole CD95 immunoblots of parent Jurkat depicted in Figure 3B of J. Immunol manuscript(1) and Figure 4A of cancer research manuscript (2) have been placed in the attached figure. These original gels confirmed that Jurkat cell (parental cells) data have been reused and unfortunately, have been switched for Jurkat-R cells in the Cancer Research manuscript. The pattern of CD95-SDS stable microaggregate formation is similar between the two cells and this could explain this inadvertent inversion. This reuse (J immunol, 2003) of the parental cell and its inversion is highly unfortunate but does not change the message, which is that CD95 mutation in Jurkat-R cells does not prevent the ability to form SDS-stable microaggregates. 10C9 is an anti-LIF IgM antibody (3) serving as a negative control for the anti-CD95 mAb 7C11 and in the raw data, you can see that the two controls u2013 meaning no antibody (0 min) and 10C9 (isotypic control for 3 hours) - have been performed. For the CD95 Immunoprecipitation data shown in Figure 6C of Cancer Research manuscript(2), there is one cut present for the c-FLIP and FADD (cut between clones Jurkat-R shFLIP1 and 2) immunoblots because clone 2 and 3 were shifted during the gel loading in these gels. Although these inadvertent mistakes do not affect the scientific message of the presented data, we are sorry for these errors. Cancer research has been contacted for a corrigendum. References 1.tLegembre P, Beneteau M, Daburon S, Moreau JF, Taupin JL. Cutting edge: SDS-stable Fas microaggregates: an early event of Fas activation occurring with agonistic anti-Fas antibody but not with Fas ligand. J Immunol 2003;171:5659-62 2.tBeneteau M, Daburon S, Moreau JF, Taupin JL, Legembre P. Dominant-negative Fas mutation is reversed by down-expression of c-FLIP. Cancer Res 2007;67:108-15 3.tTaupin JL, Gualde N, Moreau JF. A monoclonal antibody based elisa for quantitation of human leukaemia inhibitory factor. Cytokine 1997;9:112-8 ![file] ![file] , 
 2020 Editor s note. https: cancerres.aacrjournals.org content 80 2 363 The editors are publishing this note to alert readers to concerns about this article (1). The same Western blot analysis image was used for Jurkat-R cells in Fig. 4A and for Jurkat parental cells in Fig. 1B of another article previously published by the authors (2). In addition, lane 1 of Fig. 4A in this article is labeled as a 0 timepoint with 7C11 treatment, and in Fig. 1B in ref. 2 it is a 3 h timepoint with 10C9 treatment. References 1.u21b5Bu00e9nu00e9teau M, Daburon S, Moreau JF, Taupin JL, Legembre P. Dominant-negative Fas mutation is reversed by down-expression of c-FLIP. Cancer Res 2007;67:108u201315. 2.u21b5Legembre P, Beneteau M, Daburon S, Moreau JF, Taupin JL. Cutting edge: SDS-stable Fas microaggregates: an early event of Fas activation occurring with agonistic anti-Fas antibody but not with Fas ligand. J Immunol 2003;171:5659u201362. ,