Nathalie Bonnefoy | Université Lyon (original) (raw)

Papers by Nathalie Bonnefoy

OncoImmunology, Jul 20, 2017

Tumor antigen-targeting monoclonal antibodies (TA-targeting mAbs) are used as therapeutics in man... more Tumor antigen-targeting monoclonal antibodies (TA-targeting mAbs) are used as therapeutics in many malignancies and their capacity to mobilize the host immunity puts them at the forefront of anti-cancer immunotherapies. Both innate and adaptive immune cells have been associated with the therapeutic activity of such antibodies, but tumor escape from mAb-induced tumor immune surveillance remains one of the main clinical issues. In this preclinical study, we grafted immunocompetent and immunocompromised mice with the B16F10 mouse melanoma cell line and treated them with the TA99 TA-targeting mAb to analyze the immune mechanisms associated with the tumor response and resistance to TA99 monotherapy. In immunocompetent mice TA99 treatment strongly increased the fraction of CD8 and CD4 effector T cells in the tumor compared with isotype control, highlighting the specific immune modulation of the tumor microenvironment by TA99. However, in most mice, TA99 immunotherapy could not prevent immune effector exhaustion and the recruitment of regulatory CD4 T cells and consequently tumor escape from immune surveillance. Remarkably, anti-PD-1 treatment at the time of tumor emergence restored the Th1 effector functions of CD4 and CD8 T cells as well as of natural killer and gdT cells, which translated into a significant slowdown of tumor progression and extended survival. Our findings provide the first evidence that PD-1 blockade at the time of tumor emergence can efficiently boost the host anti-tumor immune response initiated several weeks before by the TA-targeting mAb. These results are promising for the design of combined therapies to sensitize non-responder or resistant patients.

Cancer Research, Jun 1, 2019

Immune cell death IFN production Antitumoral immunity Oxaliplatin + ATRi Cell autonomous cell dea... more Immune cell death IFN production Antitumoral immunity Oxaliplatin + ATRi Cell autonomous cell death Cytoplasmic DNA Proliferation inhibition Apoptosis induction DNA damage Replication stress Although many patients with colorectal cancer initially respond to the chemotherapeutic agent oxaliplatin, acquired resistance to this treatment remains a major challenge to the long-term management of this disease. To identify molecular targets of oxaliplatin resistance in colorectal cancer, we performed an shRNA-based loss-of-function genetic screen using a kinome library. We found that silencing of ataxia-telangiectasia mutated and RAD3-related (ATR), a serine/threonine protein kinase involved in the response to DNA stress, restored oxaliplatin sensitivity in a cellular model of oxaliplatin resistance. Combined application of the ATR inhibitor VE-822 and oxaliplatin resulted in strong synergistic effects in six different colorectal cancer cell lines and their oxaliplatin-resistant subclones, promoted DNA single-and double-strand break formation, growth arrest, and apoptosis. This treatment also increased replicative stress, cytoplasmic DNA, and signals related to immunogenic cell death such as calreticulin exposure and HMGB1 and ATP release. In a syngeneic colorectal cancer mouse model, combined administration of VE-822 and oxaliplatin significantly increased survival by promoting antitumor T-cell responses. Finally, a DNA repair gene signature discriminated sensitive from drug-resistant patients with colorectal cancer. Overall, our results highlight the potential of ATR inhibition combined with oxaliplatin to sensitize cells to chemotherapy as a therapeutic option for patients with colorectal cancer. Significance: These findings demonstrate that resistance to oxaliplatin in colorectal cancer cells can be overcome with inhibitors of ATR and that combined treatment with both agents exerts synergistic antitumor effects.

Suppression of ATR expression sensitizes HCT116-R1 cells to oxaliplatin.

Frontiers in Immunology, 2020

The tumor immune microenvironment contributes to tumor initiation, progression and response to th... more The tumor immune microenvironment contributes to tumor initiation, progression and response to therapy. Among the immune cell subsets that play a role in the tumor microenvironment, innate-like T cells that express T cell receptors composed of γ and δ chains (γδ T cells) are of particular interest. Indeed, γδ T cells contribute to the immune response against many cancers, notably through their powerful effector functions that lead to the elimination of tumor cells and the recruitment of other immune cells. However, their presence in the tumor microenvironment has been associated with poor prognosis in various solid cancers (breast, colon and pancreatic cancer), suggesting that γδ T cells also display pro-tumor activities. In this review, we outline the current evidences of γδ T cell pro-tumor functions in human cancer. We also discuss the factors that favor γδ T cell polarization toward a pro-tumoral phenotype, the characteristics and functions of such cells, and the impact of pro-tumor subsets on γδ T cell-based therapies.

Blood, 1998

Polyclonal horse antilymphocyte and rabbit antithymocyte globulins (ATGs) are currently used in s... more Polyclonal horse antilymphocyte and rabbit antithymocyte globulins (ATGs) are currently used in severe aplastic anemia and for the treatment of organ allograft acute rejection and graft-versus-host disease. ATG treatment induces a major depletion of peripheral blood lymphocytes, which contributes to its overall immunosuppressive effects. Several mechanisms that may account for lymphocyte lysis were investigated in vitro. At high concentrations (.1 to 1 mg/mL) ATGs activate the human classic complement pathway and induce lysis of both resting and phytohemagglutinin (PHA)-activated peripheral blood mononuclear cells. At low, submitogenic, concentration ATGs induce antibody-dependent cell cytotoxicity of PHA-activated cells, but not resting cells. They also trigger surface Fas (Apo-1, CD95) expression in naive T cells and Fas-ligand gene and protein expression in both naive and primed T cells, resulting in Fas/Fas-L interaction-mediated cell death. ATG-induced apoptosis and Fas-L expre...

Blood, 1997

In addition to their major function in antigen presentation and natural killer cell activity regu... more In addition to their major function in antigen presentation and natural killer cell activity regulation, HLA class I molecules may modulate T-cell activation and proliferation. Monoclonal antibodies (MoAbs) that recognize distinct epitopes of HLA class I molecules were reported to interfere with T-cell proliferation. We show here that two MoAbs (mouse MoAb90 and rat YTH862) that bind to an epitope of the α1 domain of HLA class I heavy chain induce apoptotic cell death of activated, but not resting, peripheral T lymphocytes. Other reference anti-HLA class I antibodies specific for distinct epitopes of the α1 (B9.12.1), α2 (W6/32), or α3 (TP25.99) domains of the heavy chain decreased T-cell proliferation but had little or no apoptotic effect. Apoptosis shown by DNA fragmentation, phosphatidylserine externalization, and decrease of mitochondrial transmembrane potential was observed whatever the type of T-cell activator. Apoptosis did not result from Fas/Fas-L interaction and distinct t...

The Journal of Immunology, 2010

Cross-talk between NK cells and dendritic cells (DCs) is critical for the potent therapeutic resp... more Cross-talk between NK cells and dendritic cells (DCs) is critical for the potent therapeutic response to dsRNA, but the receptors involved remained controversial. We show in this paper that two dsRNAs, polyadenylic-polyuridylic acid and polyinosinic-polycytidylic acid [poly(I:C)], similarly engaged human TLR3, whereas only poly(I:C) triggered human RIG-I and MDA5. Both dsRNA enhanced NK cell activation within PBMCs but only poly(I:C) induced IFN-γ. Although myeloid DCs (mDCs) were required for NK cell activation, induction of cytolytic potential and IFN-γ production did not require contact with mDCs but was dependent on type I IFN and IL-12, respectively. Poly(I:C) but not polyadenylic-polyuridylic acid synergized with mDC-derived IL-12 for IFN-γ production by acting directly on NK cells. Finally, the requirement of both TLR3 and Rig-like receptor (RLR) on mDCs and RLRs but not TLR3 on NK cells for IFN-γ production was demonstrated using TLR3- and Cardif-deficient mice and human RIG...

The Journal of Immunology, 2009

TLR are involved in the detection of microbial infection as well as endogenous ligands that signa... more TLR are involved in the detection of microbial infection as well as endogenous ligands that signal tissue and cell damage in mammals. This recognition plays an essential role in innate immune response and the initiation of adaptive immune response. We have previously shown that murine CD8 T cells express TLR2, and that costimulation of Ag-activated CD8 T cells with TLR2 ligands enhances their proliferation, survival, and effector functions. We also demonstrated that TLR2 engagement on CD8 T cells significantly reduces their need for costimulatory signals delivered by APC. We show in this study that TLR2 engagement on CD8 T cells lowers the Ag concentration required for optimal activation, and converts a partial activation into a productive process leading to a significant expansion of cells. Using altered peptide ligands, we demonstrate that TLR2 engagement increases CD8 T cell activation and enables the generation of functional memory cells in response to a low TCR signal. This inc...

The Journal of Immunology, 2009

Most memory CD8 T cell subsets that have been hitherto defined are generated in response to infec... more Most memory CD8 T cell subsets that have been hitherto defined are generated in response to infectious pathogens. In this study, we have characterized the CD8 T cells that survive priming conditions, devoid of pathogen-derived danger signals. In both a TCR-transgenic model and a model of contact hypersensitivity, we show that the priming of naive CD8 T cells under sterile inflammatory conditions generates memory. The corresponding memory CD8 T cells can be identified by their intermediate expression levels of CD44 and CD122. We also show that CD44/122int memory CD8 T cells spontaneously develop in wild type mice and that they display intermediate levels of several other memory traits including functional (IFN-γ secretion capacity, CCL5 messenger stores), phenotypic, and molecular (T-bet and eomesodermin expression levels) features. We finally show that they correspond to an early differentiation stage and can further differentiate in CD44/122high memory T cells. Altogether, our resu...

Experimental Hematology, 2011

Objective. Telomeres are protected by tightly regulated factors and elongated by telomerase. Shor... more Objective. Telomeres are protected by tightly regulated factors and elongated by telomerase. Short and/or deprotected chromosomes are recombinogenic and thereby cancer prone. Materials and Methods. Together with the quantification of telomerase activity (TA), measuring telomere length (TL) and expression of the genes that govern telomere protection and elongation are useful for assessing telomere homeostasis. Results. By these means we demonstrate that TL, hTERT, and TA are in the order acute myelogenous leukemia (AML) O T-cell acute lymphoblastic leukemia (T-ALL) O B-cell acute lymphoblastic leukemia (B-ALL) O TALL O AML, and BALL O AML O TALL. AML0 and AML3 display the lowest amounts of hTERT transcripts, and ALL and AML cells with cytogenetic abnormalities possess the shortest telomeres. hTERT expression includes phenotype-specific RNA maturation and correlates with TA but not with TL. A wide ratio of TA to hTERT expression between leukemia subtypes suggests phenotype-specific hTERT post-transcriptional deregulations. Band TALL overexpress Ku70 and Pinx1, TALL PTOP and RAP1, and BALL TRF2, the expression of which is significantly higher in cases with abnormal karyotype. hTERT transcription and TL correlate with response to intensive chemotherapy, and hTERT and RAD50 are independent prognostic factors for survival. Conclusions. Each leukemia subtype possesses specific telomere dysregulations that rely on phenotype, karyotype, response to treatment, and survival.

Cell Death & Differentiation, 2003

We analyzed regulation of the prosurvival Bcl-2 homologue A1, following T-cell receptor (TCR) or ... more We analyzed regulation of the prosurvival Bcl-2 homologue A1, following T-cell receptor (TCR) or cytokine receptor engagement. Activation of CD4 + or CD8 + T cells by antigenic peptides induced an early but transient IL-2-independent expression of A1 and Bcl-xl mRNA and proteins, whereas expression of Bcl-2 was delayed and required IL-2. Cytokines such as IL-2, IL-4, IL-7 or IL-15 prevented apoptosis of activated T cells that effect being associated with the maintenance of Bcl-2, but not of A1 expression. However, restimulation of activated or posteffector T cells with antigenic peptide strongly upregulated A1 mRNA and maintained A1 protein expression. IL-4, IL-7 or IL-15 also prevented cell death of naive T cells. In those cells, cytokines upregulated Bcl-2, but not A1 expression. Therefore, in naive, activated and posteffector T cells, expression of A1 is dependent on TCR but not on cytokine receptor engagement, indicating that A1 is differently regulated from Bcl-xl and Bcl-2.

Cell Death & Differentiation, 2005

As it has been shown for Mcl-1, Bcl-xl and Bcl-2, proteins of the Bcl-2 family play a crucial rol... more As it has been shown for Mcl-1, Bcl-xl and Bcl-2, proteins of the Bcl-2 family play a crucial role during T-cell development in the thymus. We here show that the expression of the antiapoptotic gene A1 is specifically enhanced at the DN3/ DN4 transition and in DP thymocytes that have been positively selected suggesting that A1 expression might be considered as a transcriptional signature of thymocytes that have received pre-TCR or TCR survival signal. Furthermore, we observed that A1-a overexpression in recombination activation gene 1-deficient mice transgenic for the major histocompatibillity complex class I-restricted F5 TCR enhances cell survival of DP thymocytes and permits accumulation of DP cells awaiting positive selection. However, A1-a overexpression has no effect on negative selection. Therefore, our results suggest that A1 plays a specialized role in allowing survival of DP thymocytes and that its role can be distinguished from that of Mcl-1, Bcl-xl and Bcl-2.

Biology of the Cell, 1999

The anthracyclines daunorubicin and doxorubicin were shown to induce apoptosis of hematopoietic c... more The anthracyclines daunorubicin and doxorubicin were shown to induce apoptosis of hematopoietic cell lines. Here we report that they induce apoptosis of both nonactivated and phytohemagglutinin-activated human peripheral blood lymphocytes. Apoptosis demonstrated by surface expression of phosphatidylserine and typical nuclear alterations reached a maximum after 48 h of incubation with these agents. In contrast to topoisomerase inhibitors (etoposide and camptothecin) and antimetabolites (methotrexate and 5-fluorouracil) that induced apoptosis of activated cells only, daunorubicin and doxorubicin triggered apoptosis of cells in the G0-G1 phases of the cell cycle. In agreement with in vitro data, a single i.p. injection of daunorubicin or doxorubicin in BALB/c mice induced T- and B-cell depletion in spleen, lymph nodes, and to a lesser extent in the thymus. Soluble Fas-Fc, CD95 antagonistic antibodies, as well as the p55 tumor necrosis factor receptor-immunoglobulin fusion protein, did not inhibit drug-induced apoptosis. The level of reactive oxygen species was significantly increased in the presence of daunorubicin or doxorubicin only in nonactivated lymphocytes. However, antioxidants such as N-acetyl-L-cysteine or glutathione did not prevent apoptosis. Activation of caspase-3 after daunorubicin or doxorubicin treatment of either nonactivated or activated lymphocytes was demonstrated by the cleavage of poly(ADP-ribose) polymerase, which was, as apoptosis, inhibited by the peptide benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone. Finally, daunorubicin and doxorubicin induced a rapid production of ceramides. These data indicate that anthracyclines may induce major peripheral T-cell deletion, a property not shared by many cytotoxic agents.

Biochimica et Biophysica Acta (BBA) - Molecular Cell Research, 2004

The anti-proliferative effect of Bcl-2 acts mainly at the level of the G0/G1 phase of the cell cy... more The anti-proliferative effect of Bcl-2 acts mainly at the level of the G0/G1 phase of the cell cycle. Deletions and point mutations in the bcl-2 gene show that the anti-proliferative activity of Bcl-2, can in some cases, be dissociated from its anti-apoptotic function. This indicates that the effect of Bcl-2 on cell cycle progression can be a direct effect and not only a consequence of its anti-apoptotic activity. Bcl-2 appears to mediate its anti-proliferative effect by acting on both signal transduction pathways (NFAT, ERK) and on specific cell cycle regulators (p27, p130).

Figure S4. Generation of anti-cath-D human scFv fragments by phage display. (A) Enrichment of ant... more Figure S4. Generation of anti-cath-D human scFv fragments by phage display. (A) Enrichment of anti-cath-D polyclonal scFv fragments by phage display. ScFv phages specific for human mature 34+14-kDa cath-D were selected and enriched in four biopanning rounds, and analyzed by ELISA using a HRP-labeled anti-M13 antibody. BSA, negative antigen. (B) Selection of anti-cath-D monoclonal scFv fragments by ELISA. ELISA performed using bacterial culture supernatants of the best scFv clones (5 out of 400 screened clones) and recombinant human mature 34+14-kDa cath-D and 52-kDa pro-cath-D. Binding of the scFv clones to cath-D was detected with a HRP-labeled anti-Myc antibody. BSA, negative antigen; IR, irrelevant scFv from the screen. (C) Purification of the anti-human cath-D scFv fragments. His-tagged anti-cath-D scFv fragments were purified using TALON resin, resolved by 12% SDS-PAGE and stained with Coomassie blue. (D) Binding of purified anti-cath-D monoclonal scFv antibodies to human cath-...

Effect of ATR inhibition combined with oxaliplatin treatment on the ATR and ATM pathways.

Representative IHC staining of CD39 expression in human normal and tumor tissues (clone HPA014067).

Annales De Dermatologie Et De Venereologie, Nov 1, 2020

Les immunotherapies ciblant les checkpoints immunitaires constituent un tournant dans l’arsenal t... more Les immunotherapies ciblant les checkpoints immunitaires constituent un tournant dans l’arsenal therapeutique des cancers, notamment du melanome. Malgre des resultats cliniques spectaculaires, une majorite de patients presente une resistance innee ou acquise a ces therapies. Il est donc necessaire de mieux comprendre les mecanismes de resistance et d’identifier de nouvelles cibles afin d’augmenter le taux de reponse des patients. Dans le modele de melanome murin B16F10, nous avons demontre le potentiel immunomodulateur d’un anticorps ciblant la cellule tumorale, l’anticorps TA99. Cet anticorps, en essai clinique chez l’homme ( NCT01137006 ), cible l’antigene de surface TYRP-1 surexprime dans les melanocytes tumoraux. Administre a des souris porteuses d’une tumeur de melanome, il induit une reponse anti-tumorale lymphocytaire T memoire specifique assurant une protection a long terme. Dans ce modele, l’echappement au traitement est associe a l’expression de deux ectonucleotidases, CD39 et CD73, responsables de la production d’adenosine, molecule a fort potentiel immunosuppresseur. Une forte expression de CD39 est aussi observee dans des biopsies de patients atteints de melanome metastatique, et nous avons montre que le blocage de cette voie potentialise les effets d’une immunotherapie anti-PD1 dans le modele de melanome B16F10.

Journal of Leukocyte Biology, May 3, 2020

T cells contribute to the immune response against many cancers, notably through their powerful ef... more T cells contribute to the immune response against many cancers, notably through their powerful effector functions that lead to the elimination of tumor cells and the recruitment of other immune cells. However, their presence in the tumor microenvironment has been associated with poor prognosis in breast, colon, and pancreatic cancer, suggesting that T cells may also display pro-tumor activities. Here, we identified in blood from healthy donors a subpopulation of V 1T cells that represents around 20% of the whole V 1 population, expresses CD73, and displays immunosuppressive phenotype and functions (i.e., production of immunosuppressive molecules, such as IL-10, adenosine, and the chemotactic factor IL-8, and inhibition of T cell proliferation). We then found that in human breast tumors, T cells were present particularly in late stage breast cancer samples, and that ∼20% of tumor-infiltrating T cells expressed CD73. Taken together, these results suggest that regulatory T cells are present in the breast cancer microenvironment and may display immunosuppressive functions through the production of immunosuppressive molecules, such as IL-10, IL-8, and adenosine, thus promoting tumor growth.

Representative IHC staining of CD39 expression in vascular endothelial cells and lymphocytes from... more Representative IHC staining of CD39 expression in vascular endothelial cells and lymphocytes from various normal tissues (clone 22A9).

OncoImmunology, Jul 20, 2017

Tumor antigen-targeting monoclonal antibodies (TA-targeting mAbs) are used as therapeutics in man... more Tumor antigen-targeting monoclonal antibodies (TA-targeting mAbs) are used as therapeutics in many malignancies and their capacity to mobilize the host immunity puts them at the forefront of anti-cancer immunotherapies. Both innate and adaptive immune cells have been associated with the therapeutic activity of such antibodies, but tumor escape from mAb-induced tumor immune surveillance remains one of the main clinical issues. In this preclinical study, we grafted immunocompetent and immunocompromised mice with the B16F10 mouse melanoma cell line and treated them with the TA99 TA-targeting mAb to analyze the immune mechanisms associated with the tumor response and resistance to TA99 monotherapy. In immunocompetent mice TA99 treatment strongly increased the fraction of CD8 and CD4 effector T cells in the tumor compared with isotype control, highlighting the specific immune modulation of the tumor microenvironment by TA99. However, in most mice, TA99 immunotherapy could not prevent immune effector exhaustion and the recruitment of regulatory CD4 T cells and consequently tumor escape from immune surveillance. Remarkably, anti-PD-1 treatment at the time of tumor emergence restored the Th1 effector functions of CD4 and CD8 T cells as well as of natural killer and gdT cells, which translated into a significant slowdown of tumor progression and extended survival. Our findings provide the first evidence that PD-1 blockade at the time of tumor emergence can efficiently boost the host anti-tumor immune response initiated several weeks before by the TA-targeting mAb. These results are promising for the design of combined therapies to sensitize non-responder or resistant patients.

Cancer Research, Jun 1, 2019

Immune cell death IFN production Antitumoral immunity Oxaliplatin + ATRi Cell autonomous cell dea... more Immune cell death IFN production Antitumoral immunity Oxaliplatin + ATRi Cell autonomous cell death Cytoplasmic DNA Proliferation inhibition Apoptosis induction DNA damage Replication stress Although many patients with colorectal cancer initially respond to the chemotherapeutic agent oxaliplatin, acquired resistance to this treatment remains a major challenge to the long-term management of this disease. To identify molecular targets of oxaliplatin resistance in colorectal cancer, we performed an shRNA-based loss-of-function genetic screen using a kinome library. We found that silencing of ataxia-telangiectasia mutated and RAD3-related (ATR), a serine/threonine protein kinase involved in the response to DNA stress, restored oxaliplatin sensitivity in a cellular model of oxaliplatin resistance. Combined application of the ATR inhibitor VE-822 and oxaliplatin resulted in strong synergistic effects in six different colorectal cancer cell lines and their oxaliplatin-resistant subclones, promoted DNA single-and double-strand break formation, growth arrest, and apoptosis. This treatment also increased replicative stress, cytoplasmic DNA, and signals related to immunogenic cell death such as calreticulin exposure and HMGB1 and ATP release. In a syngeneic colorectal cancer mouse model, combined administration of VE-822 and oxaliplatin significantly increased survival by promoting antitumor T-cell responses. Finally, a DNA repair gene signature discriminated sensitive from drug-resistant patients with colorectal cancer. Overall, our results highlight the potential of ATR inhibition combined with oxaliplatin to sensitize cells to chemotherapy as a therapeutic option for patients with colorectal cancer. Significance: These findings demonstrate that resistance to oxaliplatin in colorectal cancer cells can be overcome with inhibitors of ATR and that combined treatment with both agents exerts synergistic antitumor effects.

Suppression of ATR expression sensitizes HCT116-R1 cells to oxaliplatin.

Frontiers in Immunology, 2020

The tumor immune microenvironment contributes to tumor initiation, progression and response to th... more The tumor immune microenvironment contributes to tumor initiation, progression and response to therapy. Among the immune cell subsets that play a role in the tumor microenvironment, innate-like T cells that express T cell receptors composed of γ and δ chains (γδ T cells) are of particular interest. Indeed, γδ T cells contribute to the immune response against many cancers, notably through their powerful effector functions that lead to the elimination of tumor cells and the recruitment of other immune cells. However, their presence in the tumor microenvironment has been associated with poor prognosis in various solid cancers (breast, colon and pancreatic cancer), suggesting that γδ T cells also display pro-tumor activities. In this review, we outline the current evidences of γδ T cell pro-tumor functions in human cancer. We also discuss the factors that favor γδ T cell polarization toward a pro-tumoral phenotype, the characteristics and functions of such cells, and the impact of pro-tumor subsets on γδ T cell-based therapies.

Blood, 1998

Polyclonal horse antilymphocyte and rabbit antithymocyte globulins (ATGs) are currently used in s... more Polyclonal horse antilymphocyte and rabbit antithymocyte globulins (ATGs) are currently used in severe aplastic anemia and for the treatment of organ allograft acute rejection and graft-versus-host disease. ATG treatment induces a major depletion of peripheral blood lymphocytes, which contributes to its overall immunosuppressive effects. Several mechanisms that may account for lymphocyte lysis were investigated in vitro. At high concentrations (.1 to 1 mg/mL) ATGs activate the human classic complement pathway and induce lysis of both resting and phytohemagglutinin (PHA)-activated peripheral blood mononuclear cells. At low, submitogenic, concentration ATGs induce antibody-dependent cell cytotoxicity of PHA-activated cells, but not resting cells. They also trigger surface Fas (Apo-1, CD95) expression in naive T cells and Fas-ligand gene and protein expression in both naive and primed T cells, resulting in Fas/Fas-L interaction-mediated cell death. ATG-induced apoptosis and Fas-L expre...

Blood, 1997

In addition to their major function in antigen presentation and natural killer cell activity regu... more In addition to their major function in antigen presentation and natural killer cell activity regulation, HLA class I molecules may modulate T-cell activation and proliferation. Monoclonal antibodies (MoAbs) that recognize distinct epitopes of HLA class I molecules were reported to interfere with T-cell proliferation. We show here that two MoAbs (mouse MoAb90 and rat YTH862) that bind to an epitope of the α1 domain of HLA class I heavy chain induce apoptotic cell death of activated, but not resting, peripheral T lymphocytes. Other reference anti-HLA class I antibodies specific for distinct epitopes of the α1 (B9.12.1), α2 (W6/32), or α3 (TP25.99) domains of the heavy chain decreased T-cell proliferation but had little or no apoptotic effect. Apoptosis shown by DNA fragmentation, phosphatidylserine externalization, and decrease of mitochondrial transmembrane potential was observed whatever the type of T-cell activator. Apoptosis did not result from Fas/Fas-L interaction and distinct t...

The Journal of Immunology, 2010

Cross-talk between NK cells and dendritic cells (DCs) is critical for the potent therapeutic resp... more Cross-talk between NK cells and dendritic cells (DCs) is critical for the potent therapeutic response to dsRNA, but the receptors involved remained controversial. We show in this paper that two dsRNAs, polyadenylic-polyuridylic acid and polyinosinic-polycytidylic acid [poly(I:C)], similarly engaged human TLR3, whereas only poly(I:C) triggered human RIG-I and MDA5. Both dsRNA enhanced NK cell activation within PBMCs but only poly(I:C) induced IFN-γ. Although myeloid DCs (mDCs) were required for NK cell activation, induction of cytolytic potential and IFN-γ production did not require contact with mDCs but was dependent on type I IFN and IL-12, respectively. Poly(I:C) but not polyadenylic-polyuridylic acid synergized with mDC-derived IL-12 for IFN-γ production by acting directly on NK cells. Finally, the requirement of both TLR3 and Rig-like receptor (RLR) on mDCs and RLRs but not TLR3 on NK cells for IFN-γ production was demonstrated using TLR3- and Cardif-deficient mice and human RIG...

The Journal of Immunology, 2009

TLR are involved in the detection of microbial infection as well as endogenous ligands that signa... more TLR are involved in the detection of microbial infection as well as endogenous ligands that signal tissue and cell damage in mammals. This recognition plays an essential role in innate immune response and the initiation of adaptive immune response. We have previously shown that murine CD8 T cells express TLR2, and that costimulation of Ag-activated CD8 T cells with TLR2 ligands enhances their proliferation, survival, and effector functions. We also demonstrated that TLR2 engagement on CD8 T cells significantly reduces their need for costimulatory signals delivered by APC. We show in this study that TLR2 engagement on CD8 T cells lowers the Ag concentration required for optimal activation, and converts a partial activation into a productive process leading to a significant expansion of cells. Using altered peptide ligands, we demonstrate that TLR2 engagement increases CD8 T cell activation and enables the generation of functional memory cells in response to a low TCR signal. This inc...

The Journal of Immunology, 2009

Most memory CD8 T cell subsets that have been hitherto defined are generated in response to infec... more Most memory CD8 T cell subsets that have been hitherto defined are generated in response to infectious pathogens. In this study, we have characterized the CD8 T cells that survive priming conditions, devoid of pathogen-derived danger signals. In both a TCR-transgenic model and a model of contact hypersensitivity, we show that the priming of naive CD8 T cells under sterile inflammatory conditions generates memory. The corresponding memory CD8 T cells can be identified by their intermediate expression levels of CD44 and CD122. We also show that CD44/122int memory CD8 T cells spontaneously develop in wild type mice and that they display intermediate levels of several other memory traits including functional (IFN-γ secretion capacity, CCL5 messenger stores), phenotypic, and molecular (T-bet and eomesodermin expression levels) features. We finally show that they correspond to an early differentiation stage and can further differentiate in CD44/122high memory T cells. Altogether, our resu...

Experimental Hematology, 2011

Objective. Telomeres are protected by tightly regulated factors and elongated by telomerase. Shor... more Objective. Telomeres are protected by tightly regulated factors and elongated by telomerase. Short and/or deprotected chromosomes are recombinogenic and thereby cancer prone. Materials and Methods. Together with the quantification of telomerase activity (TA), measuring telomere length (TL) and expression of the genes that govern telomere protection and elongation are useful for assessing telomere homeostasis. Results. By these means we demonstrate that TL, hTERT, and TA are in the order acute myelogenous leukemia (AML) O T-cell acute lymphoblastic leukemia (T-ALL) O B-cell acute lymphoblastic leukemia (B-ALL) O TALL O AML, and BALL O AML O TALL. AML0 and AML3 display the lowest amounts of hTERT transcripts, and ALL and AML cells with cytogenetic abnormalities possess the shortest telomeres. hTERT expression includes phenotype-specific RNA maturation and correlates with TA but not with TL. A wide ratio of TA to hTERT expression between leukemia subtypes suggests phenotype-specific hTERT post-transcriptional deregulations. Band TALL overexpress Ku70 and Pinx1, TALL PTOP and RAP1, and BALL TRF2, the expression of which is significantly higher in cases with abnormal karyotype. hTERT transcription and TL correlate with response to intensive chemotherapy, and hTERT and RAD50 are independent prognostic factors for survival. Conclusions. Each leukemia subtype possesses specific telomere dysregulations that rely on phenotype, karyotype, response to treatment, and survival.

Cell Death & Differentiation, 2003

We analyzed regulation of the prosurvival Bcl-2 homologue A1, following T-cell receptor (TCR) or ... more We analyzed regulation of the prosurvival Bcl-2 homologue A1, following T-cell receptor (TCR) or cytokine receptor engagement. Activation of CD4 + or CD8 + T cells by antigenic peptides induced an early but transient IL-2-independent expression of A1 and Bcl-xl mRNA and proteins, whereas expression of Bcl-2 was delayed and required IL-2. Cytokines such as IL-2, IL-4, IL-7 or IL-15 prevented apoptosis of activated T cells that effect being associated with the maintenance of Bcl-2, but not of A1 expression. However, restimulation of activated or posteffector T cells with antigenic peptide strongly upregulated A1 mRNA and maintained A1 protein expression. IL-4, IL-7 or IL-15 also prevented cell death of naive T cells. In those cells, cytokines upregulated Bcl-2, but not A1 expression. Therefore, in naive, activated and posteffector T cells, expression of A1 is dependent on TCR but not on cytokine receptor engagement, indicating that A1 is differently regulated from Bcl-xl and Bcl-2.

Cell Death & Differentiation, 2005

As it has been shown for Mcl-1, Bcl-xl and Bcl-2, proteins of the Bcl-2 family play a crucial rol... more As it has been shown for Mcl-1, Bcl-xl and Bcl-2, proteins of the Bcl-2 family play a crucial role during T-cell development in the thymus. We here show that the expression of the antiapoptotic gene A1 is specifically enhanced at the DN3/ DN4 transition and in DP thymocytes that have been positively selected suggesting that A1 expression might be considered as a transcriptional signature of thymocytes that have received pre-TCR or TCR survival signal. Furthermore, we observed that A1-a overexpression in recombination activation gene 1-deficient mice transgenic for the major histocompatibillity complex class I-restricted F5 TCR enhances cell survival of DP thymocytes and permits accumulation of DP cells awaiting positive selection. However, A1-a overexpression has no effect on negative selection. Therefore, our results suggest that A1 plays a specialized role in allowing survival of DP thymocytes and that its role can be distinguished from that of Mcl-1, Bcl-xl and Bcl-2.

Biology of the Cell, 1999

The anthracyclines daunorubicin and doxorubicin were shown to induce apoptosis of hematopoietic c... more The anthracyclines daunorubicin and doxorubicin were shown to induce apoptosis of hematopoietic cell lines. Here we report that they induce apoptosis of both nonactivated and phytohemagglutinin-activated human peripheral blood lymphocytes. Apoptosis demonstrated by surface expression of phosphatidylserine and typical nuclear alterations reached a maximum after 48 h of incubation with these agents. In contrast to topoisomerase inhibitors (etoposide and camptothecin) and antimetabolites (methotrexate and 5-fluorouracil) that induced apoptosis of activated cells only, daunorubicin and doxorubicin triggered apoptosis of cells in the G0-G1 phases of the cell cycle. In agreement with in vitro data, a single i.p. injection of daunorubicin or doxorubicin in BALB/c mice induced T- and B-cell depletion in spleen, lymph nodes, and to a lesser extent in the thymus. Soluble Fas-Fc, CD95 antagonistic antibodies, as well as the p55 tumor necrosis factor receptor-immunoglobulin fusion protein, did not inhibit drug-induced apoptosis. The level of reactive oxygen species was significantly increased in the presence of daunorubicin or doxorubicin only in nonactivated lymphocytes. However, antioxidants such as N-acetyl-L-cysteine or glutathione did not prevent apoptosis. Activation of caspase-3 after daunorubicin or doxorubicin treatment of either nonactivated or activated lymphocytes was demonstrated by the cleavage of poly(ADP-ribose) polymerase, which was, as apoptosis, inhibited by the peptide benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone. Finally, daunorubicin and doxorubicin induced a rapid production of ceramides. These data indicate that anthracyclines may induce major peripheral T-cell deletion, a property not shared by many cytotoxic agents.

Biochimica et Biophysica Acta (BBA) - Molecular Cell Research, 2004

The anti-proliferative effect of Bcl-2 acts mainly at the level of the G0/G1 phase of the cell cy... more The anti-proliferative effect of Bcl-2 acts mainly at the level of the G0/G1 phase of the cell cycle. Deletions and point mutations in the bcl-2 gene show that the anti-proliferative activity of Bcl-2, can in some cases, be dissociated from its anti-apoptotic function. This indicates that the effect of Bcl-2 on cell cycle progression can be a direct effect and not only a consequence of its anti-apoptotic activity. Bcl-2 appears to mediate its anti-proliferative effect by acting on both signal transduction pathways (NFAT, ERK) and on specific cell cycle regulators (p27, p130).

Figure S4. Generation of anti-cath-D human scFv fragments by phage display. (A) Enrichment of ant... more Figure S4. Generation of anti-cath-D human scFv fragments by phage display. (A) Enrichment of anti-cath-D polyclonal scFv fragments by phage display. ScFv phages specific for human mature 34+14-kDa cath-D were selected and enriched in four biopanning rounds, and analyzed by ELISA using a HRP-labeled anti-M13 antibody. BSA, negative antigen. (B) Selection of anti-cath-D monoclonal scFv fragments by ELISA. ELISA performed using bacterial culture supernatants of the best scFv clones (5 out of 400 screened clones) and recombinant human mature 34+14-kDa cath-D and 52-kDa pro-cath-D. Binding of the scFv clones to cath-D was detected with a HRP-labeled anti-Myc antibody. BSA, negative antigen; IR, irrelevant scFv from the screen. (C) Purification of the anti-human cath-D scFv fragments. His-tagged anti-cath-D scFv fragments were purified using TALON resin, resolved by 12% SDS-PAGE and stained with Coomassie blue. (D) Binding of purified anti-cath-D monoclonal scFv antibodies to human cath-...

Effect of ATR inhibition combined with oxaliplatin treatment on the ATR and ATM pathways.

Representative IHC staining of CD39 expression in human normal and tumor tissues (clone HPA014067).

Annales De Dermatologie Et De Venereologie, Nov 1, 2020

Les immunotherapies ciblant les checkpoints immunitaires constituent un tournant dans l’arsenal t... more Les immunotherapies ciblant les checkpoints immunitaires constituent un tournant dans l’arsenal therapeutique des cancers, notamment du melanome. Malgre des resultats cliniques spectaculaires, une majorite de patients presente une resistance innee ou acquise a ces therapies. Il est donc necessaire de mieux comprendre les mecanismes de resistance et d’identifier de nouvelles cibles afin d’augmenter le taux de reponse des patients. Dans le modele de melanome murin B16F10, nous avons demontre le potentiel immunomodulateur d’un anticorps ciblant la cellule tumorale, l’anticorps TA99. Cet anticorps, en essai clinique chez l’homme ( NCT01137006 ), cible l’antigene de surface TYRP-1 surexprime dans les melanocytes tumoraux. Administre a des souris porteuses d’une tumeur de melanome, il induit une reponse anti-tumorale lymphocytaire T memoire specifique assurant une protection a long terme. Dans ce modele, l’echappement au traitement est associe a l’expression de deux ectonucleotidases, CD39 et CD73, responsables de la production d’adenosine, molecule a fort potentiel immunosuppresseur. Une forte expression de CD39 est aussi observee dans des biopsies de patients atteints de melanome metastatique, et nous avons montre que le blocage de cette voie potentialise les effets d’une immunotherapie anti-PD1 dans le modele de melanome B16F10.

Journal of Leukocyte Biology, May 3, 2020

T cells contribute to the immune response against many cancers, notably through their powerful ef... more T cells contribute to the immune response against many cancers, notably through their powerful effector functions that lead to the elimination of tumor cells and the recruitment of other immune cells. However, their presence in the tumor microenvironment has been associated with poor prognosis in breast, colon, and pancreatic cancer, suggesting that T cells may also display pro-tumor activities. Here, we identified in blood from healthy donors a subpopulation of V 1T cells that represents around 20% of the whole V 1 population, expresses CD73, and displays immunosuppressive phenotype and functions (i.e., production of immunosuppressive molecules, such as IL-10, adenosine, and the chemotactic factor IL-8, and inhibition of T cell proliferation). We then found that in human breast tumors, T cells were present particularly in late stage breast cancer samples, and that ∼20% of tumor-infiltrating T cells expressed CD73. Taken together, these results suggest that regulatory T cells are present in the breast cancer microenvironment and may display immunosuppressive functions through the production of immunosuppressive molecules, such as IL-10, IL-8, and adenosine, thus promoting tumor growth.

Representative IHC staining of CD39 expression in vascular endothelial cells and lymphocytes from... more Representative IHC staining of CD39 expression in vascular endothelial cells and lymphocytes from various normal tissues (clone 22A9).