Les structures lymphoïdes tertiaires orchestrent le microenvironement tumorale et guide la réponse à l’immunothérapie du cancer

Les tumeurs sont un mélange de cellules tumorales, immunitaires et stromales, composant le microenvironnement tumoral (MET). La composition et l'orientation fonctionnelle du MET influencent le pronostic et la réponse aux inhibiteurs de points de contrôles (IPC). Dans le MET, on trouve des cellules B associées à des cellules T, formant des centres germinatifs appelées structures lymphoïdes tertiaires (SLT). Le principal travail de ma thèse a été d'étudier l'impact des SLT sur l'organisation spatiale du MET et de découvrir les rôles des cellules B et des SLT dans la réponse anti-tumorale. Nous avons d'abord établi le profil de l'infiltrat immunitaire des lésions hépatiques précoces et découvert que les SLT présentaient un phénotype immature associé à des signaux immunosuppresseurs. Dans le cancer du rein, nous avons utilisé la transcriptomique spatiale pour étudier les SLT et découvert qu'ils pouvaient générer et propager des plasmocytes produisant des anticorps anti-tumoraux. Le marquage des cellules tumorales par les anticorps produits localement était associé à l'apoptose tumorale et à la réponse aux IPC. Enfin, j'ai utilisé MCP-counter pour effectuer une classification immunitaire non supervisée de patients atteints de carcinome rénal à cellules claires métastatiques. Cette classification a permis d'identifier les patients qui répondent à l’IPC et dont le MET est composé d'une forte infiltration de cellules immunitaires et d'une faible composante stromale. Dans l'ensemble, ces résultats démontrent les rôles majeurs des cellules B et de la TME dans la réponse immunitaire anti-tumorale et ouvrent la voie à des traitements personnalisés contre le cancer.Tumors are a heterogeneous mix of tumor, immune and stromal cells all of which composing the tumor microenvironment (TME). The composition and functional orientation of the TME can greatly influence the prognosis and response to therapy such as immune checkpoint blockade (ICB). For a long time, T cells have been described as the main effector of the anti-tumor immune response. Recently, several teams have demonstrated the association of B cells with response to ICB. In the TME, B cells are found associated with T cells, forming germinal center-like structures also called tertiary lymphoid structures (TLS). The major work of my PhD was to study the TLS impact on the spatial organization of the TME and uncover the roles of B cells and TLS in the anti-tumor response. We first profiled the immune infiltrate of early-hepatic lesions and discovered that TLS featured an immature phenotype which was associated with immuno- supressive signals. In renal cancer, we used spatial transcriptomics to study TLS, and discovered that they could generate and propagate anti-tumor antibody producing plasma cells. Tumoral cells staining by locally produced antibodies was associated to tumor apoptosis and response to ICB. Finally, I used MCP-counter to perform an unsupervised immune classification of metastatic clear cell renal cell carcinoma patients. This classification identified responders to ICB with a TME composed by high infiltration of immune cells and a low stromal component. Altogether, these results demonstrate the major roles of B cells and TLS in the anti-tumor immune response and pave the way for personalized cancer treatments

Maintien en emploi des seniors et expérimentations partenariales de cinq Aract : quels apports pour la conception et la mise en œuvre de la politique publique ?

International audienceOver the course of the reforms of the French retirement system, keeping seniors in employment has become an issue for public policy. Between 2016 and 2019, five regional agencies for the improvement of working conditions (Aract) carried out experiments combining a partnership dimension, a dimension of support for the employers involved and a dimension of learning on a territorial scale. A capitalization assistance carried out by a pair of economist and ergonomist researchers analyzed these experiments based on reports and support documents produced by Aract, interviews with the project managers of each Aract and reflective collective exchanges between December 2017 and April 2019. Three aspects are discussed here: “territorial partnership configurations”, appropriate support for businesses and the different learning effects of the experiments.Au fil des réformes du système de retraite français, le maintien en emploi des seniors est devenu un enjeu pour la politique publique. Entre 2016 et 2019, cinq Agences régionales pour l’amélioration des conditions de travail (Aract) ont mené des expérimentations combinant une dimension partenariale, une dimension d’accompagnement des employeurs impliqués et une dimension d’apprentissage à une échelle territoriale. Une aide à la capitalisation réalisée par un binôme de chercheuses économiste et ergonome a analysé ces expérimentations à partir des bilans et documents supports produits par les Aract, d’entretiens avec les chargés de mission de chaque Aract et d’échanges collectifs réflexifs entre décembre 2017 et avril 2019. Trois aspects sont ici discutés : les « configurations partenariales territoriales », l’accompagnement adapté des entreprises et les différents effets d’apprentissage des expérimentations

The Tumor Microenvironment in the Response to Immune Checkpoint Blockade Therapies

International audienceTumor cells constantly interact with their microenvironment, which comprises a variety of immune cells together with endothelial cells and fibroblasts. The composition of the tumor microenvironment (TME) has been shown to influence response to immune checkpoint blockade (ICB). ICB takes advantage of immune cell infiltration in the tumor to reinvigorate an efficacious antitumoral immune response. In addition to tumor cell intrinsic biomarkers, increasing data pinpoint the importance of the TME in guiding patient selection and combination therapies. Here, we review recent efforts in determining how various components of the TME can influence response and resistance to ICB. Although a large body of evidence points to the extent and functional orientation of the T cell infiltrate as important in therapy response, recent studies also confirm a role for other components of the TME, such as B cells, myeloid lineage cells, cancer-associated fibroblasts, and vasculature. If the ultimate goal of curative cancer therapies is to induce a long-term memory T cell response, the other components of the TME may positively or negatively modulate the induction of efficient antitumor immunity. The emergence of novel high-throughput methods for analyzing the TME, including transcriptomics, has allowed tremendous developments in the field, with the expansion of patient cohorts, and the identification of TME-based markers of therapy response. Together, these studies open the possibility of including TME-based markers for selecting patients that are likely to respond to specific therapies, and pave the way to personalized medicine in oncology

An Eight-Gene Hypoxia Signature Predicts Survival in Pancreatic Cancer and Is Associated With an Immunosuppressed Tumor Microenvironment

International audienceIntratumoral hypoxia is a widely established element of the pancreatic tumor microenvironment (TME) promoting immune escape, tumor invasion, and progression, while contributing to treatment resistance and poor survival. Despite this critical role, hypoxia is underrepresented in molecular signatures of pancreatic ductal adenocarcinoma (PDA) and concurrent investigations into the hypoxia-immune status are lacking. In this work a literature-based approach was applied to derive an eight-gene hypoxia signature that was validated in fourteen cancer cell lines and in a cohort of PDA. The eight-gene hypoxia signature was significantly associated with overall survival in two distinct PDA datasets and showed independent prognostic value in multivariate analysis. Comparative analysis of tumors according to their hypoxia score (high versus low) determined that tumors with high hypoxia were significantly less enriched in cytotoxic T-cells, and cytolytic activity. In addition, they had lower expression of cytokines and tumor inflammatory markers, pointing to the signature’s ability to discern an immune “cold”, hypoxic TME. Combining the signature with an immune metric highlighted a worse survival probability in patients with high hypoxia and low immune reactivity, indicating that this approach could further refine survival estimates. Hypoxia as determined by our signature, was significantly associated with certain immune checkpoint inhibitors (ICI) biomarkers, suggesting that the signature reflects an aspect of the TME that is worth pursuing in future clinical trials. This is the first work of its kind in PDA, and our findings on the hypoxia-immune tumor contexture are not only relevant for ICI but could also guide combinatorial hypoxia-mediated therapeutic strategies in this cancer type

B cells and cancer: To B or not to B?

International audienceWhereas T cells have been considered the major immune cells of the tumor microenvironment able to induce tumor regression and control cancer clinical outcome, a burst of recent publications pointed to the fact that B cells may also play a prominent role. Activated in germinal centers of tertiary lymphoid structures, B cells can directly present tumor-associated antigens to T cells or produce antibodies that increase antigen presentation to T cells or kill tumor cells, resulting in a beneficial clinical impact. Immune complexes can also increase inflammation, angiogenesis, and immunosuppression via macrophage and complement activation, resulting in deleterious impact

Tertiary Lymphoid Structures and B cells: Clinical impact and therapeutic modulation in cancer

International audienceTumors progression is under the control of a heterogeneous microenvironment composed of immune cells, fibroblasts, blood and lymphatic vessels, in which T cells have been demonstrated to be major actors, through their cytotoxic and cytokine producing effector functions and their long term memory that protects against metastasis. In this scenario, lessons from mouse models taught that B cells exert a protumoral role, via macrophage-dependent activation of inflammation. However, it became progressively evident from studies in patients with human cancers that the anti-tumor responses can be generated and controlled in tertiary lymphoid structures (TLS) that concentrate most of the intratumoral B cells and where B cells can differentiate into plasma cells and memory cells. Furthermore, recent studies demonstrated that the presence in tumors of B cells and TLS are associated with favorable outcome in patients treated by immunotherapy, unraveling TLS as a new predictive marker of anti-tumor response human cancers. This review encompasses the characteristics and functions of TLS and of B cells in human tumors, their prognostic and theranostic impact and summarizes the mouse models used to induce TLS neogenesis in tumors

Low-dose photodynamic therapy promotes a cytotoxic immunological response in a murine model of pleural mesothelioma

OBJECTIVES: Malignant pleural mesothelioma (MPM) is a deadly disease with limited treatment options. Approaches to enhance patient immunity against MPM have been tested but shown variable results. Previously, we have demonstrated interesting vascular modulating properties of low-dose photodynamic therapy (L-PDT) on MPM. Here, we hypothesized that L-PDT vascular modulation could favour immune cell extravasation in MPM and improve tumour control in combination with immune checkpoint inhibitors.METHODS: First, we assessed the impact of L-PDT on vascular endothelial E-selectin expression, a key molecule for immune cell extravasation, in vitro and in a syngeneic murine model of MPM. Second, we characterized the tumour immune cell infiltrate by 15-colour flow cytometry analysis 2 and 7 days after L-PDT treatment of the murine MPM model. Third, we determined how L-PDT combined with immune checkpoint inhibitor anti-CTLA4 affected tumour growth in a murine MPM model.RESULTS: L-PDT significantly enhanced E-selectin expression by endothelial cells in vitro and in vivo. This correlated with increased CD8(+) T cells and activated antigen-presenting cells (CD11b(+) dendritic cells and macrophages) infiltration in MPM. Also, compared to anti-CTLA4 that only affects tumour growth, the combination of L-PDT with anti-CTLA4 caused complete MPM regression in 37.5% of animals.CONCLUSIONS: L-PDT enhances E-selectin expression in the MPM endothelium, which favours immune infiltration of tumours. The combination of L-PDT with immune checkpoint inhibitor anti-CTLA4 allows best tumour control and regression

The murine Microenvironment Cell Population counter method to estimate abundance of tissue-infiltrating immune and stromal cell populations in murine samples using gene expression

International audienceQuantifying tissue-infiltrating immune and stromal cells provides clinically relevant information for various diseases. While numerous methods can quantify immune or stromal cells in human tissue samples from transcriptomic data, few are available for mouse studies. We introduce murine Microenvironment Cell Population counter (mMCP-counter), a method based on highly specific transcriptomic markers that accurately quantify 16 immune and stromal murine cell populations. We validated mMCP-counter with flow cytometry data and showed that mMCP-counter outperforms existing methods. We showed that mMCP-counter scores are predictive of response to immune checkpoint blockade in cancer mouse models and identify early immune impacts of Alzheimer's disease

Natural killer cells in the human lung tumor microenvironment display immune inhibitory functions

Background Natural killer (NK) cells play a crucial role in tumor immunosurveillance through their cytotoxic effector functions and their capacity to interact with other immune cells to build a coordinated antitumor immune response. Emerging data reveal NK cell dysfunction within the tumor microenvironment (TME) through checkpoint inhibitory molecules associated with a regulatory phenotype.Objective We aimed at analyzing the gene expression profile of intratumoral NK cells compared with non-tumorous NK cells, and to characterize their inhibitory function in the TME.Methods NK cells were sorted from human lung tumor tissue and compared with non- tumoral distant lungs.Results In the current study, we identify a unique gene signature of NK cell dysfunction in human non-small cell lung carcinoma (NSCLC). First, transcriptomic analysis reveals significant changes related to migratory pattern with a downregulation of sphingosine-1-phosphate receptor 1 (S1PR1) and CX3C chemokine receptor 1 (CX3CR1) and overexpression of C-X-C chemokine receptor type 5 (CXCR5) and C-X-C chemokine receptor type 6 (CXCR6). Second, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and killer cell lectin like receptor (KLRC1) inhibitory molecules were increased in intratumoral NK cells, and CTLA-4 blockade could partially restore MHC class II level on dendritic cell (DC) that was impaired during the DCs/NK cell cross talk. Finally, NK cell density impacts the positive prognostic value of CD8+ T cells in NSCLC.Conclusions These findings demonstrate novel molecular cues associated with NK cell inhibitory functions in NSCLC