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Epithelial-to-mesenchymal transition (EMT) is associated with tumor aggressiveness, drug resistance, and poor survival in non-small cell lung cancer (NSCLC) and other cancers. The identification of immune-checkpoint ligands (ICPLs) associated with NSCLCs that display a mesenchymal phenotype (mNSCLC) could help to define subgroups of patients who may benefit from treatment strategies using immunotherapy.We evaluated ICPL expression in silico in 130 NSCLC cell lines. In vitro, CRISPR/Cas9-mediated knockdown and lentiviral expression were used to assess the impact of ZEB1 expression on CD70. Gene expression profiles of lung cancer samples from the TCGA (n = 1018) and a dataset from MD Anderson Cancer Center (n = 275) were analyzed. Independent validation was performed by immunohistochemistry and targeted-RNA sequencing in 154 NSCLC whole sections, including a large cohort of pulmonary sarcomatoid carcinomas (SC, n = 55).We uncover that the expression of CD70, a regulatory ligand from the tumor necrosis factor ligand family, is enriched in mNSCLC in vitro models. Mechanistically, the EMT-inducer ZEB1 impacted CD70 expression and fostered increased activity of the CD70 promoter. CD70 overexpression was also evidenced in mNSCLC patient tumor samples and was particularly enriched in SC, a lung cancer subtype associated with poor prognosis. In these tumors, CD70 expression was associated with decreased CD3Our results provide evidence on the pivotal roles of CD70 and ZEB1 in immune escape in mNSCLC, suggesting that EMT might promote cancer progression and metastasis by not only increasing cancer cell plasticity but also reprogramming the immune response in the local tumor microenvironment.

Benoîte Mery,1,2,* Christine Ménétrier-Caux,2,3,* Laure Montané,4 Pierre-Etienne Heudel,1 Isabelle Ray-Coquard,1 Thomas Bachelot,1 Olfa Derbel,5 Paule Augereau,6 Isabelle Treilleux,2,7 Justine Berthet,2,3 Axelle Nkodia,3 Christine Bardin-Dit-Courageot,3 Valery Attignon,8 Anthony Ferrari,9 Gwenaele Garin,4 David Perol,4 Christophe Caux,2,3 Bertrand Dubois,2,3,* Olivier Trédan1,2,* 1Department of Medical Oncology, Centre Léon Bérard, Lyon, France; 2Inserm U1052, CNRS 5286, Cancer Research Center of Lyon, Université Claude Bernard Lyon 1, Lyon, France; 3Laboratory of Cancer Immunotherapy of LYON (LICL), Centre Léon Bérard, Lyon, France; 4Clinical Research Platform (DRCI), Centre Léon Bérard, Lyon, France; 5Department of Medical Oncology, Hôpital Privé Jean-Mermoz, Lyon, France; 6Department of Medical Oncology, Institut de Cancérologie de L’ouest- Paul Papin, Angers, France; 7Biopathology Department, Centre Léon Bérard, Lyon, France; 8Genomic of Cancer Platform, Centre Léon Bérard, Lyon, France; 9Gilles Thomas Bioinformatics Platform, Synergie Lyon Cancer Foundation, Centre Léon Bérard, Lyon, France*These authors contributed equally to this workCorrespondence: Benoîte Mery, Department of Medical Oncology, Centre Léon Bérard, 28 Rue Laennec, Lyon, 69008, France, Tel +33 4 78 78 26 44, Fax +33 4 78 78 27 15, Email Benoite.mery@lyon.unicancer.frPurpose: Metastatic endocrine-resistant breast cancer (MBC) is a disease with poor prognosis and few treatment options. Low lymphocyte count is associated with limited overall survival. In a prospective cohort of lymphopenic patients with HER-2 negative MBC, we assessed the clinical and biological impact of pembrolizumab combined with metronomic cyclophosphamide.Experimental Design: This multicenter Phase II study evaluated the safety and clinical activity of pembrolizumab (intravenous (IV), 200mg, every 3 weeks) combined with metronomic cyclophosphamide (50mg/day, per os) in lymphopenic adult patients with HER2-negative MBC previously treated by at least one line of chemotherapy in this setting according to a Simon’s minimax two-stage design. Blood and tumor samples were collected to assess the impact of the combined treatment on circulating immune cells and the tumor immune microenvironment through multiparametric flow cytometry and multiplex immunofluorescence analyses. Primary endpoint was the clinical benefit rate at 6 months of treatment (CBR-6M). Secondary endpoints were objective response rate (ORR), duration of response, progression free survival (PFS), and overall survival (OS).Results: Two out of the twenty treated patients presented clinical benefit (one Tumor Mutational Burden (TMB)-high patient with complete response (CR) and one patient with objective response (OR) per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST V1.1) associated with a strong increase of cytokine-producing and proliferating CD4+ T cells and higher CD8+ T cells to macrophage ratios in the tumor. This impact on CD4+ and CD8+ T cell polyfunctionality was still observed more than one year for the patient with CR. A decreased in their absolute number of CD4+ and CD8+ memory T cells was observed in other patients.Conclusion: Pembrolizumab combined with metronomic cyclophosphamide was well tolerated, and displayed limited anti-tumoral activity in lymphopenic MBC. Correlative translational data of our trial advocates for additional studies with other chemotherapy combinations.Keywords: metastatic breast cancer, lymphopenia, immunotherapy, chemotherapy, immunomonitoring

Th1.17 characteristics of CD73+ CD4+ Teff based on the expression of CXCR3, CCR6, CRTH2, the migration in response to CXCL10 or CCL20 gradient and the MDR-1-specific Rhodamine 123 exclusion assay

The production of CD73-derived adenosine (Ado) by Tregs has been proposed as a resistance mechanism to anti-PD-1 therapy in murine tumor models. We reported that human Tregs express the ectonucleotidase CD39, which generates AMP from ATP, but do not express the AMPase CD73. In contrast, CD73 defined a subset of effector CD4+ T cells (Teffs) enriched in polyfunctional Th1.17 cells characterized by expression of CXCR3, CCR6, and MDR1, and production of IL17A/IFNγ/IL22/GM-CSF. CD39+ Tregs selectively targeted CD73+ Teffs through cooperative degradation of ATP into Ado inhibiting and restricting the ability of CD73+ Teffs to secrete IL17A. CD73+ Teffs infiltrating breast and ovarian tumors were functionally blunted by Tregs expressing upregulated levels of CD39 and ATPase activity. Moreover, tumor-infiltrating CD73+ Teffs failed to express inhibitory immune checkpoints, suggesting that CD73 might be selected under pressure from immune checkpoint blockade therapy and thus may represent a nonredundant target for restoring antitumor immunity.Significance: Polyfunctional CD73+ T-cell effectors lacking other immune checkpoints are selectively targeted by CD39 overexpressing Tregs that dominate the breast tumor environment. Cancer Res; 78(13); 3604–18. ©2018 AACR.

Immunohistochemical analysis of FOXP3 in primary breast tumors showed that a high number of tumor-infiltrating regulatory T cells (Ti-Treg) within lymphoid infiltrates surrounding the tumor was predictive of relapse and death, in contrast to those present within the tumor bed. Ex vivo analysis showed that these tumor-infiltrating FOXP3+ T cells are typical Treg based on their CD4+CD25highCD127lowFOXP3+ phenotype, their anergic state on in vitro stimulation, and their suppressive functions. These Ti-Treg could be selectively recruited through CCR4 as illustrated by (a) selective blood Treg CCR4 expression and migration to CCR4 ligands, (b) CCR4 down-regulation on Ti-Treg, and (c) correlation between Ti-Treg in lymphoid infiltrates and intratumoral CCL22 expression. Importantly, in contrast to other T cells, Ti-Treg are selectively activated locally and proliferate in situ, showing T-cell receptor engagement and suggesting specific recognition of tumor-associated antigens (TAA). Immunohistochemical stainings for ICOS, Ki67, and DC-LAMP show that Ti-Treg were close to mature DC-LAMP+ dendritic cells (DC) in lymphoid infiltrates but not in tumor bed and were activated and proliferating. Furthermore, proximity between Ti-Treg, CD3+, and CD8+ T cells was documented within lymphoid infiltrates. Altogether, these results show that Treg are selectively recruited within lymphoid infiltrates and activated by mature DC likely through TAA presentation, resulting in the prevention of effector T-cell activation, immune escape, and ultimately tumor progression. This study sheds new light on Treg physiology and validates CCR4/CCL22 and ICOS as therapeutic targets in breast tumors, which represent a major health problem. [Cancer Res 2009;69(5):2000–9]

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PDF file, 67K, Identification of pDC and mDC in blood and tissues.

PDF file, 64K, Breast TUMSN, but not BCCSN, inhibit IFN-α production by CpGA- or Flu-activated pDC in a dose-dependent manner.

Supplementary Data from Regulatory T Cells Recruited through CCL22/CCR4 Are Selectively Activated in Lymphoid Infiltrates Surrounding Primary Breast Tumors and Lead to an Adverse Clinical Outcome

PDF file, 46K, Purified healthy pDC were cultured with IL-3 either alone or in combination with 25% of TUMSN for 40 h and then incubated for 5 days with allogeneic naive CD4+ T cells.

This file contains 3 Supplementary Figures and 1 supplementary table Supplementary Figure S1:ICOSL expression on immune cells in lymphoma and on cell line by flow cytometry Supplementary Figure S2: Antagonist anti-ICOS Abs favor upregulation of ICOSL on FL B cells and on murine B cells Supplementary Figure S3: Inhibition of FL B cells proliferation by Tregs Supplemntary Table S1: Monoclonal antibodies used for flow cytometry

Supplementary Figures 1-4 from Quantitative and Functional Alterations of Plasmacytoid Dendritic Cells Contribute to Immune Tolerance in Ovarian Cancer

PDF file, 114K, Overall survival and relapse-free survival of patients according to the presence of CD123+ pDC in primary breast carcinoma.

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Supplementary Tables 1-2 from Quantitative and Functional Alterations of Plasmacytoid Dendritic Cells Contribute to Immune Tolerance in Ovarian Cancer

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PDF file, 768K, IHC analysis on frozen BT sections was performed using anti-BDCA2 (brown) together with anti-CD3 (green, a) or anti- cytokeratine (green, b) antibodies (x10)

PDF file - 296K, Figure S1: ICOS is mainly expressed by TA-Treg. Figure S2: pDC expanded Treg sustain suppressive activity. Figure S3: ICOS-L is highly expressed on R848-activated HD-pDC. Figure S4: ICOS blockade reduces Treg but not Tconv proliferation induced by pDC without impacting mDC/T cell activation. Figure S5: Strong IL-10 secretion in culture of BT single cell suspension. Figure S6: Correlation between TA-pDC and TA-Treg percentages in fresh primary BT and in retrospective IHC cohort

PDF file - 103K, Table S1: Clinical characteristic of the cohort of BT patients enrolled for TMA analysis (n=120) Table S2: clones of mAbs used for the multi-parametric flow cytometry analyses

PDF file, 77K, Correlations between tumor characteristics and TA(p/m)DC.

This file contains legends of 3 Supplementary Figures Supplementary Figure S1:ICOSL expression on immune cells in lymphoma and on cell line by flow cytometry Supplementary Figure S2: Antagonist anti-ICOS Abs favor upregulation of ICOSL on FL B cells and on murine B cells Supplementary Figure S3: Inhibition of FL B cells proliferation by Tregs

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Tumor-associated macrophages (TAM) are critical determinant of resistance to programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) blockade. This phase I study (MEDIPLEX,NCT02777710) investigated the safety and efficacy of pexidartinib, a CSF-1R-directed tyrosine kinase inhibitor (TKI), and durvalumab (anti-PD-L1) in patients with advanced colorectal (CRC) and pancreatic (PDAC) carcinoma with the aim to enhance responses to PD-L1 blockade by eliminating CSF-1-dependent suppressive TAM. No unexpected toxicities were observed and 2% and 15% of patients achieved partial response and stable disease respectively. Increase of CSF-1 levels and decrease of CD14lowCD16highmonocytes in peripheral blood mononuclear cells (PBMC) confirmed CSF-1R engagement. Treatment significantly decreased blood dendritic cell (DC) subsets and impaired IFN-λ/IL-29 production by type-1 conventional DC inex vivoTLR3-stimulated PBMC. Pexidartinib also targets c-KIT and FLT3, both key growth factor receptors of DC development and maturation. In patients, FLT3-L levels increased with pexidartinib treatment.In vitro, pexidartinib impaired the FLT3-L but not GM-CSF-dependent generation of DC subsets from murine bone marrow progenitors. Our results demonstrate that pexidartinib, through the inhibition of FLT3 signaling, has deleterious effect on DC differentiation, which may explain the limited anti-tumor clinical activity observed in this study. This study suggests that inhibition of FLT3 should be taken into account when combining TKIs with immune checkpoint blockers.One-sentence summaryPexidartinib affects the development of dendritic cells

Introduction: EVT801 is a highly selective small molecule inhibitor of VEGFR3 and acts by inhibiting lymphangiogenesis and tumor angiogenesis in and around the tumor. It has shown compelling activity in a wide range of cancer models and is well-tolerated in preclinical toxicology studies. A phase I study is underway and will focus primarily on understanding the safety, tolerability, and pharmacokinetics of EVT801 across a range of doses. Methods: The first stage of the study is designed to determine the maximum tolerated dose (MTD) and recommended Phase II dose (RP2D) for EVT801, with a second stage aiming to confirm RP2D in selected cancer patient populations. Clinical samples from these patients will be used to explore preliminary signals of clinical efficacy and investigate the biological activity of the drug using several biomarkers. Efficacy biomarkers will include imaging approaches (DCE-MRI and CEUS) to characterize tumor vascularization, as well as analysis of protein and mRNA quantification in on-treatment biopsies vs pre-treatment biopsies. Moreover, the relationship between activity of EVT801 and expression of key markers at protein and mRNA level will be investigated to potentially establish biomarkers for patient stratification and selection. Lastly, target engagement and pharmacodynamics effects will be investigated by immuno-monitoring as well as assessment of a defined set of proteins as markers of inflammation and angiogenesis as identified in preclinical in vivo models. We expect that these analyses will help to better understand the effects of the drug in human subjects and may also help to select the most responsive patients and provide early signs of clinical efficacy. Citation Format: Michael R. Paillasse, James Garner, Michael Fitzgerald, Lise Davenne, Pierre-Benoit Ancey, celine Poussereau-Pomie, Michael Esquerre, Gaelle Badet, Joel Tuyaret, Marie Mandron, Philippe Rochaix, Maha Ayyoub, Clara Maria Scarlata, Christine Ménétrier-Caux, Chrsitophe CAUX, Philippe Cassier, Jean-Pierre Delord, Carlos Gomez Roca, Pierre Fons. Cutting edge biomarkers strategy to provide early insights into activity of EVT-801, a novel selective VEGFR-3 inhibitor that targets tumor angiogenesis during the FIH clinical trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3203.

Simple Summary The immune response against cancer is generated by effector T cells, among them cytotoxic CD8+ T cells that destroy cancer cells and helper CD4+ T cells that mediate and support the immune response. This antitumor function of T cells is tightly regulated by a particular subset of CD4+ T cells, named regulatory T cells (Tregs), through different mechanisms. Even if the complete inhibition of Tregs would be extremely harmful due to their tolerogenic role in impeding autoimmune diseases in the periphery, the targeted blockade of their accumulation at tumor sites or their targeted depletion represent a major therapeutic challenge. This review focuses on the mechanisms favoring Treg recruitment, expansion and stabilization in the tumor microenvironment and the therapeutic strategies developed to block these mechanisms. Abstract Regulatory T cells (Tregs) are present in a large majority of solid tumors and are mainly associated with a poor prognosis, as their major function is to inhibit the antitumor immune response contributing to immunosuppression. In this review, we will investigate the mechanisms involved in the recruitment, amplification and stability of Tregs in the tumor microenvironment (TME). We will also review the strategies currently developed to inhibit Tregs’ deleterious impact in the TME by either inhibiting their recruitment, blocking their expansion, favoring their plastic transformation into other CD4+ T-cell subsets, blocking their suppressive function or depleting them specifically in the TME to avoid severe deleterious effects associated with Treg neutralization/depletion in the periphery and normal tissues.

International audience; Three series of nucleotide analogues were synthesized and evaluated as potential CD73 inhibitors. Nucleobase replacement consisted in connecting the appropriate aromatic or purine residues through a triazole moiety that is generated from 1,3-dipolar cycloaddition. The first series is related to 4substituted-1,2,3-triazolo--hydroxyphosphonate ribonucleosides. Additional analogues were also obtained, in which the phosphonate group was replaced by a bisphosphonate pattern (P-C-P-C, series 2) or the ribose moiety was removed leading to acyclic derivatives (series 3). The βhydroxyphosphonylphosphonate ribonucleosides (series 2) were found to be potent inhibitors of CD73 using both purified recombinant protein and cell-based assays. Two compounds (2a and 2b) that contained a bis(trifluoromethyl)phenyl or a naphthyl substituents proved to be the most potent inhibitors, with IC50 values of 4.8 ± 0.8 µM and 0.86 ± 0.2 µM, compared to the standard AOPCP (IC50 value of 3.8 ± 0.9 µM), and were able to reverse the adenosine-mediated immune suppression on human T cells. This series of compounds illustrates a new type of CD73 inhibitors.

IntroductionPatients with metastatic non-small cell lung cancer (mNSCLC) suffer from numerous symptoms linked to disease and treatment which may further impair the patient’s overall condition. In addition to its benefits on quality of life and fatigue, physical exercise may improve treatment response, notably due to its known effects on the immune system. The ERICA study is designed to assess the feasibility of a supervised acute physical exercise therapy realised immediately prior immune-chemotherapy infusion in patients with mNSCLC. Secondary objectives will examine the effects of acute exercise combined with an unsupervised home-walking programme on clinical, physical, psychosocial and biological parameters.Methods and analysisERICA is a prospective, monocentric, randomised controlled, open-label feasibility study conducted at the Centre Léon Bérard Comprehensive Cancer Center (France). Thirty patients newly diagnosed with mNSCLC will be randomised (2:1 ratio) to the ‘exercise’ or the ‘control’ group. At baseline and during the last treatment cycle, participants in both groups will receive Physical Activity recommendations, and two nutritional assessments. In the exercise group, participants will receive a 3-month programme consisting of a supervised acute physical exercise session prior to immune-chemotherapy infusion, and an unsupervised home-based walking programme with an activity tracker. The acute exercise consists of 35 min interval training at submaximal intensity scheduled to terminate 15 min prior to infusion. Clinical, physical, biological and psychosocial parameters will be assessed at baseline, 3 and 6 months after inclusion. Biological measures will include immune, inflammatory, metabolic, oxidative stress biomarkers and molecular profiling.Ethics and disseminationThe study protocol was approved by the French ethics committee (Comité de protection des personnes Ile de France II, N°ID-RCB 20.09.04.65226, 8 December 2020). The study is registered on ClinicalTrials.gov (NCT number:NCT04676009) and is at the pre-results stage. All participants will sign an informed consent form. The findings will be disseminated in peer-reviewed journals and academic conferences.

International audience; Soft tissue sarcomas are a group of rare and aggressive connective tissue neoplasms for which curative therapeutic opportunities are limited in advanced phase. Clinical trials assessing immunotherapy in these tumors have so far reported limited efficacy. The objective of this study is to provide a description of the immunologic landscape of sarcomas to guide the next clinical trials of immunotherapy in these diseases. The gene expression profile of 93 immune checkpoint (ICP) and membrane markers (MM) of immune cells was analyzed in a series of 253 soft tissue sarcoma (synovial sarcoma, myxoid liposarcoma, sarcoma with complex genomic and GIST) using Agilent Whole Human Genome Microarrays. The unsupervised hierarchical clustering of gene expression level was found able to properly group patients according to the histological subgroup of sarcoma, indicating that each sarcoma subgroup is associated with a specific immune signature defined by its gene expression pattern. Using the prognostic impact of CIBERSORT signature on metastatic-free survival in each subgroup, specific target could be proposed for each of the four groups: Treg through ICOS and GITR in GIST, M0 macrophages in all four sarcoma subtypes, OX40 in SS, CD40 in GIST and SS. The immune landscape of sarcoma was found to be as heterogeneous as the histotypes and molecular subtypes, but strongly correlated to the histotype. Histotype adapted immunotherapeutic approaches in each sarcoma subtypes must be considered in view of these results, consistently with the already reported specific response of histotypes of ICPs.

Objectives The accumulation of tumor‐associated macrophages (TAMs) is correlated with poor clinical outcome, but the mechanisms governing their differentiation from circulating monocytes remain unclear in humans. Methods Using multicolor flow cytometry, we evaluated TAMs phenotype in 93 breast cancer (BC) patients. Furthermore, monocytes from healthy donors were cultured in the presence of supernatants from dilacerated primary tumors to investigate their differentiation into macrophages (MΦ) in vitro. Additionally, we used transcriptomic analysis to evaluate BC patients’ blood monocytes profiles. Results We observed that high intra‐tumor CD163‐expressing TAM density is predictive of reduced survival in BC patients. In vitro, M‐CSF, TGF‐β and VEGF from primary tumor supernatants skewed the differentiation of healthy donor blood monocytes towards CD163highCD86lowIL‐10high M2‐like MΦ that strongly suppressed CD4+ T‐cell expansion via PD‐L1 and IL‐10. In addition, blood monocytes from about 40% of BC patients displayed an altered response to in vitro stimulation, being refractory to type‐1 MΦ (M1‐MΦ) differentiation and secreting higher amounts of immunosuppressive, metastatic‐related and angiogenic cytokines. Aside from showing that monocyte transcriptome is significantly altered by the presence of BC, we also demonstrated an overall metabolic de‐activation in refractory monocytes of BC patients. In contrast, monocytes from sensitive BC patients undergoing normal M1‐MΦ differentiation showed up‐regulation of IFN‐response genes and had no signs of metabolic alteration. Conclusion Altogether, our results suggest that systemic factors skew BC patient blood monocytes towards a pro‐metastatic profile, resulting in the accumulation of further polarised CD163high TAMs resembling type‐2 MΦ (M2‐MΦ) in the local BC microenvironment. These data indicate that monitoring circulating monocytes in BC patients may provide an indication of early systemic alterations induced by cancer and, thus, be instrumental in the development of improved personalised immunotherapeutic interventions., The mechanisms governing suppressive tumor‐associated macrophage (TAM) generation from circulating monocytes remain unclear in humans. In this study, we identify tumor‐derived M‐CSF, TGF‐β and VEGF as key factors skewing monocytes towards immunosuppressive CD163highCD86lowIL‐10high M2‐like macrophages (MΦ). We also describe an intrinsic metabolic de‐activation in breast cancer (BC) patient monocytes refractory to type‐1 MΦ (M1‐MΦ) differentiation that contrast with the active intrinsic IFN‐signalling pathway detected in sensitive BC patient monocytes undergoing normal M1‐MΦ differentiation. Thus, the combined local and systemic skewing of monocytes may give rise to the accumulation of suppressive M2‐like TAMs, contributing to the immune response failure and impacting on BC patient outcome.

The production of CD73-derived adenosine (Ado) by Tregs has been proposed as a resistance mechanism to anti-PD-1 therapy in murine tumor models. We reported that human Tregs express the ectonucleotidase CD39, which generates AMP from ATP, but do not express the AMPase CD73. In contrast, CD73 defined a subset of effector CD4 + T cells (Teffs) enriched in polyfunctional Th1.17 cells characterized by expression of CXCR3, CCR6, and MDR1, and production of IL17A/IFNγ/IL22/GM-CSF. CD39 + Tregs selectively targeted CD73 + Teffs through cooperative degradation of ATP into Ado inhibiting and restricting the ability of CD73 + Teffs to secrete IL17A. CD73 + Teffs infiltrating breast and ovarian tumors were functionally blunted by Tregs expressing upregulated levels of CD39 and ATPase activity. Moreover, tumor-infiltrating CD73 + Teffs failed to express inhibitory immune checkpoints, suggesting that CD73 might be selected under pressure from immune checkpoint blockade therapy and thus may represent a nonredundant target for restoring antitumor immunity.Significance: Polyfunctional CD73 + T-cell effectors lacking other immune checkpoints are selectively targeted by CD39 overexpressing Tregs that dominate the breast tumor environment. Cancer Res; 78(13); 3604-18. ©2018 AACR.

// Ines Monteiro 1 , Selena Vigano 2 , Mohamed Faouzi 3 , Isabelle Treilleux 4 , Olivier Michielin 5 , Christine Menetrier-Caux 6, 7 , Christophe Caux 6, 7 , Pedro Romero 2, * and Laurence de Leval 1, * 1 Institute of Pathology, Lausanne University Hospital, Lausanne, Switzerland 2 Department of Oncology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland 3 Institute of Social and Preventive Medicine (IUMSP), University Hospital, Lausanne, Switzerland 4 Anatomopathology Department, Centre Leon Berard, Lyon, France 5 Department of Oncology, Lausanne University Hospital, Lausanne, Switzerland 6 Universite Claude Bernard Lyon 1, Centre de recherche en cancerologie de Lyon, Lyon, France 7 Department of Innovation and Translational Research, Centre Leon Berard, Lyon, France * Co-last authors Correspondence to: Laurence de Leval, email: laurence.deleval@chuv.ch Keywords: CD73; ecto-5'-nucleotidase; immunohistochemistry; melanoma; prognosis Received: February 12, 2018 Accepted: April 30, 2018 Published: June 01, 2018 ABSTRACT Background: CD73 is an ectoenzyme involved in the production of adenosine. It exerts immunosuppressive and protumoral roles and has emerged as a potential immuno-oncology target. Results: CD73 expression was detected in TC in 54% of melanoma metastases, involving 37.5 or intensity > 1) significantly correlated to decreased overall survival (OS) from biopsy. Of the samples containing TIMC, 35% presented CD73+ TIMC. Highly infiltrated tumors were more likely to contain CD73+ TIMC. CD73 expression in TIMC (percentage ≥1%) significantly correlated with improved OS from biopsy. Conclusions: Immunohistochemistry detected CD73 expression in more than half of metastatic melanomas. While CD73 expression in TC significantly correlated with decreased OS, CD73 expression in TIMC significantly associated with improved OS. These results encourage the study of anti-CD73 therapies for metastatic melanoma patients. Methods: CD73 expression was assessed by immunohistochemistry in metastatic melanomas from 114 patients. Immunostainings were evaluated in tumor cells (TC) (percentage, intensity (1–3) and H-score) and in tumor-infiltrating mononuclear cells (TIMC) (percentage).

Objectives: Th1.17 are highly polyfunctional, potentially harmful CD4+ effector T cells (Teff) through IFN-&gamma, and IL-17A coproduction. Th1.17 take part in the pathophysiology of rheumatoid arthritis (RA) and psoriatic arthritis (PsA), in which their hyper activation results in part from defects in negative regulation mechanisms. We recently demonstrated that the ecto-nucleotidase CD73 delineates a Th1.17-enriched Teff population and acts as an endogenous regulatory mechanism. Because Methotrexate (MTX), used as first line treatment of RA and PsA, increases extracellular concentrations of AMP and immunosuppressive adenosine, we investigated the modulation of CD73 by MTX treatment on Teff in RA/PsA patients. Methods: In a prospective cohort of 26 RA and 15 PsA patients before or under MTX treatment, we evaluated CD73 expression on blood Teff subsets, their cytokine production and AMPase functions. Results: We showed a decreased CD73 expression on Th1.17 and Th1 in untreated patients compared to healthy donors that was partly restored under MTX. This decrease in untreated patients leads to a halved Ado production by Th1.17 cells. CD73+ Teff remained functional under MTX treatment, but their CD73 re-expression may contribute to control their activation. Conclusion: Our study unveils uncovered mode of action of MTX on Teff subsets modulation and in the adenosine-dependent termination of inflammation in RA and PsA.

T cells play a critical role in cancer control, but a range of potent immunosuppressive mechanisms can be upregulated in the tumor microenvironment (TME) to abrogate their activity. While various immunotherapies (IMTs) aiming at re-invigorating the T-cell-mediated anti-tumor response, such as immune checkpoint blockade (ICB), and the adoptive cell transfer (ACT) of natural or gene-engineered ex vivo expanded tumor-specific T cells, have led to unprecedented clinical responses, only a small proportion of cancer patients benefit from these treatments. Important research efforts are thus underway to identify biomarkers of response, as well as to develop personalized combinatorial approaches that can target other inhibitory mechanisms at play in the TME. In recent years, adenosinergic signaling has emerged as a powerful immuno-metabolic checkpoint in tumors. Like several other barriers in the TME, such as the PD-1/PDL-1 axis, CTLA-4, and indoleamine 2,3-dioxygenase (IDO-1), adenosine plays important physiologic roles, but has been co-opted by tumors to promote their growth and impair immunity. Several agents counteracting the adenosine axis have been developed, and pre-clinical studies have demonstrated important anti-tumor activity, alone and in combination with other IMTs including ICB and ACT. Here we review the regulation of adenosine levels and mechanisms by which it promotes tumor growth and broadly suppresses protective immunity, with extra focus on the attenuation of T cell function. Finally, we present an overview of promising pre-clinical and clinical approaches being explored for blocking the adenosine axis for enhanced control of solid tumors.

Quantitative lymphocyte alterations are frequent in patients with cancer, and strongly impact prognosis and survival. The development of cancers in immunosuppressed patients has demonstrated the contribution of different T cell populations, including CD4+ cells, in the control of cancer occurrence. Whereas absolute numbers of neutrophils, platelets and red blood cells are routinely monitored in clinic following treatments, because of possible short-term complications, absolute lymphocyte counts (ALC), their subpopulations or diversity (phenotype, TCR) are rarely analyzed and never used to choose therapy or as prognostic criteria. The recent identification of immune checkpoint inhibitors (ICPi) as powerful therapeutic agents has revitalized immunotherapy of cancer in a broader group of diseases than anticipated. The status of the immune system is now recognized as an important biomarker for response to these novel treatments. Blood ALC values, along with tumor infiltration by CD8+T cells, and ICPi and ICPi-ligand expression, are likely to be a potential marker of sensitivity to anti-ICPi therapy. In this article, we review the current knowledge on the incidence and significance of lymphopenia in cancer patients, and discuss therapeutic strategies to restore lymphocyte numbers.

International audience; Background: The tumor-expressed CD73 ectonucleotidase generates immune tolerance and promotes invasiveness via adenosine production from degradation of AMP. While anti-CD73 blockade treatment is a promising tool in cancer immunotherapy, a characterization of CD73 expression in human hepatobiliopancreatic system is lacking.Patients and methods: CD73 expression was investigated by immunohistochemistry in a variety of non-neoplastic and neoplastic conditions of the liver, pancreas, and biliary tract.Results: CD73 was expressed in normal hepatobiliopancreatic tissues with subcellular-specific patterns of staining: canalicular in hepatocytes, and apical in cholangiocytes and pancreatic ducts. CD73 was present in all hepatocellular carcinoma (HCC), in all pancreatic ductal adenocarcinoma (PDAC), and in the majority of intra and extrahepatic cholangiocellular carcinomas, whereas it was detected only in a subset of pancreatic neuroendocrine neoplasms and almost absent in acinar cell carcinoma. In addition to the canonical pattern of staining, an aberrant membranous and/or cytoplasmic expression was observed in invasive lesions, especially in HCC and PDAC. These two entities were also characterized by a higher extent and intensity of staining as compared to other hepatobiliopancreatic neoplasms. In PDAC, aberrant CD73 expression was inversely correlated with differentiation (p < 0.01) and was helpful to identify isolated discohesive tumor cells. In addition, increased CD73 expression was associated with reduced overall survival (HR 1.013) and loss of E-Cadherin.Conclusions: Consistent CD73 expression supports the rationale for testing anti-CD73 therapies in patients with hepatobiliopancreatic malignancies. Specific patterns of expression could also be of help in the routine diagnostic workup.

Mice reconstituted with a human immune system and bearing human tumors represent a promising model for developing novel cancer immunotherapies. Here, we used mass cytometry and multi-parametric flow cytometry to characterize human leukocytes infiltrating a human breast cancer tumor model in immunocompromised NOD.SCID.γc-null mice reconstituted with a human immune system and compared it to samples of breast cancer patients. We observed highly activated human CD4+ and CD8+ T cells in the tumor, as well as minor subsets of innate immune cells in both settings. We also report that ICOS+ CD4+ regulatory T cells (Treg) were enriched in the tumor relative to the periphery in humanized mice and patients, providing a target to affect Treg and tumor growth. Indeed, administration of a neutralizing mAb to human ICOS reduced Treg proportions and numbers and improved CD4+ T cell proliferation in humanized mice. Moreover, a combination of the anti-ICOS mAb with cyclophosphamide reduced tumor growth, and that was associated with an improved CD8 to Treg ratio. However, depletion of human CD8+ T cells only marginally affected tumor control whereas depletion of murine myeloid cells abrogated the effect of the combination therapy. Altogether, our results indicate that a combination of anti-ICOS mAb and chemotherapy controls tumor growth in humanized mice and highlight the crucial implication of innate immunity in treatment efficacy, opening new perspectives for the treatment of breast cancer.One sentence summaryICOS expressed on Tregs is a promising target to improve tumor immunity in humansAbbreviationsICOSInducible CostimulatoryNSGNOD.SCID.gc-nullTregregulatory T cellsCTXcyclophosphamideHuMicehumanized miceCyTOFcytometry time-of-flighttSNEtdistributed stochastic neighbor embeddingpDCsplasmacytoid dendritic cellsDCdendritic cellsICDimmunogenic cell death