Academic literature on the topic 'Anti-Tumoral immunity'

Abstract The majority of pancreatic ductal adenocarcinoma (PDAC) patients are metastatic at presentation with limited treatment options and a poor overall 5-year survival of 3%. The liver is the predominant site of distant metastasis in PDAC. Our group has previously shown that aerobic exercise can inhibit tumorigenesis in a primary PDAC mouse model by promoting anti-tumor immunity, however, the effects of exercise in the metastatic setting have not been explored. As such, we developed a model of PDAC liver metastasis by isolating primary pancreatic and liver metastatic cell lines from 18–20-week-old LSL-KRasG12D/+; LSL-Trp53R172H/+; p48Cre; Rosa26LSL-tdTomato/+ (KPCTpancreas or KPCTliver, respectively) mice. KPCTpancreas cells were surgically implanted into the pancreata of syngeneic wild-type mice. One week after pancreatic implantation, KPCTliver cells were implanted into the liver either by direct injection into the parenchyma or via the portal vein. The portal vein method enables us to account for the extravasation step of the metastatic cascade, while the direct parenchymal injection offers a less invasive surgery. Both models preserve the spleen, which is the largest secondary lymphoid organ and essential to the immune response. Treadmill running was initiated in the aerobic exercise cohort 5 days per week for 2 weeks or mice were allowed to rest. Endpoint analysis revealed that aerobic exercise treatment decreased tumor burden in both primary tumors and liver metastasis as measured by tumor weights and tdTomato fluorescence imaging when compared to the rested controls. Immune profiling of the liver metastases revealed elevated IL-15Rɑ+ CD8+ T cells as well as CD19+ B cells in the exercise cohort. While identification of IL-15Rɑ+ CD8+ T cells is consistent with the immune changes we have previously reported in the primary pancreatic tumor of exercised mice, the latter changes reveal organ specific immune cell recruitment not observed in the primary pancreatic tumor of exercised mice. The combined immune profiling and phenotypic changes suggest that aerobic exercise reduces PDAC metastatic growth by modulating systemic and intra-tumoral immunity. The induction of an anti-tumorigenic immune response by aerobic exercise could open avenues for potential pharmacological intervention in downstream pathways to aid in the treatment of metastatic PDAC. Citation Format: Mansour E. Riachi, Carolina G. Alcantara Hirsch, Erica Ma, Beny Shapiro, Ammar Javed, Christopher L. Wolfgang, Dafna Bar-Sagi. Exercise stimulates anti-tumoral immunity in metastatic PDAC [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr A018.

SS1P is an anti-mesothelin immunotoxin composed of a targeting antibody fragment genetically fused to a truncated fragment of Pseudomonas exotoxin A. Delayed responses reported in mesothelioma patients receiving SS1P suggest that anti-tumor immunity is induced. The goal of this study is to evaluate if SS1P therapy renders mesothelioma tumors more sensitive to cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) immune checkpoint blockade. We evaluated the ability of SS1P to induce adenosine triphosphate (ATP) secretion and calreticulin expression on the surface of AE17M mouse mesothelioma cells. Both properties are associated with immunogenic cell death. Furthermore, we treated these tumors with intra-tumoral SS1P and systemic CTLA-4. We found that SS1P increased the release of ATP from AE17M cells in a dose and time-dependent manner. In addition, SS1P induced calreticulin expression on the surface of AE17M cells. These results suggest that SS1P promotes immunogenic cell death and could sensitize tumors to anti-CTLA-4 based therapy. In mouse studies, we found that the combination of anti-CTLA-4 with intra-tumoral SS1P induced complete regressions in most mice and provided a statistically significant survival benefit compared to monotherapy. The surviving mice were protected from tumor re-challenge, indicating the development of anti-tumor immunity. These findings support the use of intra-tumoral SS1P in combination with anti-CTLA-4.

Toll-like receptors (TLRs) are typical transmembrane proteins, which are essential pattern recognition receptors in mediating the effects of innate immunity. TLRs recognize structurally conserved molecules derived from microbes and damage-associated molecular pattern molecules that play an important role in inflammation. Since the first discovery of the Toll receptor by the team of J. Hoffmann in 1996, in Drosophila melanogaster, numerous TLRs have been identified across a wide range of invertebrate and vertebrate species. TLR stimulation leads to NF-κB activation and the subsequent production of pro-inflammatory cytokines and chemokines, growth factors and anti-apoptotic proteins. The expression of TLRs has also been observed in many tumors, and their stimulation results in tumor progression or regression, depending on the TLR and tumor type. The anti-tumoral effects can result from the activation of anti-tumoral immune responses and/or the direct induction of tumor cell death. The pro-tumoral effects may be due to inducing tumor cell survival and proliferation or by acting on suppressive or inflammatory immune cells in the tumor microenvironment. The aim of this review is to draw attention to the effects of TLR stimulation in cancer, the activation of various TLRs by microbes in different types of tumors, and, finally, the role of TLRs in anti-cancer immunity and tumor rejection.

Abstract Based on promising results of recent clinical trials using oncolytic viruses, virotherapy is evolving as an alternative to treat patients with malignant glioma. Our group developed the oncolytic adenovirus Delta-24-RGD (DNX-2401) that is being tested, alone or in combination with anti-PD1, in clinical trials for recurrent glioblastoma (NCT00805376; NCT01956734; NCT02798406). The results suggest that, besides the expected oncolytic effect, the injection of the pathogen initiated, in a subset of patients, an anti-tumoral immunity that led to 20% of long-term survivors (3.5–5 years). To further enhance this effect, we have armed Delta-24-RGD to express the co-stimulatory ligand GITRL, and generated Delta-24-GREAT. The intracranial injection of Delta-24-GREAT prolonged the survival of GL261 glioma-bearing immunocompetent mice when compared to Delta-24-RGD treatment (P=0.002, log-rank test). Delta-24-GREAT treatment resulted in enhanced frequency of tumor-infiltrating lymphocytes: T lymphocytes (CD45+/CD3+) and cytotoxic T lymphocytes (CD45+CD3+CD8+). Functional studies performed by culturing splenocytes from Delta-24-GREAT-treated mice with glioma cells and analyzing secretion of Th1 cytokines, such as IL2 and IFN-γ, showed that lymphocytes recognized not only viral antigens but also tumoral antigens, suggesting the triggering of anti-tumoral immunity. Of interest, Delta-24-GREAT treatment resulted in an antigen-restricted anti-tumor memory effect and in the generation of central immune memory. Thus, rechallenging the survivor mice from the first experiment with a second implantation of glioma cells did not lead to tumor growth, and we detected an increased frequency of central memory CD8+ T cells (CD45+CD62L+). However, survivor mice developed lethal tumors when implanted intracranially with B16/F10 melanoma cells, strongly indicating that the developed immune response was specific for GL261 glioma antigens. This is a novel approach using an oncolytic adenovirus expressing GITRL to target cancer and to stimulate the immunity within the tumor. Our data strongly indicate that this type of strategy may be further developed to treat patients with malignant glioblastoma.

Our research, inspired by the pioneering works of Isaac Witz in the 1980s, established that 40% of human metastatic melanomas express ectopically inhibitory Fc gamma receptors (FcRIIB), while they are detected on less than 5% of primary cutaneous melanoma and not on melanocytes. We demonstrated that these tumoral FcRIIB act as decoy receptors that bind the Fc portion of antimelanoma IgG, which may prevent Fc recognition by the effector cells of the immune system and allow the metastatic melanoma to escape the humoral/natural immune response. The FcRIIB is able to inhibit the ADCC (antibody dependent cell cytotoxicity) in vitro. Interestingly, the percentage of melanoma expressing the FcRIIB is high (70%) in organs like the liver, which is rich in patrolling NK (natural killer) cells that exercise their antitumoral activity by ADCC. We found that this tumoral FcRIIB is fully functional and that its inhibitory potential can be triggered depending on the specificity of the anti-tumor antibody with which it interacts. Together these observations elucidate how metastatic melanomas interact with and potentially evade humoral immunity and provide direction for the improvement of anti-melanoma monoclonal antibody therapy.

Abstract B cells frequently infiltrate human tumors, and the intra-tumoral abundance of plasma cells can correlate with improved patient prognosis. However, many tumors are devoid of plasma B cells, and strategies to enhance anti-tumor B cell responses are needed. We report the existence of a negative regulatory signaling network that reprograms naïve B cells in pancreatic cancer to antagonize anti-tumor plasma B cells. This network is driven by IL-35-mediated STAT3 activation, which directly stimulates upregulation of the pioneer transcription factors Pax5 and Bcl6 in naïve B cells and impedes plasma cell differentiation while simultaneously activating regulatory B cell phenotypes. Significantly, inhibition of Bcl6 reversed this tumor-associated reprogramming of naïve B cells, enabling intra-tumoral accumulation of plasma cells, and reduced tumor growth. Our data provide evidence that B cell dysfunction in cancer involves a potentially targetable suppression program that alters the differentiation potential of naïve B cells. Citation Format: Bhalchandra Mirlekar, Yuliya Pylayeva-Gupta. Reprogramming of naïve B cells in pancreatic cancer subverts humoral immunity [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-019.

Tumor-associated macrophages (TAMs) promote tumor proliferation, invasion, angiogenesis, stemness, therapeutic resistance, and immune tolerance in a protein-dependent manner. Therefore, the traditional target paradigms are often insufficient to exterminate tumor cells. These pro-tumoral functions are mediated by the subsets of macrophages that exhibit canonical protein markers, while simultaneously having unique transcriptional features, which makes the proteins expressed on TAMs promising targets during anti-tumor therapy. Herein, TAM-associated protein-dependent target strategies were developed with the aim of either reducing the numbers of TAMs or inhibiting the pro-tumoral functions of TAMs. Furthermore, the recent advances in TAMs associated with tumor metabolism and immunity were extensively exploited to repolarize these TAMs to become anti-tumor elements and reverse the immunosuppressive tumor microenvironment. In this review, we systematically summarize these current studies to fully illustrate the TAM-associated protein targets and their inhibitors, and we highlight the potential clinical applications of targeting the crosstalk among TAMs, tumor cells, and immune cells in anti-tumor therapy.

Abstract Choroid plexus (CP) forms an anatomically functional barrier between the blood and cerebrospinal fluid (CSF) that dictates the cellular and humoral composition of the CSF. The immunological response of CP to inflammatory stimuli, such as cancer, remains unclear. Here, we find that CP orchestrates the immune composition of CSF in the steady state as well as in the presence of metastatic cancer. We show that the circulation-derived leptomeningeal monocyte-macrophages entering the CSF through CP promote the growth of leptomeningeal metastasis (LM) by perturbing the environment with a storm of dozens of pro- and anti-inflammatory cytokines. Functional manipulation of Type II Interferon pathway specifically within inflamed leptomeninges revealed that IFN-γ can serve as a dominant signal, further recruiting peripheral myeloid cells and activating their protective anti-tumoral response. This preclinical strategy was sufficient to controll the growth of syngeneic LM cancer cells and delay the onset of lethal LM.

Le mélanome est la forme la plus agressive des cancers de la peau. Si sa prise en charge à des stades précoces est de bon pronostic, l’espérance de vie des patients chute dramatiquement pour les stades métastatiques. Malgré les avancées thérapeutiques spectaculaires récentes, le problème majeur réside dans la résistance aux traitements et la récidive et le défi principal est désormais de tendre vers un contrôle efficace et durable. Les anticorps monoclonaux (AcM) ont la capacité de cibler et éliminer spécifiquement la cellule tumorale tout en recrutant des cellules du système immunitaire, permettant de développer et/ou renforcer l’immunité de l’hôte avec le développement d’une réponse immune anti-tumorale de type vaccinale. Dans un modèle de tumeur solide de mélanome murin après greffe sous-cutanée des cellules B16F10, nous avons étudié le potentiel immunomodulateur de l’AcM TA99 qui cible un antigène de surface TYRP-1 surexprimé dans les mélanocytes tumoraux. Nos résultats montrent qu’environ 30% des souris sont protégées sur le long-terme et présentent une réponse immunitaire humorale et cellulaire mémoire. Par ailleurs, l’analyse de l’infiltrat immunitaire chez les souris qui échappent au traitement par l’AcM TA99 et qui développent une tumeur à plus ou moins long terme, montre une surexpression de PD-1 et Tim3 associée à une perte de fonctionnalité des cellules effectrices au sein de la tumeur. Ce même phénotype a été observé sur des biopsies de patients atteints de mélanome métastatique. Nous montrons aussi dans le cadre de ce travail que, le blocage de l’axe PD1/PD-L1 par inoculation d’un AcM anti-PD1 au moment de l’échappement, potentialise la réponse immunitaire anti-tumorale et entraîne une augmentation de la survie. Cependant, l’absence de régression complète suggère la mise en place d’autres voies immunosuppressives. En effet nous avons observé une surexpression des ectonucleotidases CD39 et CD73 dans le micro-environnement tumoral suggérant l’implication de l’adénosine dans la résistance au traitement de l’AcM TA99 plus l’α-PD-1. Ce résultat ouvre des perspectives intéressantes pour le blocage concomitant la voie de l’adénosine et de l’axe PD1/PD-L1. Une autre stratégie a consisté à améliorer les effets immunomodulateurs précoces de l’AcM TA99 en le combinant avec l’oxaliplatine, chimiothérapie favorisant la mort immunogénique. Bien que les combinaisons thérapeutiques testées dans cette étude montrent des effets in vivo encourageants avec un délai significatif dans la survie globale, aucune augmentation significative de la réponse anti-tumorale sur le long terme n’a pu être observée, suggérant la mise en place d’autres voies immunosuppressives non redondantes ou des stratégies de combinaisons non adaptées. Une analyse dynamique approfondie, tant phénotypique que fonctionnelle, des différents acteurs cellulaires du micro-environnement tumoral sera une étape clé dans la mise en place de combinaisons pertinentes en association avec l’AcM TA99. Ce travail prend d’autant plus d’intérêt qu’un essai clinique de phase I (IMC-20D7S) utilisant le flanvotumab (équivalent humain de l’AcM TA99) réalisé chez 27 patients atteints de mélanome métastatique, montre des effets cliniques intéressants sans effets secondaires sévères, ouvrant la voie au développement de combinaisons thérapeutiques associées à cet AcM
Melanoma is the most aggressive form of skin cancer. Although early management is of good prognosis, the survival of patients decrease dramatically for metastatic stages. Despite the recent spectacular therapeutic advances, the major problem lies in resistance to treatment and relapse and the main challenge now is to develop an effective and sustainable control. Monoclonal antibodies (mAbs) have the ability to specifically target and eliminate tumor cells while recruiting cells from the immune system, to develop and / or enhance the immunity of the host with the development of a vaccinal immune response. In a solid tumor model of murine melanoma after subcutaneous transplantation of B16F10 cells, we investigated the immunomodulatory effect of TA99 mAb targeting a TYRP-1 surface antigen overexpressed in tumor melanocytes. Our results showed that about 30% of mice are protected in the long term and have an antitumoral humoral and cellular immune response. Moreover, the analysis of the immune infiltrate in mice that escape to the treatment with TA99 mAb and develop a tumor, shows an overexpression of PD-1 and Tim3 associated with a loss of effector cell functions within the tumor. This same phenotype has been observed in biopsies of patients with metastatic melanoma. Thus, blocking the PD-1 / PDL-1 axis by inoculation of an anti-PD1 mAb at the time of tumor escape potentiates the anti-tumor immune response and results in increased survival. However, the absence of complete regression suggests the establishment of other immunosuppressive pathways. Indeed we have observed an overexpression of CD39 and CD73 ectonucleotidases in the tumor microenvironment suggesting the involvement of adenosine in the resistance mechanisms observed and opening interesting perspectives for the concomitant blocking of this pathway and the PD1 / PDL-1 axis. Another strategy has been to improve the early immunomodulatory effects of TA99 mAb by combining it with oxaliplatin, a chemotherapy that promotes immunogenic death. Although the therapeutic combinations tested in this study showed encouraging in vivo effects with a significant delay in overall survival, no significant increase in the long-term anti-tumor response was observed, suggesting the establishment of other non-redundant immunosuppressive mechanisms or unsuitable combinations strategies. Both phenotypic and functional analysis of the different cellular actors of the tumor microenvironment will be a key step in the implementation of relevant combinations in association with the TA99 mAb. This work is highlighted by a phase I clinical trial (IMC-20D7S) using flanvotumab (human equivalent of mAb TA99) in 27 patients with metastatic melanoma that shows interesting clinical outcome without severe side effects, opening the way for the development of therapeutic combinations associated with this mAb

Les macrophages (Mφs) possèdent une remarquable plasticité phénotypique et fonctionnelle qui leur permet de s’adapter aux différents signaux de leur microenvironnement. Au sein du microenvironnement tumoral, les Mφs ou TAMs (Tumor-associated Mφs) représentent la population leucocytaire majeure. Au cours du développement tumoral, les cellules transformées contribuent à éduquer les TAMs qui acquièrent alors des propriétés permissives à la croissance tumorale. Ainsi, il est aujourd’hui admis que les TAMs, initialement de phénotype M1 anti-tumoral, vont se différencier vers un phénotype M2 capable de favoriser la prolifération des cellules tumorales, l’angiogenèse, les métastases, la résistance aux traitements de chimiothérapie et la suppression de la réponse immunitaire adaptative anti-tumorale. Cependant, cette dichotomie fonctionnelle M1/M2, bien que facilitant la description du phénotype des TAMs et de leurs fonctions, est une simplification de la biologie des Mφs au sein du tissu cancéreux qui est en réalité plus complexe. Ainsi, dans la première partie de ce travail de thèse, nous avons montré que l’IL-13, une cytokine Th2 bien décrite pour être impliquée dans la polarisation M2 des Mφs, inhibe la croissance tumorale d’un lymphome T et d’un adénocarcinome ovarien via la promotion de l’activité cytotoxique des Mφs. De manière intéressante, nous avons mis en évidence le rôle clé des récepteurs Lectine de type C Mannose (RM) et Dectine-1, fortement exprimés à la surface des Mφs polarisés par l’IL-13, dans la reconnaissance des cellules tumorales. Nous avons identifié l’acide sialique exprimé à la surface des cellules transformées comme un épitope critique à leur reconnaissance par les Mφs polarisés par l’IL-13. De plus, nous avons montré que, suite à cette reconnaissance, RM et Dectine-1 sont impliqués dans le déclenchement de voies de signalisations cytotoxiques menant à la production de radicaux libres oxygénés et d’arginase, deux médiateurs responsables de l’élimination des cellules tumorales par nécrose. Dans la seconde partie de ce travail, nous avons étudié l’impact du 15(S)-HETE, un ligand naturel du récepteur nucléaire PPAR-γ impliqué dans la polarisation M2 des Mφs, sur le développement tumoral. Nous avons montré que ce lipide inhibe la croissance tumorale dans un modèle murin d’adénocarcinome ovarien. De façon intéressante, nous avons démontré que cet effet anti-tumoral est dépendant de l’activation de PPAR-γ dans les Mφs. Nous avons mis en évidence que le 15(S)-HETE modifie la balance des populations de Mφs présentes au niveau de la cavité péritonéale, probablement en induisant la différenciation des Small Peritoneal Mφs (SPM) en Large Peritoneal Mφs (LPM). Ces derniers possèdent un phénotype qui contribue à augmenter le ratio lymphocytes T effecteurs/régulateurs au niveau de l’ascite tumorale, et ainsi à contrecarrer l’immunosuppression induite par la tumeur. Enfin, dans la troisième partie de ce travail nous mettons en évidence une forte hausse de la population de monocytes intermédiaires (CD14high CD16high) dans le sang d’une cohorte de 19 patientes atteintes de cancer ovarien séreux de haut grade. De manière intéressante, nous avons démontré qu’il existe une corrélation positive entre la présence de cette population intermédiaire au niveau du sang et la présence d’un microenvironnement immunosuppresseur au niveau de l’ascite de ces patientes (↗ Tregs, ↗ TAMS CD163high CD206high CCR2high CD86low et ↘ NK et CD8+ cytotoxiques). De plus, nous avons mis en évidence une corrélation positive entre l’expansion de ces monocytes intermédiaires et le développement tumoral au sein du péritoine. Ensemble, ces données souligne le rôle des monocytes sanguins comme signature prédictive du statut immun et du développement tumoral au sein du péritoine chez des patientes atteintes de cancer ovarien
Macrophages, which are crucial effectors of innate immune response, exhibit a remarkable phenotypic and functional plasticity that allows them to adapt to the different stimuli present in their microenvironment. Within the tumor microenvironment, macrophages or TAMs (Tumor-associated macrophages) represent the major leukocyte population. During tumor development, secreted mediators produced by transformed cells « educate » TAMs which acquire properties favorable to tumor growth. Thus, it is now widely accepted that TAMs, initially of anti-tumor M1 phenotype, differentiate towards an M2 phenotype able to promote tumor cell proliferation, angiogenesis, metastases, resistance to chemotherapy treatments and suppression of the adaptive anti-tumor immune response. However, this functional M1/M2 dichotomy, while facilitating the description TAMs phenotype and their associated functions, is an oversimplification of the macrophage biology within tumor tissues which is actually more complex. Thus, in the first part of this work, we showed that treatment with IL-13, a Th2 cytokine well described to be involved in macrophage M2 polarization, inhibits tumor growth in two murine models of T-cell lymphoma and ovarian adenocarcinoma via the promotion of macrophage cytotoxic activity. Interestingly, we demonstrated the key role of Mannose (RM) and Dectin-1 C-type Lectin receptors, strongly expressed on IL-13-activated macrophages, in tumor cell recognition. We specifically identified the sialic acid expressed on transformed cell surface as a critical epitope for their recognition by IL-13-activated macrophages. Moreover, we showed that, following this recognition, RM and Dectin-1 trigger cytotoxic signaling pathways leading to the production of radical oxygen species and the amplification of arginase activity. We finally demonstrated that these two mediators produced by IL-13-activated macrophages induce tumor cell necrosis. In the second part of this work, we studied the impact of 15(S)-HETE, a natural ligand of the PPAR-γ nuclear receptor involved macrophage M2 polarization, on tumor development. We showed that this lipid inhibits tumor growth in an experimental murine model of ovarian adenocarcinoma. Interestingly, we demonstrated that 15(S)-HETE anti-tumor effect depends on the activation of PPAR-γ in macrophages. We showed that 15(S)-HETE modifies peritoneal macrophage population balance, likely by promoting the differentiation of Small Peritoneal Macrophages (SPM) into Large Peritoneal Macrophages (LPMs). These LPMs display a phenotype which contributes to the increase of effector/regulatory T lymphocyte ratio in tumor ascites, and thus counteracts tumor-induced immunosuppression. Finally, in the third part of our work, the analysis of circulating blood monocytes in ovarian adenocarcinoma patients revealed a strong increase in the proportion of the « intermediate » subset (CD14high CD16+), usually poorly represented in healthy subjects. Interestingly, we demonstrated a positive correlation between a high proportion of intermediate blood monocytes and the presence of an immunosuppressive microenvironment in the tumor ascites of these patients (↗ Tregs, TAMS CD163high CD206high CCR2high CD86low and ↘ NK and CD8 + cytotoxic). In addition, we showed a positive correlation between the expansion of these intermediate monocytes and tumor development within the peritoneum. Together, these data highlight the role of blood monocytes as a predictive signature of immune status and tumor development within the peritoneum in patients with ovarian cancer

Le rationnel pour l’utilisation des agonistes des Toll-Like Récepteurs (TLR) dans le traitement du cancer repose sur leurs effets bénéfiques au niveau des cellules du système immunitaire permettant une stimulation de la réponse immunitaire innée et adaptative. Cependant, certains types de cellules tumorales expriment les TLRs qui, une fois activés, peuvent déclencher des effets “délétères” comme la tumorigénèse.Pour mieux disséquer les effets biologiques directs et indirects d’un agoniste de TLR3, l’acide polyadenylique-polyurydilique (poly(A:U)), nous avons utilisé deux modèles tumoraux murins exprimant TLR3 et ne répondant pas à la chimiothérapie, mais capables de produire des grandes quantités de CCL5 et CXCL10 en réponse au poly(A:U) et à l’IFN de type I. In vivo, la combinaison chimiothérapie – poly(A:U) n’a permis d’obtenir qu’une faible activité anti tumorale sauf lorsqu’une vaccination contre les antigènes tumoraux est inclue dans le protocole de traitement et le récepteur CCR5 est bloqué (souris Ccr5-/- ou souris sauvages traitées avec MetRANTES). L’efficacité anti tumorale du traitement combiné est associée à l’induction de cellules T CD8+CXCR3+IFNγ+ et est perdue chez les souris nu/nu, Trif-/- et Cxcr3-/-. La source du ligand de CCR5 est constituée par les cellules tumorales dont la voie TLR3 est activée. L’efficacité du traitement combiné sur ces cellules a été améliorée en inhibant la production de CCL5 à l’aide d’un shARN spécifique pour CCL5. Ces résultats soutiennent la notion que le poly(A:U) peut directement agir sur l’épithélium tumoral pour promouvoir la libération de CXCL10 qui a un effet bénéfique (recrutement des LTCs), mais aussi la sécrétion de CCL5 qui a un rôle délétère (action sur des immunosuppresseurs au niveau de l’hôte). Le découplage des effets opposés des chimiokines et la vaccination anti tumorale préalable peuvent permettre aux LTCs dépendant des ligands de CXCR3 d’infirmer l’action d’immunosuppression CCR5 dépendante et devraient être intégrés dans les essais cliniques à venir utilisant les agonistes de TLR3
The rationale for the use of Toll –Like Receptor (TLR) agonists in cancer therapy relies upon their “beneficial” effects on immune cells leading to enhanced innate and adaptive immune responses. However, a variety of cancer epithelia express TLRs which, upon triggering, may mediate “deleterious” effects such as tumorigenesis. To further dissect the direct versus indirect biological effects of the TLR3 agonist polyadenylic-polyuridylic acid (poly(A:U)), we took advantage of two murine tumor models expressing TLR3 that failed to respond to chemotherapy but did produce large amounts of CCL5 and CXCL10 in response to the poly(A:U) and type I IFN. In vivo, the combination of chemotherapy and poly(A:U) mediated low tumoricidal activity unless a vaccination against tumor antigens was included in the regimen and the CCR5 receptor was blocked (CCR5 loss-of-function mice or WT animals treated with MetRANTES). The antitumor efficacy of the combination therapy was associated with the elicitation of CD8+CXCR3+IFN+ T cells and abrogated in nu/nu, Trif-/- and Cxcr3-/- mice. The source of CCR5L is the TLR3-activated tumor cells in that stable inhibition of the chemokine production by specific shRNA CCL5 ameliorated the efficacy of the combination therapy. These results support the notion that poly(A:U) can directly act on tumor epithelia to promote the release of beneficial CXCL10 for the recruitment of intratumoral CTLs but also the release of deleterious CCL5 acting on host immunosuppressors. Uncoupling chemokine release and prior vaccination may enable the CXCR3L-dependent CTLs to overrule the CCR5-dependent suppression and may be integrated in future trials using TLR3 agonists

Les interactions complexes entre la réponse immunitaire et la progression tumorale, particulièrement dans le cadre du cancer du sein triple négatif (TNBC), ont constitué un axe majeur de la recherche en oncologie ces dernières années. Nos précédentes études nous ont permis d’identifier le rôle prépondérant du gène HLF au sein d'une signature génétique comprenant quatre gènes, soulignant son association inverse avec la présence de cellules immunitaires au sein du tissu tumoral. Au cours de ma thèse, nous avons approfondi l'étude de son implication dans la dynamique immunitaire et le développement du TNBC. L'exploitation bio-informatique des données cliniques de patientes atteintes de TNBC a démontré que de faibles niveaux d'expression d’HLF, étaient associés à une surexpression des gènes liés aux mécanismes d'attraction et d'activation du système immunitaire. La dualité du rôle du système immunitaire dans le cancer, oscillant entre une action antitumorale et un soutien à la croissance tumorale, reflète sa grande complexité au sein du microenvironnement tumoral. L'utilisation de la technologie CRISPR/Cas9 pour inactiver le gène HLF dans des lignées cellulaires de TNBC, nous a permis d’explorer les répercussions sur le réseau de chimiokines régulant la présence et l'activité des différentes populations immunitaires dans le microenvironnement tumoral. Enfin, les expérimentations in vivo, menées sur des modèles murins immunodéficients, ont démontré que la diminution d’HLF dans certains sous-types de TNBC entravait la progression tumorale. En somme, nos découvertes suggèrent que la diminution de l'expression d’HLF peut, dès les premières phases du développement tumoral, stimuler l'activité antitumorale du système immunitaire, instaurant un tonus immunologique propice à l'éradication tumorale. Ainsi, HLF se profile comme une cible thérapeutique prometteuse pour promouvoir l'engagement et l'efficacité d’une réponse immunitaire compétente face aux sous-types agressifs de TNBC
The intricate interplay between the immune response and tumor progression, particularly in the context of triple-negative breast cancer (TNBC), has been a focal point of oncological research over the last decade. Our preceding investigation highlighted the role of the HLF gene within a quartet gene signature, identifying its inverse association with the infiltration of immune cells within the tumor milieu. During my thesis, we investigated more precisely its implication in the immune response and TNBC tumor development. The bioinformatic analysis of clinical data from patients with TNBC demonstrated that low levels of HLF expression were associated with an overexpression of genes related to the mechanisms of attraction and activation of the immune system. The implication of neutrophils in cancer is contentious, as they can function either as active anti-tumoral partners or as pro-tumoral agents promoting immunosuppression and tumor growth. The duality of the immune system’s role in cancer, oscillating between antitumor action and support for tumor growth, reflects its great complexity within the tumor microenvironment. In this study, we employed CRISPR/Cas9 technology to inactivate the HLF gene in TNBC cell lines, enabling us to explore the repercussions on the chemokine network regulating the presence and activity of different immune populations in the tumor microenvironment. Finally, in vivo experiments conducted on immunodeficient mouse models demonstrated that reducing HLF in certain TNBC subtypes hindered tumor progression. Altogether, our results suggest that a reduction of HLF expression can lead in the early steps of tumor development to the awakening of the anti-tumoral function of the immune system to enforce the necessary immunological tone to tumor elimination. Thus, HLF emerges as a promising therapeutic target to promote the engagement and effectiveness of a competent immune response against aggressive subtypes of TNBC

La protéine se liant aux acyl-coenzymes A (ACBP), aussi appelée inhibiteur de liaison du diazépam (DBI), est une protéine ubiquitaire et fortement conservée au sein des organismes eucaryotes. Chez les mammifères, elle joue un rôle double : l'ACBP intracellulaire se lie aux acides gras activés (acyl-coA) et, lorsqu'elle est sécrétée, ACBP joue le rôle d'une hormone régulatrice du métabolisme et de l'obésité. L'analyse de données publiques démontre une tendance à l'augmentation d'ACBP dans de nombreuses pathologies caractérisées par un dérèglement systémique : c'est le cas, entre autres, chez les patients atteints de stéatose hépatique, de formes graves du VIH ou du COVID-19 et de certains cancers. Enfin, les concentrations d'ACBP dans le plasma sont positivement corrélées avec l'âge des individus. Il a récemment été démontré chez la souris que la modulation des niveaux d'ACBP circulant permettait de contrôler les paramètres métaboliques des animaux. L'obésité et le syndrome métabolique étant parmi les premiers facteurs de risque environnementaux pour le développement des maladies liées au vieillissement, comme les maladies cardiovasculaires et le cancer, nous nous sommes intéressés dans ces travaux à déterminer si ces maladies pouvaient être annoncées par une élévation des niveaux d'ACBP circulants. L'analyse de cohortes d'individus déclarés en bonne santé a révélé une augmentation d'ACBP dans le cas de la survenue prochaine d'événements cardiovasculaire ou de cancer. L'utilité d'ACBP ensuite été explorée dans plusieurs contextes précliniques. D'une part, la neutralisation de cette protéine étend la durée de vie des levures et est protectrice du vieillissement accéléré du cœur chez la souris, causé par les anthracyclines (une classe de chimiothérapies couramment utilisée et connue pour ses effets cardiotoxiques). Dans le cadre du cancer, la modulation de ce checkpoint métabolique a un impact positif sur l'immunosurveillance tumorale et améliore la réponse aux traitements par chimio-immunothérapie chez la souris. Ainsi, notre étude révèle qu'ACBP pourrait être un biomarqueur de l'« âge biologique » des patients, son élévation annonçant la survenue imminente de maladies liées à l'âge. Au-delà de sa valeur prédictive, les premiers essais précliniques démontrent que sa neutralisation est une piste prometteuse pour améliorer la santé métabolique des individus, qui peut être exploitée pour prévenir ou améliorer la réponse aux traitements des maladies cardiovasculaires et du cancer
Acyl-coenzyme A binding protein (ACBP), also known as diazepam binding inhibitor (DBI), is a ubiquitous and highly conserved protein in eukaryota. In mammals, it plays a dual role: intracellular ACBP binds to activated fatty acids (acyl-CoAs) and, when secreted, ACBP acts as a peptide hormone regulating metabolism and obesity. The analysis of publicly available datasets demonstrates a tendency for increased ACBP in physio-pathological contexts, such as hepatic steatosis, severe forms of HIV or COVID-19, and certain cancers. Additionally, plasma ACBP concentrations are positively correlated with chronological age.Recent studies in mice have shown that modulation of circulating ACBP levels can also control metabolic parameters in animals. Obesity and metabolic syndrome are among the primary environmental risk factors for the development of age-related diseases, such as cardiovascular diseases and cancer, therefore our research aimed to determine if these diseases could be preceded by a modification in circulating ACBP levels.In cohorts of apparently healthy of individuals, we detected an elevation of ACBP in patients who would imminently develop cardiovascular events or cancer. The utility of this aging biomarker was further explored in different preclinical contexts. On one hand, neutralization of the protein extends the lifespan of yeast and, in mice, it protects against accelerated aging of the heart caused by anthracyclines (a class of chemotherapies commonly used and known for their cardiotoxic effects). In the context of cancer, modulation of this metabolic checkpoint has a positive impact on tumor immunosurveillance and improves the response to chemotherapy-immunotherapy treatments in mice. Thus, our study reveals that ACBP could be a biomarker of patients' "biological age,", with its elevation indicating the imminent onset of age-related diseases. Beyond its predictive value, initial preclinical trials demonstrate that neutralization of ACBP is a promising option for improving metabolic health in patients, which could be exploited to prevent or enhance the response to treatments for cardiovascular diseases and cancer

Dans le cancer du sein, de nombreux types de cellules immunitaires se trouvent au sein du microenvironnement tumoral. Des effets immunitaires pro et anti-tumoraux ont été rapportés. Dans la présente étude, nous démontrons que l'IL-17, une cytokine pro-inflammatoire, principalement produite par les cellules Th17, est fortement associée à des marqueurs de mauvais pronostic chez les patientes atteintes d'un cancer du sein. L'IL-17 était fortement exprimée chez les patients ER (-) y compris le sous-groupe triple négatif. De plus, l'expression de l'IL-17 au niveau de la tumeur était étroitement corrélée à celle de PD-L1. D’autre part, IL-17 induit de manière significative l'expression de PD-L1, à l’échelle transcriptomique et protéique in vitro. Dans notre étude, l'IL-17 a spécifiquement induit la prolifération de cellules cancéreuses du cancer du sein in vitro, de manière dose dépendante. Cet effet a été aboli lorsque les cellules ont été traitées avec des anticorps neutralisants, dirigés contre le récepteur à l'IL-17 ou contre l'IL-17 elle-même. Ainsi, l'effet prolifératif induit par l'IL-17 était spécifique. Enfin, nous avons révélé que l’augmentation des taux d'IL-17 était associée à une faible survie, en particulier chez le sous-groupe de patientes n’exprimant pas le récepteur de l’estrogène. L’ensemble de nos résultats suggère fortement que l’IL-17 s’associe à un faible pronostic chez les patientes atteintes de cancer du sein et pourrait être considérée comme une éventuelle cible thérapeutique
In breast cancer, numerous types of immune cells are found within the tumor microenvironment. Both pro- and anti-tumor immune-based effects have been reported. Here, we show that IL-17, a pro-inflammatory cytokine, which is produced mainly by the Th17 T cell sub-population, was strongly associated to poor prognostic markers in breast cancer patients. When analyzed at both transcript and protein levels, IL-17 was highly expressed in ER- including TNBC patients. Furthermore, IL-17 expression in tumor tissues tightly correlated with the expression of the immune checkpoint regulator, PD-L1. Interestingly, IL-17 was found to significantly induce PD-L1 expression, in breast cancer cells in vitro, at both transcript and protein levels. IL-17 also specifically triggered proliferation of distinct breast cancer cell lines in vitro, in a dose-dependent manner, which could be abolished using neutralizing antibodies directed against IL-17 receptor or IL-17. Finally, increased IL-17 levels were associated to lower survival probability in breast cancer patients, especially when combined to the ER negative status. Altogether our data strongly suggest that IL-17 is associated to poor prognosis in breast cancer patients and could be considered as a potential therapeutic target

AbstractImmune checkpoint inhibition has emerged as an integral part of the standard-of-care for head and neck squamous cell carcinoma (HNSCC) in recurrent and/or metastatic stages. Clinical responses are impressive but remain limited to a minority of patients. Primary resistance of never-responders is considered to derive from host- and tumor-specific characteristics, the latter comprising tumor immune checkpoint activity, immune contexture, tumor mutational burden, neo-antigen load, and others. Secondary resistance of initially responding patients in addition, appears to be driven predominantly by irreversible T-cell exhaustion and therapy-induced selection of tumor cell clones with mutations in critical genes involved in the response to immune checkpoint inhibition. With particular focus on primary resistance against immune checkpoint inhibition, scientific interest of preclinical and clinical researchers currently aims at the development and evaluation of combined modality treatment approaches. Radiotherapy is a highly promising partner in this regard and represents a crucial treatment modality for patients with locally advanced HNSCC. Historically established as cytotoxic anti-cancer treatment, a growing body of evidence has shown additional locoregional and systemic immunomodulatory effects of radiotherapy. These are largely attributed to reprogramming of the tumor microenvironment driven by dying and senescent irradiated tumor and normal tissue cells and the concomitant cascade of danger signals, chemokines, and cytokines which stimulate immune cell recruitment and activation. Moreover, the irradiated state of tumor cells bears interesting analogy to the anti-viral state, since fragments of nuclear and mitochondrial DNA that are released into the cytosol can stimulate cytosolic nucleic acid sensors to produce intra-tumoral type I interferons which are essential to (re-)activate the cancer immunity cycle and (re-)invigorate systemic anti-tumor T-cell responses. Apart from these tumor adjuvanticity enhancing effects, several reports have also described increased tumor antigenicity upon radiotherapy originating from radiation-induced exposure of neo-antigens. Collectively, radiotherapy thus may serve as a means of personalized in situ vaccination which can synergize with immune checkpoint inhibition and may help to undermine primary resistance. First clinical experiences have shown that scheduling and dosing of such combined modality treatment regimens are challenging. Moreover, recent preclinical evidence suggests that particularly the role of radiation-induced cytokines and interferons appears to be complex in such combined modality settings due to their ambiguous effects on tumor and immune cells in the tumor microenvironment. The signaling cascades that orchestrate immune cell (re-)activation and cell fate decisions in irradiated tumor cells, including tumor cell survival, proliferation, and/or metastasis formation, are intimately interconnected and require further in-depth investigation.