The ectonucleotidases CD39 and CD73 on T cells: The new pillar of hematological malignancy

The role of non-malignant B cells in malignant hematologic diseases

The tumor microenvironment (TME) represents a heterogeneous, complicated ecosystem characterized by intricate interactions between tumor cells and immune cells. During the past decade, immune cells especially T cells were found to play an important role in the progression of tumor and many related immune checkpoints drugs were created. In recent years, more and more scientists revealed the critical role of B-cells within the TME, particularly various populations of non-malignant B cells. Some studies indicated that non-malignant B cells may exert a 'double-edged sword' role in solid tumors. However, there has been comparatively less focus on the role of non-malignant B cells in hematologic malignancies. In this review, we characterized the development of B cells and summarized its functions of antitumor immunity within TME, with an emphasis on elucidating the roles and potential mechanisms of non-malignant B cells in the progression of hematologic diseases including classical Hodgkin's lymphoma, non-Hodgkin's B-cell lymphoma, non-Hodgkin's T-cell lymphoma, leukemia and multiple myeloma.

Combination therapy with immune checkpoint inhibitors in colorectal cancer: Challenges, resistance mechanisms, and the role of microbiota

Colorectal cancer (CRC) is still one of the leading causes of cancer deaths worldwide. Even though there has been progress in cancer immunotherapy, the results of applying immune checkpoint inhibitors (ICIs) have been unsatisfactory, especially in microsatellite stable (MSS) CRC. Single-agent ICIs that target programmed cell death-1 (PD-1)/ PD-L1, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), T cell Ig- and mucin-domain-containing molecule-3 (TIM-3), and lymphocyte activation gene (LAG)-3 have emerged as having specific benefits. However, many primary and secondary resistance mechanisms are available in the tumor microenvironment (TME) that prevent it from happening. Combination strategies, such as the use of anti-PD-1 and anti-CTLA-4, can be effective in overcoming these resistance pathways, but toxicities remain a significant concern. Moreover, ICIs have been integrated with various treatment modalities, including chemotherapy, radiotherapy, antibiotics, virotherapy, polyadenosine diphosphate-ribose polymerase (PARP) inhibitors, and heat shock protein 90 (HSP90) inhibitors. The outcomes observed in both preclinical and clinical settings have been encouraging. Interestingly, manipulating gut microbiota via fecal microbiota transplantation (FMT) has been identified as a new strategy to increase the efficacy of immunotherapy in CRC patients. Therefore, integrating ICIs with other treatment approaches holds promise in enhancing the prognosis of CRC patients. This review focuses on the unmet need for new biomarkers to select patients for combination therapies and the ongoing work to overcome resistance and immune checkpoint blockade.

CAR Treg synergy with anti-CD154 promotes infectious tolerance and dictates allogeneic heart transplant acceptance

Successful allograft-specific tolerance induction would eliminate the need for daily immunosuppression and improve posttransplant quality of life. Adoptive cell therapy with regulatory T cells expressing donor-specific chimeric antigen receptors (CAR Tregs) is a promising strategy but, as monotherapy, cannot prolong survival with allografts with multiple MHC mismatches. Using an HLA-A2-transgenic haplo-mismatched heart transplantation model in immunocompetent C57BL/6 recipients, we showed that HLA-A2-specific CAR (A2.CAR) Tregs were able to synergize with a low dose of anti-CD154 to enhance graft survival. Using haplo-mismatched grafts expressing the 2W-OVA transgene and tetramer-based tracking of 2W- and OVA-specific T cells, we showed that in mice with accepted grafts, A2.CAR Tregs inhibited donor-specific T cell, B cell, and antibody responses and promoted a substantial increase in endogenous FOXP3+ Tregs with indirect donor specificity. By contrast, in mice where A2.CAR Tregs failed to prolong graft survival, FOXP3- A2.CAR T cells preferentially accumulated in rejecting allografts, and endogenous donor-specific responses were not controlled. This study therefore provides evidence for synergy between A2.CAR Tregs and CD154 blockade to promote infectious tolerance in immunocompetent recipients of haplo-mismatched heart grafts and defines features of A2.CAR Tregs when they fail to reshape host immunity toward allograft tolerance.

Combined oral contraceptives alter ectonucleotidase and adenosine deaminase activities in peripheral blood cells

Hormonal contraceptives, one of the most widely used contraceptive methods, are associated with the development of thromboembolism. Purinergic mediators such as soluble agonists, ectonucleotidases, and receptors play a prominent role in regulating hemostasis. This study aimed to evaluate E-NTPDase, E-5'-NT, and E-ADA activities in lymphocytes and platelets from women using combined oral contraceptives. Participants used third-generation (3G) oral contraceptives, such as drospirenone or cyproterone acetate, or fourth-generation (4G) oral contraceptives, such as gestodene or desogestrel, both combined with ethinylestradiol. The findings indicated decreased adenosine (ADO) deamination in lymphocytes (78%, p < 0.001) and decreased AMP hydrolysis (69%, p < 0.01) and ADO deamination (66%, p < 0.001) in platelets from women using 3G contraceptives compared with the control. Furthermore, the results showed decreased ADO deamination (66%, p < 0.05) in lymphocytes and decreased ATP hydrolysis (52%, p < 0.05) and decreased ADO deamination (57%, p < 0.001) in platelets from women using 4G contraceptives compared with the control. The observed patterns of AMP hydrolysis are compatible with an ADO-poor vascular microenvironment. Likewise, the decrease in E-ADA activity may be associated with lower concentrations of ADO in the vascular microenvironment, which has antiplatelet and anti-inflammatory effects. Overall, the findings demonstrated that hormonal contraceptives alter the activity of purinergic ectoenzymes, which might be related to their effects on hemostasis and a predisposition to thromboembolic events.

Reduced autoimmunity associated with deletion of host CD73

CD73 is ubiquitously expressed and regulates critical functions across multiple organ systems. The sequential actions of CD39 and CD73 accomplish the conversion of adenosine triphosphate to adenosine and shift the adenosine triphosphate-driven proinflammatory immune cell milieu toward an anti-inflammatory state. This immunological switch is a major mechanism by which regulatory T (Treg) cells control inflammation. Foxp3 engages in Treg development and function. Foxp3 mutations result in the scurfy (SF) mouse phenotype and a rapidly lethal lymphoproliferative syndrome. We generated double knockout (KO) mouse (CD73KOSF) by breeding heterozygous Foxp3sf/J females to CD73KO male mice to remove host CD73. We initially aimed to use these mice to identify a specific probiotic-CD73 effect, previously shown for Limosilactobacillus reuteri DSM 17938. We expected CD73 deletion to enhance the severity of autoimmunity in SF mice. However, we unexpectedly observed that KO of host CD73 in SF mice clinically reduced the severity of autoimmunity including reduced ear thickness, increased ear size, and less deformed ears, along with less dry and brittle skin. KO of CD73 in SF mice significantly reduced the numbers of CD4+ and CD8+T cells in spleen and blood. We identified that KO of CD73 in SF mice reduced the numbers of T cells in the thymus compared with those in SF mice, indicating that the milder clinical phenotype may be due to reduced central and peripheral lymphoproliferation. These new findings suggest targeting CD73 could improve T cell-mediated dermatitis, one of the most common symptoms in Treg deficiency-associated primary immune deficiencies.

PD-1 and CD73 on naive CD4+ T cells synergistically limit responses to self

Vaccination with self- and foreign peptides induces weak and strong expansion of antigen-specific CD4+ T cells, respectively, but the mechanism is not known. In the present study, we used computational analysis of the entire mouse major histocompatibility complex class II peptidome to test how much of the naive CD4+ T cell repertoire specific for self-antigens was shaped by negative selection in the thymus and found that negative selection only partially explained the difference between responses to self and foreign. In naive uninfected and unimmunized mice, we identified higher expression of programmed cell death protein 1 (PD-1) and CD73 mRNA and protein on self-specific CD4+ T cells compared with foreign-specific CD4+ T cells. Pharmacological or genetic blockade of PD-1 and CD73 significantly increased the vaccine-induced expansion of self-specific CD4+ T cells and their transcriptomes were similar to those of foreign-specific CD4+ T cells. We concluded that PD-1 and CD73 synergistically limited CD4+ T cell responses to self. These observations have implications for the development of tolerogenic vaccines and cancer immunotherapy.

Metabolic Reprogramming in Cancer: Implications for Immunosuppressive Microenvironment

Cancer is a complex and heterogeneous disease characterised by uncontrolled cell growth and proliferation. One hallmark of cancer cells is their ability to undergo metabolic reprogramming, which allows them to sustain their rapid growth and survival. This metabolic reprogramming creates an immunosuppressive microenvironment that facilitates tumour progression and evasion of the immune system. In this article, we review the mechanisms underlying metabolic reprogramming in cancer cells and discuss how these metabolic alterations contribute to the establishment of an immunosuppressive microenvironment. We also explore potential therapeutic strategies targeting metabolic vulnerabilities in cancer cells to enhance immune-mediated anti-tumour responses. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02044861, NCT03163667, NCT04265534, NCT02071927, NCT02903914, NCT03314935, NCT03361228, NCT03048500, NCT03311308, NCT03800602, NCT04414540, NCT02771626, NCT03994744, NCT03229278, NCT04899921.

Optimising CAR T therapy for the treatment of solid tumors

INTRODUCTION

Adoptive immunotherapy using chimeric antigen receptor (CAR)-engineered T cells has proven transformative in the management of B cell and plasma cel derived malignancies. However, solid tumors have largely proven to be resistant to this therapeutic modality. Challenges include the paucity of safe target antigens, heterogeneity of target expression within the tumor, difficulty in delivery of CAR T cells to the site of disease, poor penetration within solid tumor deposits and inability to circumvent the array of immunosuppressive and biophysical barriers imposed by the solid tumor microenvironment.

AREAS COVERED

Literature was reviewed on the PubMed database, excluding occasional papers which were not available as open access publications or through other means.

EXPERT OPINION

Here, we have surveyed the large body of technological advances that have been made in the quest to bridge the gap toward successful deployment of CAR T cells for the treatment of solid tumors. These encompass the development of more sophisticated targeting strategies to engage solid tumor cells safely and comprehensively, improved drug delivery solutions, design of novel CAR architectures that achieve improved functional persistence and which resist physical, chemical and biological hurdles present in tumor deposits. Prospects for combination therapies that incorporate CAR T cells are also considered.

Inflammasomes: potential therapeutic targets in hematopoietic stem cell transplantation

The realm of hematopoietic stem cell transplantation (HSCT) has witnessed remarkable advancements in elevating the cure and survival rates for patients with both malignant and non-malignant hematologic diseases. Nevertheless, a considerable number of patients continue to face challenges, including transplant-related complications, infection, graft failure, and mortality. Inflammasomes, the multi-protein complexes of the innate immune system, respond to various danger signals by releasing inflammatory cytokines and even mediating cell death. While moderate activation of inflammasomes is essential for immune defense and homeostasis maintenance, excessive activation precipitates inflammatory damage. The intricate interplay between HSCT and inflammasomes arises from their pivotal roles in immune responses and inflammation. This review examines the molecular architecture and composition of various types of inflammasomes, highlighting their activation and effector mechanisms within the context of the HSCT process and its associated complications. Additionally, we summarize the therapeutic implications of targeting inflammasomes and related factors in HSCT.

Antagonists of CD39 and CD73 potentiate doxycycline repositioning to induce a potent antitumor immune response

Studies have reported that cellular metabolism at the tumor-immune microenvironment (TiME) serves as a critical checkpoint and perturbs/supports anti-cancer immunity. Extra cellular ATP (eATP) may mediate anti-cancer immune response; however, its catabolism by ectonucleotidase generates immunosuppressive adenosine. In the presented work, we have tried to repurpose doxycycline with or without an antagonist of ectonucleotidase for mitigating ATP metabolism and immunosuppression. In this methodology eATP and adenosine levels were quantified. Bone marrow-derived M1 and M2 polarized macrophages were maintained in tumor mimicking condition (TMC). Total/CD4+Tcells were co-cultured with macrophages to understand the impact of doxycycline and/or antagonist of ectonucleotidase on T cell/subset differentiation. Preclinical efficacy of doxycycline and/or ectonucleotidase antagonist and their synergy was scored in 4T1-induced breast carcinoma. We found that Doxycycline manipulated macrophage polarization by decreasing the frequency of CD206+M2 macrophages, which resulted in enhanced CD4+ directed CD8+ T cell response. Doxycycline alleviated the expression of CD39 and CD73, rescuing ATP catabolism. Doxycycline delayed tumor growth by enhancing F4/80+ CD86+ M1 macrophages and subsequently anti-tumor Tbet+ CD4+Tcells, attenuating the frequency of FOXP3+ regulatory T cells, which was cooperatively supported by ARL67156 and AMPCP (CD39 and CD73 antagonist).A synergy was observed with ARL67156 and AMPC Pensuring a possibility of using doxycycline alone or in combination with an antagonist of ectonucleotidase to present adenosine-mediated immunosuppression. Subsequently, our finding indicated that prospective usage of doxycycline as a novel metabolic checkpoint blocker (IMB) against ectonucleotidase and may be modified/delivered appropriately as a monotherapy or in combination with antagonists of ectonucleotidases as an IMB.

Hypoxia-adenosinergic regulation of B cell responses

Hypoxic microenvironments induce widespread metabolic changes that have been shown to be critical in regulating innate and adaptive immune responses. Hypoxia-induced changes include the generation of extracellular adenosine followed by subsequent signaling through adenosine receptors on immune cells. This evolutionarily conserved "hypoxia-adenosinergic" pathway of hypoxia → extracellular adenosine → adenosine receptor signaling has been shown to be critical in limiting and redirecting T cell responses including in tumor microenvironments and the gut mucosa. However, the question of whether hypoxic microenvironments are involved in the development of B cell responses has remained unexplored until recently. The discovery that germinal centers (GC), the anatomic site in which B cells undergo secondary diversification and affinity maturation, develop a hypoxic microenvironment has sparked new interest in how this evolutionarily conserved pathway affects antibody responses. In this review we will summarize what is known about hypoxia-adenosinergic microenvironments in lymphocyte development and ongoing immune responses. Specific focus will be placed on new developments regarding the role of the hypoxia-adenosinergic pathway in regulating GC development and humoral immunity.

CAR Treg synergy with anti-CD154 mediates infectious tolerance to dictate heart transplant outcomes

Successful allograft specific tolerance induction would eliminate the need for daily immunosuppression and improve post-transplant quality of life. Adoptive cell therapy with regulatory T cells expressing donor-specific Chimeric Antigen Receptors (CAR-Tregs) is a promising strategy, but as monotherapy, cannot prolong the survival with allografts with multiple MHC mismatches. Using an HLA-A2-transgenic haplo-mismatched heart transplantation model in immunocompetent C57Bl/6 recipients, we show that HLA-A2-specific (A2) CAR Tregs was able to synergize with low dose of anti-CD154 to enhance graft survival. Using haplo-mismatched grafts expressing the 2W-OVA transgene and tetramer-based tracking of 2W- and OVA-specific T cells, we showed that in mice with accepted grafts, A2.CAR Tregs inhibited endogenous non-A2 donor- specific T cell, B cell and antibody responses, and promoted a significant increase in endogenous FoxP3 + Tregs with indirect donor-specificity. By contrast, in mice where A2.CAR Tregs failed to prolong graft survival, FoxP3 neg A2.CAR T cells preferentially accumulated in rejecting allografts and endogenous donor-specific responses were not controlled. This study therefore provides the first evidence for synergy between A2.CAR Tregs and CD154 blockade to promote infectious tolerance in immunocompetent recipients of haplo-mismatched heart grafts and defines features of A2.CAR Tregs when they fail to reshape host immunity towards allograft tolerance.

Advancing Immunotherapy in Pancreatic Cancer

Pancreatic cancer remains one of the deadliest malignancies, with a consistently low five-year survival rate for the past several decades. This is in stark contrast to other cancers, which have seen significant improvement in survival and prognosis due to recent developments in therapeutic modalities. These modest improvements in pancreatic cancer outcomes have primarily resulted from minor advances in cytotoxic chemotherapeutics, with limited progress in other treatment approaches. A major focus of current therapeutic research is the further development of immunomodulatory therapies characterized by antibody-based approaches, cellular therapies, and vaccines. Although initial results utilizing immunotherapy in pancreatic cancer have been mixed, recent clinical trials have demonstrated significant improvements in patient outcomes. In this review, we detail these three approaches to immunomodulation, highlighting their common targets and distinct shortcomings, and we provide a narrative summary of completed and ongoing clinical trials that utilize these approaches to immunomodulation. Within this context, we aim to inform future research efforts by identifying promising areas that warrant further exploration.

Combined cancer immunotherapy based on targeting adenosine pathway and PD-1/PDL-1 axis

INTRODUCTION

Cancer immunotherapy has revolutionized the field of oncology, offering new hope to patients with advanced malignancies. Tumor-induced immunosuppression limits the effectiveness of current immunotherapeutic strategies, such as PD-1/PDL-1 checkpoint inhibitors. Adenosine, a purine nucleoside molecule, is crucial to this immunosuppression because it stops T cells from activating and helps regulatory T cells grow. Targeting the adenosine pathway and blocking PD-1/PDL-1 is a potential way to boost the immune system's response to tumors.

AREAS COVERED

This review discusses the current understanding of the adenosine pathway in tumor immunology and the preclinical and clinical data supporting the combination of adenosine pathway inhibitors with PD-1/PDL-1 blockade. We also discuss the challenges and future directions for developing combination immunotherapy targeting the adenosine pathway and the PD-1/PDL-1 axis for cancer treatment.

EXPERT OPINION

The fact that the adenosine signaling pathway controls many immune system processes suggests that it has a wide range of therapeutic uses. Within the next five years, there will be tremendous progress in this area, and the standard of care for treating malignant tumors will have switched from point-to-point therapy to the integration of immunological networks comprised of multiple signaling pathways, like the adenosine axis.

Unleashing the potential of CD39-targeted cancer therapy: Breaking new ground and future prospects

The review article titled CD39 Transforming Cancer Therapy by Modulating Tumor Microenvironment published in June 2024 in Cancer Letters provides a comprehensive overview of CD39's multifaceted roles in cancer, particularly its influence on immunoregulation, angiogenesis, and metabolic reprogramming within the tumor microenvironment (TME). This commentary builds on that foundation by incorporating recent advancements in CD39 research, highlighting unresolved issues, and proposing future research directions. We delve into the therapeutic potential of targeting CD39, addressing clinical translation challenges, and exploring the integration of CD39-based strategies into precision oncology.

Interactions between cancer-associated fibroblasts and T-cells: functional crosstalk with targeting and biomarker potential

Cancer-associated fibroblasts (CAFs) are a heterogeneous cell population recognized as a key component of the tumour microenvironment (TME). Cancer-associated fibroblasts are known to play an important role in maintaining and remodelling the extracellular matrix (ECM) in the tumour stroma, supporting cancer progression and inhibiting the immune system's response against cancer cells. This review aims to summarize the immunomodulatory roles of CAFs, particularly focussing on their T-cell suppressive effects. Cancer-associated fibroblasts have several ways by which they can affect the tumour's immune microenvironment (TIME). For example, their interactions with macrophages and dendritic cells (DCs) create an immunosuppressive milieu that can indirectly affect T-cell anticancer immunity and enable immune evasion. In addition, a number of recent studies have confirmed CAF-mediated direct suppressive effects on T-cell anticancer capacity through ECM remodelling, promoting the expression of immune checkpoints, cytokine secretion and the release of extracellular vesicles. The consequential impact of CAFs on T-cell function is then reflected in affecting T-cell proliferation and apoptosis, migration and infiltration, differentiation and exhaustion. Emerging evidence highlights the existence of specific CAF subsets with distinct capabilities to modulate the immune landscape of TME in various cancers, suggesting the possibility of their exploitation as possible prognostic biomarkers and therapeutic targets.

Efficient enzyme-free method to assess the development and maturation of the innate and adaptive immune systems in the mouse colon

Researchers who aim to globally analyze the gastrointestinal immune system via flow cytometry have many protocol options to choose from, with specifics generally tied to gut wall layers of interest. To get a clearer idea of the approach we should use on full-thickness colon samples from mice, we first undertook a systematic comparison of three tissue dissociation techniques: two based on enzymatic cocktails and the other one based on manual crushing. Using flow cytometry panels of general markers of lymphoid and myeloid cells, we found that the presence of cell-surface markers and relative cell population frequencies were more stable with the mechanical method. Both enzymatic approaches were associated with a marked decrease of several cell-surface markers. Using mechanical dissociation, we then developed two minimally overlapping panels, consisting of a total of 26 antibodies, for serial profiling of lymphoid and myeloid lineages from the mouse colon in greater detail. Here, we highlight how we accurately delineate these populations by manual gating, as well as the reproducibility of our panels on mouse spleen and whole blood. As a proof-of-principle of the usefulness of our general approach, we also report segment- and life stage-specific patterns of immune cell profiles in the colon. Overall, our data indicate that mechanical dissociation is more suitable and efficient than enzymatic methods for recovering immune cells from all colon layers at once. Additionally, our panels will provide researchers with a relatively simple tool for detailed immune cell profiling in the murine gastrointestinal tract, regardless of life stage or experimental conditions.

Magnetic CAR T cell purification using an anti-G4S linker antibody

Chimeric antigen receptor (CAR) redirected T cells are successfully employed in the combat against several hematological malignancies, however, are often compromised by low transduction rates making refinement of the CAR T cell products necessary. Here, we report a broadly applicable enrichment protocol relying on marking CAR T cells with an anti-glycine4-serine (G4S) linker antibody followed by magnetic activated cell sorting (MACS). The protocol is broadly applicable since the G4S peptide is an integral part of the vast majority of CARs as it links the VH and VL recognition domains. We demonstrate the feasibility by using the canonical second generation CARs specific for CEA and Her2, respectively, obtaining highly purified CAR T cell products in a one-step procedure without impairing cell viability. The protocol is also applicable to a dual specific CAR (tandem CAR). Except for CD39, T cell activation/exhaustion markers were not upregulated after separation. Purified CAR T cells retained their functionality with respect to antigen-specific cytokine secretion, cytotoxicity, and the capacity to proliferate and eliminate cognate tumor cells upon repetitive stimulation. Collectively, the one-step protocol for purifying CAR T cells extends the toolbox for preclinical research and specifically for clinical CAR T cell manufacturing.

Fibrocyte Phenotype of ENTPD1+CD55+ Cells and Its Association with Pain in Osteoarthritic Synovium

Osteoarthritis (OA) is a prevalent degenerative joint disorder characterized by cartilage erosion, structural changes, and inflammation. Synovial fibroblasts play a crucial role in OA pathophysiology, with abnormal fibroblastic cells contributing significantly to joint pathology. Fibrocytes, expressing markers of both hematopoietic and stromal cells, are implicated in inflammation and fibrosis, yet their marker and role in OA remain unclear. ENTPD1, an ectonucleotidase involved in purinergic signaling and expressed in specific fibroblasts in fibrotic conditions, led us to speculate that ENTPD1 plays a role in OA pathology by being expressed in fibrocytes. This study aimed to investigate the phenotype of ENTPD1+CD55+ and ENTPD1-CD55+ synovial fibroblasts in OA patients. Proteomic analysis revealed a distinct molecular profile in ENTPD1+CD55+ cells, including the upregulation of fibrocyte markers and extracellular matrix-related proteins. Pathway analysis suggested shared mechanisms between OA and rheumatoid arthritis. Correlation analysis revealed an association between ENTPD1+CD55+ fibrocytes and resting pain in OA. These findings highlight the potential involvement of ENTPD1 in OA pain and suggest avenues for targeted therapeutic strategies. Further research is needed to elucidate the underlying molecular mechanisms and validate potential therapeutic targets.

Protective Properties of Intestinal Alkaline Phosphatase Supplementation on the Intestinal Barrier: Interactions and Effects

The intestinal barrier is critical for maintaining intestinal homeostasis, and its dysfunction is associated with various diseases. Recent findings have revealed the multifunctional role of intestinal alkaline phosphatase (IAP) in diverse biological processes, including gut health maintenance and function. This review summarizes the protective effects of IAP on intestinal barrier integrity, encompassing the physical, chemical, microbial, and immune barriers. We discuss the results and insights from in vitro, animal model, and clinical studies as well as the available evidence regarding the impact of diet on IAP activity and expression. IAP can also be used as an indicator to assess intestinal-barrier-related diseases. Further research into the mechanisms of action and long-term health effects of IAP in maintaining overall intestinal health is essential for its future use as a dietary supplement or functional component in medical foods.

Influence of Breast Cancer Extracellular Vesicles on Immune Cell Activation: A Pilot Study

Breast cancer is the leading cause of cancer-related death in women worldwide. It is well known that breast cancer shows significant alterations in the tumor microenvironment (TME), which is composed of a variety of immune cells, including natural killer (NK) cells, that have a key role in tumor development or anti-tumor responses in breast cancer patients. Luminal B (BT474) and triple-negative breast cancer (HS578T) cell lines were cultured in 2D and 3D model systems. PMBCs from healthy donors were isolated and treated with extracellular vesicles (EVs) from monolayer and spheroids of BT474 and HS578T and analyzed using cytofluorimetric approaches. We observed that EVs can alter the activation and presence of CD335+/CD11b+ NK cells. EVs derived from BT474 and HS578T cells trigger the activation and, simultaneously, a reduction in the percentage of CD335+/CD11b+ NK cells. In addition, EVs derived from BT474 also significantly reduce CD39+ T-regulatory (T-reg) cells. Our preliminary data suggest that using EVs to treat tumors could potentially alter components of the immune system, which causes hyperactivation of specific cell types and can lead to aggressive growth. These data will guide the designing of new personalized diagnostic approaches based on in-depth study of the TME.

CD39 identifies a specific CD8 + T cell population in lung adenocarcinoma-related metastatic pleural effusion

Malignant pleural effusion (MPE), which is a complex microenvironment that contains numerous immune and tumour signals, is common in lung cancer. Gene alterations, such as driver gene mutations, are believed to affect the components of tumour immunity in the microenvironment (TIME) of non-small-cell lung cancer. In this study, we have shown that pleural CD39 + CD8 + T cells are selectively elevated in lung adenocarcinoma (LUAD) with wild-type epidermal growth factor receptor (EGFRwt) compared to those with newly diagnosed mutant EGFR (EGFRmu). Furthermore, these CD39 + CD8 + T cells are more prevalent in MPE with acquired resistance to EGFR-tyrosine kinase inhibitors (AR-EGFR-TKIs). Our analysis reveals that pleural CD39 + CD8 + T cells exhibit an exhausted phenotype while still retaining cytolytic function. Additionally, they have a higher T cell receptor (TCR) repertoire clonality compared to CD39-CD8 + T cells, which is a unique characteristic of LUAD-related MPE. Further investigation has shown that TCR-Vβ clonality tends to be more enhanced in pleural CD39 + CD8 + T cells from MPE with AR-EGFR-TKIs. In summary, we have identified a subset of CD8 + T cells expressing CD39 in MPE, which may potentially be tumour-reactive CD8 + T cells. This study provides new insights into the dynamic immune composition of the EGFRmu tumour microenvironment.