The Immune Regulatory Role of Adenosine in the Tumor Microenvironment

Therapeutic potential of adenosine receptor modulators in cancer treatment

All human cells contain the universal autocoid adenosine, which interacts with four types of G protein-coupled receptors (GPCRs), namely A1, A2A, A2B, and A3 adenosine receptors (ARs). Among these receptors, A2A and A2B ARs activate adenylate cyclase, while A1 and A3 ARs suppress the adenylate cyclase activity. Adenosine-receptor interactions play a crucial role in cancer biology by modulating the immune microenvironment, which tumors exploit to create immunosuppression that promotes their growth and metastasis. When the A2A AR is activated on natural killer (NK) cells and T cells, it reduces their ability to carry out cytotoxic functions. This activation also encourages the formation of immune-suppressing cell types, such as myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs), further weakening the immune response. Targeting adenosine receptors, particularly the A2A subtype, represents a promising therapeutic strategy. By antagonizing these receptors, it may be possible to restore T cell function, helping the body to recognize and attack cancer cells more effectively. Despite recent advancements in the discovery of novel, targeted anticancer agents, these treatments have shown limited effectiveness against metastatic tumours, complicating cancer management. Moreover, developing adenosine receptor agonists or antagonists with high target selectivity and potency remains a significant challenge, as the widespread distribution of adenosine receptors throughout the body raises concerns about off-target effects and reduced therapeutic efficacy. In order to improve outcomes for patients with advanced cancer, researchers are actively investigating safer and more efficient chemotherapy substitutes. However, drugs that activate A3 adenosine receptors and block A2A receptors are being explored as a novel approach for cancer treatment. Monoclonal antibodies and small-molecule inhibitors targeting the CD39/CD73/A2A AR axis are also being tested in clinical trials, both as standalone treatments and in combination with anti-PD-1/PD-L1 immunotherapies. This review primarily focuses on the signaling pathways and the therapeutic potential of various adenosine receptor agonists and antagonists across various cancer types, highlighting their ongoing evaluation in preclinical and clinical trials, both as monotherapies and in rational combination with immunotherapy, chemotherapy, or targeted therapies, potentially leading to the development of advanced treatments that could aid in tumor suppression.

Identification of biomarkers for endometriosis based on summary-data-based Mendelian randomization and machine learning

Endometriosis (EM) significantly impacts the quality of life, and its diagnosis currently relies on surgery, which carries risks and may miss early lesions. Noninvasive biomarkers are urgently needed for early diagnosis and personalized treatment. This study utilized the genome-wide association study dataset from FinnGen and performed Multi-marker Analysis of GenoMic Annotation (MAGMA) to identify genes significantly associated with EM. Differentially expressed genes (DEGs) were then analyzed, and an intersection selection was conducted to obtain the MAGMA-related DEGs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed to explore the biological functions of these genes. Summary-data-based Mendelian randomization was used to identify potential risk and protective genes. Subsequently, a machine learning model was used to further select key biomarkers. Single-cell RNA sequencing and consensus clustering were applied to analyze the expression of biomarkers and classify the EM samples into subgroups. Immune infiltration analysis was conducted to evaluate the molecular characteristics of these subgroups. MAGMA analysis identified 2832 genes significantly associated with EM, while 3055 DEGs were detected. Intersection analysis resulted in 437 MAGMA-related DEGs. Summary-data-based Mendelian randomization analysis identified 10 candidate genes, and after further selection using a machine learning model, three core biomarkers were validated: adenosine kinase, enoyl-CoA hydratase/3-hydroxyacyl CoA dehydrogenase, and CCR4-NOT transcription complex subunit 7. Single-cell RNA sequencing revealed the expression patterns of these biomarkers. Consensus clustering analysis classified 77 EM samples into two subgroups, with immune infiltration analysis showing significant differences in immune cell composition among the subgroups. This study successfully identified three core biomarkers for EM: adenosine kinase, enoyl-CoA hydratase/3-hydroxyacyl CoA dehydrogenase, and CCR4-NOT transcription complex subunit 7, which exhibit protective roles in EM.

Purinergic System Transcript Changes in the Dorsolateral Prefrontal Cortex in Suicide and Major Depressive Disorder

Suicide is a major public health priority, and its molecular mechanisms appear to be related to imbalanced purine metabolism in the brain. This exploratory study investigates purinergic gene expression in the postmortem dorsolateral prefrontal cortex (DLPFC) tissue isolated from subjects with major depressive disorder (MDD) who died by suicide (MDD-S, n = 10), MDD subjects who did not die by suicide (MDD-NS, n = 6) and non-psychiatrically ill controls (CTL, n = 9-10). Purinergic system transcripts were assayed by quantitative polymerase chain reactions (qPCR) in superficial and deep gray matter as well as white matter DLPFC cortical layers using laser microdissection (LMD). Across all subjects, regardless of sex, P2RY12 (F(2,23) = 5.40, p = 0.004) and P2RY13 (KW statistic = 11.82, p = 0.001) transcript levels were significantly greater in MDD-S compared to MDD-NS subjects. Several other perturbations were observed in the white matter tissue isolated from females: NT5E (F(2,10) = 13.37, p = 0.001) and P2RY13 (F(2,9) = 3.99, p = 0.011, controlled for age) transcript expression was significantly greater in MDD-S vs. MDD-NS female groups. ENTPD2 (F(2,10) = 5.20, p = 0.03), ENTPD3 (F(2,10) = 28.99, p < 0.0001), and NT5E (F(2,10) = 13.37, p = 0.001) were among the transcripts whose expression was significantly elevated in MDD-S vs. CTL female groups. Transcripts that exhibited significantly altered expression in the superficial and deep gray matter included ENTPD2, NT5E, PANX1, and P2RY13 (p ≤ 0.05). Our medication analysis revealed that the expression of these transcripts was not significantly altered by antidepressants. This is the first study to holistically quantify the purinergic metabolic pathway transcripts in suicide and MDD utilizing human postmortem brain tissue. Our preliminary findings support evidence implicating changes in purinergic P2 receptors in the brain in suicide and provide support for broader purinergic system dysregulation in mood disorders.

Combination of adenosine blockade and ferroptosis for photo-immunotherapy of triple negative breast cancer with aptamer-modified copper sulfide

Combination of immunotherapy and photothermal therapy (PTT) provides a promising therapeutic performance for tumors. However, it still faces negative feedback from suppressive factors such as adenosine. Herein, we developed a new nanodrug that can combine adenosine blockade and ferroptosis to promote the photoimmunotherapy of triple negative breast cancer (TNBC). The nanodrug, named CuS-PEG@Apt, was constructed via the modification of copper sulfide (CuS) nanoparticles with adenosine aptamer and PEG. CuS-PEG@Apt could be effectively enriched in the tumor site and locally generate a strong photothermal effect, directly ablating tumors and inducing immunogenic death (ICD). On the other hand, the aptamers could block the adenosine pathway to inhibit the immune suppression by adenosine, which further promoted the anti-tumor immunity. Moreover, the CuS nanoparticles could consume GSH and inhibit GPX4 to cause the ferroptosis of tumor cells. Collectively, CuS-PEG@Apt achieved potent efficacy of tumor suppression via the combination of PTT, immune activation and ferroptosis, representing an appealing platform for TNBC treatment.

Prognostic model development using novel genetic signature associated with adenosine metabolism and immune status for patients with hepatocellular carcinoma

The high mortality rate of hepatocellular carcinoma (HCC) is partly due to advanced diagnosis, emphasizing the need for effective predictive tools in HCC treatment. The aim of this study is to propose a novel prognostic model for HCC based on adenosine metabolizing genes and explore the potential relationship between them. Regression analysis was performed to identify differentially expressed genes associated with adenosine metabolism in HCC patients using RNA sequencing data obtained from a public database. Adenosine metabolism-related risk score (AMrisk) was derived using the least absolute shrinkage and selection operator (LASSO) Cox regression and verified using another database. Changes in adenosine metabolism in HCC were analyzed using functional enrichment analysis and multiple immune scores. The gene expression levels in patient samples were validated using quantitative reverse transcription polymerase chain reaction. Thirty adenosine metabolism-related differentially expressed genes were identified in HCC, and six genes (ADA, P2RY4, P2RY6, RPIA, SLC6A3, and VEGFA) were used to calculate the AMrisk score; the higher the risk scores, the lower the overall survival. Moreover, immune infiltration activation and immune checkpoints were considerably higher in the high-risk group. Additional in vitro experiments validated the enhanced expression of these six genes in HCC. The established predictive model demonstrated that adenosine metabolism-related genes was significantly associated with prognosis in HCC patients.

Chimeric antigen receptor-macrophages: Emerging next-generation cell therapy for brain cancer

Adoptive cell-based therapy utilizing chimeric antigen receptor (CAR)-T technology holds promise in the field of neuro-oncology. Significant progress has been made in enhancing both the efficacy and safety of CAR-T-cell therapies. However, challenges such as the multifaceted immunosuppressive impact of the tumor microenvironment and insufficient CAR-T-cell infiltration into brain tumor sites remain a major hurdles. Emerging novel approaches utilizing CAR-macrophages (CAR-MACs) show potent results for brain tumor immunotherapy. CAR-MACs localize to tumor sites more readily, increase immune cell infiltrates, and demonstrate high antitumor efficacy by effectively eliminating tumor cells through mechanisms such as phagocytosis or efferocytosis. This review discusses the current advancements in CAR-MAC cell therapies for brain cancer, followed by an overview of research on manufacturing CAR-MACs for clinical application. We further highlight the potential future applications of CAR-MACs in combinatory therapies in the treatment of brain tumors.

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.

Dynamic changes in serum adenosine and the adenosine metabolism-based signature for prognosis in HER2-positive metastatic breast cancer patients

Aims

Adenosine metabolism in the breast cancer microenvironment is critical for tumor immunity. However, the prognostic significance of adenosine in breast cancer remains unclear. We aimed to dynamically monitor serum adenosine levels in patients with HER2-positive metastatic breast cancer (MBC) patients and to explore its predictive significance in trastuzumab therapy.

Methods

The sequencing and clinical data were downloaded from TCGA and GSE176078. Adenosine-related differentially expressed genes was analyzed by "DESeq2" package. Multivariate Cox and lasso-penalized Cox regressions were used to construct prognostic risk signatures. The risk scores were calculated from the identified expression of the hub genes. Bioinformatic analyses were performed using R with related packages. We also enrolled the metastatic breast cancer patients with HER2-positive from in our center and classified them into different groups according to the clinical outcomes assessed by enhanced CT. The adenosine levels were dynamically detected, and the difference in immune microenvironment between the subgroups was assessed by the immune cells that were recorded in our center.

Results

A total of 109 breast cancer patients with HER2-positive MBC were enrolled, and the expressions of 22 adenosine-related genes were filtered and matched from the TCGA database. The survival model based on the 15 differentially expressed genes was established, and the risk scores of each patient were the prognostic risk factors. Single-cell transcriptome sequencing data identified transcriptomic differences in patients with HER2-positive breast cancer. We also confirmed the predictive value of serum adenosine in the clinical progression of HER2-positive MBC patients. The different immune microenvironment between the subgroups supported the reliability of the predictive ability of adenosine in HER2-positive MBC patients.

Conclusions

The dynamic change of adenosine is a predictive biomarker for monitoring disease progression. The adenosine metabolism-based signature has the potential application in the prognosis of HER2-positive MBC patients.

Remodeling of tumour microenvironment: strategies to overcome therapeutic resistance and innovate immunoengineering in triple-negative breast cancer

Triple-negative breast cancer (TNBC) stands as the most complex and daunting subtype of breast cancer affecting women globally. Regrettably, treatment options for TNBC remain limited due to its clinical complexity. However, immunotherapy has emerged as a promising avenue, showing success in developing effective therapies for advanced cases and improving patient outcomes. Improving TNBC treatments involves reducing side effects, minimizing systemic toxicity, and enhancing efficacy. Unlike traditional cancer immunotherapy, engineered nonmaterial's can precisely target TNBC, facilitating immune cell access, improving antigen presentation, and triggering lasting immune responses. Nanocarriers with enhanced sensitivity and specificity, specific cellular absorption, and low toxicity are gaining attention. Nanotechnology-driven immunoengineering strategies focus on targeted delivery systems using multifunctional molecules for precise tracking, diagnosis, and therapy in TNBC. This study delves into TNBC's tumour microenvironment (TME) remodeling, therapeutic resistance, and immunoengineering strategies using nanotechnology.

Novel pharmacotherapies for the treatment of liposarcoma: a comprehensive update

INTRODUCTION

Liposarcomas are malignancies of adipocytic lineage and represent one of the most common types of soft tissue sarcomas. They encompass multiple histologies, each with unique molecular profiles. Treatment for localized disease includes resection, potentially with perioperative radiation or systemic therapy. Treatment for unresectable or metastatic disease revolves around palliative systemic therapy, for which improved therapies are urgently needed.

AREAS COVERED

We reviewed the literature on novel therapies in clinical development for liposarcomas within the past 5 years and discuss their potential impact on future treatment strategies.

EXPERT OPINION

Understanding of the molecular characteristics of liposarcoma subtypes has led to testing of several targeted therapies, including inhibitors of amplified gene products (CDK4 and MDM2) and upregulated proteins (XPO1). Immuno-oncology has played an increasing role in the treatment of liposarcomas, with checkpoint inhibition showing promise in dedifferentiated liposarcomas, and immune therapies targeting cancer testis antigens NY-ESO-1 and MAGE family proteins poised to become an option for myxoid/round cell liposarcomas. The search for novel agents from existing classes (tyrosine kinase inhibitors) with efficacy in liposarcoma also continues. Combination therapies as well as biomarker identification for patient selection of therapies warrant ongoing exploration.

Tumor Microenvironment Drives the Cross-Talk Between Co-Stimulatory and Inhibitory Molecules in Tumor-Infiltrating Lymphocytes: Implications for Optimizing Immunotherapy Outcomes

This review explores some of the complex mechanisms underlying antitumor T-cell response, with a specific focus on the balance and cross-talk between selected co-stimulatory and inhibitory pathways. The tumor microenvironment (TME) fosters both T-cell activation and exhaustion, a dual role influenced by the local presence of inhibitory immune checkpoints (ICs), which are exploited by cancer cells to evade immune surveillance. Recent advancements in IC blockade (ICB) therapies have transformed cancer treatment. However, only a fraction of patients respond favorably, highlighting the need for predictive biomarkers and combination therapies to overcome ICB resistance. A crucial aspect is represented by the complexity of the TME, which encompasses diverse cell types that either enhance or suppress immune responses. This review underscores the importance of identifying the most critical cross-talk between inhibitory and co-stimulatory molecules for developing approaches tailored to patient-specific molecular and immune profiles to maximize the therapeutic efficacy of IC inhibitors and enhance clinical outcomes.

The Role of Adenosine in Overcoming Resistance in Sarcomas

Resistance to systemic therapies in sarcomas poses a significant challenge to improving clinical outcomes. Recent research has concentrated on the tumor microenvironment's role in sarcoma progression and treatment resistance. This microenvironment comprises a variety of cell types and signaling molecules that influence tumor behavior, including proliferation, metastasis, and resistance to therapy. Adenosine, abundant in the tumor microenvironment, has been implicated in promoting immunosuppression and chemoresistance. Targeting adenosine receptors and associated pathways offers a novel approach to enhancing immune responses against tumors, potentially improving immunotherapy outcomes in cancers, including sarcomas. Manipulating adenosine signaling also shows promise in overcoming chemotherapy resistance in these tumors. Clinical trials investigating adenosine receptor antagonists in sarcomas have fueled interest in this pathway for sarcoma treatment. Ultimately, a comprehensive understanding of the tumor and vascular microenvironments, as well as the adenosine pathway, may open new avenues for improving treatment outcomes and overcoming resistance in sarcoma. Further studies and clinical trials are crucial to validate these findings and optimize therapeutic strategies, particularly for osteosarcoma. This study provides a literature review exploring the potential role of the adenosine pathway in sarcomas.

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.

Metabolic Reprogramming of Immune Cells in the Tumor Microenvironment

Metabolic reprogramming of immune cells within the tumor microenvironment (TME) plays a pivotal role in shaping tumor progression and responses to therapy. The intricate interplay between tumor cells and immune cells within this ecosystem influences their metabolic landscapes, thereby modulating the immune evasion tactics employed by tumors and the efficacy of immunotherapeutic interventions. This review delves into the metabolic reprogramming that occurs in tumor cells and a spectrum of immune cells, including T cells, macrophages, dendritic cells, and myeloid-derived suppressor cells (MDSCs), within the TME. The metabolic shifts in these cell types span alterations in glucose, lipid, and amino acid metabolism. Such metabolic reconfigurations can profoundly influence immune cell function and the mechanisms by which tumors evade immune surveillance. Gaining a comprehensive understanding of the metabolic reprogramming of immune cells in the TME is essential for devising novel cancer therapeutic strategies. By targeting the metabolic states of immune cells, it is possible to augment their anti-tumor activities, presenting new opportunities for immunotherapeutic approaches. These strategies hold promise for enhancing treatment outcomes and circumventing the emergence of drug resistance.

Targeting Tumor Hypoxia with Nanoparticle-Based Therapies: Challenges, Opportunities, and Clinical Implications

Hypoxia is a crucial factor in tumor biology, affecting various solid tumors to different extents. Its influence spans both early and advanced stages of cancer, altering cellular functions and promoting resistance to therapy. Hypoxia reduces the effectiveness of radiotherapy, chemotherapy, and immunotherapy, making it a target for improving therapeutic outcomes. Despite extensive research, gaps persist, necessitating the exploration of new chemical and pharmacological interventions to modulate hypoxia-related pathways. This review discusses the complex pathways involved in hypoxia and the associated pharmacotherapies, highlighting the limitations of current treatments. It emphasizes the potential of nanoparticle-based platforms for delivering anti-hypoxic agents, particularly oxygen (O2), to the tumor microenvironment. Combining anti-hypoxic drugs with conventional cancer therapies shows promise in enhancing remission rates. The intricate relationship between hypoxia and tumor progression necessitates novel therapeutic strategies. Nanoparticle-based delivery systems can significantly improve cancer treatment efficacy by targeting hypoxia-associated pathways. The synergistic effects of combined therapies underscore the importance of multimodal approaches in overcoming hypoxia-mediated resistance. Continued research and innovation in this area hold great potential for advancing cancer therapy and improving patient outcomes.

8-Aminoguanine and its actions in the metabolic syndrome

The metabolic syndrome is characterized by obesity, insulin resistance, dyslipidemia and hypertension and predisposes to cardiorenal injury. Here, we tested our hypothesis that 8-aminoguanine, an endogenous purine, exerts beneficial effects in Zucker Diabetic-Sprague Dawley (ZDSD) rats, a preclinical model of the metabolic syndrome. ZDSD rats were instrumented for blood pressure radiotelemetry and randomized to vehicle or 8-aminoguanine (10 mg/kg/day, po). The protocol was divided into four phases: Phase 1: 17 days of tap water/normal diet; Phase 2: 30 days of 1% saline/normal diet; Phase 3: 28 days of 1% saline/diabetogenic diet; Phase 4: acute/terminal measurements. 8-Aminoguanine: (1) decreased mean arterial blood pressure (P = 0.0004; 119.5 ± 1.0 (vehicle) versus 116.3 ± 1.0 (treated) mmHg) throughout all three phases of the radiotelemetry study; (2) rebalanced the purine metabolome away from hypoxanthine (pro-inflammatory) and towards inosine (anti-inflammatory); (3) reduced by 71% circulating IL-1β, a cytokine that contributes to hypertension-induced adverse cardiovascular events and type 2 diabetes; (4) attenuated renovascular responses to angiotensin II; (5) improved cardiac and renal histopathology; (6) attenuated diet-induced polydipsia/polyuria; and (7) reduced HbA1c. In the metabolic syndrome, 8-aminoguanine lowers blood pressure, improves diabetes and reduces organ damage, likely by rebalancing the purine metabolome leading to reductions in injurious cytokines such as IL-1β.

Enhancing cancer immunotherapy using cordycepin and Cordyceps militaris extract to sensitize cancer cells and modulate immune responses

Integrating immunotherapy with natural compounds holds promise in enhancing the immune system's ability to eliminate cancer cells. Cordyceps militaris, a traditional Chinese medicine, emerges as a promising candidate in this regard. This study investigates the effects of cordycepin and C. militaris ethanolic extract (Cm-EE) on sensitizing cancer cells and regulating immune responses against breast cancer (BC) and hepatocellular carcinoma (HCC) cells. Cordycepin, pentostatin and adenosine were identified in Cm-EE. Cordycepin treatment decreased HLA-ABC-positive cells in pre-treated cancer cells, while Cm-EE increased NKG2D ligand and death receptor expression. Additionally, cordycepin enhanced NKG2D receptor and death ligand expression on CD3-negative effector immune cells, particularly on natural killer (NK) cells, while Cm-EE pre-treatment stimulated IL-2, IL-6, and IL-10 production. Co-culturing cancer cells with effector immune cells during cordycepin or Cm-EE incubation resulted in elevated cancer cell death. These findings highlight the potential of cordycepin and Cm-EE in improving the efficacy of cancer immunotherapy for BC and HCC.

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.

Rewiring the T cell-suppressive cytokine landscape of the tumor microenvironment: a new frontier for precision anti-cancer therapy

T lymphocytes that infiltrate the tumor microenvironment (TME) often fail to function as effective anti-cancer agents. Within the TME, cell-to-cell inhibitory interactions play significant roles in dampening their anti-tumor activities. Recent studies have revealed that soluble factors released in the TME by immune and non-immune cells, as well as by tumor cells themselves, contribute to the exacerbation of T cell exhaustion. Our understanding of the cytokine landscape of the TME, their interrelationships, and their impact on cancer development is still at its early stages. In this review, we aim to shed light on Interleukin (IL) -6, IL-9, and IL-10, a small group of JAK/STAT signaling-dependent cytokines harboring T cell-suppressive effects in the TME and summarize their mechanisms of action. Additionally, we will explore how advancements in scientific research can help us overcoming the obstacles posed by cytokines that suppress T cells in tumors, with the ultimate objective of stimulating further investigations for the development of novel therapeutic strategies to counteract their tumor-promoting activities.

CD39 transforming cancer therapy by modulating tumor microenvironment

CD39 is a pivotal enzyme in cancer, regulating immune response and tumor progression via extracellular ATP and adenosine in the tumor microenvironment (TME). Beyond its established immunoregulatory function, CD39 influences cancer cell angiogenesis and metabolism, opening new frontiers for therapeutic interventions. Current research faces gaps in understanding CD39's full impact across cancer types, with ongoing debates about its potential beyond modulating immune evasion. This review distills CD39's multifaceted roles, examining its dual actions and implications for cancer prognosis and treatment. We analyze the latest therapeutic strategies, highlighting the need for an integrated approach that combines molecular insights with TME dynamics to innovate cancer care. This synthesis underscores CD39's integral role, charting a course for precision oncology that seeks to unravel controversies and harness CD39's therapeutic promise for improved cancer outcomes.

Apoptosis, a Metabolic "Head-to-Head" between Tumor and T Cells: Implications for Immunotherapy

Induction of apoptosis represents a promising therapeutic approach to drive tumor cells to death. However, this poses challenges due to the intricate nature of cancer biology and the mechanisms employed by cancer cells to survive and escape immune surveillance. Furthermore, molecules released from apoptotic cells and phagocytes in the tumor microenvironment (TME) can facilitate cancer progression and immune evasion. Apoptosis is also a pivotal mechanism in modulating the strength and duration of anti-tumor T-cell responses. Combined strategies including molecular targeting of apoptosis, promoting immunogenic cell death, modulating immunosuppressive cells, and affecting energy pathways can potentially overcome resistance and enhance therapeutic outcomes. Thus, an effective approach for targeting apoptosis within the TME should delicately balance the selective induction of apoptosis in tumor cells, while safeguarding survival, metabolic changes, and functionality of T cells targeting crucial molecular pathways involved in T-cell apoptosis regulation. Enhancing the persistence and effectiveness of T cells may bolster a more resilient and enduring anti-tumor immune response, ultimately advancing therapeutic outcomes in cancer treatment. This review delves into the pivotal topics of this multifaceted issue and suggests drugs and druggable targets for possible combined therapies.

The stress-responsive cytotoxic effect of diesel exhaust particles on lymphatic endothelial cells

Diesel exhaust particles (DEPs) are very small (typically < 0.2 μm) fragments that have become major air pollutants. DEPs are comprised of a carbonaceous core surrounded by organic compounds such as polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs. Inhaled DEPs reach the deepest sites in the respiratory system where they could induce respiratory/cardiovascular dysfunction. Additionally, a previous study has revealed that a portion of inhaled DEPs often activate immune cells and subsequently induce somatic inflammation. Moreover, DEPs are known to localize in lymph nodes. Therefore, in this study we explored the effect of DEPs on the lymphatic endothelial cells (LECs) that are a constituent of the walls of lymph nodes. DEP exposure induced cell death in a reactive oxygen species (ROS)-dependent manner. Following exposure to DEPs, next-generation sequence (NGS) analysis identified an upregulation of the integrated stress response (ISR) pathway and cell death cascades. Both the soluble and insoluble components of DEPs generated intracellular ROS. Three-dimensional Raman imaging revealed that DEPs are taken up by LECs, which suggests internalized DEP cores produce ROS, as well as soluble DEP components. However, significant cell death pathways such as apoptosis, necroptosis, ferroptosis, pyroptosis, and parthanatos seem unlikely to be involved in DEP-induced cell death in LECs. This study clarifies how DEPs invading the body might affect the lymphatic system through the induction of cell death in LECs.

Targeting the adenosine signaling pathway in macrophages for cancer immunotherapy

One of the ways in which macrophages support tumorigenic growth is by producing adenosine, which acts to dampen antitumor immune responses and is generated by both tumor and immune cells in the tumor microenvironment (TME). Two cell surface expressed molecules, CD73 and CD39, boost catalytic adenosine triphosphate, leading to further increased adenosine synthesis, under hypoxic circumstances in the TME. There are four receptors (A1, A2A, A2B, and A3) expressed on macrophages that allow adenosine to perform its immunomodulatory effect. Researchers have shown that adenosine signaling is a key factor in tumor progression and an attractive therapeutic target for treating cancer. Several antagonistic adenosine-targeting biological therapies that decrease the suppressive action of tumor-associated macrophages have been produced and explored to transform this result from basic research into a therapeutic advantage. Here, we'll review the newest findings from studies of pharmacological compounds that target adenosine receptors, and their potential therapeutic value based on blocking the suppressive action of macrophages in tumors.

Engineering exosomes to reshape the immune microenvironment in breast cancer: Molecular insights and therapeutic opportunities

BACKGROUND

Breast cancer remains a global health challenge, necessitating innovative therapeutic approaches. Immunomodulation and immunotherapy have emerged as promising strategies for breast cancer treatment. Engineered exosomes are the sort of exosomes modified with surface decoration and internal therapeutic molecules. Through suitable modifications, engineered exosomes exhibit the capability to overcome the limitations associated with traditional therapeutic approaches. This ability opens up novel avenues for the development of more effective, personalized, and minimally invasive interventions.

MAIN BODY

In this comprehensive review, we explore the molecular insights and therapeutic potential of engineered exosomes in breast cancer. We discuss the strategies employed for exosome engineering and delve into their molecular mechanisms in reshaping the immune microenvironment of breast cancer.

CONCLUSIONS

By elucidating the contribution of engineered exosomes to breast cancer immunomodulation, this review underscores the transformative potential of this emerging field for improving breast cancer therapy.

HIGHLIGHTS

Surface modification of exosomes can improve the targeting specificity. The engineered exosome-loaded immunomodulatory cargo regulates the tumour immune microenvironment. Engineered exosomes are involved in the immune regulation of breast cancer.

Symbiotic combination of Akkermansia muciniphila and inosine alleviates alcohol-induced liver injury by modulating gut dysbiosis and immune responses

Background

Alcoholic liver disease (ALD) is exacerbated by disruptions in intestinal microecology and immune imbalances within the gut-liver axis. The present study assesses the therapeutic potential of combining Akkermansia muciniphila (A. muciniphila) with inosine in alleviating alcohol-induced liver injury.

Methods

Male C57BL/6 mice, subjected to a Lieber-DeCarli diet with 5% alcohol for 4 weeks, served as the alcoholic liver injury model. Various analyzes, including quantitative reverse transcription polymerase chain reaction (qRT-PCR), ELISA, immunochemistry, 16S rRNA gene sequencing, and flow cytometry, were employed to evaluate liver injury parameters, intestinal barrier function, microbiota composition, and immune responses.

Results

Compared to the model group, the A. muciniphila and inosine groups exhibited significantly decreased alanine aminotransferase, aspartate aminotransferase, and lipopolysaccharide (LPS) levels, reduced hepatic fat deposition and neutrophil infiltration, alleviated oxidative stress and inflammation, and increased expression of intestinal tight junction proteins (Claudin-1, Occludin, and ZO-1). These effects were further pronounced in the A. muciniphila and inosine combination group compared to individual treatments. While alcohol feeding induced intestinal dysbiosis and gut barrier disruption, the combined treatment reduced the abundance of harmful bacteria (Oscillibacter, Escherichia/Shigella, and Alistipes) induced by alcohol consumption, promoting the growth of butyrate-producing bacteria (Akkermansia, Lactobacillus, and Clostridium IV). Flow cytometry revealed that alcohol consumption reduced T regulatory (Treg) populations while increasing those of T-helper (Th) 1 and Th17, which were restored by A. muciniphila combined with inosine treatment. Moreover, A. muciniphila and inosine combination increased the expression levels of intestinal CD39, CD73, and adenosine A2A receptor (A2AR) along with enhanced proportions of CD4+CD39+Treg and CD4+CD73+Treg cells in the liver and spleen. The A2AR antagonist KW6002, blocked the beneficial effects of the A. muciniphila and inosine combination on liver injury in ALD mice.

Conclusion

This study reveals that the combination of A. muciniphila and inosine holds promise for ameliorating ALD by enhancing the gut ecosystem, improving intestinal barrier function, upregulating A2AR, CD73, and CD39 expression, modulating Treg cells functionality, and regulating the imbalance of Treg/Th17/Th1 cells, and these beneficial effects are partly A2AR-dependent.