TGF-β inhibits the activation and functions of NK cells by repressing the mTOR pathway

Erythroblastic island: the niche for erythroid terminal differentiation and beyond

The erythroblastic island (EBI) is a multicellular structure defined by the presence of 1 or 2 central macrophages surrounded by at least 3 erythroblasts. EBIs were initially proposed as a specialized microenvironment exclusively for erythroid terminal differentiation. Recent advancements in techniques such as lineage tracing mouse models, imaging flow cytometry, and single-cell RNA sequencing, accumulating evidence has provided novel insights that challenge this conventional view. Notably, the erythropoietin receptor has been identified as a novel marker for EBI macrophages. Additionally, neutrophils have been identified as novel cellular components of EBIs, raising the intriguing hypothesis that EBIs may support other hematopoietic lineage cells as well. Beyond the diverse cellular components of various hematopoietic lineages, even within the erythroid lineage, an immune-prone erythroblast subpopulation has been reported, although it remains unclear whether and how these immune-prone erythroblasts mature in EBIs. These observations indicate that EBIs are a heterogeneous population. In this review, we summarize the most recent findings on EBIs, discuss their potential immune functions, and provide a perspective for future investigations.

Powering immunity: mitochondrial dynamics in natural killer cells

Natural killer (NK) cells are innate lymphocytes that are crucial for eliminating malignant and infected cells, and have significant therapeutic potential against cancer and viral infections. However, their functionality is often impaired under pathological conditions. Emerging evidence identifies mitochondria as key regulators of NK cell metabolism, fitness, and fate. This review examines how mitochondrial dysfunction impacts on NK cell activity in cancer, viral infections, and inflammatory disorders. We discuss strategies to target mitochondrial architecture, dynamics, and function as potential therapies to restore NK cell fitness. Finally, we highlight unanswered questions and future directions to better understand mitochondrial regulation in NK cells and its implications for therapeutic development.

The roles of natural killer cells in bone and arthritic disease: a narrative review

The skeletal system is responsible for the body's support and motor functions, and can be pathologically affected by factors, such as metabolism, autoimmune inflammation, tumors, and infections. Regarding tissue localization and biological function, the immune system is deeply involved in the physiological and pathological processes of the skeletal system. As a regulator and effector cell of the innate immune system, natural killer (NK) cells can exert cytotoxic effects through cell contact and immunomodulatory effects through cytokine secretion. In the past 30 years, many advances have been made regarding the role of NK cells and their derived cytokines on bone and joints. In this review, the role of NK cells in the physiological activities of bone remodeling is summarized first, focusing on osteoclast differentiation and function. Subsequently, the roles of NK cells in osteoarthritis, bone tumors, and bone diseases caused by microbial infections are described, meanwhile, some conflicting research results are discussed. By reviewing the state-of-the-art progress of NK cells in the above-mentioned bone physiological and pathological processes, it is helpful to clarify the blind spots of current research and provide some references for the integrated evaluation of immune factors in the study of skeletal system diseases.

HIF-1α modulates pancreatic cancer ECM proteins via the TGF-β1/Smad signaling pathway introduction

Introduction

Pancreatic cancer is characterized by its aggressive nature and poor prognosis, ranking among the most lethal malignancies. The tumor microenvironment, particularly the extracellular matrix (ECM), plays a crucial role in cancer progression. This study investigated the relationship between hypoxia-inducible factor-1α (HIF-1α) and transforming growth factor-β1 (TGF-β1) in regulating ECM protein expression in pancreatic cancer.

Methods

PANC-1 cells were cultured under both normoxic and hypoxic conditions. Pharmacological inhibition of HIF-1α and TGF-β1, as well as TGF-β1 stimulation, were employed to evaluate ECM protein expression. HIF-1α knockdown experiments and co-immunoprecipitation were performed to assess molecular interactions. Clinical specimens were analyzed for HIF-1α and TGF-β1 expression.

Results

HIF-1α was found to modulate ECM protein expression through the TGF-β1/Smad signaling pathway. Pharmacological inhibition of either HIF-1α or TGF-β1 significantly decreased the expression of ECM proteins, while TGF-β1 stimulation enhanced their production. HIF-1α knockdown abolished TGF-β1-induced ECM protein expression, indicating that HIF-1α is essential for TGF-β1-mediated ECM regulation. Co-immunoprecipitation experiments revealed a physical interaction between HIF-1α and TGF-β1. Clinical specimens showed significantly elevated expression of both HIF-1α and TGF-β1 in pancreatic cancer tissues compared to adjacent normal tissues, correlating with advanced disease stages.

Discussion

These findings elucidate a novel mechanism where HIF-1α and TGF-β1 cooperatively regulate ECM production in pancreatic cancer, providing potential therapeutic targets for intervention.

Stabilisation of extracellular matrix is crucial to rapamycin-mediated life span increase in Marfan mgR/mgR mice

Marfan syndrome is a hereditary connective tissue disorder caused by heterozygous mutations in the fibrillin-1 gene (FBN1) and altered TGF-β signalling. Life-threatening complications involve thoracic aortic aneurysms (TAA) and dissections due to the disruption of microfibrillar assembly in the aortic wall. We previously demonstrated that Rapamycin, a typical mTOR pathway inhibitor, limits the ascending aorta elastolysis and expansion, significantly increasing lifespan in an established murine model of Marfan syndrome (Zaradzki et al., Biochem Pharmacol 2022). This study aimed to investigate how mTOR inhibition stabilises the aorta in fibrillin-1 hypomorphic mgR/mgR mice and previously observed increased life expectancy. We used antibody microarrays to detect protein expression in the proximal thoracic aorta of sham or rapamycin-treated male and female mgR/mgR mice immediately after the two-week treatment. Immunofluorescence staining was performed to visualize and quantify protein expression in the ascending thoracic aorta and arch four weeks after the short-term rapamycin treatment was completed. We showed that rapamycin significantly increased the abundance of extracellular matrix (ECM) proteins like cytokeratin-18 and betaglycan, also known as the TGF-β type 3 receptor (TGFBR3). In addition, it raises the abundance of aggrecanase-2 (ADAMTS5) and xylosyltransferase-1 proteins, enzymes involved in ECM remodelling and homeostasis. In conclusion, rapamycin affects the composition and organization of key ECM components, which determine the structure-function relationships in the aorta, thereby maintaining the balance critical for the increase in life expectancy. Using mTOR modulators for targeted therapy may help to prevent aortic complications of MFS and improve clinical outcomes.

Implications of glioblastoma-derived exosomes in modifying the immune system: state-of-the-art and challenges

Glioblastoma is a brain cancer with a poor prognosis. Failure of classical chemotherapy and surgical treatments indicates that new therapeutic approaches are needed. Among cell-free options, exosomes are versatile extracellular vesicles (EVs) that carry important cargo across barriers such as the blood-brain barrier (BBB) to their target cells. This makes exosomes an interesting option for the treatment of glioblastoma. Moreover, exosomes can comprise many therapeutic cargos, including lipids, proteins, and nucleic acids, sampled from special intercellular compartments of their origin cell. Cells exposed to various immunomodulatory stimuli can generate exosomes enriched in specific therapeutic molecules. Notably, the secretion of exosomes could modify the immune response in innate and adaptive immune systems. For instance, glioblastoma-associated exosomes (GBex) uptake by macrophages could influence macrophage dynamics (e.g., shifting CD markers expression). Expression of critical immunoregulatory proteins such as cytotoxic T-lymphocyte antigen-1 (CTLA1) and programmed death-1 (PD-1) on GBex indicates the direct crosstalk of these nano-size vesicles with the immune system. The present study reviews the role of exosomes in immune system cells, including B cells, T cells, natural killer (NK) cells, and dendritic cells (DCs), as well as novel technologies in the field.

Natural killer cells: the immune frontline against circulating tumor cells

Natural killer (NK) play a key role in controlling tumor dissemination by mediating cytotoxicity towards cancer cells without the need of education. These cells are pivotal in eliminating circulating tumor cells (CTCs) from the bloodstream, thus limiting cancer spread and metastasis. However, aggressive CTCs can evade NK cell surveillance, facilitating tumor growth at distant sites. In this review, we first discuss the biology of NK cells, focusing on their functions within the tumor microenvironment (TME), the lymphatic system, and circulation. We then examine the immune evasion mechanisms employed by cancer cells to inhibit NK cell activity, including the upregulation of inhibitory receptors. Finally, we explore the clinical implications of monitoring circulating biomarkers, such as NK cells and CTCs, for therapeutic decision-making and emphasize the need to enhance NK cell-based therapies by overcoming immune escape mechanisms.

The Role of NK Cells in Cancer Immunotherapy: Mechanisms, Evasion Strategies, and Therapeutic Advances

Background/Objectives: Natural killer (NK) cells play a crucial role in tumor surveillance by exerting cytotoxic activity and modulating immune responses. However, tumors employ diverse evasion strategies that limit NK cell effectiveness. This review aims to explore the molecular mechanisms of NK cell activation and inhibition in cancer, the influence of the tumor microenvironment, and the latest advancements in NK cell-based immunotherapies, including adoptive NK cell transfer and Chimeric Antigen Receptor-Natural Killer (CAR-NK) cell therapies. Methods: A comprehensive literature review was conducted, prioritizing peer-reviewed studies from the last decade on NK cell biology, tumor immune evasion, and immunotherapeutic applications. The analysis includes data from preclinical models and clinical trials evaluating NK cell expansion strategies, cytokine-based stimulation, and CAR-NK cell therapy developments. Results: NK cells eliminate tumors through cytotoxic granule release, death receptor pathways, and cytokine secretion. However, tumor cells evade NK-mediated immunity by downregulating activating ligands, secreting immunosuppressive molecules, and altering the tumor microenvironment. Novel NK cell-based therapies, such as CAR-NK cells and combination approaches with immune checkpoint inhibitors, enhance NK cell persistence and therapeutic efficacy against both hematologic and solid malignancies. Clinical trials suggest improved safety profiles compared to CAR-T therapies, with reduced cytokine release syndrome and graft-versus-host disease. Conclusions: While NK cell-based immunotherapies hold great promise, challenges remain, including limited persistence and tumor-induced immunosuppression. Addressing these hurdles will be critical for optimizing NK cell therapies and advancing next-generation, off-the-shelf immunotherapeutics for broader clinical applications.

Enhancing human NK cell antitumor function by knocking out SMAD4 to counteract TGFβ and activin A suppression

Transforming growth factor beta (TGFβ) and activin A suppress natural killer (NK) cell function and proliferation, limiting the efficacy of adoptive NK cell therapies. Inspired by the partial resistance to TGFβ of NK cells with SMAD4 haploinsufficiency, we used CRISPR-Cas9 for knockout of SMAD4 in human NK cells. Here we show that SMAD4KO NK cells were resistant to TGFβ and activin A inhibition, retaining their cytotoxicity, cytokine secretion and interleukin-2/interleukin-15-driven proliferation. They showed enhanced tumor penetration and tumor growth control, both as monotherapy and in combination with tumor-targeted therapeutic antibodies. Notably, SMAD4KO NK cells outperformed control NK cells treated with a TGFβ inhibitor, underscoring the benefit of maintaining SMAD4-independent TGFβ signaling. SMAD4KO conferred TGFβ resistance across diverse NK cell platforms, including CD19-CAR NK cells, stem cell-derived NK cells and ADAPT-NK cells. These findings position SMAD4 knockout as a versatile and compelling strategy to enhance NK cell antitumor activity, providing a new avenue for improving NK cell-based cancer immunotherapies.

Therapeutic targeting of TGF-β in lung cancer

Transforming growth factor-β (TGF-β) plays a complex role in lung cancer pathophysiology, initially acting as a tumor suppressor by inhibiting early-stage tumor growth. However, its role evolves in the advanced stages of the disease, where it contributes to tumor progression not by directly promoting cell proliferation but by enhancing epithelial-mesenchymal transition (EMT) and creating a conducive tumor microenvironment. While EMT is typically associated with enhanced migratory and invasive capabilities rather than proliferation per se, TGF-β's influence on this process facilitates the complex dynamics of tumor metastasis. Additionally, TGF-β impacts the tumor microenvironment by interacting with immune cells, a process influenced by genetic and epigenetic changes within tumor cells. This interaction highlights its role in immune evasion and chemoresistance, further complicating lung cancer therapy. This review provides a critical overview of recent findings on TGF-β's involvement in lung cancer, its contribution to chemoresistance, and its modulation of the immune response. Despite the considerable challenges encountered in clinical trials and the development of new treatments targeting the TGF-β pathway, this review highlights the necessity for continued, in-depth investigation into the roles of TGF-β. A deeper comprehension of these roles may lead to novel, targeted therapies for lung cancer. Despite the intricate behavior of TGF-β signaling in tumors and previous challenges, further research could yield innovative treatment strategies.

Transcriptional signature of rapidly responding NK cells reveals S1P5 and CXCR4 as anti-tumor response disruptors

Natural killer (NK) cells are prototypic cytotoxic innate lymphocytes that can kill target cells, such as tumor cells, in the absence of antigen-restriction. Peripheral NK cells exhibit a high degree of heterogeneity. Here, we set out to broadly assess intrinsic modulators of NK cell degranulation in an unbiased manner. We stimulated human primary blood-borne NK cells pre-treated with different cytokine regimens with the HCT116 human colon cancer cell line and used detection of lysosome-associated membrane glycoprotein 1 (LAMP1) as an identifier of rapid NK cell degranulation. RNA sequencing of FACS-sorted LAMP1hi NK cells showed CXCR4 and S1PR5 were top down-regulated genes. Using compounds that modulate activity of CXCR4 and S1P receptor family members S1P1 and S1P5, we confirmed they play an important immunosuppressive role in NK cell cytotoxicity. Mechanistically, engagement of CXCR4 and S1P1/5 receptors triggered phosphorylation of p42 and Ca2+ influx. CXCR4 activation promoted S1P5 upregulation and vice versa, and joint activation of both receptors amplified the defect NK cell degranulation. Intriguingly, in tumor samples the expression of both receptors and the synthesis of their ligands themselves appear to be coordinately regulated. Together, these data suggest that specifically and simultaneously targeting CXCR4 and S1P5 activity in the tumor microenvironment (TME) could be a beneficial strategy to unleash full cytotoxic potential of cytotoxic NK effector cells in the tumor.

IL17A/F secreted by ASCT2-overexpression ovarian cancer cells contributes to immune escape through the suppression of natural killer (NK) cells cytotoxicity by the activation of c-JUN/ PTGS2 pathway

Ovarian cancer (OC) is a deadly gynecologic cancer associated with metastasis, recurrence, and treatment resistance. The expression of the alanine-serine-cysteine transporter 2 (ASCT2) has been linked to poor prognosis and immune cell infiltration in OC tumors, but the underlying mechanisms are unclear. Lentiviral constructs were used to manipulate ASCT2 expression in OC cells (SKOV-3). The effects of ASCT2 on SKOV-3 behaviors including proliferation, invasion, migration, apoptosis, and cell cycle were assessed using various assays. The correlation between ASCT2 expression and immune infiltration in OC was analyzed using the Cancer Genome Atlas (TCGA) database. Co-culture experiments were conducted to evaluate the impact of ASCT2 overexpression in SKOV-3 on NK cells, followed by transcriptomics and cytokine analysis. ASCT2 expression and cytokine levels were characterized using qPCR and western blotting. ASCT2 overexpression significantly promoted cell proliferation, invasion, migration, and the percentage of G1-phase cells, while inhibiting apoptosis. ASCT2 silencing had the opposite effect. The expression of ASCT2 was negatively associated with NK cells in OC. ASCT2 overexpression in SKOV-3 cells led to excessive IL-17A/F production and inhibited the antitumor activity of NK cells, possibly through activating the IL-17 signaling pathway. The core regulatory genes c-JUN/PTGS2 in this pathway were upregulated, and antitumor cytokines were decreased in co-cultured NK cells, resulting in decreased antitumor activity and immune infiltration within the tumor. Our results suggest that overexpression of ASCT2 may play a predominant role in OC and NK cell immune infiltration within the tumor.

TGF-β-mediated activation of fibroblasts in cervical cancer: implications for tumor microenvironment and prognosis

Background

Cervical cancer (CC) is a prevalent female malignancy strongly influenced by the tumor microenvironment (TME). This study focuses on the role of TGF-β signaling in cancer-associated fibroblasts (CAFs) and its interaction with immune cells, aiming to elucidate its impact on CC progression.

Methods

The TME of CC patients was analyzed using scRNA-seq data and we identified the major cell types in the TME with a focus on the activation of the TGF-β signaling pathway in fibroblasts. Gene modules related to the TGF-β signaling pathway were identified by Weighted correlation network analysis (WGCNA). Using The Cancer Genome Atlas Cervical Squamous Cell Carcinoma and Endocervical Adenocarcinoma (TCGA-CESC) dataset, a prognostic gene model was constructed by univariate Cox, LASSO Cox and multivariate Cox regression analyses. For cellular validation, the mRNA level of prognostic model-related genes was tested via quantitative real-time real-time polymerase chain reaction (PCR). Thereafter, the following assays, including cell counting kit-8, scratch and wound healing assays, were applied to assess the viability, migration and invasion of CC cells.

Results

Analysis at single-cell resolution identified nine major cell types in the TME, and significant activation of the TGF-β signaling pathway in fibroblasts was correlated with tumor proliferation and differentiation. Strong TGF-β signaling communication between fibroblasts and macrophages and NK/T cells suggested a crucial role in the shaping of the immunosuppressive microenvironment. WGCNA analysis identified gene modules significantly associated with the TGF-β signaling pathway. The prognostic model constructed based on three genes, ITGA5, SHF and SNRPN, demonstrated good predictive ability in multiple datasets, validating its potential for clinical application. Meanwhile, the cellular validation assays have revealed the higher expression of ITGA5 and SNRPN and lower expression of SHF in CC cells. Further, ITGA5 knockdown suppressed the viability, migration and invasion of CC cells.

Conclusion

This study confirmed the important role of the TGF-β signaling pathway in CC, especially in fibroblasts on tumor microenvironment and tumor progression. The current model could effectively evaluate the prognosis of CC, providing a theoretical foundation for developing CC therapies according to the TGF-β signaling pathway. The present results provide new perspectives for further research on the pathological mechanisms and clinical management of CC.

Bistable dynamics of TAN-NK cells in tumor growth and control of radiotherapy-induced neutropenia in lung cancer treatment

Neutrophils play a crucial role in the innate immune response as a first line of defense in many diseases, including cancer. Tumor-associated neutrophils (TANs) can either promote or inhibit tumor growth in various steps of cancer progression via mutual interactions with cancer cells in a complex tumor microenvironment (TME). In this study, we developed and analyzed mathematical models to investigate the role of natural killer cells (NK cells) and the dynamic transition between N1 and N2 TAN phenotypes in killing cancer cells through key signaling networks and how adjuvant therapy with radiation can be used in combination to increase anti-tumor efficacy. We examined the complex immune-tumor dynamics among N1/N2 TANs, NK cells, and tumor cells, communicating through key extracellular mediators (Transforming growth factor (TGF-$ \beta $), Interferon gamma (IFN-$ \gamma $)) and intracellular regulation in the apoptosis signaling network. We developed several tumor prevention strategies to eradicate tumors, including combination (IFN-$ \gamma $, exogenous NK, TGF-$ \beta $ inhibitor) therapy and optimally-controlled ionizing radiation in a complex TME. Using this model, we investigated the fundamental mechanism of radiation-induced changes in the TME and the impact of internal and external immune composition on the tumor cell fate and their response to different treatment schedules.

Advances in the role of NK cells in MDS immune dysfunction and antitumor research

MDS is a heterogeneous group of myeloid neoplasms originating from hematopoietic stem cells, with a high risk of transformation into acute myeloid leukemia (AML). Natural Killer (NK) cells, crucial for their role in immune surveillance and efficient tumor cell lysis, experience functional impairments due to the complex microenvironment and cytokine dynamics in MDS. This article focuses on the mechanisms of NK cell dysfunction in MDS and the latest strategies to enhance NK cell activity to restore their anti-MDS efficacy, highlighting their key role and potential in MDS therapy.

Autocrine TGF-β1 drives tissue-specific differentiation and function of resident NK cells

Group 1 innate lymphoid cells (ILCs) encompass NK cells and ILC1s, which have non-redundant roles in host protection against pathogens and cancer. Despite their circulating nature, NK cells can establish residency in selected tissues during ontogeny, forming a distinct functional subset. The mechanisms that initiate, maintain, and regulate the conversion of NK cells into tissue-resident NK (trNK) cells are currently not well understood. Here, we identify autocrine transforming growth factor-β (TGF-β) as a cell-autonomous driver for NK cell tissue residency across multiple glandular tissues during development. Cell-intrinsic production of TGF-β was continuously required for the maintenance of trNK cells and synergized with Hobit to enhance cytotoxic function. Whereas autocrine TGF-β was redundant in tumors, our study revealed that NK cell-derived TGF-β allowed the expansion of cytotoxic trNK cells during local infection with murine cytomegalovirus (MCMV) and contributed to viral control in the salivary gland. Collectively, our findings reveal tissue-specific regulation of trNK cell differentiation and function by autocrine TGF-β1, which is relevant for antiviral immunity.

The Innate Immune Sensor Zbp1 Mediates Central Nervous System Inflammation Induced by Angiostrongylus Cantonensis by Promoting Macrophage Inflammatory Phenotypes

Angiostrongylus cantonensis (AC) is the leading cause of eosinophilic meningoencephalitis worldwide. The neuroimmune interactions between peripheral and central immune systems in angiostrongyliasis remain unclear. In this study, significant infiltration of eosinophils, myeloid cells, macrophages, neutrophils, and Ly6C monocytes is observed in the brains of AC-infected mice, with macrophages being the most abundant. RNA-seq and SMART-seq analysis of pattern recognition receptor (PRR) and DNA sensor gene sets revealed a marked increase in Z-DNA binding protein 1 (Zbp1) expression in infected mice. Confocal microscopy, RT-qPCR, western blotting, and immunohistochemistry further confirmed that Zbp1 is specifically upregulated in macrophages and microglia. Using Zbp1-knockout mice and flow cytometry, it is found that knockout of Zbp1 enhanced lymphocyte infiltration and natural killer cell cytotoxicity, modulating the immune microenvironment in the central nervous system (CNS) during AC infection. Mechanistically, it is revealed that in macrophage Zbp1 directly binds to receptor-interacting protein 3 (RIP3) to promote its phosphorylation, subsequently facilitating the phosphorylation of mixed lineage kinase domain-like protein (Mlkl). The activated Zbp1-pRIP3-pMlkl axis leads to necroptosis and upregulates pro-inflammatory cytokines including TNF-α, IL-1α, CXCL9, CXCL10 in macrophages, which recruits and activates immune cells. These findings offer new insights into the pathogenic mechanisms of angiostrongyliasis and suggest potential therapeutic strategies.

Immunometabolism in head and neck squamous cell carcinoma: Hope and challenge

Immunotherapy has improved the survival rate of patients with head and neck squamous cell carcinoma (HNSCC), but less than 20 % of them have a durable response to these treatments. Excessive local recurrence and lymph node metastasis ultimately lead to death, making the 5-year survival rate of HNSCC still not optimistic. Cell metabolism has become a key determinant of the viability and function of cancer cells and immune cells. In order to maintain the enormous anabolic demand, tumor cells choose a specialized metabolism different from non-transformed somatic cells, leading to changes in the tumor microenvironment (TME). In recent years, our understanding of immune cell metabolism and cancer cell metabolism has gradually increased, and we have begun to explore the interaction between cancer cell metabolism and immune cell metabolism in a way which is meaningful for treatment. Understanding the different metabolic requirements of different cells that constitute the immune response to HNSCC is beneficial for revealing metabolic heterogeneity and plasticity, thereby enhancing the effect of immunotherapy. In this review, we have concluded that the relevant metabolic processes that affect the function of immune cells in HNSCC TME and proposed our own opinions and prospects on how to use metabolic intervention to enhance anti-tumor immune responses.

An innovative strategy harnessing self-activating CAR-NK cells to mitigate TGF-β1-driven immune suppression

The dysfunction of natural killer (NK) cells, mediated by transforming growth factor β1 (TGFβ1) within the tumor microenvironment, impedes antitumor therapy and contributes to poor clinical outcomes. Our study introduces self-activating chimeric antigen receptor (CAR)-NK cells that block TGFβ1 signaling by releasing a specifically designed peptide, P6, which targets mesothelin in pancreatic tumors. P6 originates from the interaction sites between TGFβ1 and TGFβ receptor 1 and effectively disrupts TGFβ1's inhibitory signaling in NK cells. Our analysis demonstrates that P6 treatment interrupts the SMAD2/3 pathway in NK cells, mitigating TGFβ1-mediated suppression of NK cell activity, thereby enhancing their metabolic function and cytotoxic response against pancreatic tumors. These CAR-NK cells exhibit potent antitumor capabilities, as evidenced in spheroid cultures with cancer-associated fibroblasts and in vivo mouse models. Our approach marks a substantial advancement in overcoming TGFβ1-mediated immune evasion, offering a promising avenue for revolutionizing cancer immunotherapy.

Targeting metabolic dysfunction of CD8 T cells and natural killer cells in cancer

The importance of metabolic pathways in regulating immune responses is now well established, and a mapping of the bioenergetic metabolism of different immune cell types is under way. CD8 T cells and natural killer (NK) cells contribute to cancer immunosurveillance through their cytotoxic functions and secretion of cytokines and chemokines, complementing each other in target recognition mechanisms. Several immunotherapies leverage these cell types by either stimulating their activity or redirecting their specificity against tumour cells. However, the anticancer activity of CD8 T cells and NK cells is rapidly diminished in the tumour microenvironment, closely linked to a decline in their metabolic capacities. Various strategies have been developed to restore cancer immunosurveillance, including targeting bioenergetic metabolism or genetic engineering. This Review provides an overview of metabolic dysfunction in CD8 T cells and NK cells within the tumour microenvironment, highlighting current therapies aiming to overcome these issues.

Novel gene manipulation approaches to unlock the existing bottlenecks of CAR-NK cell therapy

Currently, CAR-T cell therapy is known as an efficacious treatment for patients with relapsed/refractory hematologic malignancies. Nonetheless, this method faces several bottlenecks, including low efficacy for solid tumors, lethal adverse effects, high cost of autologous products, and the risk of GvHD in allogeneic settings. As a potential alternative, CAR-NK cell therapy can overcome most of the limitations of CAR-T cell therapy and provide an off-the-shelf, safer, and more affordable product. Although published results from preclinical and clinical studies with CAR-NK cells are promising, several bottlenecks must be unlocked to maximize the effectiveness of CAR-NK cell therapy. These bottlenecks include low in vivo persistence, low trafficking into tumor sites, modest efficacy in solid tumors, and sensitivity to immunosuppressive tumor microenvironment. In recent years, advances in gene manipulation tools and strategies have laid the groundwork to overcome the current bottlenecks of CAR-NK cell therapy. This review will introduce the existing gene manipulation tools and discuss their advantages and disadvantages. We will also explore how these tools can enhance CAR-NK cell therapy's safety and efficacy.

Fate and long-lasting therapeutic effects of mesenchymal stromal/stem-like cells: mechanistic insights

A large body of evidence suggests that mesenchymal stromal cells (MSCs) are able to respond rapidly to the cytokine milieu following systemic infusion. This encounter has the potential to dictate their therapeutic efficacy (also referred to as licensing). MSCs are able to rapidly react to cellular damage by migrating to the inflamed tissue and ultimately modifying the inflammatory microenvironment. However, the limited use of MSCs in clinical practice can be attributed to a lack of understanding of the fate of MSCs in patients after administration and long term MSC-derived therapeutic activity. While the known physiological effectors of viable MSCs make a relative contribution, an innate property of MSCs as a therapeutic agent is their caspase-dependent cell death. These mechanisms may be involving the functional reprogramming of myeloid phagocytes via efferocytosis, the process by which apoptotic bodies (ABs) are identified for engulfment by both specialized and non-specialized phagocytic cells. Recent studies have provided evidence that the uptake of ABs with a distinct genetic component can induce changes in gene expression through the process of epigenetic remodeling. This phenomenon, known as 'trained immunity', has a significant impact on immunometabolism processes. It is hypothesized that the diversity of recipient cells within the inflammatory stroma adjacent to MSCs may potentially serve as a biomarker for predicting the clinical outcome of MSC treatment, while also contributing to the variable outcomes observed with MSC-based therapies. Therefore, the long-term reconstructive process of MSCs may potentially be mediated by MSC apoptosis and subsequent phagocyte-mediated efferocytosis.

Glucose Metabolism Reprogramming of Immune Cells in the Microenvironment of Pancreatic and Hepatobiliary Cancers

BACKGROUND AND AIM

Pancreatic and hepatobiliary cancers are increasing in prevalence and contribute significantly to cancer-related mortality worldwide. Emerging therapeutic approaches, particularly immunotherapy, are gaining attention for their potential to harness the patient's immune system to combat these tumors. Understanding the role of immune cells in the tumor microenvironment (TME) and their metabolic reprogramming is key to developing more effective treatment strategies. This review aims to explore the relationship between immune cell function and glucose metabolism in the TME of pancreatic and hepatobiliary cancers.

METHODS

This review synthesizes current research on the metabolic adaptations of immune cells, specifically focusing on glucose metabolism within the TME of pancreatic and hepatobiliary cancers. We examine the mechanisms by which immune cells influence tumor progression through metabolic reprogramming and how these interactions can be targeted for therapeutic purposes.

RESULTS

Immune cells in the TME undergo significant metabolic changes, with glucose metabolism playing a central role in modulating immune responses. These metabolic shifts not only affect immune cell function but also influence tumor behavior and progression. The unique metabolic features of immune cells in pancreatic and hepatobiliary cancers provide new opportunities for targeting immune responses to combat these malignancies more effectively.

CONCLUSION

Understanding the complex relationship between immune cell glucose metabolism and tumor progression in the TME of pancreatic and hepatobiliary cancers offers promising therapeutic strategies. By modulating immune responses through targeted metabolic interventions, it may be possible to improve the efficacy of immunotherapies and better combat these aggressive cancers.

Nanoparticle-mediated efficient up-regulation of GSDMD-N to induce pyroptosis and enhance NK cell-based cancer immunotherapy

Natural killer (NK) cell-based immunotherapy has emerged as a safe and effective therapeutic modality for cancer treatment. However, therapeutic benefits can be only seen in hematological tumors (e.g., leukemia) and the treatment of solid tumors is still less effective due to the immunosuppressive tumor microenvironment (TME)-induced poor infiltration and dysfunction of NK cells in tumor tissues. We herein developed a robust nucleus-targeted nanoparticle (NP) platform for systemic delivery of plasmid expressing the N-terminal domain of GSDMD (i.e., pGSDMD-N) and augment of NK cell-based immunotherapy for oral squamous cell carcinoma (OSCC). This nanoplatform is made of a PEGylated poly(2-(diisopropylamino) ethyl methacrylate) (PDPA) polymer and a nucleus-targeting peptide amphiphile (NTPA) that can complex pGSDMD-N. After intravenous administration, this nanoplatform could specifically deliver pGSDMD-N into the nuclei of OSCC cells, leading to their pyroptosis via up-regulating GSDMD-N expression. More importantly, this pyroptosis could boost NK cell-based immunotherapy via promoting the recruitment of NK cells into tumor tissues and enhancing their activation to further enhance the anticancer effect of the pGSDMD-N delivery system. STATEMENT OF SIGNIFICANCE: : NK cell-based immunotherapy has made a significant breakthrough in the treatment of hematological tumors (e.g., leukemia), but it is still less effective for solid tumors due to immunosuppressive tumor microenvironment (TME)-induced dysfunction of NK cells. We herein developed a nucleus-targeted nanoplatform for systemic delivery of plasmid expressing the N-terminal domain of gasdermin D (denoted pGSDMD-N) and augment of NK cell-based immunotherapy for oral squamous cell carcinoma (OSCC). This delivery system could not only induce the pyroptosis of OSCC cells, but also promote the secretion of functional chemokines (e.g., CCL3) and cytokines (e.g., IL-18) to boost NK cell-based immunotherapy. The strategy demonstrated herein could be a promising strategy to enhance the NK cell-based immunotherapy for solid tumors.

Discovery of paradoxical genes: reevaluating the prognostic impact of overexpressed genes in cancer

Oncogenes are typically overexpressed in tumor tissues and often linked to poor prognosis. However, recent advancements in bioinformatics have revealed that many highly expressed genes in tumors are associated with better patient outcomes. These genes, which act as tumor suppressors, are referred to as "paradoxical genes." Analyzing The Cancer Genome Atlas (TCGA) confirmed the widespread presence of paradoxical genes, and KEGG analysis revealed their role in regulating tumor metabolism. Mechanistically, discrepancies between gene and protein expression-affected by pre- and post-transcriptional modifications-may drive this phenomenon. Mechanisms like upstream open reading frames and alternative splicing contribute to these inconsistencies. Many paradoxical genes modulate the tumor immune microenvironment, exerting tumor-suppressive effects. Further analysis shows that the stage- and tumor-specific expression of these genes, along with their environmental sensitivity, influence their dual roles in various signaling pathways. These findings highlight the importance of paradoxical genes in resisting tumor progression and maintaining cellular homeostasis, offering new avenues for targeted cancer therapy.

Adoptive NK cell therapy in AML: progress and challenges

Adoptive cell therapy (ACT) using natural killer (NK) cells has emerged as a promising therapeutic strategy for acute myeloid leukemia (AML), addressing challenges such as chemotherapy resistance and high relapse rates. Over the years, clinical trials and studies have explored various sources of NK cells, including ex vivo expanded NK cell lines, CAR-NK cells, peripheral blood-derived NK cells, and umbilical cord blood-derived NK cells. These therapies have demonstrated varying degrees of therapeutic efficacy, ranging from transient anti-leukemia activity to sustained remission in select patient groups. Toxicity profiles have generally shown favorable safety outcomes, with minimal incidence of severe adverse effects such as cytokine release syndrome (CRS) or graft-versus-host disease (GVHD). However, persistent challenges remain, including limited NK cell persistence, relapse, and heterogeneity in patient responses. This review provides a comprehensive analysis of clinical outcomes and toxicity profiles provided from clinical trials, clinical studies and case reports conducted in the last 15 years to judge on the efficacy, safety and applicability of using NK cells for ACT of AML. Our review highlights the significant potential of NK cell-based therapies for AML, while addressing the technical and biological challenges that must be overcome to enhance their efficacy and safety.

AXL: shapers of tumor progression and immunosuppressive microenvironments

As research progresses, our understanding of the tumor microenvironment (TME) has undergone profound changes. The TME evolves with the developmental stages of cancer and the implementation of therapeutic interventions, transitioning from an immune-promoting to an immunosuppressive microenvironment. Consequently, we focus intently on the significant role of the TME in tumor proliferation, metastasis, and the development of drug resistance. AXL is highly associated with tumor progression; however, previous studies on AXL have been limited to its impact on the biological behavior of cancer cells. An increasing body of research now demonstrates that AXL can influence the function and differentiation of immune cells, mediating immune suppression and thereby fostering tumor growth. A comprehensive analysis to identify and overcome the causes of immunosuppressive microenvironments represents a novel approach to conquering cancer. In this review, we focus on elucidating the role of AXL within the immunosuppressive microenvironments, discussing and analyzing the effects of AXL on tumor cells, T cells, macrophages, natural killer (NK) cells, fibroblasts, and other immune-stromal cells. We aim to clarify the contributions of AXL to the progression and drug resistance of cancer from its functional role in the immune microenvironment.

Nebulized Immunotherapy of Orthotopic Lung Cancer by Mild Magnetothermal-Based Innate Immunity Activations

Advances in adaptive immunity have greatly contributed to the development of cancer immunotherapy. However, its over-low efficacy and insufficient invasion of immune cells in the tumor tissue, and safety problems caused by cytokine storm, have seriously impeded further clinical application for solid tumor immunotherapy. Notably, the immune microenvironment of the lungs is naturally enriched with alveolar macrophages (AMs). Herein, we introduce a novel nebulized magnetothermal immunotherapy strategy to treat orthotopic lung cancer by using magnetothermal nanomaterial (Zn-CoFe2O4@Zn-MnFe2O4-PEG, named ZCMP), which can release iron ions via an acid/thermal-catalytic reaction to maximize the use of lung's immune environment through the cascade activations of AMs and natural killer (NK) cells. Nebulized administration greatly enhance drug bioavailability by localized drug accumulation at the lesion site. Upon mild magnetic hyperthermia, the released iron ions catalyze endogenous H2O2 decomposition to produce reactive oxygen species (ROS), which triggers the M1 polarization of AMs, and the resultant inflammatory cytokine IFN-β, IL-1β and IL-15 releases to activate c-Jun, STAT5 and GZMB related signaling pathways, promoting NK cells proliferation and activation. This innovative strategy optimally utilizes the lung's immune environment and shows excellent immunotherapeutic outcomes against orthotopic lung cancer.

SHP-1 alleviates acute liver injury caused by Escherichia coli sepsis through negatively regulating the canonical and non-canonical NFκB signaling pathways

SHP-1, as a protein tyrosine phosphatase, plays a key role in inflammation-related diseases. However, its function and regulatory mechanism in the imbalance of inflammatory response and acute liver injury during sepsis are still unknown. Herein, we constructed a murine model of Escherichia coli (E. coli) sepsis and demonstrated the function and novel mechanism of SHP-1 in sepsis. Overexpression of SHP-1 significantly reduced the mortality rate of mice and alleviated the histopathological deterioration of liver. In addition, it inhibited the expression and release of pro-inflammatory mediators in liver tissue and serum, but upregulated the expression of anti-inflammatory molecules. Silencing SHP-1 exhibited the completely opposite effects. Furthermore, the transcriptome data of mice liver showed that SHP-1 suppressed the progression of sepsis by negatively regulating the activation of multiple inflammation-related signaling pathways. More importantly, we fully revealed the regulation mechanism of SHP-1 on both canonical and non-canonical nuclear factor kappa-B (NFκB) signaling pathways during sepsis for the first time. SHP-1 significantly inhibited the phosphorylation and nuclear translocation of p50, while p65 inhibition was mainly achieved by inhibiting its transcription and translation levels. Meanwhile, SHP-1 inhibited the phosphorylation and nuclear translocation of p52, thereby inhibiting the activation of non-canonical NFκB signaling pathways. In summary, SHP-1 negatively regulated canonical and non-canonical NFκB signaling pathways, thereby blocking the occurrence of excessive inflammatory response and acute liver injury caused by E. coli sepsis. Our findings systematically elucidate the role and mechanism of SHP-1 during sepsis, providing new insights into the prevention and treatment of inflammation and immune-related diseases.

Unveiling immune cell response disparities in human primary cancer-associated fibroblasts between two- and three-dimensional cultures

Cancer-associated fibroblasts (CAFs) play pivotal roles in solid tumor initiation, growth, and immune evasion. However, the optimal biomimetic modeling conditions remain elusive. In this study, we investigated the effects of 2D and 3D culturing conditions on human primary CAFs integrated into a modular tumor microenvironment (TME). Using single-nucleus RNA sequencing (snRNAseq) and Proteomics' Proximity Extension Assays, we characterized CAF transcriptomic profiles and cytokine levels. Remarkably, when cultured in 2D, CAFs exhibited a myofibroblast (myCAF) subtype, whereas in 3D tumor spheroid cultures, CAFs displayed a more inflammatory (iCAF) pathological state. By integrating single-cell gene expression data with functional interrogations of critical TME-related processes [natural killer (NK)-mediated tumor killing, monocyte migration, and macrophage differentiation], we were able to reconcile form with function. In 3D TME spheroid models, CAFs enhance cancer cell growth and immunologically shield cells from NK cell-mediated cytotoxicity, in striking contrast with their 2D TME counterparts. Notably, 3D CAF-secreted proteins manifest a more immunosuppressive profile by enhancing monocyte transendothelial migration and differentiation into M2-like tumor-associated macrophages (TAMs). Our findings reveal a more immunosuppressive and clinically relevant desmoplastic TME model that can be employed in industrial drug discovery campaigns to expand the cellular target range of chemotherapeutics.

Expansion and characterization of immune suppressive CD56(bright)Perforin(-) regulatory-like natural killer cells in chronic graft-versus-host disease

BACKGROUND

Chronic graft-versus-host disease (cGvHD) is a major cause of morbidity and mortality after Hematopoietic Stem Cell Transplantation (HSCT). Previously, in large patient cohorts, we identified increased numbers of CD56brightPerforin- regulatory-like NK cells (NKreg-like) associated with cGvHD suppression. Thus, we hypothesized that NKreg-like cells may be a potential candidate for cGvHD cell therapy.

AIM

To expand NKreg-like cells while maintaining regulatory phenotype and function.

METHODS

Total NK cells were first expanded with IL-2, which was then combined with rapamycin, Transforming Growth Factor Beta 1 (TGF-β1), NECA (Adenosine A2A receptor (A2AR) agonist), metformin, or dexamethasone, to prevent change in cell phenotype/function. The functional characteristics were evaluated via T cell suppression assays and the phenotype was measured using flow cytometry. The optimal expansion protocol was compared in terms of function and metabolism for three NK expansion media, and cells from cord vs. peripheral blood. Further, expanded NKreg-like cell gene expression was characterized using bulk RNA sequencing. Finally, NKreg-like cells were differentiated from CD34+ hematopoietic stem and progenitor cells (HSPCs) and compared in terms of proliferation and function.

RESULTS

The expansion of total NK cells found the addition of TGF-β1 and/or NECA with the pulsing of rapamycin in IL-2 containing media to prevent NKreg-like differentiation (up to 200-fold expansion). Expanded NKreg-like cells maintained a phenotype, transcriptome, and T cell suppression similar to freshly isolated NKreg-like cells. NKreg-like expansion was greatest in the Immunocult media (up to 300-fold), and NKreg-like cells from peripheral blood demonstrated significantly greater proliferation than cells isolated from cord blood (65-fold). The metabolic profile of NKreg-like and cytolytic NK cells appeared similar at baseline, though rapamycin induced a shift to oxidative over glycolytic metabolism. Further, we demonstrated that suppressive NKreg-like cells may alternatively be expanded from CD34+ cells isolated from cord blood, reaching an average 340-fold expansion.

CONCLUSIONS

In conclusion, our studies have optimized two alternative expansion approaches for deriving functional NKreg-like cells. Additionally, evaluating the transcriptomic and metabolic characteristics provides useful information regarding NKreg-like cell function and differentiation. With further optimization and in vivo validation, we may work towards preparing these cells as a therapy for cGvHD.

Osteoimmunology in bone malignancies: a symphony with evil

Bone marrow is pivotal for normal hematopoiesis and immune responses, yet it is often compromised by malignancies. The bone microenvironment (BME), composed of bone and immune cells, maintains skeletal integrity and blood production. The emergence of primary or metastatic tumors in the skeletal system results in severe complications and contributes significantly to cancer-related mortality. These tumors set off a series of interactions among cancer, bone, and immune cells, and disrupt the BME locally or distantly. However, the drivers, participants, and underlying molecules of these interactions are not fully understood. This review explores the crosstalk between bone metabolism and immune responses, synthesizing current knowledge on the intersection of cancer and osteoimmune biology. It outlines how bone marrow immune cells can either facilitate or hinder tumor progression by interacting with bone cells and pinpoints the molecules responsible for immunosuppression within bone tumors. Moreover, it discusses how primary tumors remotely alter the BME, leading to systemic immune suppression in cancer patients. This knowledge provides critical rationales for emerging immunotherapies in the treatment of bone-related tumors. Taken together, by summarizing the intricate relationship between tumor cells and the BME, this review aims to deepen the understanding of the diversity, complexity, and dynamics at play during bone tumor progression. Ultimately, it highlights the potential of targeting bone-tumor interactions to correct aberrant immune functions, thereby inhibiting tumor growth and metastasis.

Crosstalk of pyroptosis and cytokine in the tumor microenvironment: from mechanisms to clinical implication

In the realm of cancer research, the tumor microenvironment (TME) plays a crucial role in tumor initiation and progression, shaped by complex interactions between cancer cells and surrounding non-cancerous cells. Cytokines, as essential immunomodulatory agents, are secreted by various cellular constituents within the TME, including immune cells, cancer-associated fibroblasts, and cancer cells themselves. These cytokines facilitate intricate communication networks that significantly influence tumor initiation, progression, metastasis, and immune suppression. Pyroptosis contributes to TME remodeling by promoting the release of pro-inflammatory cytokines and sustaining chronic inflammation, impacting processes such as immune escape and angiogenesis. However, challenges remain due to the complex interplay among cytokines, pyroptosis, and the TME, along with the dual effects of pyroptosis on cancer progression and therapy-related complications like cytokine release syndrome. Unraveling these complexities could facilitate strategies that balance inflammatory responses while minimizing tissue damage during therapy. This review delves into the complex crosstalk between cytokines, pyroptosis, and the TME, elucidating their contribution to tumor progression and metastasis. By synthesizing emerging therapeutic targets and innovative technologies concerning TME, this review aims to provide novel insights that could enhance treatment outcomes for cancer patients.

Tumor stage-driven disruption of NK cell maturation in human and murine tumors

Natural killer (NK) cells play a pivotal role against cancer, both by direct killing of malignant cells and by promoting adaptive immune response though cytokine and chemokine secretion. In the lung tumor microenvironment (TME), NK cells are scarce and dysfunctional. By conducting single-cell transcriptomic analysis of lung tumors, and exploring pseudotime, we uncovered that the intratumoral maturation trajectory of NK cells is disrupted in a tumor stage-dependent manner, ultimately resulting in the selective exclusion of the cytotoxic subset. Using functional assays, we observed intratumoral NK cell death and a reduction in cytotoxic capacities depending on the tumor stage. Finally, our analyses of human public dataset on lung cancer corroborate these findings, revealing a parallel dysfunctional maturation process of NK cells during tumor progression. These results highlight additional mechanisms by which tumor cells escape from NK cell cytotoxicity, therefore paving the way for tailored therapeutic strategies.

Prognostic impact of enhanced CD96 expression on NK cells by TGF-β1 in AML

Acute myeloid leukemia (AML) is one of the most common types of blood cancer in adults and is associated with a poor survival rate. NK cells play a crucial role in combating AML, and alterations in immune checkpoint expression can impair NK cell function against AML. Targeting certain checkpoints may restore this function. CD96, an inhibitory immune checkpoint, has unclear expression and roles on NK cells in AML patients. In this study, we initially evaluated CD96 expression and compared CD96+ NK with the inhibitory receptor and stimulatory receptors on NK cells from AML patients at initial diagnosis. We observed increased CD96 expression on NK cells with dysfunctional phenotype. Further analysis revealed that CD96+ NK cells had lower IFN-γ production than CD96- NK cells. Blocking CD96 enhanced the cytotoxicity of primary NK and cord blood-derived NK (CB-NK) cells against leukemia cells. Notably, patients with a high frequency of CD96+ NK cells at initial diagnosis exhibited poorer clinical outcomes. Additionally, TGF-β1 was found to enhance CD96 expression on NK cells via SMAD3 signaling. These findings suggest that CD96 is invovled in NK dysfunction against AML blast, and might be a potential target for restoring NK cell function in the fight against AML.

IL-32γ Induced Autophagy Through Suppression of MET and mTOR Pathways in Liver Tumor Growth Inhibition

Interleukin-32γ (IL-32γ) has diverse functions in various malignancies. In this study, we investigated the role of IL-32γ in autophagy induction in liver cancer cells and delineated the underlying mechanisms. We found that the increased IL-32γ expression inhibited the growth, cell cycle progression, and migration of HepG2 and Hep3B cell lines; it also decreased the expression of related proteins. Furthermore, the IL-32γ overexpression induced autophagy, as indicated by the number of puncta, the expression of LC3, and the expression of autophagy-related markers. The expression levels of LAMP1, a protein essential for autophagosome formation, and colocalization with LC3 also increased. Big data analysis revealed that the expression of MET, a well-known target of autophagy, and the expression of mTOR and mTOR-related proteins were decreased by the IL-32γ overexpression. The combination treatment of MET inhibitor, cabozantinib (2 µM), and IL-32γ overexpression further increased the number of puncta, the colocalization of LC3 and LAMP1, and the expression of autophagy-related proteins. In vivo, liver tumor growth was suppressed in the IL-32γ-overexpressing mouse model, and autophagy induction was confirmed by the increased expression of LC3 and LAMP1 and the decreased expression of autophagy pathway markers (MET and mTOR). Autophagy was also decreased in the liver tumor sample of human patients. ROC curve and spearman analysis revealed that the expression levels of LC3 and IL-32γ were significantly correlated in human tumor serum and tissues. Therefore, IL-32γ overexpression induced autophagy in liver tumors through the suppression of MET and mTOR pathways critical for tumor growth inhibition.

The ovarian cancer-associated microbiome contributes to the tumor's inflammatory microenvironment

A growing body of research has established a correlation between tumors and persistent chronic inflammatory infiltration. As a primary instigator of inflammation, the majority of microbiomes naturally residing within our bodies engage in a mutually beneficial symbiotic relationship. Nevertheless, alterations in the microbiome's composition or breaches in the normal barrier function can disrupt the internal environment's homeostasis, potentially leading to the development and progression of various diseases, including tumors. The investigation of tumor-related microbiomes has contributed to a deeper understanding of their role in tumorigenesis. This review offers a comprehensive overview of the microbiome alterations and the associated inflammatory changes in ovarian cancer. It may aid in advancing research to elucidate the mechanisms underlying the ovarian cancer-associated microbiome, providing potential theoretical support for the future development of microbiome-targeted antitumor therapies and early screening through convenient methods.

Radiotherapy enhances the anti-tumor effect of CAR-NK cells for hepatocellular carcinoma

BACKGROUND

Chimeric antigen receptor (CAR)-NK cell therapy has shown remarkable clinical efficacy and safety in the treatment of hematological malignancies. However, this efficacy was limited in solid tumors owing to hostile tumor microenvironment (TME). Radiotherapy is commonly used for solid tumors and proved to improve the TME. Therefore, the combination with radiotherapy would be a potential strategy to improve therapeutic efficacy of CAR-NK cells for solid tumors.

METHODS

Glypican-3 (GPC3) was used as a target antigen of CAR-NK cell for hepatocellular carcinoma (HCC). To promote migration towards HCC, CXCR2-armed CAR-NK92 cells targeting GPC3 were first developed, and their cytotoxic and migration activities towards HCC cells were evaluated. Next, the effects of irradiation on the anti-tumor activity of CAR-NK92 cells were assessed in vitro and in HCC-bearing NCG mice. Lastly, to demonstrate the potential mechanism mediating the sensitized effect of irradiation on CAR-NK cells, the differential gene expression profiles induced by irradiation were analyzed and the expression of some important ligands for the NK-cell activating receptors were further determined by qRT-PCR and flow cytometry.

RESULTS

In this study, we developed CXCR2-armed GPC3-targeting CAR-NK92 cells that exhibited specific and potent killing activity against HCC cells and the enhanced migration towards HCC cells. Pretreating HCC cells with irradiation enhanced in vitro anti-HCC effect and migration activity of CXCR2-armed CAR-NK92 cells. We further found that only high-dose (8 Gy) but not low-dose (2 Gy) irradiation in one fraction could significantly enhanced in vivo anti-HCC activity of CXCR2-armed CAR-NK92 cells. Irradiation with 8 Gy significantly up-regulated the expression of NK cell-activating ligands on HCC cells.

CONCLUSIONS

Our results indicate the evidence that irradiation could efficiently enhance the anti-tumor effect of CAR-NK cells in solid tumor model. The combination with radiotherapy would be an attractive strategy to improve therapeutic efficacy of CAR-NK cells for solid tumors.

The Role of Natural Killer Cells and Their Metabolism in HIV-1 Infection

Natural killer (NK) cells are multifaceted innate effector cells that critically influence antiviral immunity, and several protective NK cell features that modulate HIV-1 acquisition and viral control have been described. Chronic HIV-1 infection leads to NK cell impairment that has been associated with metabolic dysregulations. Therapeutic approaches targeting cellular immune metabolism represent potential novel interventions to reverse defective NK cell function in people living with HIV.

Asiaticoside modulates human NK cell functional fate by mediating metabolic flexibility in the tumor microenvironment

BACKGROUND

Transforming growth factor-beta (TGF-β), an immunosuppressive cytokine, is often elevated in various tumors and inhibits the immune system's ability to combat tumor cells. Despite promising results from TGF-β inhibitor therapies, their clinical efficacy remains limited.

PURPOSE

This study aimed to enhance the antitumor capabilities of natural killer (NK) cells in the presence of TGF-β by exploring the potential of asiaticoside, a natural compound with established clinical safety.

STUDY DESIGN

The effects of asiaticoside on NK cells were investigated to determine its potential to counteract TGF-β-induced immunosuppression and elucidate the underlying mechanisms.

METHODS

Natural compounds were screened using a Luminex assay to identify those promoting Interferon-γ (IFN-γ) secretion from NK cells. Asiaticoside-pretreated NK cells' cytotoxicity was assessed against K562, OVCAR8, and A2780 cells using organoids from ascites-derived ovarian cancer (OC) cells. In vivo efficacy was evaluated with B16 melanoma lung metastasis and subcutaneous tumor models in C57BL/6 mice, using asiaticoside as a 50 mg/kg injection. The compound's ability to enhance NK cell-driven anti-neoplastic responses was further assessed in an OC murine model. Effects on TGF-β/SMAD pathways and mitochondrial functions were examined through various microscopy and metabolomic techniques. The involvement of the mTOR/DRP1 axis in asiaticoside-mediated restoration of mitochondrial oxidation in NK cells after TGF-β suppression was determined using the mTOR inhibitor rapamycin and the DRP1 inhibitor Mdivi-1.

RESULTS

Asiaticoside-treated NK cells retained their ability to suppress tumor growth and metastasis despite TGF-β presence. Asiaticoside downregulated TGF-β receptors 1 (TGFBR1) expression, impaired the protein stability of TGFBR1 and TGF-β receptors 2 (TGFBR2), and reduced SMAD2 phosphorylation, preventing SMAD2 translocation from the mitochondria. This preserved mitochondrial respiration and maintained NK cell antitumor activity.

CONCLUSION

The study concludes that asiaticoside has significant potential as a strategy for "priming" NK cells in cellular immunotherapy. By demonstrating that asiaticoside degrades the TGF-β receptor, leading to reduced phosphorylation of SMAD2 and preventing its mitochondrial translocation, thereby maintaining mitochondrial integrity. Meantime, asiaticoside counteracts TGF-β-induced suppression of mitochondrial oxidative and aerobic respiration through the mTOR/DRP1 pathways. The research uncovers a previously unreported pathway for preserving mitochondrial respiration and NK cell functionality. A detailed mechanistic insight into how asiaticoside functions at the molecular level was explored. Its ability to counteract the immunosuppressive effects of TGF-β makes it a valuable candidate for enhancing the effectiveness of immunotherapies in treating a variety of tumors with elevated TGF-β levels.

Inhibitory immune checkpoints suppress the surveillance of senescent cells promoting their accumulation with aging and in age-related diseases

The accumulation of pro-inflammatory senescent cells within tissues is a common hallmark of the aging process and many age-related diseases. This modification has been called the senescence-associated secretory phenotype (SASP) and observed in cultured cells and in cells isolated from aged tissues. Currently, there is a debate whether the accumulation of senescent cells within tissues should be attributed to increased generation of senescent cells or to a defect in their elimination from aging tissues. Emerging studies have revealed that senescent cells display an increased expression of several inhibitory immune checkpoint ligands, especially those of the programmed cell death protein-1 (PD-1) ligand-1 (PD-L1) proteins. It is known that the PD-L1 ligands, especially those of cancer cells, target the PD-1 receptor of cytotoxic CD8+ T and natural killer (NK) cells disturbing their functions, e.g., evoking a decline in their cytotoxic activity and promoting their exhaustion and even apoptosis. An increase in the level of the PD-L1 protein in senescent cells was able to suppress their immune surveillance and inhibit their elimination by cytotoxic CD8+ T and NK cells. Senescent cells are known to express ligands for several inhibitory immune checkpoint receptors, i.e., PD-1, LILRB4, NKG2A, TIM-3, and SIRPα receptors. Here, I will briefly describe those pathways and examine whether these inhibitory checkpoints could be involved in the immune evasion of senescent cells with aging and age-related diseases. It seems plausible that an enhanced inhibitory checkpoint signaling can prevent the elimination of senescent cells from tissues and thus promote the aging process.

Multifaceted Roles of Vitamin D for Diabetes: From Immunomodulatory Functions to Metabolic Regulations

Numerous studies have established associations between vitamin D and diabetes. The vitamin D receptor is widely distributed throughout the human body, including in pancreatic beta cells (β-cells), hepatocytes, and immune cells. Therefore, vitamin D's effect on the risk, progression, or complications of diabetes may be mediated through various mechanisms. These include the regulation of insulin secretion or sensitivity and modulation of β-cell function and its immunomodulatory and anti-inflammatory effects. This review extensively explores the relationship between vitamin D status and diabetes, as well as the preventive or therapeutic effects of vitamin D supplementation on diabetes from human studies. Additionally, it examines in detail the impact of vitamin D on immune and inflammatory responses in the diabetic milieux and β-cell function to better understand the underlying mechanisms through which vitamin D influences diabetes.

Natural Killer Cell Dysfunction In Human Bladder Cancer Is Caused By Tissue-Specific Suppression of SLAMF6 Signaling

NK cells are innate lymphocytes critical for surveillance of viruses and tumors, however the mechanisms underlying NK cell dysfunction in cancer are incompletely understood. We assessed the effector function of NK cells from bladder cancer patients and found severe dysfunction in NK cells derived from tumors versus peripheral blood. While both peripheral and tumor-infiltrating NK cells exhibited conserved patterns of inhibitory receptor over-expression, this did not explain the observed defects in NK surveillance in bladder tumors. Rather, TME-specific TGF-β and metabolic perturbations such as hypoxia directly suppressed NK cell function. Specifically, an oxygen-dependent reduction in signaling through SLAMF6 was mechanistically responsible for poor NK cell function, as tumor-infiltrating NK cells cultured ex vivo under normoxic conditions exhibited complete restoration of function, while deletion of SLAMF6 abrogated NK cell cytolytic function even under normoxic conditions. Collectively, this work highlights the role of tissue-specific factors in dictating NK cell function, and implicates SLAMF6 signaling as a rational target for immuno-modulation to improve NK cell function in bladder cancer.

Natural killer cell effector function is critical for host defense against alcohol-associated bacterial pneumonia

Alcohol use is an independent risk factor for the development of bacterial pneumonia due, in part, to impaired mucus-facilitated clearance, macrophage phagocytosis, and recruitment of neutrophils. Alcohol consumption is also known to reduce peripheral natural killer (NK) cell numbers and compromise NK cell cytolytic activity, especially NK cells with a mature phenotype. However, the role of innate lymphocytes, such as NK cells during host defense against alcohol-associated bacterial pneumonia is essentially unknown. We have previously shown that indole supplementation mitigates increases in pulmonary bacterial burden and improves pulmonary NK cell recruitment in alcohol-fed mice, which were dependent on aryl hydrocarbon receptor (AhR) signaling. Employing a binge-on-chronic alcohol-feeding model we sought to define the role and interaction of indole and NK cells during pulmonary host defense against alcohol-associated pneumonia. We demonstrate that alcohol dysregulates NK cell effector function and pulmonary recruitment via alterations in two key signaling pathways. We found that alcohol increases transforming growth factor beta (TGF-β) signaling while suppressing AhR signaling. We further demonstrated that NK cells isolated from alcohol-fed mice have a reduced ability to kill Klebsiella pneumoniae. NK cell migratory capacity to chemokines was also significantly altered by alcohol, as NK cells isolated from alcohol-fed mice exhibited preferential migration in response to CXCR3 chemokines but exhibited reduced migration in response to CCR2, CXCR4, and CX3CR1 chemokines. Together this data suggests that alcohol disrupts NK cell-specific TGF-β and AhR signaling pathways leading to decreased pulmonary recruitment and cytolytic activity thereby increasing susceptibility to alcohol-associated bacterial pneumonia.

Novel quinazoline sulfonamide-based scaffolds modulate methicillin-resistant Staphylococcus aureus (MRSA) pneumonia in immunodeficient irradiated model: Regulatory role of TGF-β

A library of new quinazoline pharmacophores bearing benzenesulfonamide moiety was designed and synthesized. Compounds 3a-n were screened for their in vitro antimicrobial activity against eight multidrug-resistant clinical isolates. Compounds 3d and 3n exhibited prominent antibacterial activity, specifically against MRSA. After exhibiting relative in vitro and in vivo safety, compound 3n was selected to assess its anti-inflammatory activity displaying promising COX-2 inhibitory activity compared to Ibuprofen. In vivo experimental MRSA pneumonia model was conducted on immunodeficient (irradiated) mice to reveal the antimicrobial and anti-inflammatory responses of compound 3n compared to azithromycin (AZ). Treatment with compound 3n (10 and 20 mg/kg) as well as AZ resulted in a significant decrease in bacterial counts in lung tissues, suppression of serum C-reactive protein (CRP), lung interleukin-6 (IL-6), myeloperoxidase activity (MPO) and transforming growth factor-β (TGF-β). Compound 3n showed a non-significant deviation of lung TGF-β1 from normal values which in turn controlled the lung inflammatory status and impacted the histopathological results. Molecular docking of 3n showed promising interactions inside the active sites of TGF-β and COX-2. Our findings present a new dual-target quinazoline benzenesulfonamide derivative 3n, which possesses significant potential for treating MRSA-induced pneumonia in an immunocompromised state.

Thrombotic events associated with immune checkpoint inhibitors and novel antithrombotic strategies to mitigate bleeding risk

Although immunotherapy is expanding treatment options for cancer patients, the prognosis of advanced cancer remains poor, and these patients must contend with both cancers and cancer-related thrombotic events. In particular, immune checkpoint inhibitors are associated with an increased risk of atherosclerotic thrombotic events. Given the fundamental role of platelets in atherothrombosis, co-administration of antiplatelet agents is always indicated. Platelets are also involved in all steps of cancer progression. Classical antithrombotic drugs can cause inevitable hemorrhagic side effects due to blocking integrin β3 bidirectional signaling, which regulates simultaneously thrombosis and hemostasis. Meanwhile, many promising new targets are emerging with minimal bleeding risk and desirable anti-tumor effects. This review will focus on the issue of thrombosis during immune checkpoint inhibitor treatment and the role of platelet activation in cancer progression as well as explore the mechanisms by which novel antiplatelet therapies may exert both antithrombotic and antitumor effects without excessive bleeding risk.

Decoding the secret of extracellular vesicles in the immune tumor microenvironment of the glioblastoma: on the border of kingdoms

Over the last decades, extracellular vesicles (EVs) have become increasingly popular for their roles in various pathologies, including cancer and neurological and immunological disorders. EVs have been considered for a long time as a means for normal cells to get rid of molecules it no longer needs. It is now well established that EVs play their biological roles also following uptake or by the interaction of EV surface proteins with cellular receptors and membranes. In this review, we summarize the current status of EV production and secretion in glioblastoma, the most aggressive type of glioma associated with high mortality. The main purpose is to shed light on the EVs as a universal mediator of interkingdom and intrakingdom communication in the context of tumor microenvironment heterogeneity. We focus on the immunomodulatory EV functions in glioblastoma-immune cross-talk to enhance immune escape and reprogram tumor-infiltrating immune cells. We critically examine the evidence that GBM-, immune cell-, and microbiome-derived EVs impact local tumor microenvironment and host immune responses, and can enter the circulatory system to disseminate and drive premetastatic niche formation in distant organs. Taking into account the current state of the art in intratumoral microbiome studies, we discuss the emerging role of bacterial EV in glioblastoma and its response to current and future therapies including immunotherapies.

Tumor microenvironment induced switch to mitochondrial metabolism promotes suppressive functions in immune cells

Understanding the intricacies of the metabolic phenotype in immune cells and its plasticity within the tumor microenvironment is pivotal in understanding the pathology and prognosis of cancer. Unfavorable conditions and cellular stress in the tumor microenvironment (TME) exert a profound impact on cellular functions in immune cells, thereby influencing both tumor progression and immune responses. Elevated AMP:ATP ratio, a consequence of limited glucose levels, activate AMP-activated protein kinase (AMPK) while concurrently repressing the activity of mechanistic target of rapamycin (mTOR) and hypoxia-inducible factor 1-alpha (HIF-1α). The intricate balance between AMPK, mTOR, and HIF-1α activities defines the metabolic phenotype of immune cells in the TME. These Changes in metabolic phenotype are strongly associated with immune cell functions and play a crucial role in creating a milieu conducive to tumor progression. Insufficiency of nutrient and oxygen supply leads to a metabolic shift in immune cells characterized by a decrease in glycolysis and an increase in oxidative phosphorylation (OXPHOS) and fatty acid oxidation (FAO) rates. In most cases, this shift in metabolism is accompanied by a compromise in the effector functions of these immune cells. This metabolic adaptation prompts immune cells to turn down their effector functions, entering a quiescent or immunosuppressive state that may support tumor growth. This article discusses how tumor microenvironment alters the metabolism in immune cells leading to their tolerance and tumor progression, with emphasis on mitochondrial metabolism (OXPHOS and FAO).

HPK1 Dysregulation-Associated NK Cell Dysfunction and Defective Expansion Promotes Metastatic Melanoma Progression

Distant metastasis, the leading cause of cancer death, is efficiently kept in check by immune surveillance. Studies have uncovered peripheral natural killer (NK) cells as key antimetastatic effectors and their dysregulation during metastasis. However, the molecular mechanism governing NK cell dysfunction links to metastasis remains elusive. Herein, MAP4K1 encoding HPK1 is aberrantly overexpressed in dysfunctional NK cells in the periphery and the metastatic site. Conditional HPK1 overexpression in NK cells suffices to exacerbate melanoma lung metastasis but not primary tumor growth. Conversely, MAP4K1-deficient mice are resistant to metastasis and further protected by combined immune-checkpoint inhibitors. Mechanistically, HPK1 restrains NK cell cytotoxicity and expansion via activating receptors. Likewise, HPK1 limits human NK cell activation and associates with melanoma NK cell dysfunction couples to TGF-β1 and patient response to immune checkpoint therapy. Thus, HPK1 is an intracellular checkpoint controlling NK-target cell responses, which is dysregulated and hijacked by tumors during metastatic progression.

High-dimensional single-cell analysis of human natural killer cell heterogeneity

Natural killer (NK) cells are innate lymphoid cells (ILCs) contributing to immune responses to microbes and tumors. Historically, their classification hinged on a limited array of surface protein markers. Here, we used single-cell RNA sequencing (scRNA-seq) and cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq) to dissect the heterogeneity of NK cells. We identified three prominent NK cell subsets in healthy human blood: NK1, NK2 and NK3, further differentiated into six distinct subgroups. Our findings delineate the molecular characteristics, key transcription factors, biological functions, metabolic traits and cytokine responses of each subgroup. These data also suggest two separate ontogenetic origins for NK cells, leading to divergent transcriptional trajectories. Furthermore, we analyzed the distribution of NK cell subsets in the lung, tonsils and intraepithelial lymphocytes isolated from healthy individuals and in 22 tumor types. This standardized terminology aims at fostering clarity and consistency in future research, thereby improving cross-study comparisons.