IL-2 regulates tumor-reactive CD8(+) T cell exhaustion by activating the aryl hydrocarbon receptor

Immunotherapy resistance in solid tumors: mechanisms and potential solutions

While the emergence of immunotherapies has fundamentally altered the management of solid tumors, cancers exploit many complex biological mechanisms that result in resistance to these agents. These encompass a broad range of cellular activities - from modification of traditional paradigms of immunity via antigen presentation and immunoregulation to metabolic modifications and manipulation of the tumor microenvironment. Intervening on these intricate processes may provide clinical benefit in patients with solid tumors by overcoming resistance to immunotherapies, which is why it has become an area of tremendous research interest with practice-changing implications. This review details the major ways cancers avoid both natural immunity and immunotherapies through primary (innate) and secondary (acquired) mechanisms of resistance, and it considers available and emerging therapeutic approaches to overcoming immunotherapy resistance.

Transient-resting culture after activation enhances the generation of CD8+ stem cell-like memory T cells from peripheral blood mononuclear cells

Adoptive cell therapy (ACT) has revolutionized the treatment of patients with cancer. The success of ACT depends largely on transferred T cell status, particularly their less-differentiated state with stem cell-like properties, which enhances ACT effectiveness. Stem cell-like memory T (TSCM) cells exhibit continuous self-renewal and multilineage differentiation similar to pluripotent stem cells. TSCM cells are promising candidates for cancer immunotherapies, whereas maintenance of a more stem-cell-like state before transfer is challenging. Here, we established a highly efficient protocol for generating CD8+ TSCM cells from peripheral blood mononuclear cells (PBMCs). The process involved activating PBMCs using anti-CD3 monoclonal antibody and RetroNectin, followed by a transient-resting culture period (24 h) and subsequent long-term expansion in vitro with interlukien-2. We report that this transient-resting culture after activation preserves CD8+ T cells in a stem memory phenotype (CD95+ CD45RA+ CCR7+) compared to the conventional culture method. Further, this approach reduces the expression of T cell immunoglobulin mucin-3, an exhaustion marker, and increases the expression of T cell factor-1, a master regulator of stemness even after long-term culture compared to the conventional culture method. In conclusion, our study presents a simplified and cost-effective method for generating and expanding CD8+ TSCM cells ex vivo. This approach streamlines the optimization of cancer immunotherapy using ACT.

Focusing on CD8+ T-cell phenotypes: improving solid tumor therapy

Vigorous CD8+ T cells play a crucial role in recognizing tumor cells and combating solid tumors. How T cells efficiently recognize and target tumor antigens, and how they maintain the activity in the "rejection" of solid tumor microenvironment, are major concerns. Recent advances in understanding of the immunological trajectory and lifespan of CD8+ T cells have provided guidance for the design of more optimal anti-tumor immunotherapy regimens. Here, we review the newly discovered methods to enhance the function of CD8+ T cells against solid tumors, focusing on optimizing T cell receptor (TCR) expression, improving antigen recognition by engineered T cells, enhancing signal transduction of the TCR-CD3 complex, inducing the homing of polyclonal functional T cells to tumors, reversing T cell exhaustion under chronic antigen stimulation, and reprogramming the energy and metabolic pathways of T cells. We also discuss how to participate in the epigenetic changes of CD8+ T cells to regulate two key indicators of anti-tumor responses, namely effectiveness and persistence.

Targeting epigenetic regulation and post-translational modification with 5-Aza-2' deoxycytidine and SUMO E1 inhibition augments T-cell receptor therapy

BACKGROUND

Cellular immunotherapy using modified T cells offers new avenues for cancer treatment. T-cell receptor (TCR) engineering of CD8 T cells enables these cells to recognize tumor-associated antigens and tumor-specific neoantigens. Improving TCR T-cell therapy through increased potency and in vivo persistence will be critical for clinical success.

METHODS

We evaluated a novel drug combination to enhance TCR therapy in mouse models for acute myeloid leukemia (AML) and multiple myeloma (MM).

RESULTS

Combining TCR therapy with the SUMO E1 inhibitor TAK981 and the DNA methylation inhibitor 5-Aza-2' deoxycytidine resulted in strong antitumor activity in a persistent manner against two in vivo tumor models of established AML and MM. We uncovered that the drug combination caused strong T-cell proliferation, increased cytokine signaling in T cells, improved persistence of T cells, and reduced differentiation towards exhausted phenotype. Simultaneously the drug combination enhanced immunogenicity of the tumor by increasing HLA and co-stimulation and surprisingly reducing inhibitory ligand expression.

CONCLUSION

Combining T-cell therapy with TAK981 and 5-Aza-2' deoxycytidine may be an important step towards improved clinical outcome.

Molecular Insights into the Interaction of Tryptophan Metabolites with the Human Aryl Hydrocarbon Receptor in Silico: Tryptophan as Antagonist and no Direct Involvement of Kynurenine

BACKGROUND

A direct link between the tryptophan (Trp) metabolite kynurenine (Kyn) and the aryl hydrocarbon receptor (AhR) is not supported by metabolic considerations and by studies demonstrating the failure of Kyn concentrations of up to 100 μM to activate the receptor in cell culture systems using the proxy system of cytochrome P-450-dependent metabolism. The Kyn metabolite kynurenic acid (KA) activates the AhR and may mediate the Kyn link. Recent studies demonstrated down regulation and antagonism of activation of the AhR by Trp. We have addressed the link between Kyn and the AhR by looking at their direct molecular interaction in silico.

METHODS

Molecular docking of Kyn, KA, Trp and a range of Trp metabolites to the crystal structure of the human AhR was performed under appropriate docking conditions.

RESULTS

Trp and 30 of its metabolites docked to the AhR to various degrees, whereas Kyn and 3-hydroxykynurenine did not. The strongest docking was observed with the Trp metabolite and photooxidation product 6-Formylindolo[3,2-b]carbazole (FICZ), cinnabarinic acid, 5-hydroxytryptophan, N-acetyl serotonin and indol-3-yllactic acid. Strong docking was also observed with other 5-hydroxyindoles.

CONCLUSIONS

We propose that the Kyn-AhR link is mediated by KA. The strong docking of Trp and its recently reported down regulation of the receptor suggest that Trp is an AhR antagonist and may thus play important roles in body homeostasis beyond known properties or simply being the precursor of biologically active metabolites. Differences in AhR activation reported in the literature are discussed.

Optimizing CAR-T cell Culture: Differential effects of IL-2, IL-12, and IL-21 on CAR-T cells

BACKGROUND

Chimeric antigen receptor (CAR)-T therapy has demonstrated sustained clinical remission in numerous hematologic malignancies and has expanded to encompass solid tumors and autoimmune diseases. While progress is being made in establishing optimal culture conditions for CAR-T cells, the identification of the most effective cytokine for promoting their persistence in vitro remains elusive.

METHODS

Here, we employed scRNA-seq (single-cell RNA sequencing) analysis to investigate the potential alterations in biological processes within CAR-T cells following exposure to cytokines (IL-2, IL-12, and IL-21) and antigens. Transcriptomic changes in diverse CAR-T groups were compared following various treatments, with a focus on epigenetic modifications, metabolic shifts, cellular senescence, and exhaustion.

RESULTS

Our study reveals that CAR-T cells treated with antigen, IL-2, and IL-12 exhibit signs of exhaustion and senescence, whereas those treated with IL-21 do not display these characteristics. The activities of glycolysis and epigenetic changes were significantly increased by treatments with antigens, IL-2, and IL-12, while IL-21 treatment maintained the oxidative phosphorylation (OXPHOS) of CAR-T cells.

CONCLUSIONS

Our findings suggest that IL-21 may play a role in preventing senescence and could be utilized in combination with other strategies, such as IL-2 and IL-12, for CAR-T culture.

Identification of PFKFB3 as a key factor in the development of colorectal cancer and immunotherapy resistance

Resistance to immunotherapy poses a significant challenge in the treatment of colorectal cancer (CRC), and the underlying mechanisms are not fully understood. Recent studies have implicated PFKFB3, a crucial glycolytic enzyme, in shaping the tumor microenvironment in CRC. Our study aimed to systematically study the role of PFKFB3 in CRC. Bioinformatic analysis revealed that PFKFB3 expression is notably elevated in CRC tissues compared to normal counterparts. In vivo experiments confirmed that suppressing PFKFB3 reduces the tumorigenesis of CRC. We identified multiple cancer-associated pathways positively correlated with high expression of PFKFB3, such as epithelial-mesenchymal transition (EMT), hypoxia, KRAS signaling, angiogenesis, PI3K/AKT/mTOR, Hedgehog, and Notch pathways. Additionally, PFKFB3 exhibited significant correlations with various immune-related pathways, including complement, IL-2/STAT5, IL-6/JAK/STAT3, IFN-α/IFN-γ, TGF-β, and TNF-α/NF-κB, as well as several immunosuppressive cell markers found in regulatory T cells (CCR8, TGFB1, STAT5B, FOXP3), M2 macrophages (CD163, VSIG4, MS4A4A), T cell exhaustion markers (CTLA-4, PDCD1, LAG3), and PD-L1. Intriguingly, increased PFKFB3 expression was observed in PD-L1 blockade-resistant patients and was associated with shorter overall survival. In a nutshell, PFKFB3 plays an important role in CRC tumorigenesis and resistance to immunotherapy. Targeting PFKFB3 inhibits tumor formation and enhances the efficacy of immunotherapy. Our findings underscore the functions of PFKFB3 in CRC, shedding light on both cancer-related and immunosuppressive pathways.

IL-4 drives exhaustion of CD8+ CART cells

Durable response to chimeric antigen receptor T (CART) cell therapy remains limited in part due to CART cell exhaustion. Here, we investigate the regulation of CART cell exhaustion with three independent approaches including: a genome-wide CRISPR knockout screen using an in vitro model for exhaustion, RNA and ATAC sequencing on baseline and exhausted CART cells, and RNA and ATAC sequencing on pre-infusion CART cell products from responders and non-responders in the ZUMA-1 clinical trial. Each of these approaches identify interleukin (IL)-4 as a regulator of CART cell dysfunction. Further, IL-4-treated CD8+ CART cells develop signs of exhaustion independently of the presence of CD4+ CART cells. Conversely, IL-4 pathway editing or the combination of CART cells with an IL-4 monoclonal antibody improves antitumor efficacy and reduces signs of CART cell exhaustion in mantle cell lymphoma xenograft mouse models. Therefore, we identify both a role for IL-4 in inducing CART exhaustion and translatable approaches to improve CART cell therapy.

Serum targeted metabolomics uncovering specific amino acid signature for diagnosis of intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (iCCA) is a hepatobiliary malignancy which accounts for approximately 5-10 % of primary liver cancers and has a high mortality rate. The diagnosis of iCCA remains significant challenges owing to the lack of specific and sensitive diagnostic tests available. Hence, improved methods are needed to detect iCCA with high accuracy. In this study, we evaluated the efficacy of serum amino acid profiling combined with machine learning modeling for the diagnosis of iCCA. A comprehensive analysis of 28 circulating amino acids was conducted in a total of 140 blood samples from patients with iCCA and normal individuals. We screened out 6 differentially expressed amino acids with the criteria of |Log2(Fold Change, FC)| > 0.585, P-value < 0.05, variable importance in projection (VIP) > 1.0 and area under the curve (AUC) > 0.8, in which amino acids L-Asparagine and Kynurenine showed an increasing tendency as the disease progressed. Five frequently used machine learning algorithms (Logistic Regression, Random Forest, Supporting Vector Machine, Neural Network and Naïve Bayes) for diagnosis of iCCA based on the 6 circulating amino acids were established and validated with high sensitivity and good overall accuracy. The resulting models were further improved by introducing a clinical indicator, gamma-glutamyl transferase (GGT). This study introduces a new approach for identifying potential serum biomarkers for the diagnosis of iCCA with high accuracy.

T cell exhaustion in human cancers

T cell exhaustion refers to a progressive state in which T cells become functionally impaired due to sustained antigenic stimulation, which is characterized by increased expression of immune inhibitory receptors, but weakened effector functions, reduced self-renewal capacity, altered epigenetics, transcriptional programme and metabolism. T cell exhaustion is one of the major causes leading to immune escape of cancer, creating an environment that supports tumor development and metastatic spread. In addition, T cell exhaustion plays a pivotal role to the efficacy of current immunotherapies for cancer. This review aims to provide a comprehensive view of roles of T cell exhaustion in cancer development and progression. We summerized the regulatory mechanisms that involved in T cell exhaustion, including transcription factors, epigenetic and metabolic reprogramming events, and various microenvironmental factors such as cytokines, microorganisms, and tumor autocrine substances. The paper also discussed the challenges posed by T cell exhaustion to cancer immunotherapies, including immune checkpoint blockade (ICB) therapies and chimeric antigen receptor T cell (CAR-T) therapy, highlightsing the obstacles encountered in ICB therapies and CAR-T therapies due to T cell exhaustion. Finally, the article provides an overview of current therapeutic options aimed to reversing or alleviating T cell exhaustion in ICB and CAR-T therapies. These therapeutic approaches seek to overcome T cell exhaustion and enhance the effectiveness of immunotherapies in treating tumors.

Bevacizumab induces ferroptosis and enhances CD8+ T cell immune activity in liver cancer via modulating HAT1 and increasing IL-9

Bevacizumab is a recombinant humanized monoclonal immunoglobulin (Ig) G1 antibody of VEGF, and inhibits angiogenesis and tumor growth in hepatocellular carcinoma (HCC). Ferroptosis, a new form of regulated cell death function independently of the apoptotic machinery, has been accepted as an attractive target for pharmacological intervention; the ferroptosis pathway can enhance cell immune activity of anti-PD1 immunotherapy in HCC. In this study we investigated whether and how bevacizumab regulated ferroptosis and immune activity in liver cancer. Firstly, we performed RNA-sequencing in bevacizumab-treated human liver cancer cell line HepG2 cells, and found that bevacizumab significantly altered the expression of a number of genes including VEGF, PI3K, HAT1, SLC7A11 and IL-9 in liver cancer, bevacizumab upregulated 37 ferroptosis-related drivers, and downregulated 17 ferroptosis-related suppressors in particular. We demonstrated that bevacizumab triggered ferroptosis in liver cancer cells by driving VEGF/PI3K/HAT1/SLC7A11 axis. Clinical data confirmed that the expression levels of VEGF were positively associated with those of PI3K, HAT1 and SLC7A11 in HCC tissues. Meanwhile, we found that bevacizumab enhanced immune cell activity in tumor immune-microenvironment. We identified that HAT1 up-regulated miR-143 targeting IL-9 mRNA 3'UTR in liver cancer cells; bevacizumab treatment resulted in the increase of IL-9 levels and its secretion via VEGF/PI3K/HAT1/miR-143/IL-9 axis, which led to the inhibition of tumor growth in vivo through increasing the release of IL-2 and Granzyme B from activated CD8+ T cells. We conclude that in addition to inhibiting angiogenesis, bevacizumab induces ferroptosis and enhances CD8+ T cell immune activity in liver cancer. This study provides new insight into the mechanisms by which bevacizumab synergistically modulates ferroptosis and CD8+ T cell immune activity in liver cancer.

De novo design of mini-binder proteins against IL-2 receptor β chain

IL-2 regulates the immune response by interacting with different IL-2 receptor (IL-2R) subunits. High dose of IL-2 binds to IL-2Rβγc heterodimer, which induce various side effects while activating immune function. Disrupting IL-2 and IL-2R interactions can block IL-2 mediated immune response. Here, we used a computational approach to de novo design mini-binder proteins against IL-2R β chain (IL-2Rβ) to block IL-2 signaling. The hydrophobic region where IL-2 binds to IL-2Rβ was selected and the promising binding mode was broadly explored. Three mini-binders with amino acid numbers ranging from 55 to 65 were obtained and binder 1 showed the best effects in inhibiting CTLL-2 cells proliferation and STAT5 phosphorylation. Molecular dynamics simulation showed that the binding of binder 1 to IL-2Rβ was stable; the free energy of binder1/IL-2Rβ complex was lower, indicating that the affinity of binder 1 to IL-2Rβ was higher than that of IL-2. Free energy decomposition suggested that the ARG35 and ARG131 of IL-2Rβ might be the key to improve the affinity of binder. Our efforts provided new insights in developing of IL-2R blocker, offering a potential strategy for ameliorating the side effects of IL-2 treatment.

Association of CTACK, IL-2, and IL-13 with increased risk of lung cancer: A Mendelian randomization study

BACKGROUND

In recent years, relevant studies have reported that inflammatory cytokines are related to the occurrence of cancer. However, the correlation with lung cancer is not clear. This study used the Mendelian random grouping method to investigate the correlation between inflammatory factors and lung cancer in different populations.

METHODS

We obtained the single nucleotide polymorphisms (SNPs) of inflammatory cytokines through the open database and the SNPs of lung cancer (European and East Asian) through the IEU OpenGWAS project. Inverse variance-weighted (IVW) MR analyses were used to determine the causalities of exposures and outcomes. Supplementary analyses were also performed using weighted median and MR-Egger regressions. Afterward, sensitivity analyses were performed to test the robustness. Search the ChEMBL database for target drugs and indications for CTACK, IL-2, and IL-13.

RESULTS

By IVW method, we found that CTACK, IL-2, and IL-13 were associated with an increased risk of lung cancer in the European population (CTACK, OR = 1.098, 95 % CI 1.001-1.204, P = 0.047; IL-2, OR = 1.112, 95 % CI 1.009-1.225, P = 0.032; IL-13, OR = 1.068, 95 % CI 1.007-1.132, P = 0.029), while only IL-13 was associated with an increased risk of lung cancer in the East Asian population (IL-13, OR = 1.110, 95 % CI 1.010-1.220, P = 0.030). The weighted median and MR-Egger regression methods were in the same direction as the IVW effect sizes. Furthermore, no evidence of multidirectionality was detected using the MR-Egger intercept as a sensitivity analysis. Currently, there are no approved or phase III studied indications for CTACK, IL-2, and IL-13 targets in lung cancer.

CONCLUSION

The study outcomes supported that the inflammatory cytokines CTACK, IL-2, and IL-13 increase the risk of lung cancer. There is a lack of indications for drugs in these three targets. We explored the causal relationship between inflammatory cytokines and lung cancer, providing a basis for future cancer prediction models and targets for anti-tumor therapy.

Discovery of an Exceptionally Orally Bioavailable and Potent HPK1 PROTAC with Enhancement of Antitumor Efficacy of Anti-PD-L1 Therapy

HPK1, a well-known negative regulator of T cell receptors, can cause T cell dysfunction when abnormally activated. In this study, a PROTAC C3 was designed and synthesized by optimizing the physicochemical properties of the warhead, linker, and CRBN ligand. C3 demonstrated significant HPK1 degradation with a DC50 of 21.26 nM, excellent oral absorption with a Cmax of 10,899.92 ng/mL, and a bioavailability (F %) of 81.7%. C3 also showed degradation selectivity and potent immune activation effects. Proteomic and WB analyses revealed that immune-activating effect of C3 is attributed to the inhibition of SLP76 and NF-κB signaling pathways, as well as the enhancement of MAPK signaling pathway transduction. In vivo efficacy study demonstrated that oral administration of C3 in combination with anti-PDL1 antibody significantly inhibited tumor growth (tumor growth inhibition = 65.58%). These findings suggest that C3, a novel HPK1 PROTAC, holds promise as a therapeutic agent for tumor immunotherapy.

A role of gut microbiota metabolites in HLA-E and NKG2 blockage immunotherapy against tumors: new insights for clinical application

One of major breakthroughs in immunotherapy against tumor is from blocking immune checkpoint molecules on tumor and reactive T cells. The development of CTLA-4 and PD-1 blockage antibodies has triggered to search for additional effective therapeutic strategies. This causes recent findings that blocking the interaction of checkpoint molecule NKG2A in NK and CD8 T cells with HLA-E in tumors is effective in defensing tumors. Interestingly, gut microbiota also affects this immune checkpoint immunotherapy against tumor. Gut microbiota such as bacteria can contribute to the regulation of host immune response and homeostasis. They not only promote the differentiation and function of immunosuppressive cells but also the inflammatory cells through the metabolites such as tryptophan (Trp) and bile acid (BA) metabolites as well as short chain fatty acids (SCFAs). These gut microbiota metabolites (GMMs) educated immune cells can affect the differentiation and function of effective CD8 and NK cells. Notably, these metabolites also directly affect the activity of CD8 and NK cells. Furthermore, the expression of CD94/NKG2A in the immune cells and/or their ligand HLA-E in the tumor cells is also regulated by gut microbiota associated immune factors. These findings offer new insights for the clinical application of gut microbiota in precise and/or personalized treatments of tumors. In this review, we will discuss the impacts of GMMs and GMM educated immune cells on the activity of effective CD8 and NK cells and the expression of CD94/NKG2A in immune cells and/or their ligand HLA-E in tumor cells.

Aryl hydrocarbon receptor: current perspectives on key signaling partners and immunoregulatory role in inflammatory diseases

The aryl hydrocarbon receptor (AhR) is a versatile environmental sensor and transcription factor found throughout the body, responding to a wide range of small molecules originating from the environment, our diets, host microbiomes, and internal metabolic processes. Increasing evidence highlights AhR's role as a critical regulator of numerous biological functions, such as cellular differentiation, immune response, metabolism, and even tumor formation. Typically located in the cytoplasm, AhR moves to the nucleus upon activation by an agonist where it partners with either the aryl hydrocarbon receptor nuclear translocator (ARNT) or hypoxia-inducible factor 1β (HIF-1β). This complex then interacts with xenobiotic response elements (XREs) to control the expression of key genes. AhR is notably present in various crucial immune cells, and recent research underscores its significant impact on both innate and adaptive immunity. This review delves into the latest insights on AhR's structure, activating ligands, and its multifaceted roles. We explore the sophisticated molecular pathways through which AhR influences immune and lymphoid cells, emphasizing its emerging importance in managing inflammatory diseases. Furthermore, we discuss the exciting potential of developing targeted therapies that modulate AhR activity, opening new avenues for medical intervention in immune-related conditions.

Multi-omics analysis reveals a feedback loop amplifying immune responses in acute graft-versus-host disease due to imbalanced gut microbiota and bile acid metabolism

Acute graft-versus-host disease (aGVHD) is primarily driven by allogeneic donor T cells associated with an altered composition of the host gut microbiome and its metabolites. The severity of aGVHD after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is not solely determined by the host and donor characteristics; however, the underlying mechanisms remain unclear. Using single-cell RNA sequencing, we decoded the immune cell atlas of 12 patients who underwent allo-HSCT: six with aGVHD and six with non-aGVHD. We performed a fecal microbiota (16SrRNA sequencing) analysis to investigate the fecal bacterial composition of 82 patients: 30 with aGVHD and 52 with non-aGVHD. Fecal samples from these patients were analyzed for bile acid metabolism. Through multi-omic analysis, we identified a feedback loop involving "immune cell-gut microbes-bile acid metabolites" contributing to heightened immune responses in patients with aGVHD. The dysbiosis of the gut microbiota and disruption of bile acid metabolism contributed to an exaggerated interleukin-1 mediated immune response. Our findings suggest that resistin and defensins are crucial in mitigating against aGVHD. Therefore, a comprehensive multi-omic atlas incorporating immune cells, gut microbes, and bile acid metabolites was developed in this study and used to propose novel, non-immunosuppressive approaches to prevent aGVHD.

TPH1 inhibits bladder tumorigenesis by targeting HIF-1α pathway in bladder cancer

Background

BCa is the most common cancer of the urinary system. TPH1 has been reported to be associated with distinct tumorigenesis. However, the role of TPH1 in BCa remains to be clarified.

Objectives

Our aim is to demonstrate the molecular mechanism of TPH1 in BCa carcinogenesis and development.

Methods

In research, we explored the effect of TPH1 on T24 cells. Colony formation, soft agar, and cell proliferation assays were used to determine the survival and proliferative capacity of cells. Moreover, TPH1-/- cell lines were analyzed using CRISP-CAS9, and the recovery experiment was conducted. Realtime fluorescence quantitative PCR (qPCR) and Western blot were used to detect HIF-1α mRNA levels and TPH1 protein.

Results

The TPH1 expression is lower in tumor tissues than in normal tissues. Colony formation, soft agar, and cell proliferation assays revealed that the overexpression of TPH1 declined cells survival. Moreover, the deficiency of TPH1 increased the number of clones. These results suggested that survival rate of TPH1 overexpression was repressed in cells. In addition, we found that HIF-1α activity was significantly downregulated with an increase in TPH1. The transcriptional activity of survivin was increased with TPH1-/- cells. Then, the proliferative ability of TPH1-/- cells was almost similar to the wild type levels with the treatment of LW6, TPH1 might play a major role to repress HIF-1α activity.

Conclusions

Taken together, these results suggested that increasing TPH1 activity could inhibit survival and proliferation of cells via HIF-1α pathway. TPH1 may be a potential target for human BCa therapy.

The immunosuppressive landscape in tumor microenvironment

Recent advances in cancer immunotherapy, especially immune checkpoint inhibitors (ICIs), have revolutionized the clinical outcome of many cancer patients. Despite the fact that impressive progress has been made in recent decades, the response rate remains unsatisfactory, and many patients do not benefit from ICIs. Herein, we summarized advanced studies and the latest insights on immune inhibitory factors in the tumor microenvironment. Our in-depth discussion and updated landscape of tumor immunosuppressive microenvironment may provide new strategies for reversing tumor immune evasion, enhancing the efficacy of ICIs therapy, and ultimately achieving a better clinical outcome.

Gut microbiota dysbiosis is associated with altered tryptophan metabolism and dysregulated inflammatory response in COVID-19

The clinical course of COVID-19 is variable and often unpredictable. To test the hypothesis that disease progression and inflammatory responses associate with alterations in the microbiome and metabolome, we analyzed metagenome, metabolome, cytokine, and transcriptome profiles of repeated samples from hospitalized COVID-19 patients and uninfected controls, and leveraged clinical information and post-hoc confounder analysis. Severe COVID-19 was associated with a depletion of beneficial intestinal microbes, whereas oropharyngeal microbiota disturbance was mainly linked to antibiotic use. COVID-19 severity was also associated with enhanced plasma concentrations of kynurenine and reduced levels of several other tryptophan metabolites, lysophosphatidylcholines, and secondary bile acids. Moreover, reduced concentrations of various tryptophan metabolites were associated with depletion of Faecalibacterium, and tryptophan decrease and kynurenine increase were linked to enhanced production of inflammatory cytokines. Collectively, our study identifies correlated microbiome and metabolome alterations as a potential contributor to inflammatory dysregulation in severe COVID-19.

Fueling CARs: metabolic strategies to enhance CAR T-cell therapy

CAR T cells are widely applied for relapsed hematological cancer patients. With six approved cell therapies, for Multiple Myeloma and other B-cell malignancies, new insights emerge. Profound evidence shows that patients who fail CAR T-cell therapy have, aside from antigen escape, a more glycolytic and weakened metabolism in their CAR T cells, accompanied by a short lifespan. Recent advances show that CAR T cells can be metabolically engineered towards oxidative phosphorylation, which increases their longevity via epigenetic and phenotypical changes. In this review we elucidate various strategies to rewire their metabolism, including the design of the CAR construct, co-stimulus choice, genetic modifications of metabolic genes, and pharmacological interventions. We discuss their potential to enhance CAR T-cell functioning and persistence through memory imprinting, thereby improving outcomes. Furthermore, we link the pharmacological treatments with their anti-cancer properties in hematological malignancies to ultimately suggest novel combination strategies.

Linking serotonin homeostasis to gut function: Nutrition, gut microbiota and beyond

Serotonin (5-HT) produced by enterochromaffin (EC) cells in the digestive tract is crucial for maintaining gut function and homeostasis. Nutritional and non-nutritional stimuli in the gut lumen can modulate the ability of EC cells to produce 5-HT in a temporal- and spatial-specific manner that toning gut physiology and immune response. Of particular interest, the interactions between dietary factors and the gut microbiota exert distinct impacts on gut 5-HT homeostasis and signaling in metabolism and the gut immune response. However, the underlying mechanisms need to be unraveled. This review aims to summarize and discuss the importance of gut 5-HT homeostasis and its regulation in maintaining gut metabolism and immune function in health and disease with special emphasis on different types of nutrients, dietary supplements, processing, and gut microbiota. Cutting-edge discoveries in this area will provide the basis for the development of new nutritional and pharmaceutical strategies for the prevention and treatment of serotonin homeostasis-related gut and systematic disorders and diseases.

Interferon subverts an AHR-JUN axis to promote CXCL13+ T cells in lupus

Systemic lupus erythematosus (SLE) is prototypical autoimmune disease driven by pathological T cell-B cell interactions1,2. Expansion of T follicular helper (TFH) and T peripheral helper (TPH) cells, two T cell populations that provide help to B cells, is a prominent feature of SLE3,4. Human TFH and TPH cells characteristically produce high levels of the B cell chemoattractant CXCL13 (refs. 5,6), yet regulation of T cell CXCL13 production and the relationship between CXCL13+ T cells and other T cell states remains unclear. Here, we identify an imbalance in CD4+ T cell phenotypes in patients with SLE, with expansion of PD-1+/ICOS+ CXCL13+ T cells and reduction of CD96hi IL-22+ T cells. Using CRISPR screens, we identify the aryl hydrocarbon receptor (AHR) as a potent negative regulator of CXCL13 production by human CD4+ T cells. Transcriptomic, epigenetic and functional studies demonstrate that AHR coordinates with AP-1 family member JUN to prevent CXCL13+ TPH/TFH cell differentiation and promote an IL-22+ phenotype. Type I interferon, a pathogenic driver of SLE7, opposes AHR and JUN to promote T cell production of CXCL13. These results place CXCL13+ TPH/TFH cells on a polarization axis opposite from T helper 22 (TH22) cells and reveal AHR, JUN and interferon as key regulators of these divergent T cell states.

Immunometabolism of CD8+ T cell differentiation in cancer

CD8+ cytotoxic T lymphocytes (CTLs) are central mediators of tumor immunity and immunotherapies. Upon tumor antigen recognition, CTLs differentiate from naive/memory-like toward terminally exhausted populations with more limited function against tumors. Such differentiation is regulated by both immune signals, including T cell receptors (TCRs), co-stimulation, and cytokines, and metabolism-associated processes. These immune signals shape the metabolic landscape via signaling, transcriptional and post-transcriptional mechanisms, while metabolic processes in turn exert spatiotemporal effects to modulate the strength and duration of immune signaling. Here, we review the bidirectional regulation between immune signals and metabolic processes, including nutrient uptake and intracellular metabolic pathways, in shaping CTL differentiation and exhaustion. We also discuss the mechanisms underlying how specific nutrient sources and metabolite-mediated signaling events orchestrate CTL biology. Understanding how metabolic programs and their interplay with immune signals instruct CTL differentiation and exhaustion is crucial to uncover tumor-immune interactions and design novel immunotherapies.

Harnessing CD8+ T cell dynamics in hepatitis B virus-associated liver diseases: Insights, therapies and future directions

Hepatitis B virus (HBV) infection playsa significant role in the etiology and progression of liver-relatedpathologies, encompassing chronic hepatitis, fibrosis, cirrhosis, and eventual hepatocellularcarcinoma (HCC). Notably, HBV infection stands as the primary etiologicalfactor driving the development of HCC. Given the significant contribution ofHBV infection to liver diseases, a comprehensive understanding of immunedynamics in the liver microenvironment, spanning chronic HBV infection,fibrosis, cirrhosis, and HCC, is essential. In this review, we focused on thefunctional alterations of CD8+ T cells within the pathogenic livermicroenvironment from HBV infection to HCC. We thoroughly reviewed the roles ofhypoxia, acidic pH, metabolic reprogramming, amino acid deficiency, inhibitory checkpointmolecules, immunosuppressive cytokines, and the gut-liver communication in shapingthe dysfunction of CD8+ T cells in the liver microenvironment. Thesefactors significantly impact the clinical prognosis. Furthermore, we comprehensivelyreviewed CD8+ T cell-based therapy strategies for liver diseases,encompassing HBV infection, fibrosis, cirrhosis, and HCC. Strategies includeimmune checkpoint blockades, metabolic T-cell targeting therapy, therapeuticT-cell vaccination, and adoptive transfer of genetically engineered CD8+ T cells, along with the combined usage of programmed cell death protein-1/programmeddeath ligand-1 (PD-1/PD-L1) inhibitors with mitochondria-targeted antioxidants.Given that targeting CD8+ T cells at various stages of hepatitis Bvirus-induced hepatocellular carcinoma (HBV + HCC) shows promise, we reviewedthe ongoing need for research to elucidate the complex interplay between CD8+ T cells and the liver microenvironment in the progression of HBV infection toHCC. We also discussed personalized treatment regimens, combining therapeuticstrategies and harnessing gut microbiota modulation, which holds potential forenhanced clinical benefits. In conclusion, this review delves into the immunedynamics of CD8+ T cells, microenvironment changes, and therapeuticstrategies within the liver during chronic HBV infection, HCC progression, andrelated liver diseases.

Pan-cancer analysis of T-cell proliferation regulatory genes as potential immunotherapeutic targets

T cells are the key to killing tumor cells. However, the exact mechanism of their role in cancer is not fully understood. Therefore, a comprehensive understanding of the role of T-cell proliferation regulatory genes in tumors is needed. In our study, we investigated the expression levels of genes controlling T-cell proliferation, their impact on prognosis, and their genetic variations. Additionally, we explored their associations with TMB, MSI, ESTIMATEScore, ImmuneScore, StromalScore, and immune cell infiltration. We examined the role of these genes in cancer-related pathways using GSEA. Furthermore, we calculated their activity levels across various types of cancer. Drug analysis was also conducted targeting these genes. Single-cell analysis, LASSO Cox model construction, and prognosis analysis were performed. We observed distinct expression patterns of T-cell proliferation regulatory genes across different malignant tumors. Their abnormal expression may be caused by CNA and DNA methylation. In certain cancers, they also showed complex associations with TMB and MSI. Moreover, in many tumors, they exhibited significant positive correlations with ESTIMATEScores, ImmuneScore, and StromalScore. Additionally, in most tumors, their GSVA scores were significantly positively correlated with various T-cell subtypes. GSEA analysis revealed their involvement in multiple immune pathways. Furthermore, we found that model scores were associated with patient prognosis and related to tumor malignancy progression. T-cell proliferation regulatory genes are closely associated with the tumor immune microenvironment (TIM), especially T cells. Targeting them may be an essential approach for cancer immunotherapy.

Calcineurin inhibition rescues alloantigen-specific central memory T cell subsets that promote chronic GVHD

Calcineurin inhibitors (CNIs) constitute the backbone of modern acute graft-versus-host disease (aGVHD) prophylaxis regimens but have limited efficacy in the prevention and treatment of chronic GVHD (cGVHD). We investigated the effect of CNIs on immune tolerance after stem cell transplantation with discovery-based single-cell gene expression and T cell receptor (TCR) assays of clonal immunity in tandem with traditional protein-based approaches and preclinical modeling. While cyclosporin and tacrolimus suppressed the clonal expansion of CD8+ T cells during GVHD, alloreactive CD4+ T cell clusters were preferentially expanded. Moreover, CNIs mediated reversible dose-dependent suppression of T cell activation and all stages of donor T cell exhaustion. Critically, CNIs promoted the expansion of both polyclonal and TCR-specific alloreactive central memory CD4+ T cells (TCM) with high self-renewal capacity that mediated cGVHD following drug withdrawal. In contrast to posttransplant cyclophosphamide (PT-Cy), CSA was ineffective in eliminating IL-17A-secreting alloreactive T cell clones that play an important role in the pathogenesis of cGVHD. Collectively, we have shown that, although CNIs attenuate aGVHD, they paradoxically rescue alloantigen-specific TCM, especially within the CD4+ compartment in lymphoid and GVHD target tissues, thus predisposing patients to cGVHD. These data provide further evidence to caution against CNI-based immune suppression without concurrent approaches that eliminate alloreactive T cell clones.

FLI1 promotes IFN-γ-induced kynurenine production to impair anti-tumor immunity

Nasopharyngeal carcinoma (NPC)-mediated immunosuppression within the tumor microenvironment (TME) frequently culminates in the failure of otherwise promising immunotherapies. In this study, we identify tumor-intrinsic FLI1 as a critical mediator in impairing T cell anti-tumor immunity. A mechanistic inquiry reveals that FLI1 orchestrates the expression of CBP and STAT1, facilitating chromatin accessibility and transcriptional activation of IDO1 in response to T cell-released IFN-γ. This regulatory cascade ultimately leads to augmented IDO1 expression, resulting in heightened synthesis of kynurenine (Kyn) in tumor cells. This, in turn, fosters CD8+ T cell exhaustion and regulatory T cell (Treg) differentiation. Intriguingly, we find that pharmacological inhibition of FLI1 effectively obstructs the CBP/STAT1-IDO1-Kyn axis, thereby invigorating both spontaneous and checkpoint therapy-induced immune responses, culminating in enhanced tumor eradication. In conclusion, our findings delineate FLI1-mediated Kyn metabolism as an immune evasion mechanism in NPC, furnishing valuable insights into potential therapeutic interventions.

Interactions between LAMP3+ dendritic cells and T-cell subpopulations promote immune evasion in papillary thyroid carcinoma

BACKGROUND

The incidence of papillary thyroid cancer (PTC) continues to rise all over the world, 10-15% of the patients have a poor prognosis. Although immunotherapy has been applied in clinical practice, its therapeutic efficacy remains far from satisfactory, necessitating further investigation of the mechanism of PTC immune remodeling and exploration of novel treatment targets.

METHODS

This study conducted a single-cell RNA sequencing (scRNA-seq) analysis using 18 surgical tissue specimens procured from 14 patients diagnosed with adjacent tissues, non-progressive PTC or progressive PTC. Key findings were authenticated through spatial transcriptomics RNA sequencing, immunohistochemistry, multiplex immunohistochemistry, and an independent bulk RNA-seq data set containing 502 samples.

RESULTS

A total of 151,238 individual cells derived from 18 adjacent tissues, non-progressive PTC and progressive PTC specimens underwent scRNA-seq analysis. We found that progressive PTC exhibits the following characteristics: a significant decrease in overall immune cells, enhanced immune evasion of tumor cells, and disrupted antigen presentation function. Moreover, we identified a subpopulation of lysosomal associated membrane protein 3 (LAMP3+) dendritic cells (DCs) exhibiting heightened infiltration in progressive PTC and associated with advanced T stage and poor prognosis of PTC. LAMP3+ DCs promote CD8+ T cells exhaustion (mediated by NECTIN2-TIGIT) and increase infiltration abundance of regulatory T cells (mediated by chemokine (C-C motif) ligand 17 (CCL17)-chemokine (C-C motif) receptor 4 (CCR4)) establishing an immune-suppressive microenvironment. Ultimately, we unveiled that progressive PTC tumor cells facilitate the retention of LAMP3+ DCs within the tumor microenvironment through NECTIN3-NECTIN2 interactions, thereby rendering tumor cells more susceptible to immune evasion.

CONCLUSION

Our findings expound valuable insights into the role of the interaction between LAMP3+ DCs and T-cell subpopulations and offer new and effective ideas and strategies for immunotherapy in patients with progressive PTC.

Targeting SIGLEC15 as an emerging immunotherapy for anaplastic thyroid cancer

Anaplastic thyroid carcinoma (ATC) is the most aggressive subtype of thyroid cancer with few effective therapies. Though immunotherapies such as targeting PD-1/PD-L1 axis have benefited patients with solid tumor, the druggable immune checkpoints are quite limited in ATC. In our study, we focused on the anti-tumor potential of sialic acid-binding Ig-like lectins (Siglecs) in ATC. Through screening by integrating microarray datasets including 216 thyroid-cancer tissues and single-cell RNA-sequencing, SIGLEC family members CD33, SIGLEC1, SIGLEC10 and SIGLEC15 were significantly overexpressed in ATC, among which SIGLEC15 increased highest and mainly expressed on cancer cells. SIGLEC15high ATC cells are characterized by high expression of serine protease PRSS23 and cancer stem cell marker CD44. Compared with SIGLEC15low cancer cells, SIGLEC15high ATC cells exhibited higher interaction frequency with tumor microenvironment cells. Further study showed that SIGLEC15high cancer cells mainly interacted with T cells by immunosuppressive signals such as MIF-TNFRSF14 and CXCL12-CXCR4. Notably, treatment of anti-SIGLEC15 antibody profoundly increased the cytotoxic ability of CD8+ T cells in a co-culture model and zebrafish-derived ATC xenografts. Consistently, administration of anti-SIGLEC15 antibody significantly inhibited tumor growth and prolonged mouse survival in an immunocompetent model of murine ATC, which was associated with increase of M1/M2, natural killer (NK) cells and CD8+ T cells, and decrease of myeloid-derived suppressor cells (MDSCs). SIGLEC15 inhibited T cell activation by reducing NFAT1, NFAT2, and NF-κB signals. Blocking SIGLEC15 increased the secretion of IFN-γ and IL-2 in vitro and in vivo. In conclusion, our finding demonstrates that SIGLEC15 is an emerging and promising target for immunotherapy in ATC.

Spatial and functional targeting of intratumoral Tregs reverses CD8+ T cell exhaustion and promotes cancer immunotherapy

Intratumoral Tregs are key mediators of cancer immunotherapy resistance, including anti-programmed cell death (ligand) 1 [anti-PD-(L)1] immune checkpoint blockade (ICB). The mechanisms driving Treg infiltration into the tumor microenvironment (TME) and the consequence on CD8+ T cell exhaustion remain elusive. Here, we report that heat shock protein gp96 (also known as GRP94) was indispensable for Treg tumor infiltration, primarily through the roles of gp96 in chaperoning integrins. Among various gp96-dependent integrins, we found that only LFA-1 (αL integrin), and not αV, CD103 (αE), or β7 integrin, was required for Treg tumor homing. Loss of Treg infiltration into the TME by genetic deletion of gp96/LFA-1 potently induced rejection of tumors in multiple ICB-resistant murine cancer models in a CD8+ T cell-dependent manner, without loss of self-tolerance. Moreover, gp96 deletion impeded Treg activation primarily by suppressing IL-2/STAT5 signaling, which also contributed to tumor regression. By competing for intratumoral IL-2, Tregs prevented the activation of CD8+ tumor-infiltrating lymphocytes, drove thymocyte selection-associated high mobility group box protein (TOX) induction, and induced bona fide CD8+ T cell exhaustion. By contrast, Treg ablation led to striking CD8+ T cell activation without TOX induction, demonstrating clear uncoupling of the 2 processes. Our study reveals that the gp96/LFA-1 axis plays a fundamental role in Treg biology and suggests that Treg-specific gp96/LFA-1 targeting represents a valuable strategy for cancer immunotherapy without inflicting autoinflammatory conditions.

Development of pharmacological immunoregulatory anti-cancer therapeutics: current mechanistic studies and clinical opportunities

Immunotherapy represented by anti-PD-(L)1 and anti-CTLA-4 inhibitors has revolutionized cancer treatment, but challenges related to resistance and toxicity still remain. Due to the advancement of immuno-oncology, an increasing number of novel immunoregulatory targets and mechanisms are being revealed, with relevant therapies promising to improve clinical immunotherapy in the foreseeable future. Therefore, comprehending the larger picture is important. In this review, we analyze and summarize the current landscape of preclinical and translational mechanistic research, drug development, and clinical trials that brought about next-generation pharmacological immunoregulatory anti-cancer agents and drug candidates beyond classical immune checkpoint inhibitors. Along with further clarification of cancer immunobiology and advances in antibody engineering, agents targeting additional inhibitory immune checkpoints, including LAG-3, TIM-3, TIGIT, CD47, and B7 family members are becoming an important part of cancer immunotherapy research and discovery, as are structurally and functionally optimized novel anti-PD-(L)1 and anti-CTLA-4 agents and agonists of co-stimulatory molecules of T cells. Exemplified by bispecific T cell engagers, newly emerging bi-specific and multi-specific antibodies targeting immunoregulatory molecules can provide considerable clinical benefits. Next-generation agents also include immune epigenetic drugs and cytokine-based therapeutics. Cell therapies, cancer vaccines, and oncolytic viruses are not covered in this review. This comprehensive review might aid in further development and the fastest possible clinical adoption of effective immuno-oncology modalities for the benefit of patients.

Priming with LSD1 inhibitors promotes the persistence and antitumor effect of adoptively transferred T cells

The antitumor efficacy of adoptively transferred T cells is limited by their poor persistence, in part due to exhaustion, but the underlying mechanisms and potential interventions remain underexplored. Here, we show that targeting histone demethylase LSD1 by chemical inhibitors reshapes the epigenome of in vitro activated and expanded CD8+ T cells, and potentiates their antitumor efficacy. Upon T cell receptor activation and IL-2 signaling, a timely and transient inhibition of LSD1 suffices to improve the memory phenotype of mouse CD8+ T cells, associated with a better ability to produce multiple cytokines, resist exhaustion, and persist in both antigen-dependent and -independent manners after adoptive transfer. Consequently, OT1 cells primed with LSD1 inhibitors demonstrate an enhanced antitumor effect in OVA-expressing solid tumor models implanted in female mice, both as a standalone treatment and in combination with PD-1 blockade. Moreover, priming with LSD1 inhibitors promotes polyfunctionality of human CD8+ T cells, and increases the persistence and antitumor efficacy of human CD19-CAR T cells in both leukemia and solid tumor models. Thus, pharmacological inhibition of LSD1 could be exploited to improve adoptive T cell therapy.

IL-2-free tumor-infiltrating lymphocyte therapy with PD-1 blockade demonstrates potent efficacy in advanced gynecologic cancer

BACKGROUND

Tumor-infiltrating lymphocyte (TIL) therapy has been restricted by intensive lymphodepletion and high-dose intravenous interleukin-2 (IL-2) administration. To address these limitations, we conducted preclinical and clinical studies to evaluate the safety, antitumor activity, and pharmacokinetics of an innovative modified regimen in patients with advanced gynecologic cancer.

METHODS

Patient-derived xenografts (PDX) were established from a local recurrent cervical cancer patient. TILs were expanded ex vivo from minced tumors without feeder cells in the modified TIL therapy regimen. Patients underwent low-dose cyclophosphamide lymphodepletion followed by TIL infusion without intravenous IL-2. The primary endpoint was safety; the secondary endpoints included objective response rate, duration of response, and T cell persistence.

RESULTS

In matched patient-derived xenografts (PDX) models, homologous TILs efficiently reduced tumor size (p < 0.0001) and underwent IL-2 absence in vivo. In the clinical section, all enrolled patients received TIL infusion using a modified TIL therapy regimen successfully with a manageable safety profile. Five (36%, 95% CI 16.3-61.2) out of 14 evaluable patients experienced objective responses, and three complete responses were ongoing at 19.5, 15.4, and 5.2 months, respectively. Responders had longer overall survival (OS) than non-responders (p = 0.036). Infused TILs showed continuous proliferation and long-term persistence in all patients and showed greater proliferation in responders which was indicated by the Morisita overlap index (MOI) of TCR clonotypes between infused TILs and peripheral T cells on day 14 (p = 0.004) and day 30 (p = 0.004). Higher alteration of the CD8+/CD4+ ratio on day 14 indicated a longer OS (p = 0.010).

CONCLUSIONS

Our modified TIL therapy regimen demonstrated manageable safety, and TILs could survive and proliferate without IL-2 intravenous administration, showing potent efficacy in patients with advanced gynecologic cancer.

TRIAL REGISTRATION

NCT04766320, Jan 04, 2021.

TIM-3 Expression on Dendritic Cells in Colorectal Cancer

TIM-3 was originally identified as a negative regulator of helper T cells and is expressed on dendritic cells (DCs). Since the inhibition of TIM-3 on DCs has been suggested to enhance T cell-mediated anti-tumor immunity, we examined its expression on DCs within the tumor microenvironment (TME) in colorectal cancer (CRC) using transcriptomic data from a public database (n = 592) and immunohistochemical evaluations from our cohorts of CRC (n = 115). The expression of TIM-3 on DCs in vitro was examined by flow cytometry, while the expression of its related molecules, cGAS and STING, on immature and mature DCs was assessed by Western blotting. The expression of HAVCR2 (TIM-3) was strongly associated with the infiltration of DCs within the TME of CRC. Immunohistochemical staining of clinical tissue samples revealed that tumor-infiltrating DCs expressed TIM-3; however, their number at the tumor-invasive front significantly decreased with stage progression. TIM-3 expression was higher on immature DCs than on mature DCs from several different donors (n = 6). Western blot analyses showed that the expression of STING was higher on mature DCs than on immature DCs, which was opposite to that of TIM-3. We demonstrated that TIM-3 was highly expressed on tumor-infiltrating DCs of CRC and that its expression was higher on immature DCs than on mature DCs.

The impact of the P2X7 receptor on the tumor immune microenvironment and its effects on tumor progression

Cancer is a significant global health concern, and finding effective methods to treat it has been a focus of scientific research. It has been discovered that the growth, invasion, and metastasis of tumors are closely related to the environment in which they exist, known as the tumor microenvironment (TME). The immune response interacting with the tumor occurring within the TME constitutes the tumor immune microenvironment, and the immune response can lead to anti-tumor and pro-tumor outcomes and has shown tremendous potential in immunotherapy. A channel called the P2X7 receptor (P2X7R) has been identified within the TME. It is an ion channel present in various immune cells and tumor cells, and its activation can lead to inflammation, immune responses, angiogenesis, immunogenic cell death, and promotion of tumor development. This article provides an overview of the structure, function, and pharmacological characteristics of P2X7R. We described the concept and components of tumor immune microenvironment and the influence immune components has on tumors. We also outlined the impact of P2X7R regulation and how it affects the development of tumors and summarized the effects of drugs targeting P2X7R on tumor progression, both past and current, assisting researchers in treating tumors using P2X7R as a target.

Phase 1 first-in-human dose-escalation study of ANV419 in patients with relapsed/refractory advanced solid tumors

Patients with advanced cancer, previously treated with immune checkpoint blockade therapy, may retain residual treatment when undergoing the initial infusion of experimental monotherapy in phase 1 clinical trials. ANV419, an antibody-cytokine fusion protein, combines interleukin-2 (IL-2) with an anti-IL-2 monoclonal antibody, aiming to stimulate the expansion of CD8 T and natural killer lymphocytes while restricting regulatory T lymphocytes. In the recent publication of the phase 1 dose escalation study of ANV419, a notable gap exists in detailed information regarding patients' prior antitumoral treatments, specifically programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) targeted monoclonal antibodies. Some patients likely retained residual anti-PD-1/PD-L1 monoclonal antibodies, potentially influencing the outcomes of ANV419. In a separate clinical cohort, we retrospectively measured the residual concentration of nivolumab and pembrolizumab, revealing persistent serum concentrations of anti-PD-1/PD-L1 antibodies even months after treatment cessation. This underscores the importance of comprehensively documenting prior immunotherapy details in clinical trials. Such information is crucial for understanding potential interactions that may impact both immunological and clinical effects.

Cellular metabolism regulates the differentiation and function of T-cell subsets

T cells are an important component of adaptive immunity and protect the host from infectious diseases and cancers. However, uncontrolled T cell immunity may cause autoimmune disorders. In both situations, antigen-specific T cells undergo clonal expansion upon the engagement and activation of antigens. Cellular metabolism is reprogrammed to meet the increase in bioenergetic and biosynthetic demands associated with effector T cell expansion. Metabolites not only serve as building blocks or energy sources to fuel cell growth and expansion but also regulate a broad spectrum of cellular signals that instruct the differentiation of multiple T cell subsets. The realm of immunometabolism research is undergoing swift advancements. Encapsulating all the recent progress within this concise review in not possible. Instead, our objective is to provide a succinct introduction to this swiftly progressing research, concentrating on the metabolic intricacies of three pivotal nutrient classes-lipids, glucose, and amino acids-in T cells. We shed light on recent investigations elucidating the roles of these three groups of metabolites in mediating the metabolic and immune functions of T cells. Moreover, we delve into the prospect of "editing" metabolic pathways within T cells using pharmacological or genetic approaches, with the aim of synergizing this approach with existing immunotherapies and enhancing the efficacy of antitumor and antiinfection immune responses.

Stratifying ICIs-responsive tumor microenvironment in HCC: from parsing out immune-hypoxic crosstalk to clinically applicable MRI-radiomics models

BACKGROUND

We aimed to redefine Immune checkpoint inhibitors (ICIs)-responsive "hot" TME and develop a corresponding stratification model to maximize ICIs-efficacy in Hepatocellular Carcinoma (HCC).

METHODS

Hypoxic scores were designed, and the relevance to immunotherapy responses were validated in pan-cancers through single cell analysis. Multi-omics analysis using the hypoxic scores and immune infiltrate abundance was performed to redefine the ICIs-responsive TME subtype in HCC patients from TCGA (n = 363) and HCCDB database (n = 228). The immune hypoxic stress index (IHSI) was constructed to stratify the ICIs-responsive TME subtype, with exploring biological mechanism in vitro and in vivo. MRI-radiomics models were built for clinical applicability.

RESULTS

The hypoxic scores were lower in the dominant cell-subclusters of responders in pan-cancers. The higher immune infiltrate-normoxic (HIN) subtype was redefined as the ICIs-responsive TME. Stratification of the HIN subtype using IHSI effectively identified ICIs-responders in Melanoma (n = 122) and urological cancer (n = 22). TRAF3IP3, the constituent gene of IHSI, was implicated in ICIs-relevant "immune-hypoxic" crosstalk by stimulating MAVS/IFN-I pathway under normoxic condition. MRI-radiomics models assessing TRAF3IP3 with HIF1A expression (AUC > 0.80) screened ICIs-Responders in HCC cohort (n = 75).

CONCLUSION

The hypoxic-immune stratification redefined ICIs-responsive TME and provided MRI-Radiomics models for initial ICIs-responders screening, with IHSI facilitating further identification.

Importance of CD8 Tex cell-associated gene signatures in the prognosis and immunology of osteosarcoma

As a highly aggressive bone malignancy, osteosarcoma poses a significant therapeutic challenge, especially in the setting of metastasis or recurrence. This study aimed to investigate the potential of CD8-Tex cell-associated genes as prognostic biomarkers to reveal the immunogenomic profile of osteosarcoma and guide therapeutic decisions. mRNA expression data and clinical details of osteosarcoma patients were obtained from the TCGA database (TARGET-OS dataset). The GSE21257 dataset (from the GEO database) was used as an external validation set to provide additional information on osteosarcoma specimens. 84 samples from the TARGET-OS dataset were used as the training set, and 53 samples from the GSE21257 dataset served as the external validation cohort. Univariate Cox regression analysis was utilized to identify CD8 Tex cell genes associated with prognosis. The LASSO algorithm was performed for 1000 iterations to select the best subset to form the CD8 Tex cell gene signature (TRS). Final genes were identified using the multivariate Cox regression model of the LASSO algorithm. Risk scores were calculated to categorize patients into high- and low-risk groups, and clinical differences were explored by Kaplan-Meier survival analysis to assess model performance. Prediction maps were constructed to estimate 1-, 3-, and 5 year survival rates for osteosarcoma patients, including risk scores for CD8 Texcell gene markers and clinicopathologic factors. The ssGSEA algorithm was used to assess the differences in immune function between TRS-defined high- and low-risk groups. TME and immune cell infiltration were further assessed using the ESTIMATE and CIBERSORT algorithms. To explore the relationship between immune checkpoint gene expression levels and the two risk-defined groups. A CD8 Tex cell-associated gene signature was extracted from the TISCH database and prognostic markers including two genes were developed. The high-risk group showed lower survival, and model performance was validated by ROC curves and C-index. Predictive plots were constructed to demonstrate survival estimates, combining CD8 Tex cell gene markers and clinical factors. This study provides valuable insights into the molecular and immune characteristics of osteosarcoma and offers potential avenues for advances in therapeutic approaches.

The potential role of CMC1 as an immunometabolic checkpoint in T cell immunity

T cell immunity is critical for human defensive immune response. Exploring the key molecules during the process provides new targets for T cell-based immunotherapies. CMC1 is a mitochondrial electron transport chain (ETC) complex IV chaperon protein. By establishing in-vitro cell culture system and Cmc1 gene knock out mice, we evaluated the role of CMC1 in T cell activation and differentiation. The B16-OVA tumor model was used to test the possibility of targeting CMC1 for improving T cell anti-tumor immunity. We identified CMC1 as a positive regulator in CD8+T cells activation and terminal differentiation. Meanwhile, we found that CMC1 increasingly expressed in exhausted T (Tex) cells. Genetic lost of Cmc1 inhibits the development of CD8+T cell exhaustion in mice. Instead, deletion of Cmc1 in T cells prompts cells to differentiate into metabolically and functionally quiescent cells with increased memory-like features and tolerance to cell death upon repetitive or prolonged T cell receptor (TCR) stimulation. Further, the in-vitro mechanistic study revealed that environmental lactate enhances CMC1 expression by inducing USP7, mediated stabilization and de-ubiquitination of CMC1 protein, in which a mechanism we propose here that the lactate-enriched tumor microenvironment (TME) drives CD8+TILs dysfunction through CMC1 regulatory effects on T cells. Taken together, our study unraveled the novel role of CMC1 as a T cell regulator and its possibility to be utilized for anti-tumor immunotherapy.

STAT5 is essential for inducing the suppressive subset and attenuate cytotoxicity of Vδ2+ T cells in acute myeloid leukemia

Under the sustained exposure to tumor microenvironment, effector lymphocytes may transform into the suppressive populations. γδ T cells are recognized as a crucial mediator and effector of immune surveillance and thereby a promising candidate for anti-tumor immunotherapy. Emerging clinical studies implicate that some γδ T subsets play an important role in promoting tumor progression. Our previous study identified an abnormal Vδ2+ T cells subset with regulatory features (Reg-Vδ2) in the patients with newly diagnosed acute myeloid leukemia (AML), and demonstrated that Reg-Vδ2 cells significantly suppressed the anti-AML effects of effector Vδ2 cells (Eff-Vδ2). The molecular mechanism underlying the subset transformation of Vδ2 cells remains unclear. Here, we found that the expression and activity of STAT5 were significantly induced in Reg-Vδ2 cells compared with Eff-Vδ2 cells, which was consistent with the differences found in primary Vδ2 cells between AML patients and healthy donors. In-vitro experiments further indicated that STAT5 was required for the induction of Reg-Vδ2 cells. The combined immunophenotypical and functional assays showed that blockage of STAT5 alleviated the immunosuppressive effect of Reg-Vδ2 cells on Eff-Vδ2 cells and enhanced the anti-AML capacity of Vδ2 cells from health donors and AML patients. Collectively, these results suggest that STAT5 acts as a critical regulator in the transformation of effector Vδ2 cells into a subset with immunosuppressive characteristics, providing a potential target for the improvement the efficacy of γδ T cells-based immunotherapy to treat AML and other hematologic malignancies.

ARID5A stabilizes Indoleamine 2,3-dioxygenase expression and enhances CAR T cell exhaustion in colorectal cancer

Resistance to chimeric antigen receptor (CAR) T-cell therapy remains a significant challenge in the treatment of solid tumors. This resistance is attributed to various factors, including antigen loss, immunosuppressive tumor microenvironment, and upregulated checkpoint molecules. Indoleamine 2,3-dioxygenase 1 (IDO1) is an immunosuppressive enzyme that promotes immune escape in tumors. In this study, we investigated the role of ARID5A (AT-rich interactive domain 5A) in resistance to CAR-T cell therapy. Our findings revealed that ARID5A upregulation in tumor cells induces T cell exhaustion and immune evasion. Mechanistically, ARID5A plays a crucial role in resistance to CAR-T cell therapy by stabilizing IDO1 mRNA, leading to upregulation of IDO1 expression. Elevated IDO1 expression facilitates the conversion of tryptophan to kynurenine, which contributes to CAR-T cell exhaustion. Moreover, kynurenine accumulation within CAR-T cells activates the aryl hydrocarbon receptor (AhR), further exacerbating the exhaustion phenotype. Importantly, we demonstrated that targeting the ARID5A-IDO1-AhR axis using AhR or IDO1 inhibitors effectively alleviated T cell exhaustion induced by ARID5A. These findings suggest that modulating the ARID5A-IDO1-AhR axis may represent a promising therapeutic strategy to overcome CAR T-cell therapy resistance in solid tumors and enhance treatment efficacy.

A microbially produced AhR ligand promotes a Tph1-driven tolerogenic program in multiple sclerosis

Multiple sclerosis is a debilitating autoimmune disease, characterized by chronic inflammation of the central nervous system. While the significance of the gut microbiome on multiple sclerosis pathogenesis is established, the underlining mechanisms are unknown. We found that serum levels of the microbial postbiotic tryptophan metabolite indole-3-carboxaldehyde (3-IAld) inversely correlated with disease duration in multiple sclerosis patients. Much like the host-derived tryptophan derivative L-Kynurenine, 3-IAld would bind and activate the Aryl hydrocarbon Receptor (AhR), which, in turn, controls endogenous tryptophan catabolic pathways. As a result, in peripheral lymph nodes, microbial 3-IAld, affected mast-cell tryptophan metabolism, forcing mast cells to produce serotonin via Tph1. We thus propose a protective role for AhR-mast-cell activation driven by the microbiome, whereby natural metabolites or postbiotics will have a physiological role in immune homeostasis and may act as therapeutic targets in autoimmune diseases.

Uremic toxins mediate kidney diseases: the role of aryl hydrocarbon receptor

Aryl hydrocarbon receptor (AhR) was originally identified as an environmental sensor that responds to pollutants. Subsequent research has revealed that AhR recognizes multiple exogenous and endogenous molecules, including uremic toxins retained in the body due to the decline in renal function. Therefore, AhR is also considered to be a uremic toxin receptor. As a ligand-activated transcriptional factor, the activation of AhR is involved in cell differentiation and senescence, lipid metabolism and fibrogenesis. The accumulation of uremic toxins in the body is hazardous to all tissues and organs. The identification of the endogenous uremic toxin receptor opens the door to investigating the precise role and molecular mechanism of tissue and organ damage induced by uremic toxins. This review focuses on summarizing recent findings on the role of AhR activation induced by uremic toxins in chronic kidney disease, diabetic nephropathy and acute kidney injury. Furthermore, potential clinical approaches to mitigate the effects of uremic toxins are explored herein, such as enhancing uremic toxin clearance through dialysis, reducing uremic toxin production through dietary interventions or microbial manipulation, and manipulating metabolic pathways induced by uremic toxins through controlling AhR signaling. This information may also shed light on the mechanism of uremic toxin-induced injury to other organs, and provide insights into clinical approaches to manipulate the accumulated uremic toxins.

Targeting the gut microbiota to enhance the antitumor efficacy and attenuate the toxicity of CAR-T cell therapy: a new hope?

Chimeric antigen receptor (CAR) -T cell therapy has achieved tremendous efficacy in the treatment of hematologic malignancies and represents a promising treatment regimen for cancer. Despite the striking response in patients with hematologic malignancies, most patients with solid tumors treated with CAR-T cells have a low response rate and experience major adverse effects, which indicates the need for biomarkers that can predict and improve clinical outcomes with future CAR-T cell treatments. Recently, the role of the gut microbiota in cancer therapy has been established, and growing evidence has suggested that gut microbiota signatures may be harnessed to personally predict therapeutic response or adverse effects in optimizing CAR-T cell therapy. In this review, we discuss current understanding of CAR-T cell therapy and the gut microbiota, and the interplay between the gut microbiota and CAR-T cell therapy. Above all, we highlight potential strategies and challenges in harnessing the gut microbiota as a predictor and modifier of CAR-T cell therapy efficacy while attenuating toxicity.

Sustained AhR activity programs memory fate of early effector CD8+ T cells

Identification of mechanisms that program early effector T cells to either terminal effector T (Teff) or memory T (Tm) cells has important implications for protective immunity against infections and cancers. Here, we show that the cytosolic transcription factor aryl hydrocarbon receptor (AhR) is used by early Teff cells to program memory fate. Upon antigen engagement, AhR is rapidly up-regulated via reactive oxygen species signaling in early CD8+ Teff cells, which does not affect the effector response, but is required for memory formation. Mechanistically, activated CD8+ T cells up-regulate HIF-1α to compete with AhR for HIF-1β, leading to the loss of AhR activity in HIF-1αhigh short-lived effector cells, but sustained in HIF-1αlow memory precursor effector cells (MPECs) with the help of autocrine IL-2. AhR then licenses CD8+ MPECs in a quiescent state for memory formation. These findings partially resolve the long-standing issue of how Teff cells are regulated to differentiate into memory cells.

Interleukin-2 signaling in the regulation of T cell biology in autoimmunity and cancer

Interleukin-2 (IL-2) is a critical cytokine for T cell peripheral tolerance and immunity. Here, we review how IL-2 interaction with the high-affinity IL-2 receptor (IL-2R) supports the development and homeostasis of regulatory T cells and contributes to the differentiation of helper, cytotoxic, and memory T cells. A critical element for each T cell population is the expression of CD25 (Il2rα), which heightens the receptor affinity for IL-2. Signaling through the high-affinity IL-2R also reinvigorates CD8+ exhausted T (Tex) cells in response to checkpoint blockade. We consider the molecular underpinnings reflecting how IL-2R signaling impacts these various T cell subsets and the implications for enhancing IL-2-dependent immunotherapy of autoimmunity, other inflammatory disorders, and cancer.

CD81 and CD82 expressing tumor-infiltrating lymphocytes in the NSCLC tumor microenvironment play a crucial role in T-cell activation and cytokine production

Introduction

To understand the immune system within the tumor microenvironment (TME) of non-small cell lung cancer (NSCLC), it is crucial to elucidate the characteristics of molecules associated with T cell activation.

Methods

We conducted an in-depth analysis using single-cell RNA sequencing data obtained from tissue samples of 19 NSCLC patients. T cells were classified based on the Tumor Proportion Score (TPS) within the tumor region, and molecular markers associated with activation and exhaustion were analyzed in T cells from high TPS areas.

Results

Notably, tetraspanins CD81 and CD82, belonging to the tetraspanin protein family, were found to be expressed in activated T cells, particularly in cytotoxic T cells. These tetraspanins showed strong correlations with activation and exhaustion markers. In vitro experiments confirmed increased expression of CD81 and CD82 in IL-2-stimulated T cells. T cells were categorized into CD81highCD82high and CD81lowCD82low groups based on their expression levels, with CD81highCD82high T cells exhibiting elevated activation markers such as CD25 and CD69 compared to CD81lowCD82low T cells. This trend was consistent across CD3+, CD8+, and CD4+ T cell subsets. Moreover, CD81highCD82high T cells, when stimulated with anti-CD3, demonstrated enhanced secretion of cytokines such as IFN-γ, TNF-α, and IL-2, along with an increase in the proportion of memory T cells. Bulk RNA sequencing results after sorting CD81highCD82high and CD81lowCD82low T cells consistently supported the roles of CD81 and CD82. Experiments with overexpressed CD81 and CD82 showed increased cytotoxicity against target cells.

Discussion

These findings highlight the multifaceted roles of CD81 and CD82 in T cell activation, cytokine production, memory subset accumulation, and target cell cytolysis. Therefore, these findings suggest the potential of CD81 and CD82 as promising candidates for co-stimulatory molecules in immune therapeutic strategies for cancer treatment within the intricate TME.

Comprehensive analysis of T cell exhaustion related signature for predicting prognosis and immunotherapy response in HNSCC

BACKGROUND

T cell exhaustion (TEX) signifies a condition of T cell disorder which implicate the therapeutic benefits and prognostic significance in patients with cancer. However, its role in the Head and Neck Squamous Carcinoma (HNSCC) remains incompletely understood.

METHODS

The detailed data of HNSCC samples were obtained from The Cancer Genome Atlas (TCGA) database and two Gene Expression Omnibus (GEO) datasets. We computed the expression scores of four TEX-related pathways and detected gene modules closely linked to these pathways, indicating prognostic significance. Following this, regression analyses were performed to select eight genes for the development of a predictive signature. The predictive capacity of this signature was evaluated. Additionally, we examined the relationships between TEX-related signature risk scores and the effectiveness of immunotherapy as well as drug sensitivity.

RESULTS

A novel prognostic model, comprising eight TEX-related genes, was established for patients with HNSCC. The prognostic value was further confirmed using additional GEO datasets: GSE65858 and GSE27020. This signature enables the stratification of patients into high- and low- risk groups, each showing distinct survival outcomes and responsiveness to immunotherapy. The low-risk group demonstrated improved prognosis and enhanced efficacy of immunotherapy. In addition, AZD6482, TAF1, Ribociclib, LGK974, PF4708671 and other drugs showed increased sensitivity in the high-risk group based on drug sensitivity values, offering tailored therapeutic recommendations for individuals with various risks profiles.

CONCLUSION

In conclusion, we developed a novel T cell exhaustion-associated signature, which holds considerable predictive value for both the prognosis of patients with HNSCC and the effectiveness of tumor immunotherapy.