CD28 costimulation drives tumor-infiltrating T cell glycolysis to promote inflammation

METTL14 Mediates Glut3 m6A methylation to improve osteogenesis under oxidative stress condition

OBJECTIVES

Bone remodeling imbalance contributes to osteoporosis. Though current medications enhance osteoblast involvement in bone formation, the underlying pathways remain unclear. This study was aimed to explore the pathways involved in bone formation by osteoblasts, we investigate the protective role of glycolysis and N6-methyladenosine methylation (m6A) against oxidative stress-induced impairment of osteogenesis in MC3T3-E1 cells.

METHODS

We utilized a concentration of 200 μM hydrogen peroxide (H2O2) to establish an oxidative damage model of MC3T3-E1 cells. Subsequently, we examined the alterations in the m6A methyltransferases (METTL3, METTL14), glucose transporter proteins (GLUT1, GLUT3) and validated m6A methyltransferase overexpression in vitro and in an osteoporosis model. The osteoblast differentiation and osteogenesis-related molecules and serum bone resorption markers were measured by biochemical analysis, Alizarin Red S staining, Western blot and ELISA.

RESULTS

H2O2 treatment inhibited glycolysis and osteoblast differentiation in MC3T3-E1 cells. However, when METTL14 was overexpressed, these changes induced by H2O2 could be mitigated. Our findings indicate that METTL14 promotes GLUT3 expression via YTHDF1, leading to the modulation of various parameters in the H2O2-induced model. Similar positive effects of METTL14 on osteogenesis were observed in an ovariectomized mouse osteoporosis model.

DISCUSSION

METTL14 could serve as a potential therapeutic approach for enhancing osteoporosis treatment.

Glut3 overexpression improves environmental glucose uptake and antitumor efficacy of CAR-T cells in solid tumors

BACKGROUND

Glucose deprivation inhibits T-cell metabolism and function. Glucose levels are low in the tumor microenvironment of solid tumors and insufficient glucose uptake limits the antitumor response of T cells. Furthermore, glucose restriction can contribute to the failure of chimeric antigen receptor T (CAR-T) cell therapy for solid tumors. However, the impact of glucose restriction remains unknown in CAR-T cell therapy.

METHODS

Glucose transporters were detected and overexpressed in CAR-T cells. The impacts of glucose restriction on CAR-T cells were checked in vitro and in vivo.

RESULTS

Glucose restriction significantly decreased CAR-T cell activation, effector function, and expansion. CAR-T cells expressed high levels of the glucose transporter Glut1, which has a low affinity for glucose. Overexpression of Glut1 failed to improve CAR-T cell function under glucose-restricted conditions. In contrast, the function and antitumor potential of CAR-T cells was enhanced by the overexpression of Glut3, which has the highest affinity for glucose among the Glut transporter family and is expressed in minor parts of CAR-T cells. Glut3-overexpressing CAR-T cells demonstrated increased tumoricidal efficacy in multiple xenografts and syngenetic mouse models. Furthermore, Glut3 overexpression activated the PI3K/Akt pathway and increased OXPHOS and mitochondrial fitness.

CONCLUSIONS

We provide a direct and effective approach to enhance low glucose uptake levels by CAR-T cells and improve their antitumor efficacy against solid tumors.

PI3K/AKT/mTOR and PD‑1/CTLA‑4/CD28 pathways as key targets of cancer immunotherapy (Review)

T cells play an important role in cancer, and energy metabolism can determine both the proliferation and differentiation of T cells. The inhibition of immune checkpoint molecules programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte associated protein 4 (CTLA-4) are a promising cancer treatment. In recent years, research on CD28 has increased. Although numerous reports involve CD28 and its downstream PI3K/AKT/mTOR signaling mechanisms in T cell metabolism, they have not yet been elucidated. A literature search strategy was used for the databases PubMed, Scopus, Web of Science and Cochrane Library to ensure broad coverage of medical and scientific literature, using a combination of keywords including, but not limited to, 'lung cancer' and 'immunotherapy'. Therefore, the present study reviewed the interaction and clinical application of the PD-1/CTLA-4/CD28 and PI3K/AKT/mTOR pathways in T cells, aiming to provide a theoretical basis for immunotherapy in clinical cancer patients.

CD28 co-stimulation: novel insights and applications in cancer immunotherapy

Substantial progress in understanding T cell signalling, particularly with respect to T cell co-receptors such as the co-stimulatory receptor CD28, has been made in recent years. This knowledge has been instrumental in the development of innovative immunotherapies for patients with cancer, including immune checkpoint blockade antibodies, adoptive cell therapies, tumour-targeted immunostimulatory antibodies, and immunostimulatory small-molecule drugs that regulate T cell activation. Following the failed clinical trial of a CD28 superagonist antibody in 2006, targeted CD28 agonism has re-emerged as a technologically viable and clinically promising strategy for cancer immunotherapy. In this Review, we explore recent insights into the molecular functions and regulation of CD28. We describe how CD28 is central to the success of current cancer immunotherapies and examine how new questions arising from studies of CD28 as a clinical target have enhanced our understanding of its biological role and may guide the development of future therapeutic strategies in oncology.

Targeting mitochondria: restoring the antitumor efficacy of exhausted T cells

Immune checkpoint blockade therapy has revolutionized cancer treatment, but resistance remains prevalent, often due to dysfunctional tumor-infiltrating lymphocytes. A key contributor to this dysfunction is mitochondrial dysfunction, characterized by defective oxidative phosphorylation, impaired adaptation, and depolarization, which promotes T cell exhaustion and severely compromises antitumor efficacy. This review summarizes recent advances in restoring the function of exhausted T cells through mitochondria-targeted strategies, such as metabolic remodeling, enhanced biogenesis, and regulation of antioxidant and reactive oxygen species, with the aim of reversing the state of T cell exhaustion and improving the response to immunotherapy. A deeper understanding of the role of mitochondria in T cell exhaustion lays the foundation for the development of novel mitochondria-targeted therapies and opens a new chapter in cancer immunotherapy.

Multifaceted roles of mitochondria in asthma

Mitochondria are essential organelles within cells, playing various roles in numerous cellular processes, including differentiation, growth, apoptosis, energy conversion, metabolism, and cellular immunity. The phenotypic variation of mitochondria is specific to different tissues and cell types, resulting in significant differences in their function, morphology, and molecular characteristics. Asthma is a chronic, complex, and heterogeneous airway disease influenced by external factors such as environmental pollutants and allergen exposure, as well as internal factors at the tissue, cellular, and genetic levels, including lung and airway structural cells, immune cells, granulocytes, and mast cells. Therefore, a comprehensive understanding of the specific responses of mitochondria to various external environmental stimuli and internal changes are crucial for elucidating the pathogenesis of asthma. Previous research on mitochondrial-targeted therapy for asthma has primarily focused on antioxidants. Consequently, it is necessary to summarize the multifaceted roles of mitochondria in the pathogenesis of asthma to discover additional strategies targeting mitochondria in this context. In this review, our goal is to describe the changes in mitochondrial function in response to various exposure factors across different cell types and other relevant factors in the context of asthma, utilizing a new mitochondrial terminology framework that encompasses cell-dependent mitochondrial characteristics, molecular features, mitochondrial activity, function, and behavior.

Immune suppression by human thymus-derived effector Tregs relies on glucose/lactate-fueled fatty acid synthesis

Regulatory T cells (Tregs) suppress pro-inflammatory conventional T cell (Tconv) responses. As lipids impact cell signaling and function, we compare the lipid composition of CD4+ thymus-derived (t)Tregs and Tconvs. Lipidomics reveal constitutive enrichment of neutral lipids in Tconvs and phospholipids in tTregs. TNFR2-co-stimulated effector tTregs and Tconvs are both glycolytic, but only in tTregs are glycolysis and the tricarboxylic acid (TCA) cycle linked to a boost in fatty acid (FA) synthesis (FAS), supported by relevant gene expression. FA chains in tTregs are longer and more unsaturated than in Tconvs. In contrast to Tconvs, tTregs effectively use either lactate or glucose for FAS and rely on this process for proliferation. FASN and SCD1, enzymes responsible for FAS and FA desaturation, prove essential for the ability of tTregs to suppress Tconvs. These data illuminate how effector tTregs can thrive in inflamed or cancerous tissues with limiting glucose but abundant lactate levels.

Comparative Analysis of Inhibitory and Activating Immune Checkpoints PD-1, PD-L1, CD28, and CD86 in Non-Melanoma Skin Cancer

The establishment of immunotherapy applying immune checkpoint inhibitors (ICI) has provided an important new option for the treatment of solid malignant diseases. However, different tumor entities show dramatically different responses to this therapy. BCC responds worse to anti-PD-1 ICIs as compared to cSCC. Differential immune checkpoint expression could explain this discrepancy and, therefore, the aim of this study was to analyze activating and inhibitory immune checkpoints in cSCC and BCC tissues. Tissue microarrays of the invasive front as well as the tumor core of BCC and cSCC samples were used to evaluate PD-1, PD-L1, CD28, and CD86 expression and their topographic distribution profiles by chromogenic immunohistochemistry. QuPath was used to determine the labeling index. The expression of PD-1, PD-L1, and CD28 was significantly higher in both the tumor core and the invasive front of cSCC samples as compared to BCC (p < 0.001). In addition, the ratios of PD-L1/CD86 (p < 0.001) and CD28/CD86 (p < 0.001) were significantly higher in cSCC. The invasive front of both tumor entities showed higher expression levels of all immune markers compared to the tumor core in both tumor entities. The significantly higher expression of PD-1, PD-L1, and CD28 in cSCC, along with the predominance of the inhibitory ligand PD-L1 as compared to the activating CD86 in cSCC, provide a potential explanation for the better objective response rates to anti-PD-1 immunotherapy as compared to BCC. Furthermore, the predominant site of interaction between the immune system and the tumor was within the invasive front in both tumor types.

Hypothalamic SLC7A14 accounts for aging-reduced lipolysis in white adipose tissue of male mice

The central nervous system has been implicated in the age-induced reduction in adipose tissue lipolysis. However, the underlying mechanisms remain unclear. Here, we show the expression of SLC7A14 is reduced in proopiomelanocortin (POMC) neurons of aged mice. Overexpression of SLC7A14 in POMC neurons alleviates the aging-reduced lipolysis, whereas SLC7A14 deletion mimics the age-induced lipolysis impairment. Metabolomics analysis reveals that POMC SLC7A14 increased taurochenodeoxycholic acid (TCDCA) content, which mediates the SLC7A14 knockout- or age-induced WAT lipolysis impairment. Furthermore, SLC7A14-increased TCDCA content is dependent on intestinal apical sodium-dependent bile acid transporter (ASBT), which is regulated by intestinal sympathetic afferent nerves. Finally, SLC7A14 regulates the intestinal sympathetic afferent nerves by inhibiting mTORC1 signaling through inhibiting TSC1 phosphorylation. Collectively, our study suggests the function for central SLC7A14 and an upstream mechanism for the mTORC1 signaling pathway. Moreover, our data provides insights into the brain-gut-adipose tissue crosstalk in age-induced lipolysis impairment.

Phase I studies of davoceticept (ALPN-202), a PD-L1-dependent CD28 co-stimulator and dual PD-L1/CTLA-4 inhibitor, as monotherapy and in combination with pembrolizumab in advanced solid tumors (NEON-1 and NEON-2)

BACKGROUND

Davoceticept (ALPN-202) is an Fc fusion of a CD80 variant immunoglobulin domain designed to mediate programmed death-ligand 1 (PD-L1)-dependent CD28 co-stimulation while inhibiting the PD-L1 and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) checkpoints. The safety and efficacy of davoceticept monotherapy and davoceticept and pembrolizumab combination therapy in adult patients with advanced solid tumors were explored in NEON-1 and NEON-2, respectively.

METHODS

In NEON-1 (n=58), davoceticept 0.001-10 mg/kg was administered intravenous either once weekly (Q1W) or once every 3 weeks (Q3W). In NEON-2 (n=29), davoceticept was administered intravenously at 2 dose levels (0.1 or 0.3 mg/kg) Q1W or Q3W with pembrolizumab (400 mg once every 6 weeks). In both studies, primary endpoints included incidence of dose-limiting toxicities (DLT); type, incidence, and severity of adverse events (AEs) and laboratory abnormalities; and seriousness of AEs. Secondary endpoints included antitumor efficacy assessed using RECIST v1.1, pharmacokinetics, anti-drug antibodies, and pharmacodynamic biomarkers.

RESULTS

The incidence of treatment-related AEs (TRAEs) and immune-related adverse events (irAEs) was 67% (39/58) and 36% (21/58) with davoceticept monotherapy, and 62% (18/29) and 31% (9/29) with davoceticept and pembrolizumab combination, respectively. The incidence of ≥grade (Gr)3 TRAEs and ≥Gr3 irAEs was 12% (7/58) and 5% (3/58) with davoceticept monotherapy, and 24% (7/29) and 10% (3/29) with davoceticept and pembrolizumab combination, respectively. One DLT of Gr3 immune-related gastritis occurred during davoceticept monotherapy 3 mg/kg Q3W. During davoceticept combination with pembrolizumab, two Gr5 cardiac DLTs occurred; one instance each of cardiogenic shock (0.3 mg/kg Q3W, choroidal melanoma metastatic to the liver) and immune-mediated myocarditis (0.1 mg/kg Q3W, microsatellite stable metastatic colorectal adenocarcinoma), prompting early termination of both studies. Across both studies, five patients with renal cell carcinoma (RCC) exhibited evidence of clinical benefit (two partial response, three stable disease).

CONCLUSIONS

Davoceticept was generally well tolerated as monotherapy at intravenous doses up to 10 mg/kg. Evidence of clinical activity was observed with davoceticept monotherapy and davoceticept in combination with pembrolizumab, notably in RCC. However, two fatal cardiac events occurred with the combination of low-dose davoceticept and pembrolizumab. Future clinical investigation with davoceticept should not consider combination with programmed death-1-inhibitor anticancer mechanisms, until its safety profile is more fully elucidated.

TRIAL REGISTRATION NUMBER

NEON-1 (NCT04186637) and NEON-2 (NCT04920383).

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.

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.

Targeting metabolism to improve CAR-T cells therapeutic efficacy

ABSTRACT

Chimeric antigen receptor T (CAR-T) cell therapy achieved advanced progress in the treatment of hematological tumors. However, the application of CAR-T cell therapy for solid tumors still faces many challenges. Competition with tumor cells for metabolic resources in an already nutrient-poor tumor microenvironment is a major contributing cause to CAR-T cell therapy's low effectiveness. Abnormal metabolic processes are now acknowledged to shape the tumor microenvironment, which is characterized by increased interstitial fluid pressure, low pH level, hypoxia, accumulation of immunosuppressive metabolites, and mitochondrial dysfunction. These factors are important contributors to restriction of T cell proliferation, cytokine release, and suppression of tumor cell-killing ability. This review provides an overview of how different metabolites regulate T cell activity, analyzes the current dilemmas, and proposes key strategies to reestablish the CAR-T cell therapy's effectiveness through targeting metabolism, with the aim of providing new strategies to surmount the obstacle in the way of solid tumor CAR-T cell treatment.

Endogenous CD28 drives CAR T cell responses in multiple myeloma

Recent FDA approvals of chimeric antigen receptor (CAR) T cell therapy for multiple myeloma (MM) have reshaped the therapeutic landscape for this incurable cancer. In pivotal clinical trials B cell maturation antigen (BCMA) targeted, 4-1BB co-stimulated (BBζ) CAR T cells dramatically outperformed standard-of-care chemotherapy, yet most patients experienced MM relapse within two years of therapy, underscoring the need to improve CAR T cell efficacy in MM. We set out to determine if inhibition of MM bone marrow microenvironment (BME) survival signaling could increase sensitivity to CAR T cells. In contrast to expectations, blocking the CD28 MM survival signal with abatacept (CTLA4-Ig) accelerated disease relapse following CAR T therapy in preclinical models, potentially due to blocking CD28 signaling in CAR T cells. Knockout studies confirmed that endogenous CD28 expressed on BBζ CAR T cells drove in vivo anti-MM activity. Mechanistically, CD28 reprogrammed mitochondrial metabolism to maintain redox balance and CAR T cell proliferation in the MM BME. Transient CD28 inhibition with abatacept restrained rapid BBζ CAR T cell expansion and limited inflammatory cytokines in the MM BME without significantly affecting long-term survival of treated mice. Overall, data directly demonstrate a need for CD28 signaling for sustained in vivo function of CAR T cells and indicate that transient CD28 blockade could reduce cytokine release and associated toxicities.

CD8+ T cell metabolic flexibility elicited by CD28-ARS2 axis-driven alternative splicing of PKM supports antitumor immunity

Metabolic flexibility has emerged as a critical determinant of CD8+ T-cell antitumor activity, yet the mechanisms driving the metabolic flexibility of T cells have not been determined. In this study, we investigated the influence of the nuclear cap-binding complex (CBC) adaptor protein ARS2 on mature T cells. In doing so, we discovered a novel signaling axis that endows activated CD8+ T cells with flexibility of glucose catabolism. ARS2 upregulation driven by CD28 signaling reinforced splicing factor recruitment to pre-mRNAs and affected approximately one-third of T-cell activation-induced alternative splicing events. Among these effects, the CD28-ARS2 axis suppressed the expression of the M1 isoform of pyruvate kinase in favor of PKM2, a key determinant of CD8+ T-cell glucose utilization, interferon gamma production, and antitumor effector function. Importantly, PKM alternative splicing occurred independently of CD28-driven PI3K pathway activation, revealing a novel means by which costimulation reprograms glucose metabolism in CD8+ T cells.

Unlocking the potential of T-cell metabolism reprogramming: Advancing single-cell approaches for precision immunotherapy in tumour immunity

As single-cell RNA sequencing enables the detailed clustering of T-cell subpopulations and facilitates the analysis of T-cell metabolic states and metabolite dynamics, it has gained prominence as the preferred tool for understanding heterogeneous cellular metabolism. Furthermore, the synergistic or inhibitory effects of various metabolic pathways within T cells in the tumour microenvironment are coordinated, and increased activity of specific metabolic pathways generally corresponds to increased functional activity, leading to diverse T-cell behaviours related to the effects of tumour immune cells, which shows the potential of tumour-specific T cells to induce persistent immune responses. A holistic understanding of how metabolic heterogeneity governs the immune function of specific T-cell subsets is key to obtaining field-level insights into immunometabolism. Therefore, exploring the mechanisms underlying the interplay between T-cell metabolism and immune functions will pave the way for precise immunotherapy approaches in the future, which will empower us to explore new methods for combating tumours with enhanced efficacy.

Discovering the strength of immunometabolism in cancer therapy: Employing metabolic pathways to enhance immune responses

Immunometabolism, which studies cellular metabolism and immune cell function, is a possible cancer treatment. Metabolic pathways regulate immune cell activation, differentiation, and effector functions, crucial to tumor identification and elimination. Immune evasion and tumor growth can result from tumor microenvironment metabolic dysregulation. These metabolic pathways can boost antitumor immunity. This overview discusses immune cell metabolism, including glycolysis, oxidative phosphorylation, amino acid, and lipid metabolism. Amino acid and lipid metabolic manipulations may improve immune cell activity and antitumor immunity. Combination therapy using immunometabolism-based strategies may enhance therapeutic efficacy. The complexity of the metabolic network, biomarker development, challenges, and future approaches are all covered, along with a summary of case studies demonstrating the effectiveness of immunometabolism-based therapy. Metabolomics, stable isotope tracing, single-cell analysis, and computational modeling are also reviewed for immunometabolism research. Personalized and combination treatments are considered. This review adds to immunometabolism expertise and sheds light on metabolic treatments' ability to boost cancer treatment immunological response. Also, in this review, we discussed the immune response in cancer treatment and altering metabolic pathways to increase the immune response against malignancies.

Engaging stimulatory immune checkpoint interactions in the tumour immune microenvironment of primary liver cancers - how to push the gas after having released the brake

Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) are the first and second most common primary liver cancer (PLC). For decades, systemic therapies consisting of tyrosine kinase inhibitors (TKIs) or chemotherapy have formed the cornerstone of treating advanced-stage HCC and CCA, respectively. More recently, immunotherapy using immune checkpoint inhibition (ICI) has shown anti-tumour reactivity in some patients. The combination regimen of anti-PD-L1 and anti-VEGF antibodies has been approved as new first-line treatment of advanced-stage HCC. Furthermore, gemcibatine plus cisplatin (GEMCIS) with an anti-PD-L1 antibody is awaiting global approval for the treatment of advanced-stage CCA. As effective anti-tumour reactivity using ICI is achieved in a minor subset of both HCC and CCA patients only, alternative immune strategies to sensitise the tumour microenvironment of PLC are waited for. Here we discuss immune checkpoint stimulation (ICS) as additional tool to enhance anti-tumour reactivity. Up-to-date information on the clinical application of ICS in onco-immunology is provided. This review provides a rationale of the application of next-generation ICS either alone or in combination regimen to potentially enhance anti-tumour reactivity in PLC patients.

Construction of an immune-related risk score signature for gastric cancer based on multi-omics data

Early identification of gastric cancer (GC) is associated with a superior survival rate compared to advanced GC. However, the poor specificity and sensitivity of traditional biomarkers suggest the importance of identifying more effective biomarkers. This study aimed to identify novel biomarkers for the prognosis of GC and construct a risk score (RS) signature based on these biomarkers, with to validation of its predictive performance. We used multi-omics data from The Cancer Genome Atlas to analyze the significance of differences in each omics data and combined the data using Fisher's method. Hub genes were subsequently subjected to univariate Cox and LASSO regression analyses and used to construct the RS signature. The RS of each patient was calculated, and the patients were divided into two subgroups according to the RS. The RS signature was validated in two independent datasets from the Gene Expression Omnibus and subsequent analyses were subsequently conducted. Five immune-related genes strongly linked to the prognosis of GC patients were obtained, namely CGB5, SLC10A2, THPO, PDGFRB, and APOD. The results revealed significant differences in overall survival between the two subgroups (p < 0.001) and indicated the high accuracy of the RS signature. When validated in two independent datasets, the results were consistent with those in the training dataset (p = 0.003 and p = 0.001). Subsequent analyses revealed that the RS signature is independent and has broad applicability among various GC subtypes. In conclusion, we used multi-omics data to obtain five immune-related genes comprising the RS signature, which can independently and effectively predict the prognosis of GC patients with high accuracy.

CD80-Fc fusion protein as a potential cancer immunotherapy strategy

The activation of T lymphocytes is a crucial component of the immune response, and the presence of CD80, a membrane antigen, is necessary for T-cell activation. CD80 is usually expressed on antigen-presenting cells (APCs), which can interact with cluster of differentiation 28 (CD28) or programmed cell death ligand 1 (PD-L1) to promote T-cell proliferation, differentiation and function by activating costimulatory signal or blocking inhibitory signal. Simultaneously, CD80 on the APCs also interacts with cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) on the surface of T cells to suppress the response of specific effector T cells, particularly in the context of persistent antigenic stimulation. Due to the pivotal role of CD80 in the immune response, the CD80-Fc fusion protein has emerged as a promising approach for cancer immunotherapy. This review primarily focused on the crucial role of CD80 in the cancer immunotherapy. We also reviewed the current advancements in the research of CD80-Fc fusion proteins. Finally, we deliberated on the challenges encountered by CD80-Fc fusion proteins and proposed the potential strategies that could yield the benefits for patients.

Single cell dynamics of tumor specificity vs bystander activity in CD8+ T cells define the diverse immune landscapes in colorectal cancer

CD8+ T cell activation via immune checkpoint blockade (ICB) is successful in microsatellite instable (MSI) colorectal cancer (CRC) patients. By comparison, the success of immunotherapy against microsatellite stable (MSS) CRC is limited. Little is known about the most critical features of CRC CD8+ T cells that together determine the diverse immune landscapes and contrasting ICB responses. Hence, we pursued a deep single cell mapping of CRC CD8+ T cells on transcriptomic and T cell receptor (TCR) repertoire levels in a diverse patient cohort, with additional surface proteome validation. This revealed that CRC CD8+ T cell dynamics are underscored by complex interactions between interferon-γ signaling, tumor reactivity, TCR repertoire, (predicted) TCR antigen-specificities, and environmental cues like gut microbiome or colon tissue-specific 'self-like' features. MSI CRC CD8+ T cells showed tumor-specific activation reminiscent of canonical 'T cell hot' tumors, whereas the MSS CRC CD8+ T cells exhibited tumor unspecific or bystander-like features. This was accompanied by inflammation reminiscent of 'pseudo-T cell hot' tumors. Consequently, MSI and MSS CRC CD8+ T cells showed overlapping phenotypic features that differed dramatically in their TCR antigen-specificities. Given their high discriminating potential for CD8+ T cell features/specificities, we used the single cell tumor-reactive signaling modules in CD8+ T cells to build a bulk tumor transcriptome classification for CRC patients. This "Immune Subtype Classification" (ISC) successfully distinguished various tumoral immune landscapes that showed prognostic value and predicted immunotherapy responses in CRC patients. Thus, we deliver a unique map of CRC CD8+ T cells that drives a novel tumor immune landscape classification, with relevance for immunotherapy decision-making.

Signaling via a CD28/CD40 chimeric costimulatory antigen receptor (CoStAR™), targeting folate receptor alpha, enhances T cell activity and augments tumor reactivity of tumor infiltrating lymphocytes

Transfer of autologous tumor infiltrating lymphocytes (TIL) to patients with refractory melanoma has shown clinical efficacy in a number of trials. However, extending the clinical benefit to patients with other cancers poses a challenge. Inefficient costimulation in the tumor microenvironment can lead to T cell anergy and exhaustion resulting in poor anti-tumor activity. Here, we describe a chimeric costimulatory antigen receptor (CoStAR) comprised of FRα-specific scFv linked to CD28 and CD40 intracellular signaling domains. CoStAR signaling alone does not activate T cells, while the combination of TCR and CoStAR signaling enhances T cell activity resulting in less differentiated T cells, and augmentation of T cell effector functions, including cytokine secretion and cytotoxicity. CoStAR activity resulted in superior T cell proliferation, even in the absence of exogenous IL-2. Using an in vivo transplantable tumor model, CoStAR was shown to improve T cell survival after transfer, enhanced control of tumor growth, and improved host survival. CoStAR could be reliably engineered into TIL from multiple tumor indications and augmented TIL activity against autologous tumor targets both in vitro and in vivo. CoStAR thus represents a general approach to improving TIL therapy with synthetic costimulation.

Mitochondrial Dynamics and Cristae Shape Changes During Metabolic Reprogramming

Significance: The architecture of the mitochondrial network and cristae critically impact cell differentiation and identity. Cells undergoing metabolic reprogramming to aerobic glycolysis (Warburg effect), such as immune cells, stem cells, and cancer cells, go through controlled modifications in mitochondrial architecture, which is critical for achieving the resulting cellular phenotype. Recent Advances: Recent studies in immunometabolism have shown that the manipulation of mitochondrial network dynamics and cristae shape directly affects T cell phenotype and macrophage polarization through altering energy metabolism. Similar manipulations also alter the specific metabolic phenotypes that accompany somatic reprogramming, stem cell differentiation, and cancer cells. The modulation of oxidative phosphorylation activity, accompanied by changes in metabolite signaling, reactive oxygen species generation, and adenosine triphosphate levels, is the shared underlying mechanism. Critical Issues: The plasticity of mitochondrial architecture is particularly vital for metabolic reprogramming. Consequently, failure to adapt the appropriate mitochondrial morphology often compromises the differentiation and identity of the cell. Immune, stem, and tumor cells exhibit striking similarities in their coordination of mitochondrial morphology with metabolic pathways. However, although many general unifying principles can be observed, their validity is not absolute, and the mechanistic links thus need to be further explored. Future Directions: Better knowledge of the molecular mechanisms involved and their relationships to both mitochondrial network and cristae morphology will not only further deepen our understanding of energy metabolism but may also contribute to improved therapeutic manipulation of cell viability, differentiation, proliferation, and identity in many different cell types. Antioxid. Redox Signal. 39, 684-707.

Tumor microenvironmental nutrients, cellular responses, and cancer

Over the last two decades, the rapidly expanding field of tumor metabolism has enhanced our knowledge of the impact of nutrient availability on metabolic reprogramming in cancer. Apart from established roles in cancer cells themselves, various nutrients, metabolic enzymes, and stress responses are key to the activities of tumor microenvironmental immune, fibroblastic, endothelial, and other cell types that support malignant transformation. In this article, we review our current understanding of how nutrient availability affects metabolic pathways and responses in both cancer and "stromal" cells, by dissecting major examples and their regulation of cellular activity. Understanding the relationship of nutrient availability to cellular behaviors in the tumor ecosystem will broaden the horizon of exploiting novel therapeutic vulnerabilities in cancer.

Tumor aerobic glycolysis confers immune evasion through modulating sensitivity to T cell-mediated bystander killing via TNF-α

Metabolic reprogramming toward glycolysis is a hallmark of cancer malignancy. The molecular mechanisms by which the tumor glycolysis pathway promotes immune evasion remain to be elucidated. Here, by performing genome-wide CRISPR screens in murine tumor cells co-cultured with cytotoxic T cells (CTLs), we identified that deficiency of two important glycolysis enzymes, Glut1 (glucose transporter 1) and Gpi1 (glucose-6-phosphate isomerase 1), resulted in enhanced killing of tumor cells by CTLs. Mechanistically, Glut1 inactivation causes metabolic rewiring toward oxidative phosphorylation, which generates an excessive amount of reactive oxygen species (ROS). Accumulated ROS potentiate tumor cell death mediated by tumor necrosis factor alpha (TNF-α) in a caspase-8- and Fadd-dependent manner. Genetic and pharmacological inactivation of Glut1 sensitizes tumors to anti-tumor immunity and synergizes with anti-PD-1 therapy through the TNF-α pathway. The mechanistic interplay between tumor-intrinsic glycolysis and TNF-α-induced killing provides new therapeutic strategies to enhance anti-tumor immunity.

Sustained CD28 costimulation is required for self-renewal and differentiation of TCF-1+ PD-1+ CD8 T cells

During persistent antigen stimulation, such as in chronic infections and cancer, CD8 T cells differentiate into a hypofunctional programmed death protein 1-positive (PD-1+) exhausted state. Exhausted CD8 T cell responses are maintained by precursors (Tpex) that express the transcription factor T cell factor 1 (TCF-1) and high levels of the costimulatory molecule CD28. Here, we demonstrate that sustained CD28 costimulation is required for maintenance of antiviral T cells during chronic infection. Low-level CD28 engagement preserved mitochondrial fitness and self-renewal of Tpex, whereas stronger CD28 signaling enhanced glycolysis and promoted Tpex differentiation into TCF-1neg exhausted CD8 T cells (Tex). Furthermore, enhanced differentiation by CD28 engagement did not reduce the Tpex pool. Together, these findings demonstrate that continuous CD28 engagement is needed to sustain PD-1+ CD8 T cells and suggest that increasing CD28 signaling promotes Tpex differentiation into more functional effector-like Tex, possibly without compromising long-term responses.

Immunogenicity in renal cell carcinoma: shifting focus to alternative sources of tumour-specific antigens

Renal cell carcinoma (RCC) comprises a group of malignancies arising from the kidney with unique tumour-specific antigen (TSA) signatures that can trigger cytotoxic immunity. Two classes of TSAs are now considered potential drivers of immunogenicity in RCC: small-scale insertions and deletions (INDELs) that result in coding frameshift mutations, and activation of human endogenous retroviruses. The presence of neoantigen-specific T cells is a hallmark of solid tumours with a high mutagenic burden, which typically have abundant TSAs owing to non-synonymous single nucleotide variations within the genome. However, RCC exhibits high cytotoxic T cell reactivity despite only having an intermediate non-synonymous single nucleotide variation mutational burden. Instead, RCC tumours have a high pan-cancer proportion of INDEL frameshift mutations, and coding frameshift INDELs are associated with high immunogenicity. Moreover, cytotoxic T cells in RCC subtypes seem to recognize tumour-specific endogenous retrovirus epitopes, whose presence is associated with clinical responses to immune checkpoint blockade therapy. Here, we review the distinct molecular landscapes in RCC that promote immunogenic responses, discuss clinical opportunities for discovery of biomarkers that can inform therapeutic immune checkpoint blockade strategies, and identify gaps in knowledge for future investigations.

Multifactorial Distress, the Warburg Effect, and Respiratory and pH Imbalance in Cancer Development

Oncogenes are thought to play an important role in aberrant regulation of growth factors, which is believed to be an initiation event of carcinogenesis. However, recent genetic and pharmacological studies have shown that the Warburg effect (WE) is needed for tumour growth. It refers to extensively studied aerobic glycolysis over the past decade, although its impact on cancer remains unclear. Meanwhile, a large body of evidence has indicated that oxidative stress (OS) is connected with the occurrence and progression of various forms of cancer. Psychosocial factors (PSF), such as chronic depression, sadness, stressful life experiences, stress-prone personality, and emotional distress or poor quality of life affect the immune system and contribute to cancer outcomes. Here, we examine the relationship between WE, OS, PSF, metal ions, other carcinogens, and the development of different cancers from the viewpoint of physiological and biochemical mechanisms.

Shutting off the fuel supply to target metabolic vulnerabilities in multiple myeloma

Pathways that govern cellular bioenergetics are deregulated in tumor cells and represent a hallmark of cancer. Tumor cells have the capacity to reprogram pathways that control nutrient acquisition, anabolism and catabolism to enhance their growth and survival. Tumorigenesis requires the autonomous reprogramming of key metabolic pathways that obtain, generate and produce metabolites from a nutrient-deprived tumor microenvironment to meet the increased bioenergetic demands of cancer cells. Intra- and extracellular factors also have a profound effect on gene expression to drive metabolic pathway reprogramming in not only cancer cells but also surrounding cell types that contribute to anti-tumor immunity. Despite a vast amount of genetic and histologic heterogeneity within and between cancer types, a finite set of pathways are commonly deregulated to support anabolism, catabolism and redox balance. Multiple myeloma (MM) is the second most common hematologic malignancy in adults and remains incurable in the vast majority of patients. Genetic events and the hypoxic bone marrow milieu deregulate glycolysis, glutaminolysis and fatty acid synthesis in MM cells to promote their proliferation, survival, metastasis, drug resistance and evasion of immunosurveillance. Here, we discuss mechanisms that disrupt metabolic pathways in MM cells to support the development of therapeutic resistance and thwart the effects of anti-myeloma immunity. A better understanding of the events that reprogram metabolism in myeloma and immune cells may reveal unforeseen vulnerabilities and advance the rational design of drug cocktails that improve patient survival.

Immunometabolic reprogramming, another cancer hallmark

Molecular carcinogenesis is a multistep process that involves acquired abnormalities in key biological processes. The complexity of cancer pathogenesis is best illustrated in the six hallmarks of the cancer: (1) the development of self-sufficient growth signals, (2) the emergence of clones that are resistant to apoptosis, (3) resistance to the antigrowth signals, (4) neo-angiogenesis, (5) the invasion of normal tissue or spread to the distant organs, and (6) limitless replicative potential. It also appears that non-resolving inflammation leads to the dysregulation of immune cell metabolism and subsequent cancer progression. The present article delineates immunometabolic reprogramming as a critical hallmark of cancer by linking chronic inflammation and immunosuppression to cancer growth and metastasis. We propose that targeting tumor immunometabolic reprogramming will lead to the design of novel immunotherapeutic approaches to cancer.

Metabolic programming and immune suppression in the tumor microenvironment

Increased glucose metabolism and uptake are characteristic of many tumors and used clinically to diagnose and monitor cancer progression. In addition to cancer cells, the tumor microenvironment (TME) encompasses a wide range of stromal, innate, and adaptive immune cells. Cooperation and competition between these cell populations supports tumor proliferation, progression, metastasis, and immune evasion. Cellular heterogeneity leads to metabolic heterogeneity because metabolic programs within the tumor are dependent not only on the TME cellular composition but also on cell states, location, and nutrient availability. In addition to driving metabolic plasticity of cancer cells, altered nutrients and signals in the TME can lead to metabolic immune suppression of effector cells and promote regulatory immune cells. Here we discuss how metabolic programming of cells within the TME promotes tumor proliferation, progression, and metastasis. We also discuss how targeting metabolic heterogeneity may offer therapeutic opportunities to overcome immune suppression and augment immunotherapies.

Tumor-derived extracellular vesicles in the colorectal cancer immune environment and immunotherapy

Despite significant advances in the screening, diagnosis, and treatment of colorectal cancer (CRC) immune checkpoint inhibitors (ICIs) continue to have limited utility outside of microsatellite-high disease. Given the durable response to immunotherapy seen across malignancies, increasing CRC response rates to ICI therapy is an active area of clinical research. An increasing body of work has demonstrated that tumor-derived extracellular vesicles (TEVs) are key modulators in tumor signaling and the determinants of the tumor microenvironment. Pre-clinical models have shown that TEVs are directly involved in antigen presentation and are involved in radiation-induced DNA damage signaling. Both direct and indirect modifications of these TEVs can alter CRC immunogenicity and ICI treatment response, making them attractive targets for potential therapeutic development. In addition, modified TEVs can be developed using several different mechanisms, with varied cargo including micro-RNAs and small peptide molecules. Recent work has shown strong pre-clinical evidence of injected modified TEV-induced ICI activity, with knockdown of the micro-RNA miR-424 in TEVs improving CRC immunogenicity and increasing anti-PD-1 activity in mouse models. Clinical trials are ongoing in the evaluation of modified TEVs in cancer therapy, but they appear to be a promising therapeutic target in CRC.

Mitochondria dysfunction in CD8+ T cells as an important contributing factor for cancer development and a potential target for cancer treatment: a review

CD8+ T cells play a central role in anti-tumor immunity. Naïve CD8+ T cells are active upon tumor antigen stimulation, and then differentiate into functional cells and migrate towards the tumor sites. Activated CD8+ T cells can directly destroy tumor cells by releasing perforin and granzymes and inducing apoptosis mediated by the death ligand/death receptor. They also secrete cytokines to regulate the immune system against tumor cells. Mitochondria are the central hub of metabolism and signaling, required for polarization, and migration of CD8+ T cells. Many studies have demonstrated that mitochondrial dysfunction impairs the anti-tumor activity of CD8+ T cells through various pathways. Mitochondrial energy metabolism maladjustment will cause a cellular energy crisis in CD8+ T cells. Abnormally high levels of mitochondrial reactive oxygen species will damage the integrity and architecture of biofilms of CD8+ T cells. Disordered mitochondrial dynamics will affect the mitochondrial number and localization within cells, further affecting the function of CD8+ T cells. Increased mitochondria-mediated intrinsic apoptosis will decrease the lifespan and quantity of CD8+ T cells. Excessively low mitochondrial membrane potential will cause the release of cytochrome c and apoptosis of CD8+ T cells, while excessively high will exacerbate oxidative stress. Dysregulation of mitochondrial Ca2+ signaling will affect various physiological pathways in CD8+ T cells. To some extent, mitochondrial abnormality in CD8+ T cells contributes to cancer development. So far, targeting mitochondrial energy metabolism, mitochondrial dynamics, mitochondria-mediated cell apoptosis, and other mitochondrial physiological processes to rebuild the anti-tumor function of CD8+ T cells has proved effective in some cancer models. Thus, mitochondria in CD8+ T cells may be a potential and powerful target for cancer treatment in the future.

Prognostic significance of Naples prognostic score in operable renal cell carcinoma

Background

Naples prognostic score (NPS), a novel scoring system based on nutritional and inflammatory status, is associated with prognosis in several cancers. This study aimed to evaluate the prognostic significance of preoperative NPS in patients undergoing nephrectomy.

Patients and Methods

This study retrospectively analyzed patients with renal cell carcinoma (RCC) who underwent radical or partial nephrectomy between 2010 and 2013. The clinicopathological characteristics of patients stratified by preoperative NPS were compared. Survival analysis was performed using the Kaplan–Meier method and log-rank test. Univariate and multivariate Cox proportional hazards models were used to identify independent prognostic factors. Receiver operating characteristic curves were used to evaluate prediction efficiency.

Results

A total of 638 patients with operable RCC were included. The high-NPS group (NPS group 2) was significantly associated with older age (P < 0.001), larger tumor size (P < 0.001), worse pathological T stage (P < 0.001), positive lymph node pathology (P = 0.002), higher tumor grade (P < 0.001), and greater tumor necrosis (P < 0.001). Multivariable analysis demonstrated that the high-NPS subgroup had significantly worse overall survival (OS) [hazard ratio (HR): 2.25, 95% confidence interval (CI): 1.45–3.50, P < 0.001] and progression-free survival (PFS) (HR: 2.26, 95% CI: 1.48–3.44, P < 0.001). Among several preoperative scoring systems, NPS had the strongest discriminatory power for predicting OS and PFS.

Conclusion

Preoperative NPS can serve as a simple novel risk stratification tool to optimize the prognosis of patients with operable RCC. Further prospective and large-scale studies are needed to validate our findings.

Enforcing GLUT3 expression in CD8+ T cells improves fitness and tumor control by promoting glucose uptake and energy storage

Despite the tremendous success of adoptive T-cell therapies (ACT) in fighting certain hematologic malignancies, not all patients respond, a proportion experience relapse, and effective ACT of most solid tumors remains elusive. In order to improve responses to ACT suppressive barriers in the solid tumor microenvironment (TME) including insufficient nutrient availability must be overcome. Here we explored how enforced expression of the high-affinity glucose transporter GLUT3 impacted tumor-directed T cells. Overexpression of GLUT3 in primary murine CD8+ T cells enhanced glucose uptake and increased glycogen and fatty acid storage, and was associated with increased mitochondrial fitness, reduced ROS levels, higher abundance of the anti-apoptotic protein Mcl-1, and better resistance to stress. Importantly, GLUT3-OT1 T cells conferred superior control of B16-OVA melanoma tumors and, in this same model, significantly improved survival. Moreover, a proportion of treated mice were cured and protected from re-challenge, indicative of long-term T cell persistence and memory formation. Enforcing expression of GLUT3 is thus a promising strategy to improve metabolic fitness and sustaining CD8+ T cell effector function in the context of ACT.

Comprehensive Analysis of the Role of SLC2A3 on Prognosis and Immune Infiltration in Head and Neck Squamous Cell Carcinoma

Background. SLC2A3 is upregulated in various cancer types and promotes proliferation, invasion, and metabolism. However, its role in the prognosis and immune regulation of head and neck squamous cell carcinoma (HNSCC) is still obscure. This study is aimed at exploring the prognostic and immunotherapeutic potential of SLC2A3 in HNSCC. Methods. All data were downloaded from TCGA database and integrated via R software. SLC2A3 expression was evaluated using R software, TIMER, CPTAC, and HPA databases. The association between SLC2A3 expression and clinicopathologic characteristics was assessed by R software. The effect of SLC2A3 on survival was analyzed by R software and Kaplan-Meier Plotter. Genomic alterations in SLC2A3 were investigated using the cBioPortal database. Coexpression of SLC2A3 was studied using LinkedOmics and STRING, and enrichment analyses were performed with R software. The relationship between SLC2A3 expression and immune infiltration was determined using TIMER and TISIDB databases. Immune checkpoints and ESTIMATE score were analyzed via the SangerBox database. Results. SLC2A3 expression was upregulated in HNSCC tissues compared to normal tissues. It was significantly related to TNM stage, histological grade, and alcohol history. High SLC2A3 expression was associated with poor prognosis in HNSCC. Coexpression analysis indicated that SLC2A3 mostly participated in the HIF-1 signaling pathway and glycolysis. Furthermore, SLC2A3 expression strongly correlated with tumor-infiltrating lymphocytes in HNSCC. Conclusion. SLC2A3 could serve as a potential prognostic biomarker for tumor immune infiltration in HNSCC.

Transcriptomic Correlates of Tumor Cell PD-L1 Expression and Response to Nivolumab Monotherapy in Metastatic Clear Cell Renal Cell Carcinoma

PURPOSE

PD-L1 expression on tumor cells (TC) is associated with response to anti-PD-1-based therapies in some tumor types, but its significance in clear cell renal cell carcinoma (ccRCC) is uncertain. We leveraged tumor heterogeneity to identify molecular correlates of TC PD-L1 expression in ccRCC and assessed their role in predicting response to anti-PD-1 monotherapy.

EXPERIMENTAL DESIGN

RNA sequencing was performed on paired TC PD-L1 positive and negative areas isolated from eight ccRCC tumors and transcriptomic features associated with PD-L1 status were identified. A cohort of 232 patients with metastatic ccRCC from the randomized CheckMate-025 (CM-025) trial was used to confirm the findings and correlate transcriptomic profiles with clinical outcomes.

RESULTS

In both the paired samples and the CM-025 cohort, TC PD-L1 expression was associated with combined overexpression of immune- and cell proliferation-related pathways, upregulation of T-cell activation signatures, and increased tumor-infiltrating immune cells. In the CM-025 cohort, TC PD-L1 expression was not associated with clinical outcomes. A molecular RCC subtype characterized by combined overexpression of immune- and cell proliferation-related pathways (previously defined by unsupervised clustering of transcriptomic data) was enriched in TC PD-L1 positive tumors and displayed longer progression-free survival (HR, 0.32; 95% confidence interval, 0.13-0.83) and higher objective response rate (30% vs. 0%, P = 0.04) on nivolumab compared with everolimus.

CONCLUSIONS

Both TC-extrinsic (immune-related) and TC-intrinsic (cell proliferation-related) mechanisms are likely intertwined in the regulation of TC PD-L1 expression in ccRCC. The quantitation of these transcriptional programs may better predict benefit from anti-PD-1-based therapy compared with TC PD-L1 expression alone in ccRCC.

Mechanism of tonifying-kidney Chinese herbal medicine in the treatment of chronic heart failure

According to traditional Chinese medicine (TCM), chronic heart failure has the basic pathological characteristics of “heart-kidney yang deficiency.” Chronic heart failure with heart- and kidney-Yang deficiency has good overlap with New York Heart Association (NYHA) classes III and IV. Traditional Chinese medicine classical prescriptions for the treatment of chronic heart failure often take “warming and tonifying kidney-Yang” as the core, supplemented by herbal compositions with functions of “promoting blood circulation and dispersing blood stasis.” Nowadays, there are still many classical and folk prescriptions for chronic heart failure treatment, such as Zhenwu decoction, Bushen Huoxue decoction, Shenfu decoction, Sini decoction, as well as Qili Qiangxin capsule. This review focuses on classical formulations and their active constituents that play a key role in preventing chronic heart failure by suppressing inflammation and modulating immune and neurohumoral factors. In addition, given that mitochondrial metabolic reprogramming has intimate relation with inflammation, cardiac hypertrophy, and fibrosis, the regulatory role of classical prescriptions and their active components in metabolic reprogramming, including glycolysis and lipid β-oxidation, is also presented. Although the exact mechanism is unknown, the classical TCM prescriptions still have good clinical effects in treating chronic heart failure. This review will provide a modern pharmacological explanation for its mechanism and offer evidence for clinical medication by combining TCM syndrome differentiation with chronic heart failure clinical stages.

Loss of CD47 alters CD8+ T cell activation in vitro and immunodynamics in mice

CD47 has established roles in the immune system for regulating macrophage phagocytosis and lymphocyte activation, with growing evidence of its cell-intrinsic regulatory roles in natural killer and CD8+ T cells. CD47 limits antigen-dependent cytotoxic activities of human and murine CD8+ T cells, but its role in T cell activation kinetics remains unclear. Using in vitro and in vivo models, we show here that CD47 differentially regulates CD8+ T cell responses to short- versus long-term activation. Although CD47 was not required for T cell development in mice and early activation in vitro, short-term stimuli elevated pathogen-reactive gene expression and enhanced proliferation and the effector phenotypes of Cd47-deficient relative to Cd47-sufficient CD8+ T cells. In contrast, persistent TCR stimulation limited the effector phenotypes of Cd47 -/- CD8+ T cells and enhanced their apoptosis signature. CD8+ T cell expansion and activation in vivo induced by acute lymphocytic choriomeningitis virus (LCMV) infection did not differ in the absence of CD47. However, the frequency and effector phenotypes of Cd47-/- CD8+ T cells were constrained in chronic LCMV-infected as well as in mice bearing B16 melanoma tumors. Therefore, CD47 regulates CD8+ T cell activation, proliferation, and fitness in a context-dependent manner.

Systems Immunology Analyses of STAT1 Gain-of-Function Immune Phenotypes Reveal Heterogeneous Response to IL-6 and Broad Immunometabolic Roles for STAT1

Patients with STAT1 gain-of-function (GOF) pathogenic variants have enhanced or prolonged STAT1 phosphorylation following cytokine stimulation and exhibit increased yet heterogeneous susceptibility to infections, autoimmunity, and cancer. Although disease phenotypes are diverse and other genetic factors contribute, how STAT1 GOF affects cytokine sensitivity and cell biology remains poorly defined. In this study, we analyzed the immune and immunometabolic profiles of two patients with known pathogenic heterozygous STAT1 GOF mutation variants. A systems immunology approach of peripheral blood cells from these patients revealed major changes in multiple immune cell compartments relative to healthy adult and pediatric donors. Although many phenotypes of STAT1 GOF donors were shared, including increased Th1 cells but decreased class-switched B cells and plasmacytoid dendritic cell populations, others were heterogeneous. Mechanistically, hypersensitivity for cytokine-induced STAT1 phosphorylation in memory T cell populations was particularly evident in response to IL-6 in one STAT1 GOF patient. Immune cell metabolism directly influences cell function, and the STAT1 GOF patients shared an immunometabolic phenotype of heightened glucose transporter 1 (GLUT1) and carnitine palmitoyl transferase 1A (CPT1a) expression across multiple immune cell lineages. Interestingly, the metabolic phenotypes of the pediatric STAT1 GOF donors more closely resembled or exceeded those of healthy adult than healthy age-similar pediatric donors, which had low expression of these metabolic markers. These results define new features of STAT1 GOF patients, including a differential hypersensitivity for IL-6 and a shared increase in markers of metabolism in many immune cell types that suggests a role for STAT1 in metabolic regulation of immunity.

P2 Receptors: Novel Disease Markers and Metabolic Checkpoints in Immune Cells

Extracellular ATP (eATP) and P2 receptors are novel emerging regulators of T-lymphocyte responses. Cellular ATP is released via multiple pathways and accumulates at sites of tissue damage and inflammation. P2 receptor expression and function are affected by numerous single nucleotide polymorphisms (SNPs) associated with diverse disease conditions. Stimulation by released nucleotides (purinergic signalling) modulates several T-lymphocyte functions, among which energy metabolism. Energy metabolism, whether oxidative or glycolytic, in turn deeply affects T-cell activation, differentiation and effector responses. Specific P2R subtypes, among which the P2X7 receptor (P2X7R), are either up- or down-regulated during T-cell activation and differentiation; thus, they can be considered indexes of activation/quiescence, reporters of T-cell metabolic status and, in principle, markers of immune-mediated disease conditions.

Glucose transport in the regulation of T-cell activation: the journey may be as important as the destination

A shift in the energy-metabolism balance from oxidative phosphorylation to glycolysis is observed in several phenomena, from oncogenesis to differentiation. And this shift is not merely an indicator of the phenotypic change-an increase in glucose delivery often drives the adaption. At first blush, it seems that any route of entry should be equivalent, as long as sufficient quantities are supplied. However, an extensive study comparing the Th17 and Th1 subtypes of T cells now suggests that similar glucose transporters may not be interchangeable. Manipulation of individual transporters, or the downstream metabolites of their substrates, may afford dampening of autoimmunity potential with some degree of precision.

Impact of radiotherapy on the immune landscape in oesophageal adenocarcinoma

BACKGROUND

In the contemporary era of cancer immunotherapy, an abundance of clinical and translational studies have reported radiotherapy (RT) and immunotherapies as a viable option for immunomodulation of many cancer subtypes, with many related clinical trials ongoing. In locally advanced disease, chemotherapy or chemoradiotherapy followed by surgical excision of the tumour remain the principal treatment strategy in oesophageal adenocarcinoma (OAC), however, the use of the host immune system to improve anti-tumour immunity is rapidly garnering increased support in the curative setting.

AIM

To immunophenotype OAC patients’ immune checkpoint (IC) expression with and without radiation and evaluate the effects of checkpoint blockade on cell viability.

METHODS

In the contemporary era of cancer immunotherapy, an abundance of studies have demonstrated that combination RT and IC inhibitors (ICIs) are effective in the immunomodulation of many cancer subtypes, with many related clinical trials ongoing. Although surgical excision and elimination of tumour cells by chemotherapy or chemoradiotherapy remains the gold standard approach in OAC, the propagation of anti-tumour immune responses is rapidly garnering increased support in the curative setting. The aim of this body of work was to immunophenotype OAC patients’ IC expression with and without radiation and to establish the impact of checkpoint blockade on cell viability. This study was a hybrid combination of in vitro and ex vivo models. Quantification of serum immune proteins was performed by enzyme-linked immunosorbent assay. Flow cytometry staining was performed to evaluate IC expression for in vitro OAC cell lines and ex vivo OAC biopsies. Cell viability in the presence of radiation with and without IC blockade was assessed by a cell counting kit-8 assay.

RESULTS

We identified that conventional dosing and hypofractionated approaches resulted in increased IC expression (PD-1, PD-L1, TIM3, TIGIT) in vitro and ex vivo in OAC. There were two distinct subcohorts with one demonstrating significant upregulation of ICs and the contrary in the other cohort. Increasing IC expression post RT was associated with a more aggressive tumour phenotype and adverse features of tumour biology. The use of anti-PD-1 and anti-PD-L1 immunotherapies in combination with radiation resulted in a significant and synergistic reduction in viability of both radiosensitive and radioresistant OAC cells in vitro. Interleukin-21 (IL-21) and IL-31 significantly increased, with a concomitant reduction in IL-23 as a consequence of 4 Gray radiation. Similarly, radiation induced an anti-angiogenic tumour milieu with reduced expression of vascular endothelial growth factor-A, basic fibroblast growth factor, Flt-1 and placental growth factor.

CONCLUSION

The findings of the current study demonstrate synergistic potential for the use of ICIs and ionising radiation to potentiate established anti-tumour responses in the neoadjuvant setting and is of particular interest in those with advanced disease, adverse features of tumour biology and poor treatment responses to conventional therapies.

Drug delivery for metabolism targeted cancer immunotherapy

Drug delivery vehicles have made a great impact on cancer immunotherapies in clinics and pre-clinical research. Notably, the science of delivery of cancer vaccines and immunotherapeutics, modulating immune cell functions has inspired development of several successful companies and clinical products. Interestingly, these drug delivery modalities not only modulate the function of immune cells (often quantified at the mRNA and protein levels), but also modulate the metabolism of these cells. Specifically, cancer immunotherapy often leads to activation of different immune cells such as dendritic cells, macrophages and T cells, which is driven by energy metabolism of these cells. Recently, there has been a great excitement about interventions that can directly modulate the energy metabolism of these immune cells and thus affect their function and in turn lead to a robust cancer immune response. Here we review few strategies that have been tested in clinic and pre-clinical research for generating effective metabolism-associated cancer therapies and immunotherapies.

The glucose transporter GLUT3 controls T helper 17 cell responses through glycolytic-epigenetic reprogramming

Metabolic reprogramming is a hallmark of activated T cells. The switch from oxidative phosphorylation to aerobic glycolysis provides energy and intermediary metabolites for the biosynthesis of macromolecules to support clonal expansion and effector function. Here, we show that glycolytic reprogramming additionally controls inflammatory gene expression via epigenetic remodeling. We found that the glucose transporter GLUT3 is essential for the effector functions of Th17 cells in models of autoimmune colitis and encephalomyelitis. At the molecular level, we show that GLUT3-dependent glucose uptake controls a metabolic-transcriptional circuit that regulates the pathogenicity of Th17 cells. Metabolomic, epigenetic, and transcriptomic analyses linked GLUT3 to mitochondrial glucose oxidation and ACLY-dependent acetyl-CoA generation as a rate-limiting step in the epigenetic regulation of inflammatory gene expression. Our findings are also important from a translational perspective because inhibiting GLUT3-dependent acetyl-CoA generation is a promising metabolic checkpoint to mitigate Th17-cell-mediated inflammatory diseases.

The engineered CD80 variant fusion therapeutic davoceticept combines checkpoint antagonism with conditional CD28 costimulation for anti-tumor immunity

Despite the recent clinical success of T cell checkpoint inhibition targeting the CTLA-4 and PD-1 pathways, many patients either fail to achieve objective responses or they develop resistance to therapy. In some cases, poor responses to checkpoint blockade have been linked to suboptimal CD28 costimulation and the inability to generate and maintain a productive adaptive anti-tumor immune response. To address this, here we utilize directed evolution to engineer a CD80 IgV domain with increased PD-L1 affinity and fuse this to an immunoglobulin Fc domain, creating a therapeutic (ALPN-202, davoceticept) capable of providing CD28 costimulation in a PD-L1-dependent fashion while also antagonizing PD-1 - PD-L1 and CTLA-4–CD80/CD86 interactions. We demonstrate that by combining CD28 costimulation and dual checkpoint inhibition, ALPN-202 enhances T cell activation and anti-tumor efficacy in cell-based assays and mouse tumor models more potently than checkpoint blockade alone and thus has the potential to generate potent, clinically meaningful anti-tumor immunity in humans.

Addressing the Elephant in the Immunotherapy Room: Effector T-Cell Priming versus Depletion of Regulatory T-Cells by Anti-CTLA-4 Therapy

Cytotoxic T-lymphocyte Associated Protein 4 (CTLA-4) is an immune checkpoint molecule highly expressed on regulatory T-cells (Tregs) that can inhibit the activation of effector T-cells. Anti-CTLA-4 therapy can confer long-lasting clinical benefits in cancer patients as a single agent or in combination with other immunotherapy agents. However, patient response rates to anti-CTLA-4 are relatively low, and a high percentage of patients experience severe immune-related adverse events. Clinical use of anti-CTLA-4 has regained interest in recent years; however, the mechanism(s) of anti-CTLA-4 is not well understood. Although activating T-cells is regarded as the primary anti-tumor mechanism of anti-CTLA-4 therapies, mounting evidence in the literature suggests targeting intra-tumoral Tregs as the primary mechanism of action of these agents. Tregs in the tumor microenvironment can suppress the host anti-tumor immune responses through several cell contact-dependent and -independent mechanisms. Anti-CTLA-4 therapy can enhance the priming of T-cells by blockading CD80/86-CTLA-4 interactions or depleting Tregs through antibody-dependent cellular cytotoxicity and phagocytosis. This review will discuss proposed fundamental mechanisms of anti-CTLA-4 therapy, novel uses of anti-CTLA-4 in cancer treatment and approaches to improve the therapeutic efficacy of anti-CTLA-4.

Systems-based approaches to study immunometabolism

Technical advances at the interface of biology and computation, such as single-cell RNA-sequencing (scRNA-seq), reveal new layers of complexity in cellular systems. An emerging area of investigation using the systems biology approach is the study of the metabolism of immune cells. The diverse spectra of immune cell phenotypes, sparsity of immune cell numbers in vivo, limitations in the number of metabolites identified, dynamic nature of cellular metabolism and metabolic fluxes, tissue specificity, and high dependence on the local milieu make investigations in immunometabolism challenging, especially at the single-cell level. In this review, we define the systemic nature of immunometabolism, summarize cell- and system-based approaches, and introduce mathematical modeling approaches for systems interrogation of metabolic changes in immune cells. We close the review by discussing the applications and shortcomings of metabolic modeling techniques. With systems-oriented studies of metabolism expected to become a mainstay of immunological research, an understanding of current approaches toward systems immunometabolism will help investigators make the best use of current resources and push the boundaries of the discipline.

Metabolic Implications of Immune Checkpoint Proteins in Cancer

Expression of immune checkpoint proteins restrict immunosurveillance in the tumor microenvironment; thus, FDA-approved checkpoint inhibitor drugs, specifically PD-1/PD-L1 and CTLA-4 inhibitors, promote a cytotoxic antitumor immune response. Aside from inflammatory signaling, immune checkpoint proteins invoke metabolic reprogramming that affects immune cell function, autonomous cancer cell bioenergetics, and patient response. Therefore, this review will focus on the metabolic alterations in immune and cancer cells regulated by currently approved immune checkpoint target proteins and the effect of costimulatory receptor signaling on immunometabolism. Additionally, we explore how diet and the microbiome impact immune checkpoint blockade therapy response. The metabolic reprogramming caused by targeting these proteins is essential in understanding immune-related adverse events and therapeutic resistance. This can provide valuable information for potential biomarkers or combination therapy strategies targeting metabolic pathways with immune checkpoint blockade to enhance patient response.

The therapeutic implications of immunosuppressive tumor aerobic glycolysis

In 2011, Hanahan and Weinberg added "Deregulating Cellular Energetics" and "Avoiding Immune Destruction" to the six previous hallmarks of cancer. Since this seminal paper, there has been a growing consensus that these new hallmarks are not mutually exclusive but rather interdependent. The following review summarizes how founding genetic events for tumorigenesis ultimately increase tumor cell glycolysis, which not only supports the metabolic demands of malignancy but also provides an immunoprotective niche, promoting malignant cell proliferation, maintenance and progression. The mechanisms by which altered metabolism contributes to immune impairment are multifactorial: (1) the metabolic demands of proliferating tumor cells and activated immune cells are similar, thus creating a situation where immune cells may be in competition for key nutrients; (2) the metabolic byproducts of aerobic glycolysis directly inhibit antitumor immunity while promoting a regulatory immune phenotype; and (3) the gene programs associated with the upregulation of glycolysis also result in the generation of immunosuppressive cytokines and metabolites. From this perspective, we shed light on important considerations for the development of new classes of agents targeting cancer metabolism. These types of therapies can impair tumor growth but also pose a significant risk of stifling antitumor immunity.