Glutamine blockade induces divergent metabolic programs to overcome tumor immune evasion

A relative metabolic flux analysis model of glucose anaplerosis

Glucose provides substrate for the predominant anaplerotic pathway which involves the activity of pyruvate carboxylase (PC). PC-mediated anaplerosis has been extensively studied as a metabolic regulator in glycolytic cells during tumorigenesis and metastasis. Herein, inaccuracies in established methods to measure relative intracellular flux through PC are highlighted and a compartmentalized condensed metabolic network (CCMN) is used to resolve the total malate pool into relative contributions from PC and other sources by metabolic flux analysis (MFA) with [U-13C6]glucose tracing. Performance of the CCMN method is evaluated in breast cancer cell lines that are exposed to small molecules targeting metabolism. Across conditions and cell lines, the CCMN approach yields results nearest to an accepted gold-standard methodology, using [3-13C]glucose, or even exposes the gold standard's limitations. The CCMN method does not require a separate experiment with a much more costly and generally less informative metabolic tracer, such as [3-13C]glucose, and in some cases, may outperform its application.

Cancer stem cells amino acid metabolism: Roles, mechanisms, and intervention strategies

Cancer stem cells (CSCs) are recognized as key drivers of tumor recurrence and therapy resistance due to their capacity for self-renewal and differentiation. Amino acid metabolic reprogramming, a hallmark of cancer, underpins CSC biology. Methionine, tryptophan, and glutamine support CSC survival and the maintenance of stemness, while proline plays a role in CSC differentiation and susceptibility to cell death. Consequently, the impact of amino acid metabolism on CSCs is multifaceted and complex. This review first outlines the intrinsic amino acid metabolic features of CSCs. It then provides a comprehensive analysis of the distinct roles of various amino acids in regulating CSC biology. Additionally, strategies targeting amino acid metabolism to eliminate CSCs in clinical therapies are discussed, offering new perspectives for the development of innovative tumor-targeting approaches.

Integrative Analysis of Immune- and Metabolism-Related Genes Identifies Robust Prognostic Signature and PYCR1 as a Carcinogenic Regulator in Clear Cell Renal Cell Carcinoma

Clear cell renal cell carcinoma (ccRCC) is distinguished by metabolic irregularities and unique immunological profiles. Nevertheless, the comprehensive examination of immune and metabolic attributes within the tumor microenvironment of ccRCC remains inadequately elucidated. In this study, we identified two distinct molecular subtypes (C1 and C2) of ccRCC using the non-negative matrix factorization (NMF) algorithm. Utilizing univariate and least absolute shrinkage and selection operator (LASSO) Cox regression analyses, we developed a prognostic signature comprising eight immune- and metabolism-related genes (IMRGs) associated with the tumor microenvironment. The validation of this signature was performed using both testing and entire datasets. A nomogram was developed using IMRGs prognostic signature and various clinical parameters, including age and TNM stage. We also performed the in vitro experiments to validate the carcinogenic role of PYCR1 in ccRCC cells. Subtype C1 exhibited a more favorable prognosis and higher levels of immune cell infiltration compared to subtype C2. The AUCs of the nomogram at 1-, 3-, and 5-year intervals (AUC = 0.874, 0.820, and 0.794) were slightly higher than those of the IMRGs signature alone (AUC = 0.773, 0.755, and 0.764). The association between risk score and immune checkpoint expressions, immunophenoscore (IPS), and microsatellite instability (MSI) collectively predicted treatment efficacy accurately. Additionally, in vitro experiments confirmed the involvement of PYCR1 in promoting the aggressive behaviors of ccRCC cells, as evidenced by reduced proliferation, invasion, and enhanced apoptosis upon PYCR1 knockdown. In conclusion, the IMRGs signature shows promise in predicting prognostic risk, assessing the effectiveness of immunotherapy, and tailoring treatment for ccRCC patients.

Computational modeling of cancer cell metabolism along the catabolic-anabolic axes

Abnormal metabolism is a hallmark of cancer, this was initially recognized nearly a century ago through the observation of aerobic glycolysis in cancer cells. Mitochondrial respiration can also drive tumor progression and metastasis. However, it remains largely unclear the mechanisms by which cancer cells mix and match different metabolic modalities (oxidative/reductive) and leverage various metabolic ingredients (glucose, fatty acids, glutamine) to meet their bioenergetic and biosynthetic needs. Here, we formulate a phenotypic model for cancer metabolism by coupling master gene regulators (AMPK, HIF-1, MYC) with key metabolic substrates (glucose, fatty acids, and glutamine). The model predicts that cancer cells can acquire four metabolic phenotypes: a catabolic phenotype characterized by vigorous oxidative processes-O, an anabolic phenotype characterized by pronounced reductive activities-W, and two complementary hybrid metabolic states-one exhibiting both high catabolic and high anabolic activity-W/O, and the other relying mainly on glutamine oxidation-Q. Using this framework, we quantified gene and metabolic pathway activity by developing scoring metrics based on gene expression. We validated the model-predicted gene-metabolic pathway association and the characterization of the four metabolic phenotypes by analyzing RNA-seq data of tumor samples from TCGA. Strikingly, carcinoma samples exhibiting hybrid metabolic phenotypes are often associated with the worst survival outcomes relative to other metabolic phenotypes. Our mathematical model and scoring metrics serve as a platform to quantify cancer metabolism and study how cancer cells adapt their metabolism upon perturbations, which ultimately could facilitate an effective treatment targeting cancer metabolic plasticity.

Targeting Metabolic Reprogramming in Bladder Cancer Immunotherapy: A Precision Medicine Approach

Bladder cancer, as a highly heterogeneous malignant tumor of the urinary system, is significantly affected by tumor metabolic reprogramming in its response to immunotherapy. This review systematically elaborates on the molecular mechanisms of abnormal glucose and lipid metabolism in the bladder cancer microenvironment and immune escape, and discusses precision treatment strategies based on metabolic regulation. In the future, it will be necessary to combine spatiotemporal omics and artificial intelligence technologies to construct a multi-target intervention system for the metabolic-immune interaction network, promoting a paradigm shift in precision treatment for bladder cancer.

Metabolic pathway analysis of tumors using stable isotopes

Metabolic reprogramming is pivotal in malignant transformation and cancer progression. Tumor metabolism is shaped by a complex interplay of both intrinsic and extrinsic factors that are not yet fully elucidated. It is of great value to unravel the complex metabolic activity of tumors in patients. Metabolic flux analysis (MFA) is a versatile technique for investigating tumor metabolism in vivo, it has increasingly been applied to the assessment of metabolic activity in cancer in the past decade. Stable-isotope tracing have shown that human tumors use diverse nutrients to fuel central metabolic pathways, such as the tricarboxylic acid cycle and macromolecule synthesis. Precisely how tumors use different fuels, and the contribution of alternative metabolic pathways in tumor progression, remain areas of intensive investigation. In this review, we systematically summarize the evidence from in vivo stable- isotope tracing in tumors and describe the catabolic and anabolic processes involved in altered tumor metabolism. We also discuss current challenges and future perspectives for MFA of human cancers, which may provide new approaches in diagnosis and treatment of cancer.

Mn-coordination driven glutamine and cancer stemness dual-tailored nano-herb for high-efficiency activation of dendritic cells

Dendritic cells (DCs), as specialized antigen-presenting cells, are the commanders of the human immune cell system, directing and controlling various functions of the immune system. However, the competitive plunder of glutamine by tumor cells and the cancer cell stemness significantly impair the functional activation of DCs. Herein, we developed a Mn-coordination driven glutamine and cancer stemness dual-tailored nano-herb (HA/E-M@Purpurin NPs) for high-efficiency activation of DCs. The nano-herb is composed of ellagic acid (EA), divalent manganese ion (Mn2+), and purpurin. EA exerts an inhibitory effect on cell stemness, Mn2+ activate DCs by activating the cGAS-STING pathway, and purpurin inhibits the breakdown of glutamine, leading to a compensatory increase in glutamine content and further activating DCs. After surface modification with hyaluronic acid (HA), the nano-herb can target tumor cells and release drugs to exert corresponding effects. Taken together, our findings underscore the substantial promise of nano-herbs in overcoming cancer stemness-driven immune escape, offering a transformative approach to enhance the success of immunotherapy regimens.

Model systems to study Mycobacterium tuberculosis infections: an overview of scientific potential and impediments

Despite years of global efforts to combat tuberculosis (TB), Mycobacterium tuberculosis (Mtb), the causative agent of this disease, continues to haunt the humankind making TB elimination a distant task. To comprehend the pathogenic nuances of this organism, various in vitro, ex vivo and in vivo experimental models have been employed by researchers. This review focuses on the salient features as well as pros and cons of various model systems employed for TB research. In vitro and ex vivo macrophage infection models have been extensively used for studying Mtb physiology. Animal models have provided us with great wealth of information and have immensely contributed to the understanding of TB pathogenesis and host responses during infection. Additionally, they have been used for evaluation of anti-mycobacterial drug therapy as well as for determining the efficacy of potential vaccine candidates. Advancements in various 'omics' based approaches have enhanced our understanding about the host-pathogen interface. Although animal models have been the cornerstone to TB research, none of them is ideal that gives us a complete picture of human infection, disease and progression. Further, the review also discusses about the newer systems including three dimensional (3D)-tissue models, lung-on-chip infection model, in vitro TB granuloma model and their limitations for studying TB. Thus, converging information gained from various in vitro and ex vivo models in tandem with in vivo experiments will ultimately bridge the gap that exists in understanding human TB.

Unleashing the Full Potential of Metabolic Interventions in T-ALL

Drugs targeting metabolism have been effectively used in patients with T-cell acute lymphoblastic leukemia (T-ALL) for decades; still, the full therapeutic potential of targeting metabolism has not been completely exploited yet. Here, we highlight the critical need for metabolic biomarkers to advance precision medicine in T-ALL, explore the identification of novel metabolic vulnerabilities, and discuss the potential of targeted therapies and dietary interventions to optimize treatment outcomes.

Immunometabolism of tumor-associated macrophages: A therapeutic perspective

Tumor-associated macrophages (TAMs) play a pivotal role in the tumor microenvironment (TME), actively contributing to the formation of an immunosuppressive niche that fosters tumor progression. Consequently, there has been a growing interest in targeting TAMs as a promising avenue for cancer therapy. Recent advances in the field of immunometabolism have shed light on the influence of metabolic adaptations on macrophage physiology in the context of cancer. Here, we discuss the key metabolic pathways that shape the phenotypic diversity of macrophages. We place special emphasis on how metabolic reprogramming impacts the activation status of TAMs and their functions within the TME. Additionally, we explore alterations in TAM metabolism and their effects on phagocytosis, production of cytokines/chemokines and interaction with cytotoxic T and NK immune cells. Moreover, we examine the application of nanomedical approaches to target TAMs and assess the clinical significance of modulating the metabolism of TAMs as a strategy to develop new anti-cancer therapies. Taken together, in this comprehensive review article focusing on TAMs, we provide invaluable insights for the development of effective immunotherapeutic strategies and the enhancement of clinical outcomes for cancer patients.

Carnitine palmitoyltransferase 2 as a novel prognostic biomarker and immunoregulator in colorectal cancer

BACKGROUND

Metabolic interventions are critical for enhancing immunotherapy efficacy, but reliable metabolic targets remain absent for colorectal cancer (CRC). This study aims to investigate the interplay between metabolic and immunological factors in CRC, identify metabolic immunoregulatory molecules, and propose targets for prognostic and therapeutic applications.

METHODS

Immune infiltration and metabolic pathways in CRC were analyzed using CIBERSORT and gene set variation analyses. Cox regression identified survival-related metabolic genes, forming a metabolic-related gene prognostic index (MRGPI), which was validated through survival analysis, timeROC, GSEA, CIBERSORT, and TIDE. Hub genes in the MRGPI were assessed using enrichment and co-expression network analyses. The expression of carnitine palmitoyltransferase 2 (CPT2) was validated through multiplex immunofluorescence of tissue microarrays. While its role was examined by western blot, CCK-8 assay, flow cytometry, qRT-PCR, Elisa, chemotaxis assays, etc. RESULTS: Fatty acid oxidation (FAO) pathways were significantly altered in CRC and correlated with immune cell infiltration and patient survival. The MRGPI, constructed from five survival-related metabolic genes, demonstrated strong prognostic and immunotherapeutic predictive value. Moreover, CPT2, a key hub gene in the MRGPI, whose lower expression in plasma cells predicts unfavorable patients' survival and could be an independent prognostic indicator, while its knockout in tumor cells significantly increases the infiltrating levels of CD8+ T cells via promoting the release of CCL25.

CONCLUSION

The FAO-dominated MRGPI is a promising biomarker for predicting patient outcomes and immunotherapy response. CPT2 holds potential as a prognostic marker and therapeutic target for CRC metabolic immunotherapy.

Tumor microenvironment as niche constructed by cancer stem cells: Breaking the ecosystem to combat cancer

BACKGROUND

Cancer stem cells (CSCs) are a distinct subpopulation of cancer cells with the capacity to constantly self-renew and differentiate, and they are the main driver in the progression of cancer resistance and relapse. The tumor microenvironment (TME) constructed by CSCs is the "soil" adapted to tumor growth, helping CSCs evade immune killing, enhance their chemical resistance, and promote cancer progression.

AIM OF REVIEW

We aim to elaborate the tight connection between CSCs and immunosuppressive components of the TME. We attempt to summarize and provide a therapeutic strategy to eradicate CSCs based on the destruction of the tumor ecological niche.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review is focused on three main key concepts. First, we highlight that CSCs recruit and transform normal cells to construct the TME, which further provides ecological niche support for CSCs. Second, we describe the main characteristics of the immunosuppressive components of the TME, targeting strategies and summarize the progress of corresponding drugs in clinical trials. Third, we explore the multilevel insights of the TME to serve as an ecological niche for CSCs.

Tumour interstitial fluid-enriched phosphoethanolamine suppresses T cell function

Nutrient stress represents an important barrier for anti-tumour immunity, and tumour interstitial fluid often contains metabolites that hinder immune function. However, it is difficult to isolate the effects of tumour nutrient stress from other suppressive factors. Thus, we used a chemically defined cell culture medium based on the metabolomic profile of tumour interstitial fluid: tumour interstitial fluid medium (TIFM). Culture of CD8+ T cells in TIFM limited cell expansion and impaired CD8+ T cell effector functions upon restimulation, suggesting that tumour nutrient stress alone is sufficient to drive T cell dysfunction. We identified phosphoethanolamine (pEtn), a phospholipid intermediate, as a driver of T cell dysfunction. pEtn dampened T cell receptor signalling by depleting T cells of diacylglycerol required for T cell receptor signal transduction. The reduction of pEtn accumulation in tumours improved intratumoural T cell function and tumour control, suggesting that pEtn accumulation plays a dominant role in immunosuppression in the tumour microenvironment.

Agrimonia Pilosa Extract suppresses NSCLC growth through regulating PI3K/AKT/Bcl-2 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Agrimonia Pilosa is a traditional Chinese medicine with a long history, which is often used in clinic alone or in combined with other Chinese herb medicine to anti-inflammatory, hemostasis and treat many types cancers, including lung cancer. Agrimonia Pilosa Extract (APE) is extracted from the Agrimonia Pilosa. The potential molecular mechanism of APE on the non-small cell lung cancer remains unclear.

AIM OF THIS STUDY

The aim of this study was to investigate the molecular mechanism of APE induced apoptosis in NSCLC cells and its effect on metabolism.

MATERIALS AND METHODS

Constructed mouse transplantation tumor models to evaluate the anti-tumor effect of APE by pharmacodynamics test, histological staining and TUNEL staining. Analyzed alterations in metabolites and metabolic pathways in serum and tumor tissues from tumor-bearing mice by liquid chromatography-mass spectrometry (LC-MS)-based untargeted metabolomics. In addition, the key proteins and genes on the signaling pathway were verified by Western blotting (WB) and real-time fluorescence quantitative PCR(RT-qPCR) to reveal the anti-tumor mechanism of APE.

RESULTS

APE inhibited tumor growth by promoting apoptosis and caused metabolic changes. Specifically, they inhibited the PI3K/AKT/Bcl-2 signaling pathway while upregulating apoptotic markers such as TP53, Bax, Caspase-3, and Cytochrome c. Through metabolomics analysis of mouse serum and tumor tissue, 120 different metabolites were identified, including glutamate, PC(24:0/18:0), and LysoPE(18:0/0). Among these, 13 serum metabolites were down-regulated, 16 were up-regulated, 28 tumor metabolites were down-regulated, and 63 were up-regulated. Studies indicate that APE can regulate metabolic disorders associated with non-small cell lung cancer by influencing pathways like glycerophospholipid metabolism, amino acid metabolism, and the TCA cycle, thereby inducing cell apoptosis and leading to significant metabolic changes.

CONCLUSIONS

In this study, APE affected the apoptosis of non-small cell lung cancer cells by regulating the PI3K/AKT/Bcl-2 signal transduction pathway and various metabolic pathways thereby inhibited the growth of tumor cells.This deepened the understanding of the metabolic characteristics and apoptosis-related pathways in APE intervened NSCLC, and provided a reference for further research on the mechanism of action of its anticancer drugs.

Radiotherapy-induced alterations in tumor microenvironment: metabolism and immunity

Tumor metabolism plays a pivotal role in shaping immune responses within the tumor microenvironment influencing tumor progression, immune evasion, and the efficacy of cancer therapies. Radiotherapy has been shown to impact both tumor metabolism and immune modulation, often inducing immune activation through damage-associated molecular patterns and the STING pathway. In this study, we analyse the particular characteristics of the tumour metabolic microenvironment and its effect on the immune microenvironment. We also review the changes in the metabolic and immune microenvironment that are induced by radiotherapy, with a focus on metabolic sensitisation to the effects of radiotherapy. Our aim is to contribute to the development of research ideas in the field of radiotherapy metabolic-immunological studies.

DON-Loaded Nanodrug-T Cell Conjugates With PD-L1 Blockade for Solid Tumor Therapy

Adoptive T-cell therapy (ACT) holds significant promise for treating solid tumors but is often constrained by insufficient T-cell infiltration, survival, and functional persistence. To overcome these obstacles, we developed DON-loaded nanodrug-T cell conjugates with PD-L1 blockade, forging a dynamic mutualistic relationship between T cells and therapeutic agents. Sustained release of glutamine antagonist 6-diazo-5-oxo-L-norleucine (DON) within these conjugates continuously enhances T-cell endurance and potency by promoting memory differentiation and elevating crucial adhesion and motility genes. Concurrently, PD-L1 blocking peptides liberate T cells from immunosuppression, assisting T cells with precision toward tumor sites. This dual-targeting strategy-T cells directed at tumor antigens and peptides at PD-L1- enriches the tumor microenvironment with potent therapeutics, amplifying T cell-driven tumor destruction. Our approach effectively overcomes the critical barriers of ACT-infiltration, persistence, and efficacy-unlocking the full therapeutic potential of T-cell therapy against complex solid tumors.

Metabolic reprogramming of tumor-associated neutrophils in tumor treatment and therapeutic resistance

Tumor-associated neutrophils (TANs), pivotal immune cells within the tumor microenvironment (TME), exhibit dual potential in both pro- and anti-tumorigenic effects. These cells display remarkable heterogeneity and plasticity within the TME, adapting to hypoxic and nutrient-deprived conditions through metabolic reprogramming while critically influencing tumor progression, metastasis, and immune evasion. The metabolic reprogramming of TANs not only modulates their functional phenotypes but also reshapes tumor biological behaviors and therapeutic responses by regulating metabolic intermediates and cellular interactions within the TME. Therefore, elucidating the mechanisms underlying TANs metabolic reprogramming has significant implications for deciphering the molecular basis of tumorigenesis, identifying novel therapeutic targets, and optimizing immunotherapeutic strategies. This review systematically summarizes current knowledge regarding metabolic reprogramming mechanisms of TANs in the TME and their impact on tumor progression. We particularly focus on: 1) TAN-specific alterations in glucose, lipid, and amino acid metabolism within the TME; 2) Emerging immunotherapeutic strategies targeting TANs metabolic pathways; 3) Recent advances in understanding TAN-mediated immune evasion and therapy resistance. Furthermore, this review discusses potential challenges and corresponding solutions in targeting TANs metabolic reprogramming for therapeutic intervention, aiming to provide novel insights for advancing cancer immunotherapy.

Amino acids in cancer: Understanding metabolic plasticity and divergence for better therapeutic approaches

Metabolic reprogramming is a hallmark of malignant transformation. While initial studies in the field of cancer metabolism focused on central carbon metabolism, the field has expanded to metabolism beyond glucose and glutamine and uncovered the important role of amino acids in tumorigenesis and tumor immunity as energy sources, signaling molecules, and precursors for (epi)genetic modification. As a result of the development and application of new technologies, a multifaceted picture has emerged, showing that context-dependent heterogeneity in amino acid metabolism exists between tumors and even within distinct regions of solid tumors. Understanding the complexity and flexibility of amino acid metabolism in cancer is critical because it can influence therapeutic responses and predict clinical outcomes. This overview discusses the current findings on the heterogeneity in amino acid metabolism in cancer and how understanding the metabolic diversity of amino acids can be translated into more clinically relevant therapeutic interventions.

CRISPR/Cas9-mediated SHP-1-knockout T cells combined with simvastatin enhances anti-tumor activity in humanized-PDX HCC model

Hepatocellular carcinoma (HCC) resists immunotherapy due to its immunosuppressive microenvironment. Sarcoma homology 2 domain-containing protein tyrosine phosphatase-1 (SHP-1) inhibits T cell receptor signaling, and its pharmacological inhibition is limited by poor selectivity and membrane permeability. Here, we generated CRISPR-edited SHP-1-knockout (KO) CD8+ T cells to enhance adoptive therapy against HCC. Single-cell RNA sequencing of HCC patient T cells revealed elevated SHP-1 in exhausted subsets. SHP-1-KO T cells exhibited increased effector memory T cells (TEM) proportions and enhanced IFN-γ/Granzyme B/perforin secretion, improving cytotoxicity against HCC lines. In humanized PDX models, SHP-1-KO T cells demonstrated superior tumor-killing activity. Transcriptomics identified upregulated lipid metabolism pathways, with HMGCR as a hub gene. Combining SHP-1-KO T cells with simvastatin (HMGCR inhibitor) synergistically amplified anti-HCC efficacy. This study proposes a dual strategy combining SHP-1-targeted cell therapy and metabolic modulation to overcome immunotherapy resistance, offering a translatable approach for HCC treatment.

Immunotherapeutic strategies in head and neck cancer: challenges and opportunities

HNSCC remains a substantial health issue, with treatment options including surgery, radiation, and platinum-based chemotherapy. Unfortunately, despite progress in research, only modest gains have been made in disease control, with existing treatments resulting in significant functional and quality-of-life issues. The introduction of immunotherapy in the treatment of HNSCC has resulted in some improvements in outlook for patients and is now standard of care for populations with both recurrent and metastatic disease. However, despite the early successes, responses to immune checkpoint inhibition (ICI) remain modest to low, approaching 14%-22% objective response rates. Challenges to the effectiveness of ICI and other immunotherapies are complex, including the diverse and dynamic molecular plasticity and heterogeneity of HNSCCs; lack of immunogenic antigens; accumulated suppressive immune populations such as myeloid cells and dysfunctional T cells; nutrient depletion; and metabolic dysregulation in the HNSCC tumor microenvironment. In this Review, we explore the mechanisms responsible for immunotherapy resistance, dissect these challenges, and discuss potential opportunities for overcoming hurdles to the development of successful immunotherapy for HNSCC.

The impact of metabolic reprogramming on tertiary lymphoid structure formation: enhancing cancer immunotherapy

BACKGROUND

Cancer immunotherapy has achieved unprecedented success in the field of cancer therapy. However, its potential is constrained by a low therapeutic response rate.

MAIN BODY

Tertiary lymphoid structure (TLS) plays a crucial role in antitumor immunity and is associated with a good prognosis. Metabolic reprogramming, as a hallmark of the tumor microenvironment, can influence tumor immunity and promote the formation of follicular helper T cells and germinal centers. However, many current studies focus on the correlation between metabolism and TLS formation factors, and there is insufficient direct evidence to suggest that metabolism drives TLS formation. This review provided a comprehensive summary of the relationship between metabolism and TLS formation, highlighting glucose metabolism, lipid metabolism, amino acid metabolism, and vitamin metabolism.

CONCLUSIONS

In the future, an in-depth exploration of how metabolism affects cell interactions and the role of microorganisms in TLS will significantly advance our understanding of metabolism-enhanced antitumor immunity.

Immunogenic Cell Death and Metabolic Reprogramming in Cancer: Mechanisms, Synergies, and Innovative Therapeutic Strategies

Immunogenic cell death (ICD) is a promising cancer therapy where dying tumor cells release damage-associated molecular patterns (DAMPs) to activate immune responses. Recent research highlights the critical role of metabolic reprogramming in tumor cells, including the Warburg effect, oxidative stress, and lipid metabolism, in modulating ICD and shaping the immune microenvironment. These metabolic changes enhance immune activation, making tumors more susceptible to immune surveillance. This review explores the molecular mechanisms linking ICD and metabolism, including mitochondrial oxidative stress, endoplasmic reticulum (ER) stress, and ferroptosis. It also discusses innovative therapeutic strategies, such as personalized combination therapies, metabolic inhibitors, and targeted delivery systems, to improve ICD efficacy. The future of cancer immunotherapy lies in integrating metabolic reprogramming and immune activation to overcome tumor immune evasion, with multi-omics approaches and microbiome modulation offering new avenues for enhanced treatment outcomes.

Modulating Intracellular Autophagy and Macropinocytosis for Increased Neighboring Drug Delivery

Neighboring effects provided a valuable direction for in-depth penetration of nanoparticles into tumors. However, the uncontrollable drug transcytosis and limited drug uptake hindered by viscous cancer-associated fibroblasts (CAFs) greatly limit their in-depth penetration. Here, we proposed and demonstrated that intracellular autophagosomes could carry the remaining drugs to neighboring cells, and the enhanced macropinocytosis played a major role in neighboring delivery. To enhance the autophagosome-based neighboring delivery, Ca2+-doped polydopamine was prepared to load GLS1 inhibitor CB-839 and modified glutamine (839/CG) for triggering macropinocytosis-based active cells uptake. After Ca2+-release caused lysosome damage, 839/CG escaped from lysosomes and hindered the autophagosome maturation. Then, Ca2+-induced endoplasmic reticulum oscillations and glutamine starvation both increased and blocked autophagy flow, causing 839/CG-contained autophagosome accumulation. Meanwhile, the tumor increased its macropinocytosis in response to mTOR downregulation-induced glutamine hunger, causing "the more you eat, the hungrier you get". After tumor death, the 839/CG-contained autophagosomes were released and actively ingested by neighboring hungry tumor cells through macropinocytosis. Combined with the photothermal effect triggered CAF decrease, neighboring cells repeated the above process for in-depth tumor delivery. Also, immunogenic death enhanced the antigen presentation of DCs and infiltration of T cells, thereby inhibiting tumor growth and lung metastasis.

Identification and analysis of amino acid metabolism-related subtypes in lung adenocarcinoma

We aimed to explore the role of amino acid metabolism (AAM) and identify biomarkers for prognosis management and treatment of lung adenocarcinoma. Differentially expressed genes (DEGs) associated with AAM in lung adenocarcinoma were selected from public databases. Samples were clustered into varying subtypes using ConsensusClusterPlus based on gene levels. Survival analysis was conducted using a survival package, and immune analysis was performed using ssGSEA and ESTIMATE. Enrichment analysis was performed using gene set enrichment analysis, and a protein-protein interaction network of DEGs between subgroups was established through STRING. Hub genes were screened and verified using survival analysis, and drug sensitivity prediction was performed. One hundred sixty-three DEGs associated with AAM in lung adenocarcinoma were obtained, and two AAM-associated subtypes were identified. Cluster 1 showed higher survival rates and immune levels compared with cluster 2. The two subtypes were mainly enriched in immune-related signaling pathways, such as B cell receptor, Jak-Stat, and natural killer cell-mediated cytotoxicity. In addition, the mutation landscape between the two groups was significantly different. F2, AHSG, and APOA1 were key hub genes that significantly affected the prognosis differences between the two subtypes. Cluster 2 showed higher sensitivity to drugs, such as mithramycin, depsipeptide, and actinomycin than cluster 1. This study identified two AAM-associated gene subtypes and their biomarkers and predicted the immune status and drug treatment sensitivity of varying subtypes. The results are instructive in the clinical treatment of lung adenocarcinoma.NEW & NOTEWORTHY Two amino acid metabolism-related subtypes were identified based on differentially expressed genes associated with amino acid metabolism. Cluster 1 showed higher survival rates and immune levels compared with cluster 2. Cluster 2 showed higher sensitivity to drugs, such as mithramycin, depsipeptide, and actinomycin compared with cluster 1.

Immunostimulatory Hydrogel with Synergistic Blockage of Glutamine Metabolism and Chemodynamic Therapy for Postoperative Management of Glioblastoma

Glioblastoma multiforme (GBM) is one of the most lethal malignant brain tumors in the central nervous system. Patients face many challenges after surgery, including tumor recurrence, intracranial pressure increase due to cavitation, and limitations associated with immediate postoperative oral chemotherapy. Here an injected peptide gel with in situ immunostimulatory functions is developed to coordinate the regulation of glutamine metabolism and chemodynamic therapy for overcoming these postoperative obstacles. The methodology entails crafting injectable gel scaffolds with short peptide molecules, incorporating the glutaminase inhibitor CB-839 and copper peptide self-assembled particles (Cu-His NPs) renowned for their chemodynamic therapy (CDT) efficacy. By fine-tuning glutamic acid production via metabolic pathways, this system not only heightens the therapeutic prowess of copper peptide particles in CDT but also escalates intracellular oxidative stress. This dual mechanism culminates in augmented immunogenic cell death within glioblastoma multiforme cells and improves a conducive immune microenvironment. Based on the concept of metabolic reprogramming, this treatment strategy has great potential to significantly reduce GBM tumor recurrence and prolong median survival in murine models.

Metabolic interplays between the tumour and the host shape the tumour macroenvironment

Metabolic reprogramming of cancer cells and the tumour microenvironment are pivotal characteristics of cancers, and studying these processes offer insights and avenues for cancer diagnostics and therapeutics. Recent advancements have underscored the impact of host systemic features, termed macroenvironment, on facilitating cancer progression. During tumorigenesis, these inherent features of the host, such as germline genetics, immune profile and the metabolic status, influence how the body responds to cancer. In parallel, as cancer grows, it induces systemic effects beyond the primary tumour site and affects the macroenvironment, for example, through inflammation, the metabolic end-stage syndrome of cachexia, and metabolic dysregulation. Therefore, understanding the intricate metabolic interplay between the tumour and the host is a growing frontier in advancing cancer diagnosis and therapy. In this Review, we explore the specific contribution of the metabolic fitness of the host to cancer initiation, progression and response to therapy. We then delineate the complex metabolic crosstalk between the tumour, the microenvironment and the host, which promotes disease progression to metastasis and cachexia. The metabolic relationships among the host, cancer pathogenesis and the consequent responsive systemic manifestations during cancer progression provide new perspectives for mechanistic cancer therapy and improved management of patients with cancer.

Abnormal changes in metabolites caused by m6A methylation modification: The leading factors that induce the formation of immunosuppressive tumor microenvironment and their promising potential for clinical application

BACKGROUND

N6-methyladenosine (m6A) RNA methylation modifications have been widely implicated in the metabolic reprogramming of various cell types within the tumor microenvironment (TME) and are essential for meeting the demands of cellular growth and maintaining tissue homeostasis, enabling cells to adapt to the specific conditions of the TME. An increasing number of research studies have focused on the role of m6A modifications in glucose, amino acid and lipid metabolism, revealing their capacity to induce aberrant changes in metabolite levels. These changes may in turn trigger oncogenic signaling pathways, leading to substantial alterations within the TME. Notably, certain metabolites, including lactate, succinate, fumarate, 2-hydroxyglutarate (2-HG), glutamate, glutamine, methionine, S-adenosylmethionine, fatty acids and cholesterol, exhibit pronounced deviations from normal levels. These deviations not only foster tumorigenesis, proliferation and angiogenesis but also give rise to an immunosuppressive TME, thereby facilitating immune evasion by the tumor.

AIM OF REVIEW

The primary objective of this review is to comprehensively discuss the regulatory role of m6A modifications in the aforementioned metabolites and their potential impact on the development of an immunosuppressive TME through metabolic alterations.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review aims to elaborate on the intricate networks governed by the m6A-metabolite-TME axis and underscores its pivotal role in tumor progression. Furthermore, we delve into the potential implications of the m6A-metabolite-TME axis for the development of novel and targeted therapeutic strategies in cancer research.

Mechanism Study of E2F8 Activation of SPC25-Mediated Glutamine Metabolism Promoting Immune Escape in Lung Adenocarcinoma

Tumour cell immune infiltration is linked to spindle pole component 25 (SPC25). The purpose of this work was to examine the function and molecular mechanism of SPC25 in immune escape in lung adenocarcinoma (LUAD). SPC25 expression in LUAD was examined using The Cancer Genome Atlas (TCGA) database, and RT-qPCR was used to confirm the results. The study involved the use of CD8+ T lymphocytes for immunoinfiltration analysis of SPC25, Gene Set Enrichment Analysis (GSEA) analysis of signalling pathways enriched by SPC25, identification of putative regulatory molecules of SPC25, and confirmation through the use of dual-luciferase and ChIP tests. To evaluate LUAD cell capacity for immune escape, a co-culture technique was employed. Measurements of glutamine uptake, glutamate and α-ketoglutarate levels, NADPH/NADP and GSH/GSSG ratios, and SLC1A5 expression were used to assess the levels of glutamine metabolism. LUAD had increased SPC25 expression. In LUAD cells, immune escape was facilitated by SPC25 knockdown, whereas overexpression had the reverse effect. SPC25 enrichment in the glutamine metabolism pathway was shown by GSEA analysis. Through increased glutamine metabolism brought on by SPC25 overexpression, immune escape was improved in LUAD and could be mitigated by GPNA therapy. E2F8 was also shown to be the transcription factor associated with SPC25, and they showed a binding interaction. By inhibiting glutamine metabolism through SPC25, knocking down E2F8 prevented immune escape in LUAD cells. On the other hand, the suppression of immune escape in LUAD cells caused by E2F8 knockdown was overcome by overexpression of SPC25. In LUAD, E2F8 stimulates SPC25 expression to facilitate glutamine metabolism and encourage immune escape. Our research validates a novel immune escape pathway driven by SPC25 in LUAD cells, providing LUAD patients with potentially effective immunotherapeutic approaches.

Tumor Microenvironment: Obstacles and Opportunities for T Cell-Based Tumor Immunotherapies

The complex composition and dynamic change of the tumor microenvironment (TME), mainly consisting of tumor cells, immune cells, stromal cells, and extracellular components, significantly impede the effector function of cytotoxic T lymphocytes (CTL), thus representing a major obstacle for tumor immunotherapies. In this review, we summarize and discuss the impacts and underlying mechanisms of major elements in the TME (different cell types, extracellular matrix, nutrients and metabolites, etc.) on the infiltration, survival, and effector functions of T cells, mainly CD8+ CTLs. Moreover, we also highlight recent advances that may potentiate endogenous antitumor immunity and improve the efficacy of T cell-based immunotherapies in patients with cancer by manipulating components inside/outside of the TME. A deeper understanding of the effects and action mechanisms of TME components on the tumor-eradicating ability of CTLs may pave the way for discovering new targets to augment endogenous antitumor immunity and for designing combinational therapeutic regimens to enhance the efficacy of tumor immunotherapies in the clinic.

CircMFN2/miR-361-3p/ELK1 feedback loop promotes glutaminolysis and the progression of hepatocellular carcinoma

Current evidence indicates that circRNAs are involved in the development of multiple malignancies including hepatocellular carcinoma (HCC). However, the specific functions of circRNAs in HCC metabolism and progression and their underlying regulatory mechanisms remain unclear. We have identified a novel circRNA circMFN2, by bioinformatics analysis of circRNA microarray data from the GEO database. The levels of circMFN2 were assessed in HCC cell lines and tissues, and its clinical relevance was assessed. The effect of circMFN2 on HCC cells was evaluated in vitro and in vivo. The effect of ELK1 on glutaminolysis and HCC progression was also explored. Patients with HCC and high circMFN2 expression exhibited worse survival outcomes. Functionally, downregulation of circMFN2 repressed the proliferation, invasion, and migration of HCC cells in vitro, whereas ectopic expression of circMFN2 had the opposite effects. The effects of tumor enhancement by circMFN2 on HCC were confirmed by in vivo experiments. Mechanistically, circMFN2 acted as a sponge for miR-361-3p, leading to the upregulation of its target ELK1, whereas ELK1 was enriched in the MFN2 promoter to enhance the transcription and expression of MFN2, indirectly leading to the upregulation of circMFN2. Additionally, we found that circMFN2 promotes glutaminolysis in HCC by increasing ELK1 phosphorylation. We concluded that circMFN2 facilitates HCC progression via a circMFN2/miR-361-3p/ELK1 feedback loop, which promotes glutaminolysis mediated by the upregulation of phosphorylated ELK1. Therefore, circMFN2 not only serves as a potential prognostic indicator, but it could also serve as a therapeutic target for HCC. Further studies are warranted.

Metabolic landscape of disseminated cancer dormancy

Cancer dormancy is a phenomenon defined by the entry of cancer cells into a reversible quiescent, nonproliferative state, and represents an essential part of the metastatic cascade responsible for cancer recurrence and mortality. Emerging evidence suggests that metabolic reprogramming plays a pivotal role in enabling entry, maintenance, and exit from dormancy in the face of the different environments of the metastatic cascade. Here, we review the current literature to understand the dynamics of metabolism during dormancy, highlighting its fine-tuning by the host micro- and macroenvironment, and put forward the importance of identifying metabolic vulnerabilities of the dormant state as therapeutic targets to eradicate recurrent disease.

Myeloid cells: key players in tumor microenvironments

Cancer is the result of evolving crosstalk between neoplastic cell and its immune microenvironment. In recent years, immune therapeutics targeting T lymphocytes, such as immune checkpoint blockade (ICB) and CAR-T, have made significant progress in cancer treatment and validated targeting immune cells as a promising approach to fight human cancers. However, responsiveness to the current immune therapeutic agents is limited to only a small proportion of solid cancer patients. As major components of most solid tumors, myeloid cells played critical roles in regulating the initiation and sustentation of adaptive immunity, thus determining tumor progression as well as therapeutic responses. In this review, we discuss emerging data on the diverse functions of myeloid cells in tumor progression through their direct effects or interactions with other immune cells. We explain how different metabolic reprogramming impacts the characteristics and functions of tumor myeloid cells, and discuss recent progress in revealing different mechanisms-chemotaxis, proliferation, survival, and alternative sources-involved in the infiltration and accumulation of myeloid cells within tumors. Further understanding of the function and regulation of myeloid cells is important for the development of novel strategies for therapeutic exploitation in cancer.

T cell-based cancer immunotherapy: opportunities and challenges

T cells play a central role in the cancer immunity cycle. The therapeutic outcomes of T cell-based intervention strategies are determined by multiple factors at various stages of the cycle. Here, we summarize and discuss recent advances in T cell immunotherapy and potential barriers to it within the framework of the cancer immunity cycle, including T-cell recognition of tumor antigens for activation, T cell trafficking and infiltration into tumors, and killing of target cells. Moreover, we discuss the key factors influencing T cell differentiation and functionality, including TCR stimulation, costimulatory signals, cytokines, metabolic reprogramming, and mechanistic forces. We also highlight the key transcription factors dictating T cell differentiation and discuss how metabolic circuits and specific metabolites shape the epigenetic program of tumor-infiltrating T cells. We conclude that a better understanding of T cell fate decision will help design novel strategies to overcome the barriers to effective cancer immunity.

YY1-induced transcription of AKR1C3 activates the Hedgehog signalling pathway to enhance lenalidomide resistance and glycolytic activity in multiple myeloma cells

Lenalidomide (LEN) is a mainstay for treating multiple myeloma (MM), but its efficacy is often limited by resistance. We investigated the interaction between aldo-keto reductase family 1 member C3 (AKR1C3) and Yin Yang 1 (YY1) and their roles in LEN resistance. We induced LEN-resistant MM cell lines (H929R and U266R). Loss- or gain-of-function assays of AKR1C3 and YY1 were used to analyse the half maximal inhibitory concentration (IC50) values, cell senescence, DNA damage, and glycolytic activity under LEN treatment. Chromatin immunoprecipitation was used to determine the interaction between YY1 and AKR1C3. As results, AKR1C3 and YY1 were upregulated in H929R and U266R cells. AKR1C3 silencing decreased the LEN's IC50, slowed cell growth, enhanced senescence and DNA damage, reduced metabolic reprogramming. YY1 activated the transcription of AKR1C3 by binding to its promoter region. Similarly, silencing YY1 enhanced LEN sensitivity, suppressed glycolysis, and was counteracted by AKR1C3 overexpression. Mechanistically, YY1-AKR1C3 activated the Hedgehog pathway; fluticasone reversed the effects of AKR1C3 silencing on LEN resistance and glycolysis in H929R and U266R cells. Overall, YY1 activates AKR1C3 transcription and the Hedgehog pathway to increase LEN resistance and glycolytic activity in MM cells.

Rethinking corticosteroids use in oncology

Corticosteroids (CSs), widely used in oncology for their anti-inflammatory and immunosuppressive properties, help manage cancer-related symptoms and side effects. However, their long-term use may negatively affect patient survival and exacerbate tumor progression. Elevated glucose and glutamine metabolism, disruption of vitamin D levels, and alterations in the microbiome are some of the key factors contributing to these adverse outcomes. Approaches such as ketogenic diets, fasting, sartans, and vitamin D supplementation have shown promise in providing similar benefits to CSs while mitigating the risks associated with the mechanisms identified as contributing to tumor progression. This perspective underscores the necessity for a reevaluation of CSs use in cancer care and advocates for further research into safer, more effective therapeutic strategies.

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

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

iMetAct: An integrated systematic inference of metabolic activity for dissecting tumor metabolic preference and tumor-immune microenvironment

Metabolic enzymes play a central role in cancer metabolic reprogramming, and their dysregulation creates vulnerabilities that can be exploited for therapy. However, accurately measuring metabolic enzyme activity in a high-throughput manner remains challenging due to the complex, multi-layered regulatory mechanisms involved. Here, we present iMetAct, a framework that integrates metabolic-transcription networks with an information propagation strategy to infer enzyme activity from gene expression data. iMetAct outperforms expression-based methods in predicting metabolite conversion rates by accounting for the effects of post-translational modifications. With iMetAct, we identify clinically significant subtypes of hepatocellular carcinoma with distinct metabolic preferences driven by dysregulated enzymes and metabolic regulators acting at both the transcriptional and non-transcriptional levels. Moreover, applying iMetAct to single-cell RNA sequencing data allows for the exploration of cancer cell metabolism and its interplay with immune regulation in the tumor microenvironment. An accompanying online platform further facilitates tumor metabolic analysis, patient stratification, and immune microenvironment characterization.

[Immune Checkpoints Mediate Tumor Immune Regulation through Metabolic Pathways]

Immune checkpoints include a series of receptor-ligand pairs that play a key role in the proliferation, activation, and immune regulatory responses of immune cells. Although immune checkpoint inhibitors (ICIs), such as programmed death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) have achieved good therapeutic effects in clinical practice, some patients still experience ineffective treatment and immune resistance. A large amount of evidence has shown that immune checkpoint proteins are related to cell metabolism during immune regulation. On the one hand, immune checkpoints connect to alter the metabolic reprogramming of tumor cells to compete for nutrients required by immune cells. On the other hand, immune checkpoints regulate the metabolic pathways of immune cells, such as phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) to affect the activation of immune cells. Based on a review of the literature, this article reviews the mechanisms by which PD-1, CTLA-4, T cell immunoreceptor with Ig and ITIM domains (TIGIT), T cell immunoglobulin and mucin domain-containing protein 3 (TIM-3), cluster of differentiation 47 (CD47), and indoleamine 2,3-dioxygenase 1 (IDO1) regulate cell metabolic reprogramming, and looks forward to whether targeting the ligand-receptor pairs of immune checkpoints in a "dual regulation" manner and inhibiting metabolic pathways can effectively solve the problem of tumor immune resistance.
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Metabolic mechanisms of immunotherapy resistance

Immunotherapy has revolutionized cancer treatment, yet its efficacy is frequently compromised by metabolic mechanisms that drive resistance. Understanding how tumor metabolism shapes the immune microenvironment is essential for developing effective therapeutic strategies. This review examines key metabolic pathways influencing immunotherapy resistance, including glucose, lipid, and amino acid metabolism. We discuss their impact on immune cell function and tumor progression, highlighting emerging therapeutic strategies to counteract these effects. Tumor cells undergo metabolic reprogramming to sustain proliferation, altering the availability of essential nutrients and generating toxic byproducts that impair cytotoxic T lymphocytes (CTLs) and natural killer (NK) cell activity. The accumulation of lactate, deregulated lipid metabolism, and amino acid depletion contribute to an immunosuppressive tumor microenvironment (TME). Targeting metabolic pathways, such as inhibiting glycolysis, modulating lipid metabolism, and restoring amino acid balance, has shown promise in enhancing immunotherapy response. Addressing metabolic barriers is crucial to overcoming immunotherapy resistance. Integrating metabolic-targeted therapies with immune checkpoint inhibitors may improve clinical outcomes. Future research should focus on personalized strategies to optimize metabolic interventions and enhance antitumor immunity.

Folate-targeted nanoparticles for glutamine metabolism inhibition enhance anti-tumor immunity and suppress tumor growth in ovarian cancer

Ovarian cancer (OC) is a highly malignant gynecological tumor, and its effective treatment is frequently impeded by drug resistance and recurrent tumor growth. The reprogramming of glutamine metabolism in ovarian cancer is closely associated with tumor progression and the immunosuppressive tumor microenvironment. Recently, targeting metabolic reprogramming has emerged as a promising approach for cancer therapy. However, the application of such therapies is often constrained by their significant toxicity to normal tissues. In this study, we fabricated folate-targeted nanoparticles (FA-DCNPs) that co-encapsulate the glutamine metabolism inhibitor 6-diazo-5-oxo-L-norleucine (DON) and calcium carbonate (CaCO3). These nanoparticles alleviate damage to normal tissues by specifically targeting tumor cells via folate receptors (FOLR) mediation. Under acidic conditions, the FA-DCNPs release DON and Ca2+, generating a synergistic anti-tumor effect by impeding glutamine metabolism and inducing calcium overload. Additionally, FA-DCNPs target M2 phenotype tumor-associated macrophages (TAMs) via FOLR2, attenuating M2-TAMs activity. When partially phagocytosed by M0-TAMs, the nanoparticles restrict glutamate production, inhibiting polarization towards the M2 phenotype. This resulted in an increased proportion of M1-TAMs, thereby improving the tumor immune microenvironment. Our study explores a nanotherapeutic strategy that enhances the biosafety of anti-glutamine metabolism therapy through folate targeting, effectively suppresses tumor cell proliferation, and enhances the anti-tumor immune response.

Bridging epigenomics and tumor immunometabolism: molecular mechanisms and therapeutic implications

Epigenomic modifications-such as DNA methylation, histone acetylation, and histone methylation-and their implications in tumorigenesis, progression, and treatment have emerged as a pivotal field in cancer research. Tumors undergo metabolic reprogramming to sustain proliferation and metastasis in nutrient-deficient conditions, while suppressing anti-tumor immunity in the tumor microenvironment (TME). Concurrently, immune cells within the immunosuppressive TME undergo metabolic adaptations, leading to alterations in their immune function. The complicated interplay between metabolites and epigenomic modulation has spotlighted the significance of epigenomic regulation in tumor immunometabolism. In this review, characteristics of the epigenomic modification associated with tumors are systematically summarized alongside with their regulatory roles in tumor metabolic reprogramming and immunometabolism. Classical and emerging approaches are delineated to broaden the boundaries of research on the crosstalk research on the crosstalk between tumor immunometabolism and epigenomics. Furthermore, we discuss potential therapeutic strategies that target tumor immunometabolism to modulate epigenomic modifications, highlighting the burgeoning synergy between metabolic therapies and immunotherapy as a promising avenue for cancer treatment.

Alterations in PD-L1 succinylation shape anti-tumor immune responses in melanoma

Tumors undergo metabolic reprogramming to meet the energetic, synthetic and redox demands essential for malignancy, often characterized by increased glycolysis and lactate production. However, the role of mitochondrial metabolism in tumor immunity remains unclear. The present study integrates spatial transcriptomics, bulk transcriptomics and proteomics, revealing a strong link between the metabolite succinyl-CoA and tumor immunity as well as the efficacy of anti-programmed cell death protein-1 (PD-1) therapy in patients with melanoma. Elevated succinyl-CoA levels, through α-ketoglutarate or succinate supplementation, enhanced T cell-mediated tumor elimination, both in vitro and in vivo. Mechanistically, succinylation of the ligand of PD-1 (PD-L1) at lysine 129 led to its degradation. Increased carnitine palmitoyltransferase 1A (CPT1A), identified as a succinyltransferase for PD-L1, boosted anti-tumor activity. Preclinically, bezafibrate, a hyperlipidemia drug, upregulated CPT1A and synergized with CTLA-4 monoclonal antibody to inhibit tumor growth. Clinically, higher PD-L1 and lower CPT1A levels in tumors correlated with better anti-PD-1 therapy responses, suggesting potential biomarkers for prediction of treatment efficacy.

Tumor-Targeted Glutamine Metabolism Blocker Synergizes with TiO2-Au Janus Nanoparticles for Enhanced Sono-Metabolic Antitumor Therapy

Sonodynamic therapy (SDT) is a promising therapeutic modality known for its non-invasiveness, temporal-spatial controllability, and deeper tissue penetration. However, the SDT treatment efficacy is still hampered by the scarcity of ideal sonosensitizers and complex tumor microenvironment (TME). To address these challenges, a sono-metabolic nano-composite (TiO2-Au@DON) using the metabolic reprogramming prodrugs of 6-Diazo-5-oxo-l-norleucine (DON) grafted on TiO2-Au Janus nanoparticles (NPs) is fabricated. The coupling of TiO2 and gold in the TiO2-Au@DON effectively prevents the fast recombination of excited electrons and holes under ultrasound irradiation. The result is the generation of higher levels of both type I and II reactive oxygen species (ROS) compared to pure TiO2, which helps overcome the limitations of SDT in the hypoxic TME. Furthermore, the TiO2-Au Janus NPs act as nano-carriers, delivering DON prodrugs to the tumor site. The released DON can disrupt nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) and tumor redox homeostasis by reprogramming the metabolic pathways while it intensifies the activities of immune cells. This metabolic disruption amplifies SDT-mediated oxidative stress, resulting in the increase of tumor sensitivity to ROS through TiO2-Au@DON-integrated synergistic effects of SDT and glutamine reprogramming strategies. This increased sensitivity ultimately induces robust immunogenic cell death (ICD), enhancing antitumor therapeutic efficacy and remodeling the tumor's immunosuppressive microenvironment.

KNTC1 introduces segmental heterogeneity to mitochondria

Mitochondria contribute to cellular metabolism by providing a specialised milieu for energising cells by incorporating and processing the metabolites. However, heterogeneity between mitochondria has only partially been elucidated. Mitochondria dynamically alter their morphology and function during the life of an animal, when cells proliferate and grow. We here show that Kntc1, a highly evolutionarily conserved protein, translocates from the Golgi apparatus to linear mitochondrial segments (LMSs) upon glutamine deprivation and plays an essential role in maintaining LMSs. The LMSs to which Kntc1 localised exhibited an increase in the mitochondrial membrane potential, suggesting the role of Kntc1 in functioning as a reservoir for the energy-generating potential. Suppression of Kntc1 led to glutamine consumption and lactate production, thus impacting cellular metabolism, eventually leading to anchorage-independent growth of cells. Indeed, a KNTC1 variant was identified in a patient with ovarian cancer, suggesting that segmental regulation of the mitochondrial function is essential for maintaining tissue integrity.

MicroRNA-335 inhibits invasion and metastasis of prostate cancer by inhibiting glutamine metabolism pathway

MicroRNAs play a crucial role in regulating tumor progression and invasion. Nevertheless, the expression of miRNA-335 in prostate cancer (PCa) and its clinical significance remain unelucidated. Here, we report that miRNA-335 functions as a tumor suppressor by regulating expression of glutaminase 1 (GLS1), a key enzyme of glutamine metabolism pathway, in PCa. In this study, we show that the expression of miRNA-335 is downregulated in PCa tissues. The level of miRNA-335 is even lower in highly invasive PCa cell lines. Furthermore, enhancing the expression of miRNA-335 inhibits PCa cell migration and invasion in vitro. Additionally, we identify GLS1 as the downstream effector, governed by miRNA-335 via 3'-untranslated region, and the direct regulation is verified by dual luciferase reporter assay. MiRNA-335 interrupts glutamine catabolism by inhibiting GLS1 enzymatic activity. Overexpression of miRNA-335 markedly suppresses tumor growth of PCa in vivo. To sum up, our results indicate that miRNA-335 acts as a tumor suppressor and has an important role in restraining the metastasis of PCa cells by targeting GLS1. These discoveries indicate that miRNA-335 could serve as a new prospective therapeutic target for PCa. SIGNIFICANCE STATEMENT: miRNA-335, a metabolism-related microRNA, is a potential therapeutic target for prostate cancer by interfering with glutaminase 1 activity.

Glutamine deprivation confers immunotherapy resistance by inhibiting IFN-γ signaling in cancer cells

Glutamine metabolism is emerging as a target for improving immunotherapy efficacy. However, the outcomes remain inconclusive. Given that the tumor-intrinsic response to interferon-γ (IFN-γ) is a key determinant of immunotherapy efficacy, we investigated whether and how glutamine deprivation in cancer cells affects their response to IFN-γ. By using human lung cancer cell lines, patient-derived tumor explants, and a syngeneic mouse model of lung cancer, we demonstrated that glutamine deprivation reduced the IFN-γ-driven response in cancer cells by promoting autophagy-dependent IFN-γ receptor (IFNGR1) degradation and rendering tumors resistant to anti-PD-1 or anti-PD-L1 therapy. Treatment with V9302, an inhibitor of the alanine-serine-cysteine transporter (ASCT2), enhanced the IFN-γ-driven response of cancer cells and increased the efficacy of PD-1 blockade therapy. Mechanistic analysis revealed that V9302 inhibited autophagy by impairing lysosomal activity independent of glutamine deprivation, likely because of its physiochemical properties, thereby preventing IFNGR1 degradation. Moreover, V9302 also increased Glut1 expression through the inhibition of lysosomal pathway-dependent degradation of Glut1 and consequently increased cancer cell glucose uptake, in turn retaining the levels of intracellular alpha-ketoglutarate (α-KG) and ATP, which are involved in maintaining IFN-γ signal transduction in cancer cells. In support of these findings, targeting lysosomal activity with chloroquine (CQ) also increased IFNGR1 expression and the IFN-γ-driven response in cancer cells. The administration of CQ increased the sensitivity of ASCT2-deficient tumors to anti-PD-L1 therapy. Glutamine deprivation per se leads to resistance to immunotherapy, whereas V9302 treatment results in increased immunotherapy efficacy through impaired lysosomal activity, which is independent of glutamine deprivation.

Anti-Tumor Strategies Targeting Nutritional Deprivation: Challenges and Opportunities

Higher and richer nutrient requirements are typical features that distinguish tumor cells from AU: cells, ensuring adequate substrates and energy sources for tumor cell proliferation and migration. Therefore, nutrient deprivation strategies based on targeted technologies can induce impaired cell viability in tumor cells, which are more sensitive than normal cells. In this review, nutrients that are required by tumor cells and related metabolic pathways are introduced, and anti-tumor strategies developed to target nutrient deprivation are described. In addition to tumor cells, the nutritional and metabolic characteristics of other cells in the tumor microenvironment (including macrophages, neutrophils, natural killer cells, T cells, and cancer-associated fibroblasts) and related new anti-tumor strategies are also summarized. In conclusion, recent advances in anti-tumor strategies targeting nutrient blockade are reviewed, and the challenges and prospects of these anti-tumor strategies are discussed, which are of theoretical significance for optimizing the clinical application of tumor nutrition deprivation strategies.

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

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

Ferroptosis: iron release mechanisms in the bioenergetic process

Ferroptosis, an iron-dependent form of cell death, has been the focus of extensive research over the past decade, leading to the elucidation of key molecules and mechanisms involved in this process. While several studies have highlighted iron sources for the Fenton reaction, the predominant mechanism for iron release in ferroptosis has been identified as ferritinophagy, which occurs in response to iron starvation. However, much of the existing literature has concentrated on lipid peroxidation rather than on the mechanisms of iron release. This review proposes three distinct mechanisms of iron mobilization: ferritinophagy, reductive pathways with selective gating of ferritin pores, and quinone-mediated iron mobilization. Notably, the latter two mechanisms operate independently of iron starvation and rely primarily on reductants such as NADH and O2•-. The inhibition of the respiratory chain, particularly under the activation of α-ketoglutarate dehydrogenase, leads to the accumulation of these reductants, which in turn promotes iron release from ferritin and indirectly inhibits AMP-activated protein kinase through excessive iron levels. In this work, we delineate the intricate relationship between iron mobilization and bioenergetic processes under conditions of oxidative stress. Furthermore, this review aims to enhance the understanding of the connections between ferroptosis and these mechanisms.

Metabolism of Tryptophan, Glutamine, and Asparagine in Cancer Immunotherapy-Synergism or Mechanism of Resistance?

Amino acids are crucial components of proteins, key molecules in cellular physiology and homeostasis. However, they are also involved in a variety of other mechanisms, such as energy homeostasis, nitrogen exchange, further synthesis of bioactive compounds, production of nucleotides, or activation of signaling pathways. Moreover, amino acids and their metabolites have immunoregulatory properties, significantly affecting the behavior of immune cells. Immunotherapy is one of the oncological treatment methods that improves cytotoxic properties of one's own immune system. Thus, enzymes catalyzing amino acid metabolism, together with metabolites themselves, can affect immune antitumor properties and responses to immunotherapy. In this review, we will discuss the involvement of tryptophan, glutamine, and asparagine metabolism in the behavior of immune cells targeted by immunotherapy and summarize results of the most recent investigations on the impact of amino acid metabolites on immunotherapy.