Cancer SLC43A2 alters T cell methionine metabolism and histone methylation

Metabolic reprogramming of tumor microenviroment by engineered bacteria

The tumor microenvironment (TME) is a complex ecosystem that plays a crucial role in tumor progression and response to therapy. The metabolic characteristics of the TME are fundamental to its function, influencing not only cancer cell proliferation and survival but also the behavior of immune cells within the tumor. Metabolic reprogramming-where cancer cells adapt their metabolic pathways to support rapid growth and immune evasion-has emerged as a key factor in cancer immunotherapy. Recently, the potential of engineered bacteria in cancer immunotherapy has gained increasing recognition, offering a novel strategy to modulate TME metabolism and enhance antitumor immunity. This review summarizes the metabolic properties and adaptations of tumor and immune cells within the TME and summarizes the strategies by which engineered bacteria regulate tumor metabolism. We discuss how engineered bacteria can overcome the immunosuppressive TME by reprogramming its metabolism to improve antitumor therapy. Furthermore, we examine the advantages, potential challenges, and future clinical translation of engineered bacteria in reshaping TME metabolism.

Age- and diet-instructed metabolic rewiring of the tumor-immune microenvironment

The tumor-immune microenvironment (TIME) plays a critical role in tumor development and metastasis, as it influences the evolution of tumor cells and fosters an immunosuppressive state by intervening the metabolic reprogramming of infiltrating immune cells. Aging and diet significantly impact the metabolic reprogramming of the TIME, contributing to cancer progression and immune evasion. With aging, immune cell function declines, leading to a proinflammatory state and metabolic alterations such as increased oxidative stress and mitochondrial dysfunction, which compromise antitumor immunity. Similarly, dietary factors, particularly high-fat and high-sugar diets, promote metabolic shifts, creating a permissive TIME by fostering tumor-supportive immune cell phenotypes while impairing the tumoricidal activity of immune cells. In contrast, dietary restrictions have been shown to restore immune function by modulating metabolism and enhancing antitumor immune responses. Here, we discuss the intricate interplay between aging, diet, and metabolic reprogramming in shaping the TIME, with a particular focus on T cells, and highlight therapeutic strategies targeting these pathways to empower antitumor immunity.

L-methionine promotes CD8+ T cells killing hepatocellular carcinoma by inhibiting NR1I2/PCSK9 signaling

BACKGROUND

Liver cancer has consistently high incidence and mortality rates among malignant tumors. PCSK9, a target for hypercholesterolemia therapy, has recently been identified as an inhibitor of anti-tumor immunity, and targeting PCSK9 effectively inhibits tumor progression. However, small molecule inhibitors are lacking due to its flat protein structure.

METHODS

PCSK9 transcription inhibitor screening was conducted using a PCSK9 promoter-driven td-Tomato plasmid. Quantitative real-time PCR and immunoblotting were employed to assess the effect of L-methionine on PCSK9 expression in HCC cell lines. Co-culture experiments were performed to evaluate the impact of L-methionine on CD8+ T cell-mediated killing of liver cancer cells. RNA sequencing, CUT&Tag, gene editing, and luciferase reporter assays were utilized to identify the transcription factor regulating PCSK9. Additionally, liver cancer xenograft and spontaneous liver cancer mouse models were used to evaluate the anti-cancer efficacy of L-methionine.

RESULTS

Our study identified L-methionine, an essential amino acid, as a transcriptional inhibitor of PCSK9. The optimal dose of L-methionine to inhibit PCSK9 expression and enhance CD8+ T cell-mediated killing of liver cancer cells in vitro is 50 μM. Furthermore, intraperitoneal injection of 5 mg/kg/day of L-methionine significantly inhibited tumor growth in both liver cancer xenograft and spontaneous liver cancer mouse models. Mechanistically, we identified NR1I2 as a key transcription factor for PCSK9 and their crucial binding site was TGCACCCTGACAC. L-methionine inhibits PCSK9 transcription by downregulating NR1I2.

CONCLUSIONS

This work demonstrates that L-methionine promotes CD8+ T cell-mediated killing of hepatocellular carcinoma by inhibiting NR1I2/PCSK9 signaling. Our study introduces a novel and convenient approach to inhibit PCSK9 and provides a theoretical basis for the rational supplementation of L-methionine in liver cancer patients.

T cell aging and exhaustion: Mechanisms and clinical implications

T cell senescence and exhaustion represent critical aspects of adaptive immune system dysfunction, with profound implications for health and the development of disease prevention and therapeutic strategies. These processes, though distinct, are interconnected at the molecular level, leading to impaired effector functions and reduced proliferative capacity of T cells. Such impairments increase susceptibility to diseases and diminish the efficacy of vaccines and treatments. Importantly, T cell senescence and exhaustion can dynamically influence each other, particularly in the context of chronic diseases. A deeper understanding of the molecular mechanisms underlying T cell senescence and exhaustion, as well as their interplay, is essential for elucidating the pathogenesis of related diseases and restoring dysfunctional immune responses. This knowledge will pave the way for the development of targeted therapeutic interventions and strategies to enhance immune competence. This review aims to summarize the characteristics, mechanisms, and disease associations of T cell senescence and exhaustion, while also delineating the distinctions and intersections between these two states to enhance our comprehension.

Dynamic characteristics of metabolism and small extracellular vesicles during malignant transformation of BEAS-2B cells induced by coal tar pitch extract

Lung cancer poses a significant global burden with rising morbidity and mortality. Coal tar pitch-induced lung cancer is an occupational disease where early detection is crucial but challenging due to unclear pathogenesis. We established a malignant transformation model using BEAS-2B cells treated with coal tar pitch extract (CTPE). Macro- and micro-observations showed CTPE-induced alterations, including changes in cell morphology, enhanced proliferation and migration abilities, upregulated EGFR expression, modified levels of CYP1A1 and GSTM1 metabolizing enzymes, and a transition towards a mesenchymal phenotype. These findings strongly suggest that the cells have undergone malignant transformation. Metabolomics analysis revealed changes in 1120 metabolites, with 31 co-expressed, mainly in energy and amino acid metabolism. Small extracellular vesicles (SEVs) concentrations and EGFR levels were significantly altered. Correlation analysis identified a relationship between these biomarkers, implying their potential significance as early events in the initiation and progression of lung cancer. These findings provide valuable insights and a rationale for lung cancer screening and mechanistic investigations, thereby contributing to a deeper understanding of the disease.

Harnessing nutrient scarcity for enhanced CAR-T-cell potency and safety in solid tumors

Despite significant advancements, the effectiveness of chimeric antigen receptor (CAR)-T-cell-based therapies in solid tumors remains limited. Key challenges include on-target effects, off-tumor toxicity and reduced CAR-T-cell function within the tumor microenvironment, which is often characterized by metabolic stress triggered by factors such as amino acid scarcity. Activating transcription factor-4 (ATF4) and its upstream regulator GCN2 play crucial roles in the metabolic reprogramming and functionality of CD4+ and CD8+ T cells. ATF4 can be activated by various cellular stress signals, including amino acid deprivation. While ATF4 activation may be associated with T-cell dysfunction, its role in stress adaptation presents an opportunity for therapeutic intervention-particularly in the tumor microenvironment, where T-cell exhaustion is a major challenge. In this study, we developed a strategy to harness the GCN2‒ATF4 axis in CAR-T cells. We employed an amino acid-dependent inducible promoter, which triggers ATF4-dependent gene expression to regulate CAR expression in T cells under conditions of amino acid scarcity within the tumor microenvironment. In vitro and murine xenograft models demonstrate the potential of this system to effectively restrict CAR expression to the tumor site. This targeted strategy not only enhances safety by minimizing off-tumor activity but also CAR-T-cell fitness by reducing exhaustion. By validating this pathophysiologically regulatable CAR expression system for solid tumors, our findings address key limitations of current CAR-T-cell therapies and pave the way for innovative strategies targeting solid malignancies.

Alcohol-induced C/EBP β-driven VIRMA decreases oxidative stress and promotes pancreatic ductal adenocarcinoma growth and metastasis via the m6A/YTHDF2/SLC43A2 pathway

N6-methyladenosine (m6A) plays a role in the development of tumors. However, the specific role of VIRMA, an RNA methyltransferase, in pancreatic ductal adenocarcinoma (PDAC) remains unclear. This study shows that VIRMA expression is elevated in PDAC. Increased VIRMA levels promoted PDAC growth and spread, while reducing VIRMA expression slowed these processes. VIRMA facilitated SLC43A2 mRNA degradation through an m6A-YTHDF2 pathway. The resulting decrease in SLC43A2 reduced phenylalanine absorption and oxidative stress, further driving PDAC progression. Furthermore, alcohol increased C/EBP β expression, which bound to VIRMA's promoter, enhancing its transcription. These findings suggest a connection between alcohol consumption, m6A modifications, and phenylalanine absorption in PDAC progression, offering a new approach to combat this disease.

Epigenetic modification and tumor immunity: Unraveling the interplay with the tumor microenvironment and its therapeutic vulnerability and implications

In the ever-evolving arena of molecular biology, epigenetic modifications stand out as crucial determinants in the orchestration of cellular identity, function, and fate. This review analyzes the close relationship between epigenetics and tumor immunity, emphasizing the intricate interplay with the tumor microenvironment (TME). Rooted in the knowledge that the incidence of cancer correlates strongly with the biological and genetic age, we highlight DNA methylation as a cornerstone of the "epigenetic aging" process with close ties to tumorigenesis. The TME, with its diverse cellular and acellular constituents, is an active participant in tumor biology, further complicated by epigenetic alterations. These modifications, from DNA methylation to histone changes, not only shape the TME but are reciprocally influenced by it, reinforcing a cycle that propels malignancy. Through this exploration, we underline the importance of understanding this mutual relationship, as it holds significant implications for tumor growth, heterogeneity, and therapeutic resistance. Ultimately, this review illuminates the potential of harnessing epigenetic insights for innovative cancer therapeutic strategies, pointing towards a promising avenue for future cancer management.

Relationship between plasma homocysteine and clinical grading of varicocele

ABSTRACT

This study aims to explore the correlation between plasma homocysteine (Hcy) levels and the clinical grading of varicocele (VC) when analyzing the potential pathogenesis of endothelial cells injury by Hcy. A total of 184 VC patients, aged 18-46 years, were included in this study. These patients visited The Second Hospital of Dalian Medical University (Dalian, China), between January 2022 and September 2024. Patients were divided into three groups based on clinical grading: Group A (59 cases, Grade I), Group B (28 cases, Grade II), and Group C (97 cases, Grade III). Additionally, 120 individuals with normal fertility test results during the same period were selected as the control group. Routine blood and biochemical indices were collected from the patients. Differences in clinical indices between groups were compared, and univariate and multivariate linear regression analyses were performed to identify factors associated with clinical grading. The results showed that the median Hcy levels in the control group and in patients with Grade I, II, and III VC were 9.56 (interquartile range [IQR]: 8.66, 14.02) µmol l-1, 11.28 (IQR: 9.71, 14.55) µmol l-1, 11.84 (IQR: 10.14, 15.60) µmol l-1, and 12.27 (IQR: 9.52, 15.40) µmol l-1, respectively. The differences between the four groups were statistically significant (χ2 = 12.41, P = 0.006). Multivariate regression analysis indicated that Hcy is a factor associated with the clinical grading of VC (t = 2.53, P = 0.013). Hcy is associated with the clinical grading and may have clinical value in assessing severity of VC.

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.

The crosstalk between broad epigenetic modification and T cell metabolism within tumor microenvironment

T cells play an important role in adaptive immune responses, providing antigen specificity for pathogen and tumor recognition. Recent studies have elucidated the complex interplay between T cell metabolism and broad epigenetic modifications in response to tumors, occurring at transcriptional, post-transcriptional, and post-translational levels. At the transcriptional level, gene expression is regulated through mechanisms such as DNA methylation, chromatin remodeling, and transcription factor activity. Post-transcriptionally, gene expression is further modulated by non-coding RNAs and RNA modifications, an area of increasing research interest. In addition, histone proteins are primarily regulated by well-established post-translational modifications (PTMs), including acetylation and methylation. Novel PTMs such as succinylation, glycosylation, glutamylation, and lactylation add complexity to the regulation and warrant further investigation. At present, the interaction between CD8+ T cell metabolism and epigenetic modifications in response to malignancies has been reported extensively. However, the interplay in CD4+ T cells remains less understood. In this review, we introduce the differentiation trajectories of T cells and critically evaluate existing interplay between metabolic activity and epigenetic modifications influences the functional dynamics in both CD8+ and CD4+ T cells, offering promising avenues for the development of novel cancer immunotherapies.

Methionine in embryonic development: metabolism, redox homeostasis, epigenetic modification and signaling pathway

Methionine, an essential sulfur-containing amino acid, plays a critical role in methyl metabolism, folate metabolism, polyamine synthesis, redox homeostasis maintenance, epigenetic modification and signaling pathway regulation, particularly during embryonic development. Animal and human studies have increasingly documented that methionine deficiency or excess can negatively impact metabolic processes, translation, epigenetics, and signaling pathways, with ultimate detrimental effects on pregnancy outcomes. However, the underlying mechanisms by which methionine precisely regulates epigenetic modifications and affects signaling pathways remain to be elucidated. In this review, we discuss methionine and the metabolism of its metabolites, the influence of folate-mediated carbon metabolism, redox reactions, DNA and RNA methylation, and histone modifications, as well as the mammalian rapamycin complex and silent information regulator 1-MYC signaling pathway. This review also summarizes our present understanding of the contribution of methionine to these processes, and current nutritional and pharmaceutical strategies for the prevention and treatment of developmental defects in embryos.

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.

Epigenome-wide association study of household air pollution exposure in an area with high lung cancer incidence

Background

Lung cancer incidence among never-smoking women in Xuanwei, China, ranks among the highest worldwide and is largely attributed to household air pollution (HAP) from smoky (bituminous) coal combustion, with early-life exposures possibly playing a critical role. We conducted an epigenome-wide DNA methylation (DNAm) analysis across multiple exposure windows to elucidate molecular mechanisms.

Methods

Leukocyte DNAm was measured in 106 never-smoking women (23 with repeated measurements). Fuel use was obtained through questionnaires, and extensive personal and environmental monitoring was conducted. Validated exposure models estimated 43 HAP constituents, primarily polycyclic aromatic hydrocarbons (PAHs), across childhood, current, and cumulative exposure windows. Hierarchical clustering derived exposure clusters. We used generalized estimating equations to identify CpG sites associated with HAP exposure and PAH clusters, including 5-methylchrysene, a methylated PAH previously linked to lung cancer.

Results

We identified several differentially methylated CpG sites, predominantly hypomethylated with HAP exposure. Although some DNAm signatures overlapping with smoking (cg05575921; AHRR) were observed, most changes were distinct. A life-course assessment indicated persistent epigenetic variations across childhood and cumulative exposures, suggesting that early-life exposures may have lasting effects at certain sites (SLC43A2). Within the PAH clusters, 5-methylchrysene appears to be a significant contributor to DNAm variations. Top CpG sites were linked to immune regulation, cell growth and proliferation, and molecular mechanisms of cancer, including lung cancer.

Conclusions

Our findings provide novel insights into HAP-induced DNAm changes and their potential health effects. Future studies with larger sample sizes, and diverse coal use settings are needed to validate and extend these findings.

A Methionine Allocation Nanoregulator for the Suppression of Cancer Stem Cells and Support to the Immune Cells by Epigenetic Regulation

Epigenetic dysregulation is prevalent in human cancers, affecting gene expression and metabolic patterns to meet the demands of malignant evolution and abnormal epigenetic processes, and resulting in a protumor immune microenvironment. Tumors require a steady supply of methionine for maintaining epigenetic flexibility, which is the only exogenous precursor of methyl donor S-adenosylmethionine for methylation, crucial for their resistance to therapies and survival in a nutrient-deficient microenvironment. Thus, tumor cells upregulate the Lat4 transporter to compete and deprive methionine in the microenvironment, sustaining their malignant phenotypes and also impairing immune cell functions. Addressing this methionine addiction is the key to overcoming drug resistance and improving immune response. Despite the challenge of lacking specific Lat4 inhibitors, an oxaliplatin prodrug crosslinked fluorinated polycation/anti-Lat4 small interfering RNA complex nanoregulator (AS-F-NP) has been designed and developed here. This nanoregulator restricted the greedy methionine uptake of tumor cells by knocking down Lat4, which in turn inhibited the malignant evolution of the tumor while restoring the viability and function of tumor-infiltrating immune cells.

Metabolic Dialogue Shapes Immune Response in the Tumor Microenvironment

The fate of immune cells is fundamentally linked to their metabolic program, which is also influenced by the metabolic landscape of their environment. The tumor microenvironment represents a unique system for intercellular metabolic interactions, where tumor-derived metabolites suppress effector CD8+ T cells and promote tumor-promoting macrophages, reinforcing an immune-suppressive niche. This review will discuss recent advancements in metabolism research, exploring the interplay between various metabolites and their effects on immune cells within the tumor microenvironment.

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.

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.

PRMT5-mediated arginine methylation stabilizes GPX4 to suppress ferroptosis in cancer

The activation of ferroptosis has shown great potential for cancer therapy from an unconventional perspective, but revealing the mechanisms underlying the suppression of tumour-intrinsic ferroptosis to promote tumorigenesis remains a challenging task. Here we report that methionine is metabolized into S-adenosylmethionine, which functions as a methyl-group donor to trigger symmetric dimethylation of glutathione peroxidase 4 (GPX4) at the conserved arginine 152 (R152) residue, along with a prolonged GPX4 half-life. Inhibition of protein arginine methyltransferase 5 (PRMT5), which catalyses GPX4 methylation, decreases GPX4 protein levels by impeding GPX4 methylation and increasing ferroptosis inducer sensitivity in vitro and in vivo. This methylation prevents Cullin1-FBW7 E3 ligase binding to GPX4, thereby abrogating the ubiquitination-mediated GPX4 degradation. Notably, combining PRMT5 inhibitor treatment with ferroptotic therapies markedly suppresses tumour progression in mouse tumour models. In addition, the levels of GPX4 are negatively correlated with the levels of FBW7 and a poor prognosis in patients with human carcinoma. In summary, we found that PRMT5 functions as a target for improving cancer therapy efficacy, by acting to reduce the counteraction of ferroptosis by tumour cells by means of PRMT5-enhanced GPX4 stability.

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.

Protein Synthesis and Metabolism in T Cells

T lymphocytes are essential for immune responses to pathogens and tumors. Their ability to rapidly clonally expand and differentiate to effector cells following infection, and then to curb effector function following infection clearance, is fundamental for adaptive immunity. Proteome remodeling in response to immune activation is a fundamental mechanism that allows T cells to swiftly reprogram for acquisition of effector function and is possible only because antigen receptor- and cytokine-driven signal transduction pathways can trigger massive increases in protein synthesis. Equally, the ability to repress protein synthesis supports a return to quiescence once pathogens are cleared to avoid autoimmunity and to generate memory T cell populations. This review discusses what is known about T cell proteomes and the regulatory mechanisms that control protein synthesis in T cells. The focus is on how this fundamental process is dynamically controlled to ensure immune homeostasis.

Methionine-driven YTHDF1 expression facilitates bladder cancer progression by attenuating RIG-I-modulated immune responses and enhancing the eIF5B-PD-L1 axis

The impact of amino acids on tumor immunotherapy is gradually being uncovered. In this study, we screened various essential and non-essential amino acids and found that methionine enhances mRNA methylation and reduced the activation of Type I interferon pathway in bladder cancer. Through RNA sequencing, point mutations, MB49 mouse tumor models, and single-cell RNA sequencing, we demonstrated that high methionine levels elevate the expression of m6A reader YTHDF1, promoting the degradation of RIG-I, thereby inhibiting the RIG-I/MAVS-mediated IFN-I pathway and reducing the efficacy of tumor immunotherapy. Additionally, immunoprecipitation and mass spectrometry revealed that YTHDF1 binds to the eukaryotic translation initiation factor eIF5B, which acts on PD-L1 mRNA to enhance its translation and promote immune evasion. By intravesical administration of oncolytic bacteria VNP20009, we effectively depleted methionine locally, significantly prolonging mouse survival and enhancing immune cell infiltration and differentiation within tumors. Multiplex immunofluorescence assays in bladder cancer immunotherapy patients confirmed our findings. Our research elucidates two mechanisms by which methionine inhibits bladder cancer immunotherapy and proposes a targeted methionine depletion strategy that advances research while minimizing nutritional impact on patients.

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.

Immunogenomic cancer evolution: A framework to understand cancer immunosuppression

The process of tumor development involves tumor cells eluding detection and suppression of immune responses, which can cause decreased tumor cell antigenicity, expression of immunosuppressive molecules, and immunosuppressive cell recruitment to the tumor microenvironment (TME). Immunologically and genomically integrated analysis (immunogenomic analysis) of patient specimens has revealed that oncogenic aberrant signaling is involved in both carcinogenesis and immune evasion. In noninflamed cancers such as epidermal growth factor receptor (EGFR)-mutated lung cancers, genetic abnormalities in cancer cells contribute to the formation of an immunosuppressive TME by recruiting immunosuppressive cells, which cannot be fully explained by the cancer immunoediting hypothesis. This review summarizes the latest findings regarding the links between cancer genetic abnormalities and immunosuppression causing clinical resistance to immunotherapy. We propose the concepts of immunogenomic cancer evolution, in which cancer cell genomic evolution shapes the immunosuppressive TME, and immunogenomic precision medicine, in which cancer immunotherapy can be combined with molecularly targeted reagents that modulate the immunosuppressive TME.

CDKN2A Low cancer cells outcompete macrophages for microenvironmental zinc to drive immunotherapy resistance

Approximately 50% of cancers exhibit decreased CDKN2A expression ( CDKN2A Low ), which is linked to immune checkpoint blockade (ICB) resistance. While CDKN2A is traditionally recognized as a tumor suppressor and cell cycle regulator, we have previously put forth a new paradigm demonstrating its role in intracellular metabolic reprogramming. Whether the metabolic derangement due to CDKN2A loss alters metabolites within the tumor microenvironment (TME) and how that affects the immune compartment and ICB response has never been investigated. Here we found that CDKN2A Low cancer cells reorganize zinc compartmentalization by upregulating the zinc importer SLC39A9 in the plasma membrane, leading to intracellular zinc accumulation in cancer cells and concurrent zinc depletion in the TME. This competition for zinc results in zinc-starved tumor-associated macrophages (TAMs), leading to reduced phagocytic activity. Increasing zinc in TAMs through multiple approaches, including a dietary intervention that increases availability of TME zinc, re-educates these TAMs to a pro-phagocytic phenotype. Remarkably, both knockdown of Slc39a9 in cancer cells or providing a high zinc diet sensitizes Cdkn2a Low tumors to ICB. TAMs, not T cells, are indispensable for ICB response. Clinically, TAMs from CDKN2A Low cancer patients have decreased zinc signatures, corresponding to reduced phagocytosis signatures. Moreover, patients with low circulating zinc levels have reduced time-to-event outcomes compared to those with higher zinc levels. Our work reveals a previously unrecognized mechanism through which CDKN2A Low cancer cells outcompete TAMs for zinc, directly disrupting their function and ICB efficacy.

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.

Methionine Metabolism Dictates PCSK9 Expression and Antitumor Potency of PD-1 Blockade in MSS Colorectal Cancer

Nutrient metabolisms are vitally interrelated to cancer progression and immunotherapy. However, the mechanisms by which nutrient metabolisms interact to remodel immune surveillance within the tumor microenvironment remain largely unexplored. Here it is demonstrated that methionine restriction inhibits the expression of proprotein convertase subtilisin/kexin type 9 (PCSK9), a key regulator of cholesterol homeostasis and a potential target for cancer immunotherapy, in colorectal cancer (CRC) but not in the liver. Mechanistically, methionine is catabolized to S-adenosylmethionine (SAM), promoting mRNA transcription of PCSK9 through increased DNA methyltransferase 1 (DNMT1)-mediated DNA methylation and suppression of sirtuin 6 (SIRT6) expression. Furthermore, both PCSK9 inhibition and dietary methionine restriction (DMR) potentiate PD-1 blockade therapy and foster the infiltration of CD8+ T cells in Colon 26 tumor-bearing mice-a proficient mismatch repair (pMMR)/microsatellite stable (MSS) CRC model that exhibits limited response to anti-PD-1 therapy. Moreover, combining 5-fluorouracil (5-FU) chemotherapy with PCSK9 inhibition and PD-1 blockade further augments therapeutic efficacy for MSS CRC. The findings establish a mechanistic link between amino acid metabolism and cholesterol metabolism within the tumor microenvironment where tumor cells sense methionine to regulate PCSK9 expression, highlighting promising combination therapeutic strategies that may greatly benefit MSS CRC patients.

Peptide core spherical nucleic acids circumvent tumor immunosuppression via supplementing methionine for enhanced photodynamic/gene immune/therapy of hepatocellular carcinoma

Spherical nucleic acids (SNAs) with functional peptide cores are an emerging nanoplatform for synergistic cancer therapy but have been rarely reported. We construct herein the first SNA nanoplatform based on a biodegradable binary peptide backbone of methionine (Met) and cysteine (Cys) for codelivery of a photosensitizer, Chlorin e6 (Ce6) and human liver-specific miR122 for synergistic photodynamic-gene therapy of hepatic cell carcinoma (HCC). Met supplementation by the peptide core improves the infiltration of T cells and enhances the effector function of T cells for turning a "cold" tumor into a "hot" one. The resulting SNA(+) shows the most significant inhibitory effect in a Hepa1-6 HCC primary/distal tumor model, with tumor growth inhibition (TGI) values of 98.5 ± 0.5 % and 99.1 ± 0.4 % for the primary and distant tumors, respectively. This SNA nanoplatform achieves superior high TGI values reported thus far to our knowledge with almost complete eradication for both tumors due to the simultaneous adaptive and innate immunity activation via photodynamic therapy (PDT) induced immunogenic cell death (ICD) and Met supplementation-promoted adaptive immunity, and miR122-enhanced innate immunity. Overall, this study not only develops a reliable synthetic strategy toward peptide-backboned multifunctional SNA nanoplatform, but also reports the modulation of amino acid metabolism for enhanced innate immunity for highly efficient HCC immunotherapy.

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.

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.

The epigenetic hallmarks of immune cells in cancer

Targeting the dysregulation of epigenetic mechanisms in cancer has emerged as a promising therapeutic strategy. Although the significant rationale progress of epigenetic therapies in blocking cancer cells, how epigenetic regulation shapes tumor microenvironment (TME) and establishes antitumor immunity remains less understood. Recent study focus has been put on the epigenetic-mediated changes in the fate of immune cells, including the differentiation, expansion, recruitment, functionalization, and exhaustion of T cells, natural killer (NK) cells, tumor-associated macrophages (TAMs), dendritic cells (DCs), myeloid-derived suppressor cells (MDSCs), and B cells within the TME. Here, we review the latest molecular and clinical insights into how DNA modifications, histone modification, and epitranscriptome-related regulations shape immune cells of various cancers. We also discuss opportunities for leveraging epigenetic therapies to improve cancer immunotherapies. This review provides the epigenetic foundations of cancer immunity and proposes the future direction of combination therapies.

Methionine metabolite spermidine inhibits tumor pyroptosis by enhancing MYO6-mediated endocytosis

The connection between amino acid metabolism and pyroptosis remains elusive. Herein, we screen the effect of individual amino acid on pyroptosis and identify that methionine inhibits GSDME-mediated pyroptosis. Mechanistic analyses unveil that MYO6, a unique actin-based motor protein, bridges the GSDME N-terminus (GSDME-NT) and the endocytic adaptor AP2, mediating endolysosomal degradation of GSDME-NT. This degradation is increased by the methionine-derived metabolite spermidine noncanonically by direct binding to MYO6, which enhances MYO6 selectivity for GSDME-NT. Moreover, combination targeted therapies using dietary or pharmacological inhibition in methionine-to-spermidine metabolism in the tumor promotes pyroptosis and anti-tumor immunity, leading to a stronger tumor-suppressive effect in in vivo models. Clinically, higher levels of tumor spermidine and expression of methionine-to-spermidine metabolism-related gene signature predict poorer survival. Conclusively, our research identifies an unrecognized mechanism of pyroptotic resistance mediated by methionine-spermidine metabolic axis, providing a fresh angle for cancer treatment.

Targeting Arachidonic Acid Metabolism Enhances Immunotherapy Efficacy in ARID1A-Deficient Colorectal Cancer

AT-rich interactive domain-containing protein 1A (ARID1A), a core constituent of the switch/sucrose nonfermentable (SWI/SNF) complex, is mutated in approximately 10% of colorectal cancers. Whereas ARID1A deficiency corresponds to heightened immune activity in colorectal cancer, immune checkpoint inhibitors (ICI) have shown limited efficacy in these tumors. The discovery of targetable vulnerabilities associated with ARID1A deficiency in colorectal cancer could expand treatment options for patients. In this study, we demonstrated that arachidonic acid (AA) metabolism inhibitors synergize with ICIs in ARID1A-deficient colorectal cancer by enhancing the activity of CD8+ T cells and inhibiting vasculogenic mimicry. Epigenetic analysis using ATAC-seq and ChIP-qPCR revealed that the lack of ARID1A results in reduced levels of PTGS1 and PTGS2, the key enzymes that control the AA pathway. Low PTGS1 and PTGS2 expression generated a reliance on the remaining functionality of the AA pathway in ARID1A-deficient cells. The AA pathway inhibitor aspirin selectively inhibited the growth of ARID1A-deficient colorectal cancer, and aspirin sensitized tumors lacking ARID1A to immunotherapy. Together, these findings suggest that blocking AA metabolism can enhance immune responses against tumors by activating CD8+ T cells and inhibiting vasculogenic mimicry, which synergizes with ICIs to improve treatment of ARID1A-deficient colorectal cancer. Significance: The arachidonic acid pathway is a metabolic vulnerability in ARID1A-deficient colorectal cancer that can be targeted with aspirin to suppress tumor growth and enhance sensitivity to immunotherapy, providing a promising therapeutic strategy.

Enhancer reprogramming: critical roles in cancer and promising therapeutic strategies

Transcriptional dysregulation is a hallmark of cancer initiation and progression, driven by genetic and epigenetic alterations. Enhancer reprogramming has emerged as a pivotal driver of carcinogenesis, with cancer cells often relying on aberrant transcriptional programs. The advent of high-throughput sequencing technologies has provided critical insights into enhancer reprogramming events and their role in malignancy. While targeting enhancers presents a promising therapeutic strategy, significant challenges remain. These include the off-target effects of enhancer-targeting technologies, the complexity and redundancy of enhancer networks, and the dynamic nature of enhancer reprogramming, which may contribute to therapeutic resistance. This review comprehensively encapsulates the structural attributes of enhancers, delineates the mechanisms underlying their dysregulation in malignant transformation, and evaluates the therapeutic opportunities and limitations associated with targeting enhancers in cancer.

Cytometry at the Intersection of Metabolism and Epigenetics in Lymphocyte Dynamics

Landmark studies at the turn of the century revealed metabolic reprogramming as a driving force for lymphocyte differentiation and function. In addition to metabolic changes, differentiating lymphocytes must remodel their epigenetic landscape to properly rewire their gene expression. Recent discoveries have shown that metabolic shifts can shape the fate of lymphocytes by altering their epigenetic state, bringing together these two areas of inquiry. The ongoing evolution of high-dimensional cytometry has enabled increasingly comprehensive analyses of metabolic and epigenetic landscapes in lymphocytes that transcend the technical limitations of the past. Here, we review recent insights into the interplay between metabolism and epigenetics in lymphocytes and how its dysregulation can lead to immunological dysfunction and disease. We also discuss the latest technical advances in cytometry that have enabled these discoveries and that we anticipate will advance future work in this area.

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.

Mechanisms and rationales of SAM homeostasis

S-Adenosylmethionine (SAM) is the primary methyl donor for numerous cellular methylation reactions. Its central role in methylation and involvement with many pathways link its availability to the regulation of cellular processes, the dysregulation of which can contribute to disease states, such as cancer or neurodegeneration. Emerging evidence indicates that intracellular SAM levels are maintained within an optimal range by a variety of homeostatic mechanisms. This suggests that the need to maintain SAM homeostasis represents a significant evolutionary pressure across all kingdoms of life. Here, we review how SAM controls cellular functions at the molecular level and discuss strategies to maintain SAM homeostasis. We propose that SAM exerts a broad and underappreciated influence in cellular regulation that remains to be fully elucidated.

Engineered Methioninase-expressing Tumor-targeting Salmonella typhimurium A1-R Inhibits Syngeneic-Cancer Mouse Models by Depleting Tumor Methionine

BACKGROUND/AIM

We previously developed Salmonella typhimurium A1-R, which selectively targets and kills tumors. In the present study, we established recombinant methioninase (rMETase)-producing Salmonella typhimurium A1-R (A1-R-rMETase), by transfer of the Pseudomonas putida methioninase gene, to target methionine addiction of syngeneic-cancer mouse models.

MATERIALS AND METHODS

A plasmid containing the Pseudomonas putida methioninase gene was extracted from METase-producing recombinant E. coli and inserted into Salmonella typhimurium A1-R using electroporation. Lewis Lung Carcinoma (LLC) cells (106) were injected subcutaneously in male C57BL/6 mice aged 4-6 weeks. We determined that 108 Salmonella typhimurium A1-R-rMETase administered iv was a safe dosage in C57BL/6 mice and was used for efficacy studies on LLC tumors in C57BL/6 mice. Tumor size was measured with calipers three times per week for 3 weeks. On day 22, tumor methionine levels were measured using HPLC in the control mice injected with phosphate-buffered saline (PBS) and the mice injected with Salmonella typhimurium A1-R-rMETase.

RESULTS

The mean LLC tumor size of each group on day 22 was as follows: PBS control: 741.5 mm3; mice injected with Salmonella typhimurium A1-R: 566.3 mm3 (p=0.370); and mice injected with Salmonella typhimurium A1-R-rMETase: 198.8 mm3 (p=0.0003 vs control and p=0.0117 vs. Salmonella A1-R). The mice injected with Salmonella typhimurium A1-R-rMETase showed a significantly lower mean tumor methionine level than mice injected with PBS (5.9 nM/mg protein vs 11.1 nM/mg protein, p=0.0095). Salmonella typhimurium A1-R-rMETase grew continuously in the tumors but not in the liver or spleen.

CONCLUSION

Tumor-targeting Salmonella typhimurium A1-R engineered to express the Pseudomonas putida methioninase gene, inhibited LLC tumor growth in a syngeneic mouse model and reduced the methionine level in the tumor. Salmonella typhimurium A1-R-rMETase combines the tumor targeting and killing capability of Salmonella typhimurium A1-R plus rMETase which targets the methionine addiction of cancer.

Methionine regulates maternal-fetal immune tolerance and endometrial receptivity by enhancing embryonic IL-5 secretion

Endometrial receptivity and maternal-fetal immune tolerance are two crucial processes for a successful pregnancy. However, the molecular mechanisms of nutrition involved are largely unexplored. Here, we showed that maternal methionine supply significantly improved pregnancy outcomes, which was closely related to interleukin-5 (IL-5) concentration. Mechanistically, methionine induced embryonic IL-5 secretion, which enhanced the conversion of CD4+ T cells to IL-5+ Th2 cells in the uterus, thereby improving maternal-fetal immune tolerance. Meanwhile, methionine-mediated IL-5 secretion activated the nuclear factor κB (NF-κB) pathway and enhanced integrin αvβ3 expression in endometrial cells, which improved endometrial receptivity. Further, methionine strongly influenced the DNA methylation and transcription levels of the transcription factor eomesodermin (Eomes), which bound directly to the IL-5 promoter region and inhibited IL-5 transcription. Methionine modulated IL-5 transcription, maternal-fetal immune tolerance, and endometrial receptivity via its effects on Eomes. This study reveals the crucial functions of methionine and IL-5 and offers a potential nutritional strategy for successful pregnancy.

Nanovaccines empowering CD8+ T cells: a precision strategy to enhance cancer immunotherapy

Cancer immunotherapy leveraging nanovaccines represents a cutting-edge frontier in precision medicine, specifically designed to potentiate CD8+ T cell-based immunotherapy. This review thoroughly delineates the evolving landscape of cancer nanovaccine development, emphasizing their advantageous role in modulating the immunosuppressive tumor microenvironment (TME) to enhance CD8+ T cell efficacy. We critically analyze current innovations in nanovaccine design, focusing on their capacity to deliver tumor antigens and immunostimulatory adjuvants effectively. These nanovaccines are engineered to overcome the physical and immunological barriers of the TME, facilitating the robust activation and proliferation of CD8+ T cells. Challenges such as delivery efficacy, safety, and scalable manufacturing are discussed, alongside future prospects which include the potential of developing specific biomaterial approaches to provide durable antitumor immunity. This comprehensive analysis not only underscores the transformative potential of cancer nanovaccines in enhancing CD8+ T cell responses but also highlights the critical need for advanced solutions to overcome the complex interplay of factors that limit the efficacy of current immunotherapies.

Methionine Restriction Exerts Anti-Tumor Immunity via Joint Intervention of T-Bet Palmitoylation in Gastric Cancer

BACKGROUND

Methionine restriction (MR) exerts an anti-tumor immunomodulatory role. Th1 cells facilitate CD8+ cytotoxic T cell activation and targeted tumor cell killing. Our previous work shows that MR enhances the immunotherapy effect of PD-L1/PD-1 blockade on gastric cancer, MR can simultaneously inhibit Th1 cell differentiation, which may affect their synergistic therapeutic outcome. We aim to elucidate the molecular mechanism of MR regulating Th1 cell activation in gastric cancer.

METHODS

Murine Foregastric Carcinoma (MFC) cells were injected into 615 mice to establish transplanted tumor models, which were then treated with an MR diet or combined with 2-bromopalmitate (2-BP). CD4+T cells were cultured with deficient methionine. The acyl-biotinyl exchange (ABE) method was to detect T-bet palmitoylation and cycloheximide experiments to detect protein stability. GPS-Palm tool was employed to screen palmitoyltransferases. The impact of T-bet palmitoylation on the pro-tumor-killing effect of Th1 cells was examined.

RESULTS

MR enhanced anti-PD-1's inhibition of tumor growth, while concurrently suppressing the increased Th1 cells. Combined with 2-BP further inhibited tumor and increased Th1 cells. Suppressing Th1 activity attenuated 2-BP's synergistic therapeutic effect and reduced CD8+ GZMB+ T cells. MR inhibited Th1 differentiation by reducing T-bet expression, 2-BP treatment restored, while T-bet interference reversed 2-BP's effect. MR increased palmitoylation and T-bet underwent palmitoylation modification. ZDHHC23 mediated T-bet palmitoylation and promoted T-bet degradation. MR promoted T-bet degradation, thereby decreasing T-bet content, inhibiting Th1 cell polarization and CD8+ T cell killing effect.

CONCLUSIONS

MR combined with T-bet palmitoylation intervention promotes Th1 polarization and CD8+ T cell toxicity, thereby enhancing anti-tumor immunity in gastric cancer.

Nicotinamide N-methyltransferase negatively regulates metastasis-promoting property of cancer-associated fibroblasts in lung adenocarcinoma

BACKGROUND

Recurrence and metastasis remain significant challenges in lung adenocarcinoma (LUAD) after radical resection. The mechanisms behind the recurrence and metastasis of LUAD remain elusive, and deregulated cellular metabolism is suspected to play a significant role. This study explores the metabolic and epigenetic regulation mediated by nicotinamide N-methyl transferase (NNMT) in LUAD.

METHODS

Untargeted metabolomic analyses were performed to detect metabolism irregularities. Single-cell RNA sequencing (RNA-seq) databases and multiplex immunofluorescence analysis were used to identify the location of NNMT within the tumor microenvironment. The biological functions of NNMT were investigated both in vitro and in vivo, with RNA-seq and chromatin immunoprecipitation-PCR providing insights into underlying mechanisms. Finally, single-cell RNA-seq data and immunohistochemistry of primary tumors were analyzed to validate the main findings.

RESULTS

Untargeted metabolomic analyses revealed metabolic aberrations in amino acids, organic acids, lipids, and nicotinamide pathways, which are linked to metastasis of non-small cell lung cancer. NNMT is a key enzyme in nicotinamide metabolism, and we found the bulk tissue mRNA level of NNMT gene was inversely associated with LUAD metastasis. NNMT was proved to be predominantly expressed in cancer-associated fibroblasts (CAFs) within the stromal regions of LUAD, and a low stromal NNMT expression was identified as a predictor of poor disease-free survival following radical resection of LUAD. The isolation and primary culture of CAFs from LUAD enabled in vitro and in vivo experiments, which confirmed that NNMT negatively regulated the metastasis-promoting properties of CAFs in LUAD. Mechanistically, the downregulation of NNMT led to an increase in intracellular methyl groups by reducing the activity of the methionine cycle, resulting in heightened methylation at H3K4me3. This alteration triggered the upregulation of genes involved in extracellular matrix remodeling in CAFs, including those encoding collagens, integrins, laminins, and matrix metalloproteinases, thereby facilitating cancer cell invasion and metastasis. Reanalysis of single-cell RNA-seq data and immunohistochemistry assays of primary LUAD tissues substantiated NNMT's negative regulation of these genes in CAFs.

CONCLUSIONS

This study provides novel insights into the metabolic and epigenetic regulatory functions of NNMT in CAFs, expanding the current understanding of LUAD metastasis regulation and suggesting potential avenues for future research and therapeutic development.

Tumor-induced metabolic immunosuppression: Mechanisms and therapeutic targets

Metabolic reprogramming in both immune and cancer cells plays a crucial role in the antitumor immune response. Recent studies indicate that cancer metabolism not only sustains carcinogenesis and survival via altered signaling but also modulates immune cell function. Metabolic crosstalk within the tumor microenvironment results in nutrient competition and acidosis, thereby hindering immune cell functionality. Interestingly, immune cells also undergo metabolic reprogramming that enables their proliferation, differentiation, and effector functions. This review highlights the regulation of antitumor immune responses through metabolic reprogramming in cancer and immune cells and explores therapeutic strategies that target these metabolic pathways in cancer immunotherapy, including using chimeric antigen receptor (CAR)-T cells. We discuss innovative combinations of immunotherapy, cellular therapies, and metabolic interventions that could optimize the efficacy of existing treatment protocols.

Microenvironmental β-TrCP negates amino acid transport to trigger CD8+ T cell exhaustion in human non-small cell lung cancer

CD8+ T cell exhaustion (Tex) has been widely acknowledged in human cancer, while the underlying mechanisms remain unclear. Here, we demonstrate that reduced amino acid (aa) metabolism and mTOR inactivation are accountable for Tex in human non-small cell lung cancer (NSCLC). NSCLC cells impede the T cell-intrinsic transcription of SLC7A5 and SLC38A1, disrupting aa transport and consequently leading to mTOR inactivation. Further, the ubiquitination of YAP1 protein is the basis for NSCLC-mediated transcriptional inhibition of aa transporters. Mechanistically, NSCLC cells transfer β-TrCP-containing exosomes into T cells, inducing YAP1 ubiquitination and Tex. Consequently, inhibiting cancer-associated β-TrCP effectively restores the anti-tumor immune response of CD8+ T cells and curtails tumor growth in NSCLC patient-derived organoids. Together, our findings highlight a β-TrCP-dependent mechanism in steering intrinsic metabolic adaptation and CD8+ Tex, emphasizing microenvironmental β-TrCP as an immune checkpoint for therapeutic exploration against human NSCLC.

Global Trends in Research of Amino Acid Metabolism in T Lymphocytes in Recent 15 Years: A Bibliometric Analysis

Amino acid metabolism in T cells determines the therapeutic efficacy of T-cell-targeting drugs. To assess the direction of amino acid metabolism in T cells and construct related knowledge structure, we performed a bibliometric analysis aiming at amino acid metabolism in T cells utilizing studies publicized in recent 15 years. Three hundred thirty-seven related studies were downloaded from the Web of Science Core Collection (WoSCC), and the information on countries, institutes, and authors was collected and analyzed. In addition, the present research status and future trends were explored according to the results yielded from the analysis of cited references and keywords. This study revealed that publications regarding amino acid metabolism in T cells gradually increased each year. The USA is the top producer and most influential country in this field. Recent research has focused on the correlation between the metabolism of several amino acids and regulatory T cells (Tregs) and CD8+ T cells. Overall, this research offers a comprehensive exhibition on the field of amino acid metabolism in T cells, which will help researchers to study this domain more effectively and intuitively.

VCP downstream metabolite glycerol-3-phosphate (G3P) inhibits CD8+T cells function in the HCC microenvironment

CD8+T cells within the tumor microenvironment (TME) are often functionally impaired, which limits their ability to mount effective anti-tumor responses. However, the molecular mechanisms behind this dysfunction remain incompletely understood. Here, we identified valosin-containing protein (VCP) as a key regulator of CD8+T cells suppression in hepatocellular carcinoma (HCC). Our findings reveal that VCP suppresses the activation, expansion, and cytotoxic capacity of CD8+T cells both in vitro and in vivo, significantly contributing to the immunosuppressive nature of the TME. Mechanistically, VCP stabilizes the expression of glycerol-3-phosphate dehydrogenase 1-like protein (GPD1L), leading to the accumulation of glycerol-3-phosphate (G3P), a downstream metabolite of GPD1L. The accumulated G3P diffuses into the TME and directly interacts with SRC-family tyrosine kinase LCK, a critical component of the T-cell receptor (TCR) signaling pathway in CD8+T cells. This interaction heightens the phosphorylation of Tyr505, a key inhibitory residue, ultimately reducing LCK activity and impairing downstream TCR signaling. Consequently, CD8+T cells lose their functional capacity, diminishing their ability to fight against HCC. Importantly, we demonstrated that targeting VCP in combination with anti-PD1 therapy significantly suppresses HCC tumor growth and restores the anti-tumor function of CD8+T cells, suggesting synergistic therapeutic potential. These findings highlight a previously unrecognized mechanism involving VCP and G3P in suppressing T-cell-mediated immunity in the TME, positioning VCP as a promising upstream target for enhancing immunotherapy in HCC.

Single-cell profiling of SLC family transporters: uncovering the role of SLC7A1 in osteosarcoma

BACKGROUND

Osteosarcoma is the most common malignant bone tumor in children and adolescents, characterized by high disability and mortality rates. Over the past three decades, therapeutic outcomes have plateaued, underscoring the critical need for innovative therapeutic targets. Solute carrier (SLC) family transporters have been implicated in the malignant progression of a variety of tumors, however, their specific role in osteosarcoma remains poorly understood.

METHODS

The single-cell sequencing data from GSE152048 and GSE162454, along with RNA-seq from the TARGET and GSE21257 cohorts, were utilized for the analysis in this study. LASSO regression analysis was conducted to identify prognostic genes and construct an SLC-related prognostic signature. Survival analysis and ROC analysis evaluated the validity of the prognostic signature. The ESTIMATE and CIBERSORT Packages were utilized to assess the immune infiltration status. Pseudotime and CellChat analyses were performed to investigate the relationship between SLC7A1, malignant phenotypes, and the immune microenvironment. CCK8 assays, EdU staining, colony formation assays, Transwell assays, and co-culture systems were used to assess the effects of SLC7A1 on cell proliferation, metastasis, and macrophage polarization. Finally, virtual docking identified potential drugs targeting SLC7A1.

RESULTS

SLCs displayed distinct expression patterns across various cell types within the osteosarcoma microenvironment, with myeloid cells exhibiting a preference for amino acid uptake. A prognostic model comprising nine genes was constructed via LASSO regression, with SLC7A1 showing the highest hazard ratio. Multiple analytical algorithms indicated that SLCs were associated with immune cell infiltration and immune checkpoint gene expression. Single-cell analysis indicated that SLC7A1 was predominantly expressed in osteosarcoma cells and correlated with various malignant tumor characteristics. SLC7A1 also regulate interactions between tumor cells and macrophages, as well as modulate macrophage function through multiple pathways. In vitro assays and survival analysis demonstrated that inhibition of SLC7A1 suppressed the malignant phenotype of osteosarcoma cells, with SLC7A1 expression correlating with poor prognosis. Co-culture models confirmed the involvement of SLC7A1 in macrophage polarization. Finally, virtual screening and CETSA identified Cepharanthine as potential inhibitors of SLC7A1.

CONCLUSION

SLC-related prognostic signatures can be utilized for the prognostic evaluation of osteosarcoma. Pharmacological inhibition of SLC7A1 may be a feasible therapeutic approach for osteosarcoma.

SERINC2-mediated serine metabolism promotes cervical cancer progression and drives T cell exhaustion

Cervical cancer remains the most prevalent gynecological malignant disease. Reprogramming tumor immune metabolism stands out as a novel promising therapeutic target. Here, we identified serine incorporator 2 (SERINC2) as a critical gene which highly expressed in cervical cancer and negatively correlated with clinical outcomes. Through functional assays, SERINC2 was determined to play a pro-tumoral role both in vivo and in vitro. Besides, the growth of cervical cancer cells was found to be largely dependent on serine in a manner influenced by SERINC2. As a serine transport associated protein, SERINC2 knockdown significantly reduced cervical cancer cells' intracellular serine level and altered the serine-associated-lipid metabolism. Immune infiltration analysis revealed that SERINC2 was negatively associated with CD8+ T cell infiltration and function. More importantly, we demonstrated a competitive relation between cancer cells and immune cells brought about by SERINC2. Mechanistically, cancer cells SERINC2 preferentially competed for micro-environmental serine over CD8+ T cells and rendered T cell exhaustion. Overall, SERINC2 remodels cancer development and serine metabolism in the tumor immune microenvironment (TIME), establishing an immunosuppressive and pro-tumoral milieu.

Nanomaterial-enabled metabolic reprogramming strategies for boosting antitumor immunity

Immunotherapy has become a crucial strategy in cancer treatment, but its effectiveness is often constrained. Most cancer immunotherapies focus on stimulating T-cell-mediated immunity by driving the cancer-immunity cycle, which includes tumor antigen release, antigen presentation, T cell activation, infiltration, and tumor cell killing. However, metabolism reprogramming in the tumor microenvironment (TME) supports the viability of cancer cells and inhibits the function of immune cells within this cycle, presenting clinical challenges. The distinct metabolic needs of tumor cells and immune cells require precise and selective metabolic interventions to maximize therapeutic outcomes while minimizing adverse effects. Recent advances in nanotherapeutics offer a promising approach to target tumor metabolism reprogramming and enhance the cancer-immunity cycle through tailored metabolic modulation. In this review, we explore cutting-edge nanomaterial strategies for modulating tumor metabolism to improve therapeutic outcomes. We review the design principles of nanoplatforms for immunometabolic modulation, key metabolic pathways and their regulation, recent advances in targeting these pathways for the cancer-immunity cycle enhancement, and future prospects for next-generation metabolic nanomodulators in cancer immunotherapy. We expect that emerging immunometabolic modulatory nanotechnology will establish a new frontier in cancer immunotherapy in the near future.

Tumor metabolic regulators: key drivers of metabolic reprogramming and the promising targets in cancer therapy

Metabolic reprogramming within the tumor microenvironment (TME) is a hallmark of cancer and a crucial determinant of tumor progression. Research indicates that various metabolic regulators form a metabolic network in the TME and interact with immune cells, coordinating the tumor immune response. Metabolic dysregulation creates an immunosuppressive TME, impairing the antitumor immune response. In this review, we discuss how metabolic regulators affect the tumor cell and the crosstalk of TME. We also summarize recent clinical trials involving metabolic regulators and the challenges of metabolism-based tumor therapies in clinical translation. In a word, our review distills key regulatory factors and their mechanisms of action from the complex reprogramming of tumor metabolism, identified as tumor metabolic regulators. These regulators provide a theoretical basis and research direction for the development of new strategies and targets in cancer therapy based on tumor metabolic reprogramming.