ATP and Adenosine Metabolism in Cancer: Exploitation for Therapeutic Gain

Bacteria-based biohybrids for remodeling adenosine-mediated immunosuppression to boost radiotherapy-triggered antitumor immune response

Radiotherapy (RT) can trigger immunogenic cell death (ICD) in tumor cells and release adenosine triphosphate (ATP) to activate antitumor immunity. However, the formation of immunosuppressive adenosine (ADO) mediated by ectonucleotidases including CD39 and CD73, can exacerbate the immunosuppressive effects. Herein, a radiosensitizer-based metal-organic framework (MOF) composed of bismuth (Bi) and ellagic acid (EA) was synthesized in situ on the surface of Escherichia coli Nissle 1917 (EcN) to serve as a carrier for the CD39 inhibitor sodium polyoxotungstate (POM-1). This therapeutic platform, acting as a radiosensitizer, significantly enhances cytotoxicity against tumor cells while effectively inducing ICD and releasing high concentrations of ATP. Subsequently, the released POM-1 increases the levels of pro-inflammatory extracellular ATP while preventing tumor immunosuppression caused by the accumulation of ADO. Additionally, as a natural immune adjuvant, EcN further promotes the maturation of dendritic cells (DCs) and the infiltration of cytotoxic T lymphocytes (CTLs). As a result, such treatment initiates the destruction of established tumor growth and induces strong abscopal effects, leading to a significant inhibition of tumor metastases. This strategy presents a bacterial-based biohybrid system that facilitates RT-induced ICD while simultaneously limiting the degradation of ATP into ADO, thereby achieving sustained anti-tumor immunity.

T4 DNA Polymerase-Proofread DNA Binding Identifier for Sensitive Homogeneous Immunoassays

Aptamer-based homogeneous immunoassays exhibit considerable potential in the domains of bioanalysis and biodiagnosis owing to their universality in analyzing both proteins and small molecules as well as their compatibility with nucleic acid amplification technologies. Nevertheless, the substantial signal leakage by nonspecific aptamer allostery poses a challenge to enhancing sensitivity further. Herein, we reported a T4 DNA polymerase-proofread DNA binding identifier (ReID). This strategy could harness the dual-enzymatic activity of T4 DNA polymerase to eliminate the leaked signal, thereby efficiently integrating target-induced aptamer allostery with subsequent polymerase chain reaction signal amplification. Moreover, we explored the regulation mechanism of dNTPs concentration on the dual-enzymatic activity of the T4 DNA polymerase. As a result, this strategy achieved an ultrasensitive protein detection limit of 8 fg/mL, validating the effectiveness of this proofreading approach. The universality was further confirmed by highly sensitive detection of small molecules. The exploration of ReID represents a significant advancement in the sensitivity and universality of immunoassays, even demonstrating the potential for multiple proteomic assays, offering a novel perspective for the development of high-performance homogeneous immunoassays.

A novel molecular classification system for head and neck squamous cell carcinoma: predicting treatment response and metastatic potential through multi-omics analysis

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) demonstrates significant heterogeneity, necessitating improved molecular classification for precision treatment.

METHODS

We integrated single-cell and bulk RNA sequencing data from 59,376 cells across ten datasets using Scissor and scSTAR packages. Molecular subtyping was performed through ssGSEA and WGCNA analysis, with immune infiltration evaluated using CIBERSORT. We developed a machine learning-based risk prediction model using 54 algorithms.

RESULTS

We identified three molecular subtypes with distinct prognostic implications, showing significant survival differences across independent datasets (TCGA-HNSCC, P < 0.0001; GSE65858, P = 0.018). The C3 subtype showed enhanced immunotherapy response potential, while C2 exhibited the highest genomic alteration rate (97.06%) and TP53 mutations (80%). Macrophages emerged as key players in intercellular communication networks. Our risk prediction model demonstrated robust performance across four validation cohorts.

CONCLUSION

This molecular subtyping framework provides valuable insights for patient stratification and personalized therapeutic strategies in HNSCC, potentially improving clinical outcomes through precise treatment selection.

Adenosine Monophosphate Improves Lipolysis in Obese Mice by Reducing DNA Methylation via ADORA2A Activation by Ecto-5'-Nucleotidase (CD73)

The previous work discovers the potential of adenosine monophosphate (AMP) to alleviate obesity-related metabolic diseases, but the underlying molecular mechanisms remain incompletely understood. Here, AMP is confirmed to enhance white fat decomposition and improve abnormal glucose and lipid metabolism in mice fed with a high-fat (HF) diet. Mechanically, AMP is converted to adenosine (ADO) through ecto-5'-nucleotidase (CD73), and adenosine A2A receptor (ADORA2A) signaling activation is involved in the down-regulation of methylation in white adipose tissue, thereby reducing the hormone-sensitive lipase (HSL) methylation level and promoting HSL transcription and white fat decomposition. Moreover, the metabolic benefits of AMP are found to be partially eliminated in ADORA2A knockout mice, but re-expression of ADORA2A can reproduce the AMP-induced metabolic regulation in white fat. These findings reveal the mechanism that AMP, as the upstream of ADO, stimulates ADORA2A signaling and white fat DNA methylation to participate in the anti-obesity effect.

Identification of CCNB1 as a biomarker for cellular senescence in hepatocellular carcinoma: a bioinformatics and experimental validation study

BACKGROUND

Hepatocellular carcinoma (HCC), originating in the liver and often asymptomatic in early stages, frequently metastasises and recures post-surgery. Currently, reliable diagnostic biomarkers and therapeutic targets for HCC are lacking. This study investigates the influence of cellular senescence on HCC, employing bioinformatics analysis and in vitro experiments to identify potential biomarkers.

METHODS

We integrated data from GEO microarrays (GSE14520, GSE45267 and GSE64041) to analyse differentially expressed genes (DEGs) using the R package limma. WGCNA identified gene modules highly correlated to HCC. Then, ageing-highly related differentially expressed genes (AgHDEGs) were identified. Correlation analysis, GO and KEGG functional enrichment analysis, and gene co-expression network analysis further elucidated the functions of AgHDEGs. The STRING database identified hub AgHDEGs with CCNB1 subsequently evaluated for diagnostic value using ROC curve analysis. Additionally, we explored the correlation between CCNB1 and immune cells and assessed its biological functions via GSEA. Ultimately, the conclusions from bioinformatics analysis were confirmed via in vitro experiments, complemented by molecular docking simulations of gene-drug interactions.

RESULTS

Eight AgHDEGs (KPNA2, CCT3, CCNB1, RACGAP1, CDKN3, FEN1, MT1X and FOXM1) were identified. PPI network analysis highlighted CCNB1 as hub AgHDEGs with ROC analysis confirming its strong diagnostic potential. Analysis of immune infiltration revealed a significant correlation between CCNB1 and M0 macrophages. Subsequent studies showed CCNB1's critical role in regulating the cell cycle. Validation experiments illustrated an upregulation of CCNB1 expression in HCC, while inhibiting CCNB1 may reduce HepG2 cell proliferation by promoting cellular senescence. Moreover, molecular docking indicated CCNB1 as a potential therapeutic target.

CONCLUSION

Our study underscores CCNB1's potential impact on HCC senescence and progression, suggesting its candidacy as a biomarker for HCC.

Leveraging adenosine triphosphate for cancer theranostics

Manipulation of the biochemical composition of the tumor microenvironment (TME) is a thriving research area in cancer treatment. Adenosine triphosphate (ATP), a key biochemical component, serves as an energy source for cancer cell proliferation. Notably, ATP can also act as a potent signal transducer to prime anti-tumor immune responses. There is increasing attention given to both the tumor-promoting and tumor-inhibiting roles of ATP in the context of possible new treatments for cancer. ATP levels in the TME are known to be significantly greater than in non-tumor tissues. This disparity presents an opportunity to exploit the ATP response for the delivery of anti-tumor drugs and tumor diagnosis. In this article, we provide a comprehensive overview of the existing strategies and mechanisms for ATP-based therapy and cancer diagnosis. We also discuss the current challenges in the field and propose potential areas for future research, to provide researchers with insights to further investigate the potential of ATP in cancer theranostics.

An innovative glutamine metabolism-related gene signature for predicting prognosis and immune landscape in cervical cancer

BACKGROUND

Cervical cancer (CC) is a major global malignancy affecting women. However, the precise mechanisms underlying glutamine's role in CC remain inadequately understood. This study systematically assessed the survival outcomes, immune landscape, and drug sensitivity profiles with CC patients by analyzing genes associated with glutamine metabolism.

METHODS

Transcriptomic data for the samples were sourced from the TCGA, GTEx, and GEO databases. Prognostic genes were identified through univariate, multivariate, and Least Absolute Shrinkage and Selection Operator (LASSO) regression analyses. The predictive accuracy of the model was assessed through the analysis of receiver operating characteristic (ROC) curves. A comprehensive nomogram was developed and evaluated for accuracy using calibration and Decision Curve Analysis (DCA) curves. Kaplan-Meier (K-M) survival curves were employed to estimate overall survival. The relationship between risk scores and immune infiltration was analyzed through Single-sample Gene Set Enrichment Analysis (ssGSEA) and CIBERSORT. Functional enrichment analysis and the construction of miRNA and transcription factors networks were conducted to explore the potential molecular mechanisms of the signature genes.

RESULTS

This investigation identified four signature genes associated with glutamine metabolism, UCP2, LEPR, TFRC, and RNaseH2A. We successfully developed a prognostic model with strong predictive performance. In the training set, the AUC values for 1-, 3-, and 5-year survival were 0.702, 0.719, and 0.721, respectively. In the validation set, the AUC values for these time points were 0.715, 0.696, and 0.739, respectively. Patients categorized as low-risk had notably improved survival rates than those identified as high-risk (P < 0.05). Additionally, a nomogram that combines clinical data and risk scores offered improved clinical net benefits over a broad range of threshold probabilities. Functional enrichment analysis revealed that these signature genes are strongly linked to the regulation of the cell cycle and intracellular oxygen levels. Furthermore, the gene signature displayed a significant negative correlation with the infiltration levels of most immune cell types.

CONCLUSION

This novel signature demonstrates robust predictive capability for prognostic survival probabilities and immune infiltration in CC patients, providing a fresh perspective for advancing precision treatment strategies in CC.

Polydopamine-based Nanoadjuvants Promote a Positive Feedback Loop for Cancer Immunotherapy via Overcoming Photothermally Boosted T Cell Exhaustion

Immunogenic cell death, triggered by photothermal therapy or specific chemotherapy, strives to establish a positive feedback loop in cancer immunotherapy. This loop is characterized by the rapid release of antigens and adenosine triphosphate (ATP), ultimately leading to accelerated T cell infiltration. However, this loop is hindered by T cell exhaustion caused by adenosine originating from ATP and glucose deprivation in the immunosuppressive microenvironment. To overcome this challenge, we developed a pH-low insertion peptide-functionalized mesoporous-polydopamine-based nanoadjuvant that incorporates adenosine deaminase and doxorubicin (termed as PPMAD). PPMAD aimed to overcome T cell exhaustion by reducing adenosine consumption and providing an alternative carbon source for CD8+ T cell function during glucose starvation. First, PPMAD triggered the burst release of antigens and ATP through photothermal therapy and doxorubicin-induced immunogenic cell death, culminating in the expedited infiltration of T cells. Second, adenosine deaminase depleted adenosine, reducing immunosuppressive agents and generating abundant inosine, which served as an alternative carbon source for CD8+ T cells. By implementing this "reducing suppression and broadening sources" strategy, we successfully overcome T cell exhaustion, greatly enhancing the effectiveness of cancer immunotherapy both in vitro and in vivo. Our findings highlighted the positive feedback loop between on-demand photothermal therapy, chemotherapy immunotherapy, and achieving complete tumor response.

ATP ion channel-type P2X purinergic receptors as a key regulatory molecule in breast cancer progression

Studies have confirmed that ATP ion channel P2X purinergic receptors play a key role in tumor growth and metastasis. Similarly, P2X purinergic receptors can be used as a favorable regulatory molecule of breast cancer cells to participate in the progression of breast cancer. There are abundant ATP and its cleavage products in breast cancer microenvironment, which can be used as natural activators of P2X purinergic receptors. P2X purinergic receptors play a role in regulating the growth and metastasis of breast cancer cells by mediating signal transduction, growth regulation and immune cell activity in microenvironment. However, the application of P2X purinergic receptors antagonist has the pharmacological characteristics of inhibiting the progression of breast cancer cells. Among P2X purinergic receptors, there is a close relationship between P2X7 receptor and breast cancer patients. P2X purinergic receptors can be used as a biological marker for breast cancer patients. In this paper, we discuss the functional role and regulatory molecular mechanism of P2X purinergic receptors in the progression of breast cancer. The pharmacological effects of P2X purinergic receptors selective antagonist on the growth, metastasis and invasion of breast cancer cells were further discussed. Therefore, P2X purinergic receptors can be used as a key regulatory molecule of breast cancer and a pharmacological target for potential therapy.

Rational design of peptides to overcome drug resistance by metabolic regulation

Chemotherapy is widely used clinically, however, its efficacy is often compromised by the development of drug resistance, which arises from prolonged administration of drugs or other stimuli. One of the driven causes of drug resistance in tumors or bacterial infections is metabolic reprogramming, which alters mitochondrial metabolism, disrupts metabolic pathways and causes ion imbalance. Bioactive peptide materials, due to their biocompatibility, diverse bioactivities, customizable sequences, and ease of modification, have shown promise in overcoming drug resistance. This review provides an in-depth analysis of metabolic reprogramming and associated microenvironmental changes that contribute to drug resistance in common tumors and bacterial infections, suggesting potential therapeutic targets. Additionally, we explore peptide-based materials for regulating metabolism and their potential synergic effect with other therapies, highlighting the mechanisms by which these peptides reverse drug resistance. Finally, we discuss future perspectives and the clinical challenges in peptide-based treatments, aiming to offer insights for overcoming drug-resistant diseases.

Delactylase effects of SIRT1 on a positive feedback loop involving the H19-glycolysis-histone lactylation in gastric cancer

Histone lactylation, a novel epigenetic modification, is regulated by the lactate produced by glycolysis. Glycolysis is activated in various cancers, including gastric cancer (GC). However, the molecular mechanism and clinical impact of histone lactylation in GC remain poorly understood. Here, we demonstrate that histone H3K18 lactylation (H3K18la) is elevated in GC, correlating with a worse prognosis. SIRT1 overexpression decreases H3K18la levels, whereas SIRT1 knockdown increases H3K18la levels in GC cells. RNA-seq analysis demonstrates that lncRNA H19 is markedly downregulated in GC cells with SIRT1 overexpression and those grown under glucose free condition, which confirmed decreased H3K18la levels at its promoter region. H19 knockdown decreased the expression levels of LDHA and H3K18la, and LDHA knockdown impaired H19 and H3K18la expression, suggesting an H19/glycolysis/H3K18la-positive feedback loop. Combined treatment with low doses of the SIRT1-specific activator SRT2104 and the LDHA inhibitor oxamate exerted significant antitumor effects on GC cells, with limited adverse effects on normal gastric cells. The SIRT1-weak/H3K18la-strong signature was found to be an independent prognostic factor in patients with GC. Therefore, SIRT1 acts as a histone delactylase for H3K18, and loss of SIRT1 triggers a positive feedback loop involving H19/glycolysis/H3K18la. Targeting this pathway serves as a novel therapeutic strategy for GC treatment.

The CD39/CD73/Adenosine and NAD/CD38/CD203a/CD73 Axis in Cutaneous T-Cell Lymphomas

Cutaneous T-cell lymphoma (CTCL), characterized by malignant T-cell proliferation primarily in the skin, includes subtypes such as mycosis fungoides (MF) and Sézary syndrome (SS). The tumor microenvironment (TME) is central to their pathogenesis, with flow cytometry and histology being the gold standards for detecting malignant T cells within the TME. Alongside emerging molecular markers, particularly clonality analysis, these tools are indispensable for accurate diagnosis and treatment planning. Of note, adenosine signaling within the TME has been shown to suppress immune responses, affecting various cell types. The expression of CD39, CD73, and CD38, enzymes involved in adenosine production, can be elevated in MF and SS, contributing to immune suppression. Conversely, the expression of CD26, part of the adenosine deaminase/CD26 complex, that degrades adenosine, is often lost by circulating tumoral cells. Flow cytometry has demonstrated increased levels of CD39 and CD73 on Sézary cells, correlating with disease progression and prognosis, while CD38 shows a variable expression, with its prognostic significance remaining under investigation. Understanding these markers' roles in the complexity of TME-mediated immune evasion mechanisms might enhance diagnostic precision and offer new therapeutic targets in CTCL.

Combination of adenosine blockade and ferroptosis for photo-immunotherapy of triple negative breast cancer with aptamer-modified copper sulfide

Combination of immunotherapy and photothermal therapy (PTT) provides a promising therapeutic performance for tumors. However, it still faces negative feedback from suppressive factors such as adenosine. Herein, we developed a new nanodrug that can combine adenosine blockade and ferroptosis to promote the photoimmunotherapy of triple negative breast cancer (TNBC). The nanodrug, named CuS-PEG@Apt, was constructed via the modification of copper sulfide (CuS) nanoparticles with adenosine aptamer and PEG. CuS-PEG@Apt could be effectively enriched in the tumor site and locally generate a strong photothermal effect, directly ablating tumors and inducing immunogenic death (ICD). On the other hand, the aptamers could block the adenosine pathway to inhibit the immune suppression by adenosine, which further promoted the anti-tumor immunity. Moreover, the CuS nanoparticles could consume GSH and inhibit GPX4 to cause the ferroptosis of tumor cells. Collectively, CuS-PEG@Apt achieved potent efficacy of tumor suppression via the combination of PTT, immune activation and ferroptosis, representing an appealing platform for TNBC treatment.

Prognostic model development using novel genetic signature associated with adenosine metabolism and immune status for patients with hepatocellular carcinoma

The high mortality rate of hepatocellular carcinoma (HCC) is partly due to advanced diagnosis, emphasizing the need for effective predictive tools in HCC treatment. The aim of this study is to propose a novel prognostic model for HCC based on adenosine metabolizing genes and explore the potential relationship between them. Regression analysis was performed to identify differentially expressed genes associated with adenosine metabolism in HCC patients using RNA sequencing data obtained from a public database. Adenosine metabolism-related risk score (AMrisk) was derived using the least absolute shrinkage and selection operator (LASSO) Cox regression and verified using another database. Changes in adenosine metabolism in HCC were analyzed using functional enrichment analysis and multiple immune scores. The gene expression levels in patient samples were validated using quantitative reverse transcription polymerase chain reaction. Thirty adenosine metabolism-related differentially expressed genes were identified in HCC, and six genes (ADA, P2RY4, P2RY6, RPIA, SLC6A3, and VEGFA) were used to calculate the AMrisk score; the higher the risk scores, the lower the overall survival. Moreover, immune infiltration activation and immune checkpoints were considerably higher in the high-risk group. Additional in vitro experiments validated the enhanced expression of these six genes in HCC. The established predictive model demonstrated that adenosine metabolism-related genes was significantly associated with prognosis in HCC patients.

Lessons from the physiological role of guanosine in neurodegeneration and cancer: Toward a multimodal mechanism of action?

Neurodegenerative diseases and brain tumours represent important health challenges due to their severe nature and debilitating consequences that require substantial medical care. Interestingly, these conditions share common physiological characteristics, namely increased glutamate, and adenosine transmission, which are often associated with cellular dysregulation and damage. Guanosine, an endogenous nucleoside, is safe and exerts neuroprotective effects in preclinical models of excitotoxicity, along with cytotoxic effects on tumour cells. However, the lack of well-defined mechanisms of action for guanosine hinders a comprehensive understanding of its physiological effects. In fact, the absence of specific receptors for guanosine impedes the development of structure-activity research programs to develop guanosine derivatives for therapeutic purposes. Alternatively, given its apparent interaction with the adenosinergic system, it is plausible that guanosine exerts its neuroprotective and anti-tumorigenic effects by modulating adenosine transmission through undisclosed mechanisms involving adenosine receptors, transporters, and purinergic metabolism. Here, several potential molecular mechanisms behind the protective actions of guanosine will be discussed. First, we explore its potential interaction with adenosine receptors (A1R and A2AR), including the A1R-A2AR heteromer. In addition, we consider the impact of guanosine on extracellular adenosine levels and the role of guanine-based purine-converting enzymes. Collectively, the diverse cellular functions of guanosine as neuroprotective and antiproliferative agent suggest a multimodal and complementary mechanism of action.

Endometrial epithelial cell organoids as tools for studying the CD39 family of enzymes and for validating enzyme inhibitors

Extracellular adenosine triphosphate (ATP) conducts a complex dynamic system of broadly represented cell signaling. Ectonucleotidases are the enzymes with nucleotide hydrolytic ability that regulate ATP levels in physiological and pathological conditions, thus playing a key role in the so-called purinergic signaling. Altered ectonucleotidase expression has been reported in cancer, and the ectonucleoside triphosphate diphosphohydrolase (NTPDase) family of enzymes, with its best-known form NTPDase1 (CD39), is targeted in cancer immunotherapy. The tandem of enzymes CD39-CD73 is responsible for the generation of immunosuppressive adenosine in the tumor microenvironment, and inhibition strategies are of great interest. Organoids have emerged as very convenient models for the study of tumors since they are three-dimensional cultures that retain many of the features of tissue. The present study aims to contribute to improving the methodology and the molecular tools needed for the study of ectonucleotidases in healthy and disease conditions. The study, performed in an endometrial cancer cell model, could be extended to other types of tumors and pathologies in which the purinergic system is involved. We generated organoids from endometrial cancer cells overexpressing NTPDase2 (CD39L1) and NTPDase3 (CD39L3) as fusion proteins with EGFP, and we performed functional assays by adapting in situ cytochemistry protocols. This allowed us to simultaneously detect enzyme activity and protein expression and to demonstrate that organoids can be used to test ectonucleotidase inhibitors-a result that can be used to develop new cancer treatment options.

Discrimination of superficial lymph nodes using ultrasonography and tissue metabolomics coupled with machine learning

Introduction

Diagnosing the types of malignant lymphoma could help determine the most suitable treatment, anticipate the probability of recurrence and guide long-term monitoring and follow-up care.

Methods

We evaluated the differences in benign, lymphoma and metastasis superficial lymph nodes using ultrasonography and tissue metabolomics.

Results

Our findings indicated that three ultrasonographic features, blood supply pattern, cortical echo, and cortex elasticity, hold potential in differentiating malignant lymph nodes from benign ones, and the shape and corticomedullary boundary emerged as significant indicators for distinguishing between metastatic and lymphoma groups. Metabolomics revealed the difference in metabolic profiles among lymph nodes. We observed significant increases in many amino acids, organic acids, lipids, and nucleosides in both lymphoma and metastasis groups, compared to the benign group. Specifically, the lymphoma group exhibited higher levels of nucleotides (inosine monophosphate and adenosine diphosphate) as well as glutamic acid, and the metastasis group was characterized by higher levels of carbohydrates, acylcarnitines, glycerophospholipids, and uric acid. Linear discriminant analysis coupled with these metabolites could be used for differentiating lymph nodes, achieving recognition rates ranging from 87.4% to 89.3%, outperforming ultrasonography (63.1% to 75.4%).

Discussion

Our findings could contribute to a better understanding of malignant lymph node development and provide novel targets for therapeutic interventions.

Microalgae-Derived Carotenoid Extract and Biomass Reduce Viability, Induce Oxidative Stress, and Modulate the Purinergic System in Two Melanoma Cell Lines

Cutaneous melanoma (CM) is an aggressive and metastatic tumor, resulting in high mortality rates. Despite significant advances in therapeutics, the available treatments still require improvements. Thus, purinergic signaling emerged as a potential pathway to cancer therapy due to its involvement in cell communication, proliferation, differentiation, and apoptosis. In addition, due to safety and acceptable clinical tolerability, carotenoids from microalgae have been investigated as adjuvants in anti-melanoma therapy. Then, this work aimed to investigate the in vitro anti-melanogenic effect of carotenoid extract (CA) and total biomass (BM) of the Scenedesmus obliquus microalgae on two cutaneous melanoma cell lines (A375 and B16F10). Cells were cultivated under ideal conditions and treated with 10, 25, 50, and 100 μM of CA or BM for 24 h. The effects of the compounds on viability, oxidant status, and purinergic signaling were verified. The IC50 cell viability results showed that CA and BM decreased B16F10 viability at 24.29 μM and 74.85 μM, respectively and decreased A375 viability at 73.93 μM and 127.80 μM, respectively. Carotenoid treatment for 24 h in B16F10 and A375 cells increased the release of reactive oxygen species compared to the control. In addition, CA and BM isolated or combined with cisplatin chemotherapy (CIS) modulated the purinergic system in B16F10 and A375 cell lines through P2X7, A2AR, CD39, and 5'-nucleotidase. They led to cell apoptosis and immunoregulation by activating A2A receptors and CD73 inhibition. The results disclose that CA and BM from Scenedesmus obliquus exhibit an anti-melanogenic effect, inhibiting melanoma cell growth.

Adenosine diphosphate stimulates VEGF-independent choroidal endothelial cell proliferation: A potential escape from anti-VEGF therapy

We hypothesized that a strategy employing tissue-specific endothelial cells (EC) might facilitate the identification of tissue- or organ-specific vascular functions of ubiquitous metabolites. An unbiased approach was employed to identify water-soluble small molecules with mitogenic activity on choroidal EC. We identified adenosine diphosphate (ADP) as a candidate, following biochemical purification from mouse EL4 lymphoma extracts. ADP stimulated the growth of bovine choroidal EC (BCEC) and other bovine or human eye-derived EC. ADP induced rapid phosphorylation of extracellular signal-regulated kinase in a dose- and time-dependent manner. ADP-induced BCEC proliferation could be blocked by pretreatment with specific antagonists of the purinergic receptor P2Y1 but not with a vascular endothelial growth factor (VEGF) inhibitor, indicating that the EC mitogenic effects of ADP are not mediated by stimulation of the VEGF pathway. Intravitreal administration of ADP expanded the neovascular area in a mouse model of choroidal neovascularization. Single-cell transcriptomics from human choroidal datasets show the expression of P2RY1, but not other ADP receptors, in EC with a pattern similar to VEGFR2. Although ADP has been reported to be a growth inhibitor for vascular EC, here we describe its growth-stimulating effects for BCEC and other eye-derived EC.

Neuroglia and brain energy metabolism

The glial control of energy homeostasis is of crucial importance for health and disease. Astrocytes in particular play a major role in controlling the equilibrium among adenosine 5'-triphosphate (ATP), adenosine 5'-diphosphate (ADP), adenosine 5'-monophosphate (AMP), and adenosine. Any energy crisis leads to a drop in ATP, and the resulting increase in adenosine is an evolutionary ancient mechanism to suppress energy-consuming activities. The maintenance of brain energy homeostasis, in turn, requires the availability of energy sources, such as glucose and ketones. Astrocytes have assumed an important role in enabling efficient energy utilization by neurons. In addition, neurons are under the metabolic control of astrocytes through regulation of glutamate and GABA levels. The intricate interplay between glial brain energy metabolism and brain function can be best understood once the homeostatic system of energy metabolism is brought out of control. This has best been studied within the context of epilepsy where metabolic treatments provide unprecedented opportunities for the control of seizures that are refractory to conventional antiseizure medications. This chapter will discuss astroglial energy metabolism in the healthy brain and will use epilepsy as a model condition in which glial brain energy homeostasis is disrupted. We will conclude with an outlook on how those principles can be applied to other conditions such as Alzheimer disease.

Metabolic targeting of regulatory T cells in oral squamous cell carcinoma: new horizons in immunotherapy

Oral squamous cell carcinoma (OSCC) is a prevalent oral malignancy, which poses significant health risks with a high mortality rate. Regulatory T cells (Tregs), characterized by their immunosuppressive capabilities, are intricately linked to OSCC progression and patient outcomes. The metabolic reprogramming of Tregs within the OSCC tumor microenvironment (TME) underpins their function, with key pathways such as the tryptophan-kynurenine-aryl hydrocarbon receptor, PI3K-Akt-mTOR and nucleotide metabolism significantly contributing to their suppressive activities. Targeting these metabolic pathways offers a novel therapeutic approach to reduce Treg-mediated immunosuppression and enhance anti-tumor responses. This review explores the metabolic dependencies and pathways that sustain Treg function in OSCC, highlighting key metabolic adaptations such as glycolysis, fatty acid oxidation, amino acid metabolism and PI3K-Akt-mTOR signaling pathway that enable Tregs to thrive in the challenging conditions of the TME. Additionally, the review discusses the influence of the oral microbiome on Treg metabolism and evaluates potential therapeutic strategies targeting these metabolic pathways. Despite the promising potential of these interventions, challenges such as selectivity, toxicity, tumor heterogeneity, and resistance mechanisms remain. The review concludes with perspectives on personalized medicine and integrative approaches, emphasizing the need for continued research to translate these findings into effective clinical applications for OSCC treatment.

CD73: agent development potential and its application in diabetes and atherosclerosis

CD73, an important metabolic and immune escape-promoting gene, catalyzes the hydrolysis of adenosine monophosphate (AMP) to adenosine (ADO). AMP has anti-inflammatory and vascular relaxant properties, while ADO has a strong immunosuppressive effect, suggesting that CD73 has pro-inflammatory and immune escape effects. However, CD73 also decreased proinflammatory reaction, suggesting that CD73 has a positive side to the body. Indeed, CD73 plays a protective role in diabetes, while with age, CD73 changes from anti-atherosclerosis to pro-atherosclerosis. The upregulation of CD73 with agents, including AGT-5, Aire-overexpressing DCs, Aspirin, BAFFR-Fc, CD4+ peptide, ICAs, IL-2 therapies, SAgAs, sCD73, stem cells, RAD51 inhibitor, TLR9 inhibitor, and VD, decreased diabetes and atherosclerosis development. However, the downregulation of CD73 with agents, including benzothiadiazine derivatives and CD73 siRNA, reduced atherosclerosis. Notably, many CD73 agents were investigated in clinical trials. However, no agents were used to treat diabetes and atherosclerosis. Most agents were CD73 inhibitors. Only FP-1201, a CD73 agonist, was investigated in clinical trials but its further development was discontinued. In addition, many lncRNAs, circRNAs, and genes are located at the same chromosomal location as CD73. In particular, circNT5E promoted CD73 expression. circNT5E may be a promising target for agent development. This mini-review focuses on the current state of knowledge of CD73 in diabetes, atherosclerosis, and its potential role in agent development.

Amino Acid and Glucose Fermentation Maintain ATP Content in Mouse and Human Malignant Glioma Cells

Energy is necessary for tumor cell viability and growth. Aerobic glucose-driven lactic acid fermentation is a common metabolic phenotype seen in most cancers including malignant gliomas. This metabolic phenotype is linked to abnormalities in mitochondrial structure and function. A luciferin-luciferase bioluminescence ATP assay was used to measure the influence of amino acids, glucose, and oxygen on ATP content and viability in mouse (VM-M3 and CT-2A) and human (U-87MG) glioma cells that differed in cell biology, genetic background, and species origin. Oxygen consumption was measured using the Resipher system. Extracellular lactate and succinate were measured as end products of the glycolysis and glutaminolysis pathways, respectively. The results showed that: (1) glutamine was a source of ATP content irrespective of oxygen. No other amino acid could replace glutamine in sustaining ATP content and viability; (2) ATP content persisted in the absence of glucose and under hypoxia, ruling out substantial contribution through either glycolysis or oxidative phosphorylation (OxPhos) under these conditions; (3) Mitochondrial complex IV inhibition showed that oxygen consumption was not an accurate measure for ATP production through OxPhos. The glutaminase inhibitor, 6-diazo-5-oxo-L-norleucine (DON), reduced ATP content and succinate export in cells grown in glutamine. The data suggests that mitochondrial substrate level phosphorylation in the glutamine-driven glutaminolysis pathway contributes to ATP content in these glioma cells. A new model is presented highlighting the synergistic interaction between the high-throughput glycolysis and glutaminolysis pathways that drive malignant glioma growth and maintain ATP content through the aerobic fermentation of both glucose and glutamine.

Na+/K+-ATPase: ion pump, signal transducer, or cytoprotective protein, and novel biological functions

Na+/K+-ATPase is a transmembrane protein that has important roles in the maintenance of electrochemical gradients across cell membranes by transporting three Na+ out of and two K+ into cells. Additionally, Na+/K+-ATPase participates in Ca2+-signaling transduction and neurotransmitter release by coordinating the ion concentration gradient across the cell membrane. Na+/K+-ATPase works synergistically with multiple ion channels in the cell membrane to form a dynamic network of ion homeostatic regulation and affects cellular communication by regulating chemical signals and the ion balance among different types of cells. Therefore, it is not surprising that Na+/K+-ATPase dysfunction has emerged as a risk factor for a variety of neurological diseases. However, published studies have so far only elucidated the important roles of Na+/K+-ATPase dysfunction in disease development, and we are lacking detailed mechanisms to clarify how Na+/K+-ATPase affects cell function. Our recent studies revealed that membrane loss of Na+/K+-ATPase is a key mechanism in many neurological disorders, particularly stroke and Parkinson's disease. Stabilization of plasma membrane Na+/K+-ATPase with an antibody is a novel strategy to treat these diseases. For this reason, Na+/K+-ATPase acts not only as a simple ion pump but also as a sensor/regulator or cytoprotective protein, participating in signal transduction such as neuronal autophagy and apoptosis, and glial cell migration. Thus, the present review attempts to summarize the novel biological functions of Na+/K+-ATPase and Na+/K+-ATPase-related pathogenesis. The potential for novel strategies to treat Na+/K+-ATPase-related brain diseases will also be discussed.

Regulatory T cells in immune checkpoint blockade antitumor therapy

Regulatory T cells (Tregs), an essential component of the human immune system, are a heterogeneous group of T lymphocytes with the ability to suppress immune responses and maintain immune homeostasis. Recent evidence indicates that Tregs may impair antitumor immunity and facilitate cancer progression by weakening functions of effector T cells (Teffs). Consequently, targeting Tregs to eliminate them from tumor microenvironments to improve Teffs' activity could emerge as an effective strategy for cancer immunotherapy. This review outlines the biology of Tregs, detailing their origins, classification, and crucial markers. Our focus lies on the complex role of Tregs in cancer's development, progression and treatment, particularly on their suppressive role upon antitumor responses via multiple mechanisms. We delve into Tregs' involvement in immune checkpoint blockade (ICB) therapy, their dual effect on cancer immunotherapy and their potential biomarkers for ICB therapy effectiveness. We also summarize advances in the therapies that adjust Tregs to optimize ICB therapy, which may be crucial for devising innovative cancer treatment strategies.

Lactylation in cancer: Mechanisms in tumour biology and therapeutic potentials

Lactylation, a recently identified form of protein post-translational modification (PTM), has emerged as a key player in cancer biology. The Warburg effect, a hallmark of tumour metabolism, underscores the significance of lactylation in cancer progression. By regulating gene transcription and protein function, lactylation facilitates metabolic reprogramming, enabling tumours to adapt to nutrient limitations and sustain rapid growth. Over the past decade, extensive research has revealed the intricate regulatory network underlying lactylation in tumours. Large-scale sequencing and machine learning have confirmed the widespread occurrence of lactylation sites across the tumour proteome. Targeting lactylation enzymes or metabolic pathways has demonstrated promising anti-tumour effects, highlighting the therapeutic potential of this modification. This review comprehensively explores the mechanisms of lactylation in cancer cells and the tumour microenvironment. We expound on the application of advanced omics technologies for target identification and data modelling within the lactylation field. Additionally, we summarise existing anti-lactylation drugs and discuss their clinical implications. By providing a comprehensive overview of recent advancements, this review aims to stimulate innovative research and accelerate the translation of lactylation-based therapies into clinical practice. KEY POINTS: Lactylation significantly influences tumour metabolism and gene regulation, contributing to cancer progression. Advanced sequencing and machine learning reveal widespread lactylation sites in tumours. Targeting lactylation enzymes shows promise in enhancing anti-tumour drug efficacy and overcoming chemotherapy resistance. This review outlines the clinical implications and future research directions of lactylation in oncology.

The metabolic crosstalk of cancer-associated fibroblasts and tumor cells: Recent advances and future perspectives

Tumor cells grow in a microenvironment with a lack of nutrients and oxygen. Cancer-associated fibroblasts (CAFs) as one major component of tumor microenvironment have strong ability to survive under stressful conditions through metabolic remodelling. Furthermore, CAFs are educated by tumor cells and help them adapt to the hostile microenvironment through their metabolic communication. By inducing catabolism, CAFs release nutrients into the microenvironment which are taken up by tumor cells to satisfy their metabolic requirements. Furthermore, CAFs can recycle toxic metabolic wastes produced by cancer cells into energetic substances, allowing cancer cells to undergo biosynthesis. Their metabolic crosstalk also enhances CAFs' pro-tumor phenotype and reshape the microenvironment facilitating tumor cells' metastasis and immune escape. In this review, we have analyzed the effect and mechanisms of metabolic crosstalk between tumor cells and CAFs. We also analyzed the future perspectives in this area from the points of CAFs heterogeneity, spatial metabonomics and patient-derived tumor organoids (PDOs). These information may deepen the knowledge of tumor metabolism regulated by CAFs and provide novel insights into the development of metabolism-based anti-cancer strategies.

Hyperbaric Oxygen Attenuates Chronic Postsurgical Pain by Regulating the CD73/Adenosine/A1R Axis of the Spinal Cord in Rats

Chronic postsurgical pain (CPSP) affects postoperative rehabilitation and quality of life in patients, but its mechanisms are still poorly understood. Hyperbaric oxygen (HBO) attenuates neuropathic pain in animal and human studies, but its efficacy for CPSP treatment and its underlying mechanism have not been elucidated. This study aimed to investigate the analgesic effect of HBO in a CPSP rat model and the role of spinal cord adenosine circulation in HBO-induced analgesia. A skin/muscle incision and retraction (SMIR) rat model was used to mimic CPSP, and HBO treatment (2.5 atmospheric absolute, 60 minutes) was administered once daily for 5 consecutive days beginning 3 days after surgery. The role of spinal cord adenosine circulation in HBO-induced analgesia was investigated using β-methylene ADP (a CD73 inhibitor), 8-cyclopentyl-1,3-dipropylxanthine (an A1R antagonist), or an intrathecal injection of adenosine. The mechanical paw withdrawal threshold was determined at different timepoints before and after surgery. The spinal cord adenosine and adenosine triphosphate (ATP) contents were analyzed using high-performance liquid chromatography, and the spinal cord expression of adenosine-1 receptor (A1R), extracellular 5'-nucleotidase (CD73), and adenosine kinase (ADK) was examined by Western blotting and immunofluorescence staining. The results showed that the mechanical paw withdrawal threshold of the ipsilateral hind paw and the adenosine content decreased, and the spinal cord expression of A1R, CD73, and ADK and ATP content increased within 14 days after surgery. HBO treatment alleviated mechanical allodynia, reduced ATP content, and increased adenosine content by activating CD73 but downregulated the spinal cord expression of A1R, CD73, and ADK. Intrathecal adenosine alleviated mechanical allodynia after SMIR and downregulated the spinal cord expression of A1R and CD73, and intrathecal β-methylene ADP or 8-cyclopentyl-1,3-dipropylxanthine attenuated the analgesic effect of HBO treatment on SMIR-induced CPSP. PERSPECTIVE: Spinal cord adenosine is involved in the occurrence and development of CPSP, and HBO treatment alleviates CPSP by regulating adenosine production/metabolism in the spinal cord. Thus, HBO may be employed for the treatment of CPSP with favorable efficacy.

Overview of the role of purinergic signaling and insights into its role in cancer therapy

Innovation of cancer therapy has received a dramatic acceleration over the last fifteen years thanks to the introduction of the novel immune checkpoint inhibitors (ICI). On the other hand, the conspicuous scientific knowledge accumulated in purinergic signaling since the early seventies is finally being transferred to the clinic. Several Phase I/II clinical trials are currently underway to investigate the effect of drugs interfering with purinergic signaling as stand-alone or combination therapy in cancer. This is supporting the novel concept of "purinergic immune checkpoint" (PIC) in cancer therapy. In the present review we will address a) the basic pharmacology and cell biology of the purinergic system; b) principles of its pathophysiology in human diseases; c) implications for cell death, cell proliferation and cancer; d) novel molecular tools to investigate nucleotide homeostasis in the extracellular environment; e) recent developments in the pharmacology of P1, P2 receptors and related ecto-enzymes; f) P1 and P2 ligands as novel diagnostic tools; g) current issues in PIC-based anti-cancer therapy. This review will provide an appraisal of the current status of purinergic signaling in cancer and will help identify future avenues of development.

The Importance of Predictive Biomarkers and Their Correlation with the Response to Immunotherapy in Solid Tumors-Impact on Clinical Practice

Background/Objectives: Immunotherapy has changed the therapeutic approach for various solid tumors, especially lung tumors, malignant melanoma, renal and urogenital carcinomas, demonstrating significant antitumor activity, with tolerable safety profiles and durable responses. However, not all patients benefit from immunotherapy, underscoring the need for predictive biomarkers that can identify those most likely to respond to treatment. Methods: The integration of predictive biomarkers into clinical practice for immune checkpoint inhibitors (ICI) holds great promise for personalized cancer treatment. Programmed death ligand 1 (PD-L1) expression, tumor mutational burden (TMB), microsatellite instability (MSI), gene expression profiles and circulating tumor DNA (ctDNA) have shown potential in predicting ICI responses across various cancers. Results: Challenges such as standardization, validation, regulatory approval, and cost-effectiveness must be addressed to realize their full potential. Predictive biomarkers are crucial for optimizing the clinical use of ICIs in cancer therapy. Conclusions: While significant progress has been made, further research and collaboration among clinicians, researchers, and regulatory institutes are essential to overcome the challenges of clinical implementation. However, little is known about the relationship between local and systemic immune responses and the correlation with response to oncological therapies and patient survival.

Targeting the Adenosine A2A Receptor as a Novel Therapeutic Approach for Renal Cell Carcinoma: Mechanisms and Clinical Trial Review

Renal cell carcinoma (RCC) accounts for nearly 2% of cancers diagnosed worldwide. For metastatic RCC, targeted therapy is one of the most common treatment methods. It can include approaches that target vascular endothelial growth factor (VEGFR) or rely on immune checkpoint inhibitors or mTOR inhibitors. Adenosine A2A receptor (A2AR) is a type of widely distributed G-protein-coupled receptor (GPCR). Recently, an increasing number of studies suggest that the activation of A2AR can downregulate anti-tumor immune responses and prevent tumor growth. Currently, the data on A2AR antagonists in RCC treatment are still limited. Therefore, in this article, we further investigate the clinical trials investigating A2AR drugs in RCC. We also describe the epidemiology and current treatment of RCC, along with the physiological role of A2AR, and the types of A2AR drugs that are associated with tumor treatment.

Reconfigurable Optical Sensor for Metal-Ion-Mediated Label-Free Recognition of Different Biomolecular Targets

Reconfiguration of chemical sensors, intended as the capacity of the sensor to adapt to novel operational scenarios, e.g., new target analytes, is potentially game changing and would enable rapid and cost-effective reaction to dynamic changes occurring at healthcare, environmental, and industrial levels. Yet, it is still a challenge, and rare examples of sensor reconfiguration have been reported to date. Here, we report on a reconfigurable label-free optical sensor leveraging the versatile immobilization of metal ions through a chelating agent on a nanostructured porous silica (PSiO2) optical transducer for the detection of different biomolecules. First, we show the reversible grafting of different metal ions on the PSiO2 surface, namely, Ni2+, Cu2+, Zn2+, and Fe3+, which can mediate the interaction with different biomolecules and be switched under mild conditions. Then, we demonstrate reconfiguration of the sensor at two levels: 1) switching of the metal ions on the PSiO2 surface from Cu2+ to Zn2+ and testing the ability of Cu2+-functionalized and Zn2+-reconfigured devices for the sensing of the dipeptide carnosine (CAR), leveraging the well-known chelating ability of CAR toward divalent metal ions; and 2) reconfiguration of the Cu2+-functionalized PSiO2 sensor for a different target analyte, namely, the nucleotide adenosine triphosphate (ATP), switching Cu2+ with Fe3+ ions to exploit the interaction with ATP through phosphate groups. The Cu2+-functionalized and Zn2+-reconfigured sensors show effective sensing performance in CAR detection, also evaluated in tissue samples from murine brain, and so does the Fe3+-reconfigured sensor toward ATP, thus demonstrating effective reconfiguration of the sensor with the proposed surface chemistry.

Adenosine-mediated immune responses in inflammatory bowel disease

Extracellular ATP and its derivates mediate a signaling pathway that might be pharmacologically targeted to treat inflammatory conditions. Extracellular adenosine, the product of ATP hydrolysis by ectonucleotidase enzymes, plays a key role in halting inflammation while promoting immune tolerance. The rate-limiting ectoenzyme ENTPD1/CD39 and the ecto-5'-nucleotidase/CD73 are the prototype members of the ectonucleotidase family, being responsible for ATP degradation into immunosuppressive adenosine. The biological effects of adenosine are mediated via adenosine receptors, a family of G protein-coupled receptors largely expressed on immune cells where they modulate innate and adaptive immune responses. Inflammatory bowel disease (IBD) is a serious inflammatory condition of the gastrointestinal tract, associated with substantial morbidity and often refractory to currently available medications. IBD is linked to altered interactions between the gut microbiota and the immune system in genetically predisposed individuals. A wealth of studies conducted in patients and animal models highlighted the role of various adenosine receptors in the modulation of chronic inflammatory diseases like IBD. In this review, we will discuss the most recent findings on adenosine-mediated immune responses in different cell types, with a focus on IBD and its most common manifestations, Crohn's disease and ulcerative colitis.

CD39 transforming cancer therapy by modulating tumor microenvironment

CD39 is a pivotal enzyme in cancer, regulating immune response and tumor progression via extracellular ATP and adenosine in the tumor microenvironment (TME). Beyond its established immunoregulatory function, CD39 influences cancer cell angiogenesis and metabolism, opening new frontiers for therapeutic interventions. Current research faces gaps in understanding CD39's full impact across cancer types, with ongoing debates about its potential beyond modulating immune evasion. This review distills CD39's multifaceted roles, examining its dual actions and implications for cancer prognosis and treatment. We analyze the latest therapeutic strategies, highlighting the need for an integrated approach that combines molecular insights with TME dynamics to innovate cancer care. This synthesis underscores CD39's integral role, charting a course for precision oncology that seeks to unravel controversies and harness CD39's therapeutic promise for improved cancer outcomes.

Assessment of ATP metabolism to adenosine by ecto-nucleotidases carried by tumor-derived small extracellular vesicles

Immunosuppression is a hallmark of cancer progression. Tumor-derived small extracellular vesicles (sEV), also known as TEX, produce adenosine (ADO) and can mediate tumor-induced immunosuppression.Here, the ATP pathway of ADO production (ATP →  ADP →  AMP →  ADO) by ecto-nucleotidases carried on the sEV surface was evaluated by a method using N6-etheno-ATP (eATP) and N6-etheno-AMP (eAMP) as substrates for enzymatic activity. The "downstream" N6-etheno-purines (ePurines) were measured by high performance liquid chromatography with fluorescence detection (HPLC-FL).Human melanoma cell-derived TEX (MTEX) metabolized eATP to N6-etheno-ADP (eADP), eAMP and N6-etheno-Adenosine (eADO) more robustly than control keratinocyte cell-derived sEV (CEX); due to accelerated conversion of eATP to eADP and eADP to eAMP. MTEX and CEX similarly metabolized eAMP to eADO. Blocking of the ATP pathway with the selective CD39 inhibitor ARL67156 or pan ecto-nucleotidase inhibitor POM-1 normalized the ATP pathway but neither inhibitor completely abolished it. In contrast, inhibition of CD73 by PSB12379 or AMPCP abolished eADO formation by both MTEX and CEX, suggesting that targeting CD73 is the preferred approach to eliminating ADO produced by ecto-nucleotidases located on the sEV surface.The noninvasive, sensitive, and specific assay assessing ePurine metabolism ± ecto-nucleotidase inhibitors in TEX enables the personalized identification of ecto-nucleotidase activity primarily involved in ADO production in patients with cancer. The assay could guide precision medicine by determining which purine is the preferred target for inhibitory therapeutic interventions.

Current Understanding of the Role of Adenosine Receptors in Cancer

Cancer, a complex array of diseases, involves the unbridled proliferation and dissemination of aberrant cells in the body, forming tumors that can infiltrate neighboring tissues and metastasize to distant sites. With over 200 types, each cancer has unique attributes, risks, and treatment avenues. Therapeutic options encompass surgery, chemotherapy, radiation therapy, hormone therapy, immunotherapy, targeted therapy, or a blend of these methods. Yet, these treatments face challenges like late-stage diagnoses, tumor diversity, severe side effects, drug resistance, targeted drug delivery hurdles, and cost barriers. Despite these hurdles, advancements in cancer research, encompassing biology, genetics, and treatment, have enhanced early detection methods, treatment options, and survival rates. Adenosine receptors (ARs), including A1, A2A, A2B, and A3 subtypes, exhibit diverse roles in cancer progression, sometimes promoting or inhibiting tumor growth depending on the receptor subtype, cancer type, and tumor microenvironment. Research on AR ligands has revealed promising anticancer effects in lab studies and animal models, hinting at their potential as cancer therapeutics. Understanding the intricate signaling pathways and interactions of adenosine receptors in cancer is pivotal for crafting targeted therapies that optimize benefits while mitigating drawbacks. This review delves into each adenosine receptor subtype's distinct roles and signaling pathways in cancer, shedding light on their potential as targets for improving cancer treatment outcomes.

Metabolomic profiling and accurate diagnosis of basal cell carcinoma by MALDI imaging and machine learning

Basal cell carcinoma (BCC), the most common keratinocyte cancer, presents a substantial public health challenge due to its high prevalence. Traditional diagnostic methods, which rely on visual examination and histopathological analysis, do not include metabolomic data. This exploratory study aims to molecularly characterize BCC and diagnose tumour tissue by applying matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) and machine learning (ML). BCC tumour development was induced in a mouse model and tissue sections containing BCC (n = 12) were analysed. The study design involved three phases: (i) Model training, (ii) Model validation and (iii) Metabolomic analysis. The ML algorithm was trained on MS data extracted and labelled in accordance with histopathology. An overall classification accuracy of 99.0% was reached for the labelled data. Classification of unlabelled tissue areas aligned with the evaluation of a certified Mohs surgeon for 99.9% of the total tissue area, underscoring the model's high sensitivity and specificity in identifying BCC. Tentative metabolite identifications were assigned to 189 signals of importance for the recognition of BCC, each indicating a potential tumour marker of diagnostic value. These findings demonstrate the potential for MALDI-MSI coupled with ML to characterize the metabolomic profile of BCC and to diagnose tumour tissue with high sensitivity and specificity. Further studies are needed to explore the potential of implementing integrated MS and automated analyses in the clinical setting.

TET3 boosts hepatocyte autophagy and impairs non-alcoholic fatty liver disease by increasing ENPP1 promoter hypomethylation

BACKGROUND

Dysregulated ecto-nucleotide pyrophosphatase/phosphodiesterase (ENPP) family occurs in metabolic reprogramming pathological processes. Nonetheless, the epigenetic mechanisms by which ENPP family impacts NAFLD, also known as metabolic dysfunction-associated steatotic liver disease (MASLD), is poorly appreciated.

METHODS

We investigated the causes and consequences of ENPP1 promoter hypomethylation may boost NAFLD using NAFLD clinical samples, as well as revealed the underlying mechanisms using high-fat diet (HFD) + carbon tetrachloride (CCl4) induced mouse model of NAFLD and FFA treatment of cultured hepatocyte.

RESULTS

Herein, we report that the expression level of ENPP1 are increased in patients with NAFLD liver tissue and in mouse model of NAFLD. Hypomethylation of ENPP1, is associated with the perpetuation of hepatocyte autophagy and liver fibrosis in the NAFLD. ENPP1 hypomethylation is mediated by the DNA demethylase TET3 in NAFLD liver fibrosis and hepatocyte autophagy. Additionally, knockdown of TET3 methylated ENPP1 promoter, reduced the ENPP1 expression, ameliorated the experimental NAFLD. Mechanistically, TET3 epigenetically promoted ENPP1 expression via hypomethylation of the promoter. Knocking down TET3 can inhibit the hepatocyte autophagy but an overexpression of ENPP1 showing rescue effect.

CONCLUSIONS

We describe a novel epigenetic mechanism wherein TET3 promoted ENPP1 expression through promoter hypomethylation is a critical mediator of NAFLD. Our findings provide new insight into the development of preventative measures for NAFLD.

From mechanism to therapy: the journey of CD24 in cancer

CD24 is a glycosylphosphatidylinositol-anchored protein that is expressed in a wide range of tissues and cell types. It is involved in a variety of physiological and pathological processes, including cell adhesion, migration, differentiation, and apoptosis. Additionally, CD24 has been studied extensively in the context of cancer, where it has been found to play a role in tumor growth, invasion, and metastasis. In recent years, there has been growing interest in CD24 as a potential therapeutic target for cancer treatment. This review summarizes the current knowledge of CD24, including its structure, function, and its role in cancer. Finally, we provide insights into potential clinical application of CD24 and discuss possible approaches for the development of targeted cancer therapies.

The war between the immune system and the tumor - using immune biomarkers as tracers

Nowadays, immunotherapy is one of the most promising anti-tumor therapeutic strategy. Specifically, immune-related targets can be used to predict the efficacy and side effects of immunotherapy and monitor the tumor immune response. In the past few decades, increasing numbers of novel immune biomarkers have been found to participate in certain links of the tumor immunity to contribute to the formation of immunosuppression and have entered clinical trials. Here, we systematically reviewed the oncogenesis and progression of cancer in the view of anti-tumor immunity, particularly in terms of tumor antigen expression (related to tumor immunogenicity) and tumor innate immunity to complement the cancer-immune cycle. From the perspective of integrated management of chronic cancer, we also appraised emerging factors affecting tumor immunity (including metabolic, microbial, and exercise-related markers). We finally summarized the clinical studies and applications based on immune biomarkers. Overall, immune biomarkers participate in promoting the development of more precise and individualized immunotherapy by predicting, monitoring, and regulating tumor immune response. Therefore, targeting immune biomarkers may lead to the development of innovative clinical applications.

Uracil as a biomarker for spatial pyrimidine metabolism in the development of gingivobuccal oral squamous cell carcinoma

No biomarker has yet been identified that allows accurate diagnosis and prognosis of oral cancers. In this study, we investigated the presence of key metabolites in oral cancer using proton nuclear magnetic resonance (NMR) spectroscopy to identify metabolic biomarkers of gingivobuccal oral squamous cell carcinoma (GB-OSCC). NMR spectroscopy revealed that uracil was expressed in 83.09% of tumor tissues and pyrimidine metabolism was active in GB-OSCC; these results correlated well with immunohistochemistry (IHC) and RNA sequencing data. Based on further gene and protein analyses, we proposed a pathway for the production of uracil in GB-OSCC tissues. Uridinetriphosphate (UTP) is hydrolyzed to uridine diphosphate (UDP) by CD39 in the tumor microenvironment (TME). We hypothesized that UDP enters the cell with the help of the UDP-specific P2Y6 receptor for further processing by ENTPD4/5 to produce uracil. As the ATP reserves diminish, the weakened immune cells in the TME utilize pyrimidine metabolism as fuel for antitumor activity, and the same mechanism is hijacked by the tumor cells to promote their survival. Correspondingly, the differential expression of ENTPD4 and ENTPD5 in immune and tumor cells, respectively, indicatedtheir involvement in disease progression. Furthermore, higher uracil levels were detected in patients with lymph node metastasis, indicating that metastatic potential is increased in the presence of uracil. The presence of uracil and/or expression patterns of intermediate molecules in purine and pyrimidine pathways, such asCD39, CD73, and P2Y6 receptors together with ENTPD4 and ENTPD5, hold promise as biomarker(s) for oral cancer diagnosis and prognosis.

The inhibitory effect of adenosine on tumor adaptive immunity and intervention strategies

Adenosine (Ado) is significantly elevated in the tumor microenvironment (TME) compared to normal tissues. It binds to adenosine receptors (AdoRs), suppressing tumor antigen presentation and immune cell activation, thereby inhibiting tumor adaptive immunity. Ado downregulates major histocompatibility complex II (MHC II) and co-stimulatory factors on dendritic cells (DCs) and macrophages, inhibiting antigen presentation. It suppresses anti-tumor cytokine secretion and T cell activation by disrupting T cell receptor (TCR) binding and signal transduction. Ado also inhibits chemokine secretion and KCa3.1 channel activity, impeding effector T cell trafficking and infiltration into the tumor site. Furthermore, Ado diminishes T cell cytotoxicity against tumor cells by promoting immune-suppressive cytokine secretion, upregulating immune checkpoint proteins, and enhancing immune-suppressive cell activity. Reducing Ado production in the TME can significantly enhance anti-tumor immune responses and improve the efficacy of other immunotherapies. Preclinical and clinical development of inhibitors targeting Ado generation or AdoRs is underway. Therefore, this article will summarize and analyze the inhibitory effects and molecular mechanisms of Ado on tumor adaptive immunity, as well as provide an overview of the latest advancements in targeting Ado pathways in anti-tumor immune responses.

Inducing mitochondriopathy-like damages by transformable nucleopeptide nanoparticles for targeted therapy of bladder cancer

Mitochondriopathy inspired adenosine triphosphate (ATP) depletions have been recognized as a powerful way for controlling tumor growth. Nevertheless, selective sequestration or exhaustion of ATP under complex biological environments remains a prodigious challenge. Harnessing the advantages of in vivo self-assembled nanomaterials, we designed an Intracellular ATP Sequestration (IAS) system to specifically construct nanofibrous nanostructures on the surface of tumor nuclei with exposed ATP binding sites, leading to highly efficient suppression of bladder cancer by induction of mitochondriopathy-like damages. Briefly, the reported transformable nucleopeptide (NLS-FF-T) self-assembled into nuclear-targeted nanoparticles with ATP binding sites encapsulated inside under aqueous conditions. By interaction with KPNA2, the NLS-FF-T transformed into a nanofibrous-based ATP trapper on the surface of tumor nuclei, which prevented the production of intracellular energy. As a result, multiple bladder tumor cell lines (T24, EJ and RT-112) revealed that the half-maximal inhibitory concentration (IC50) of NLS-FF-T was reduced by approximately 4-fold when compared to NLS-T. Following intravenous administration, NLS-FF-T was found to be dose-dependently accumulated at the tumor site of T24 xenograft mice. More significantly, this IAS system exhibited an extremely antitumor efficacy according to the deterioration of T24 tumors and simultaneously prolonged the overall survival of T24 orthotopic xenograft mice. Together, our findings clearly demonstrated the therapeutic advantages of intracellular ATP sequestration-induced mitochondriopathy-like damages, which provides a potential treatment strategy for malignancies.

Identification and validation of NAD+ metabolism-related biomarkers in patients with diabetic peripheral neuropathy

Background

The mechanism of Nicotinamide Adenine Dinucleotide (NAD+) metabolism-related genes (NMRGs) in diabetic peripheral neuropathy (DPN) is unclear. This study aimed to find new NMRGs biomarkers in DPN.

Methods

DPN related datasets GSE95849 and GSE185011 were acquired from the Gene Expression Omnibus (GEO) database. 51 NMRGs were collected from a previous article. To explore NMRGs expression in DPN and control samples, differential expression analysis was completed in GSE95849 to obtain differentially expressed genes (DEGs), and the intersection of DEGs and NMRGs was regarded as DE-NMRGs. Next, a protein-protein interaction (PPI) network based on DE-NMRGs was constructed and biomarkers were screened by eight algorithms. Additionally, Gene Set Enrichment Analysis (GSEA) enrichment analysis was completed, biomarker-based column line graphs were constructed, lncRNA-miRNA-mRNA and competing endogenouse (ce) RNA networks were constructed, and drug prediction was completed. Finally, biomarkers expression validation was completed in GSE95849 and GSE185011.

Results

5217 DEGs were obtained from GSE95849 and 21 overlapping genes of DEGs and NMRGs were DE-NMRGs. Functional enrichment analysis revealed that DE-NMRGs were associated with glycosyl compound metabolic process. The PPI network contained 93 protein-interaction pairs and 21 nodes, with strong interactions between NMNAT1 and NAMPT, NADK and NMNAT3, ENPP3 and NUDT12 as biomarkers based on 8 algorithms. Expression validation suggested that ENPP3 and NUDT12 were upregulated in DPN samples (P < 0.05). Moreover, an alignment diagram with good diagnostic efficacy based on ENPP3 and NUDT12 were identified was constructed. GSEA suggested that ENPP3 was enriched in Toll like receptor (TLR) pathway, NUDT12 was enriched in maturity onset diabetes of the young and insulin pathway. Furthermore, 18 potential miRNAs and 36 Transcription factors (TFs) were predicted and the miRNA-mRNA-TF networks were constructed, suggesting that ENPP3 might regulate hsa-miR-34a-5p by affecting MYNN. The ceRNA network suggested that XLOC_013024 might regulate hsa-let-7b-5p by affecting NUDT12. 15 drugs were predicted, with 8 drugs affecting NUDT12 such as resveratrol, and 13 drugs affecting ENPP3 such as troglitazone.

Conclusion

ENPP3 and NUDT12 might play key roles in DPN, which provides reference for further research on DPN.

The metabolic role of the CD73/adenosine signaling pathway in HTR-8/SVneo cells: A Double-Edged Sword?

The ecto-5'-nucleotidase (CD73)/adenosine signaling pathway has been reported to regulate tumor epithelial-mesenchymal transition (EMT), migration and proliferation. However, little is known about the metabolic mechanisms underlying its role in trophoblast proliferation and migration. In this study, we aimed to investigate the metabolic role of the CD73/adenosine signaling pathway on the proliferation and migration of trophoblast. We found that CD73 levels were upregulated in preeclamptic placentas compared with the placentas of normotensive pregnant women. EMT and migration of HTR-8/SVneo cells were enhanced when treated with a CD73 inhibitor (100 μM) in vitro. Conversely, excessive adenosine (25 or 50 μM) suppressed trophoblast cell EMT, migration and proliferation. RNA-seq, metabolomics and seahorse findings showed that adenosine treatment resulted in increased expression of PDK1, suppression of aerobic respiration, glycolysis and amino acids synthesis, as well as increased utilization of short-chain fatty acids (SCFAs). Furthermore, the 13C-adenosine isotope tracking experiment demonstrated that adenosine served as a carbon source for the tricarboxylic acid (TCA) cycle. Our results reveal the role of adenosine in regulating trophoblast energy metabolism is like a double-edged sword - either inhibiting aerobic respiration or supplementing carbon sources into metabolic flux. CD73/adenosine signaling regulated trophoblast EMT, migration, and proliferation by modulating energy metabolism. This study indicates that CD73/adenosine signaling potentially plays a role in the occurrence of placenta-derived diseases, including preeclampsia.

Stereocontrolled access to thioisosteres of nucleoside di- and triphosphates

Nucleoside diphosphates and triphosphates impact nearly every aspect of biochemistry; however, the use of such compounds as tools or medicinal leads for nucleotide-dependent enzymes and receptors is hampered by their rapid in vivo metabolism. Although a successful strategy to address the instability of the monophosphate moiety in oligonucleotide therapeutics has been accomplished by their isosteric replacement with phosphorothioates, no practical methods exist to rapidly and controllably access stereopure di- and triphosphate thioisosteres of both natural and unnatural nucleosides. Here we show how a modular, reagent-based platform can enable the stereocontrolled and scalable synthesis of a library of such molecules. This operationally simple approach provides access to pure stereoisomers of nucleoside α-thiodiphosphates and α-thiotriphosphates, as well as symmetrical or unsymmetrical dinucleoside thiodiphosphates and thiotriphosphates (including RNA cap reagents). We demonstrate that ligand-receptor interactions can be dramatically influenced by P-stereochemistry, showing that such thioisosteric replacements can have profound effects on the potency and stability of lead candidates.

Intercellular crosstalk shapes purinergic metabolism and signaling in cancer cells

CD73-derived adenosine suppresses anti-cancer immunity, and CD73 inhibitors are currently evaluated in several clinical trials. Here, we have assessed enzyme kinetics of all key purinergic ectoenzymes in five cancer cell lines (Hodgkin lymphoma, multiple myeloma, pancreas adenocarcinoma, urinary bladder carcinoma, and glioblastoma) under normoxia and hypoxia. We found that adenosine metabolism varied considerably between individual cancer types. All cell lines investigated exhibited high ecto-adenosine deaminase (ADA) activity, which critically influenced the kinetics of adenosine accumulation. Combining kinetics data with single-cell RNA sequencing data on myeloma and glioblastoma cancerous tissue revealed that purine metabolism is not homogeneously organized, but it differs in a cancer type-specific fashion between malignant cells, stromal cells, and immune cells. Since purine metabolism in cancerous tissue is most likely spatially heterogeneous and differs between the various cell types, diffusion distances in the microenvironment as well as ADA activity may be important variables that influence the level of bioactive adenosine.

Mechanistic role of quercetin as inhibitor for adenosine deaminase enzyme in rheumatoid arthritis: systematic review

Rheumatoid arthritis (RA) is an autoimmune disease involving T and B lymphocytes. Autoantibodies contribute to joint deterioration and worsening symptoms. Adenosine deaminase (ADA), an enzyme in purine metabolism, influences adenosine levels and joint inflammation. Inhibiting ADA could impact RA progression. Intracellular ATP breakdown generates adenosine, which increases in hypoxic and inflammatory conditions. Lymphocytes with ADA play a role in RA. Inhibiting lymphocytic ADA activity has an immune-regulatory effect. Synovial fluid levels of ADA are closely associated with the disease's systemic activity, making it a useful parameter for evaluating joint inflammation. Flavonoids, such as quercetin (QUE), are natural substances that can inhibit ADA activity. QUE demonstrates immune-regulatory effects and restores T-cell homeostasis, making it a promising candidate for RA therapy. In this review, we will explore the impact of QUE in suppressing ADA and reducing produced the inflammation in RA, including preclinical investigations and clinical trials.

The multifaceted role of extracellular ATP in sperm function: From spermatogenesis to fertilization

Extracellular adenosine 5'-triphosphate (ATP) is a vital signaling molecule involved in various physiological processes within the body. In recent years, studies have revealed its significant role in male reproduction, particularly in sperm function. This review explores the multifaceted role of extracellular ATP in sperm function, from spermatogenesis to fertilization. We discuss the impact of extracellular ATP on spermatogenesis, sperm maturation and sperm-egg fusion, highlighting the complex regulatory mechanisms and potential clinical applications in the context of male infertility. By examining the latest research, we emphasize the crucial role of extracellular ATP in sperm function and propose future research directions to further.