Lactic Acid and an Acidic Tumor Microenvironment suppress Anticancer Immunity

Risk factors and survival prediction model establishment for prognosis in patients with radical resection of gallbladder cancer

BACKGROUND

Gallbladder cancer (GBC) is the most common malignant tumor of the biliary system, and is often undetected until advanced stages, making curative surgery unfeasible for many patients. Curative surgery remains the only option for long-term survival. Accurate postsurgical prognosis is crucial for effective treatment planning. tumor-node-metastasis staging, which focuses on tumor infiltration, lymph node metastasis, and distant metastasis, limits the accuracy of prognosis. Nomograms offer a more comprehensive and personalized approach by visually analyzing a broader range of prognostic factors, enhancing the precision of treatment planning for patients with GBC.

AIM

To identify risk factors and develop a predictive model for GBC prognosis.

METHODS

A retrospective study analyzed the clinical and pathological data of 93 patients who underwent radical surgery for GBC at Peking University People's Hospital from January 2015 to December 2020. Kaplan-Meier analysis was used to calculate the 1-, 2- and 3-year survival rates. The log-rank test was used to evaluate factors impacting prognosis, with survival curves plotted for significant variables. Single-factor analysis revealed statistically significant differences, and multivariate Cox regression identified independent prognostic factors. A nomogram was developed and validated with receiver operating characteristic curves and calibration curves.

RESULTS

Among 93 patients who underwent radical surgery for GBC, 30 patients survived, accounting for 32.26% of the sample, with a median survival time of 38 months. The 1-year, 2-year, and 3-year survival rates were 83.87%, 68.82%, and 53.57%, respectively. Univariate analysis revealed that carbohydrate antigen 19-9 expression, T stage, lymph node metastasis, histological differentiation, surgical margins, and invasion of the liver, extrahepatic bile duct, nerves, and vessels (P ≤ 0.001) significantly impacted patient prognosis after curative surgery. Multivariate Cox regression identified lymph node metastasis (P = 0.03), histological differentiation (P < 0.05), nerve invasion (P = 0.036), and extrahepatic bile duct invasion (P = 0.014) as independent risk factors. A nomogram model with a concordance index of 0.838 was developed. Internal validation confirmed the model's consistency in predicting the 1-year, 2-year, and 3-year survival rates.

CONCLUSION

Lymph node metastasis, tumor differentiation, extrahepatic bile duct invasion, and perineural invasion are independent risk factors. A nomogram based on these factors can be used to personalize and improve treatment strategies.

The interaction between m6A modification and noncoding RNA in tumor microenvironment on cancer progression

Cancer development is thought to be closely related to aberrant epigenetic regulation, aberrant expression of specific non-coding RNAs (ncRNAs), and tumor microenvironment (TME). The m6A methylation is one of the most abundant RNA modifications found in eukaryotes, and it can determine the fate of RNA at the post-transcriptional level through a variety of mechanisms, which affects important biological processes in the organism. The m6A methylation modification is involved in RNA processing, regulation of RNA nuclear export or localisation, RNA degradation and RNA translation. This process affects the function of mRNAs and ncRNAs, thereby influencing the biological processes of cancer cells. TME accelerates and promotes cancer generation and progression during tumor development. The m6A methylation interacting with ncRNAs is closely linked to TME formation. Mutual regulation and interactions between m6A methylation and ncRNAs in TME create complex networks and mediate the progression of various cancers. In this review, we will focus on the interactions between m6A modifications and ncRNAs in TME, summarising the molecular mechanisms by which m6A interacts with ncRNAs to affect TME and their roles in the development of different cancers. This work will help to deepen our understanding of tumourigenesis and further explore new targets for cancer therapy.

Emerging trends on the uptake of fluorescent probes based on glucose analogs by cancer cells: From basic studies to therapeutics

The cancer cell metabolism, notably characterized by the Warburg effect, has been the focus of intense investigation regarding the mechanisms of the uptake of glucose analogs, opening up perspectives for diagnosis and treatment of cancer disease. In this review, we delve into the ever-evolving landscape of cancer research, centering on fluorescent probes based on glucose analogs. These analogs, resulting from modifications in the carbohydrate structure with functional groups, have stood out as versatile molecules in applications ranging from disease comprehension to therapeutic innovation, especially when combined with fluorescent compounds. Fluorescence-based assays have provided valuable contributions to the revelation of complex biological mechanisms in life sciences. This review presents selected studies from about the past six years up to 2024 related to the use of glucose-based fluorescent probes, for the investigation of their uptake profile as well as for therapeutic purposes. We believe that these investigations offer insights into the intricate interaction between glucose analogs and cancer cell metabolism, guiding future research and clinical applications in this field.

Acidity induces durable enhancement of Treg cell suppressive functions for tumor immune evasion

The microenvironment within solid tumors often becomes acidic due to various factors associated with abnormal metabolism and cellular activities, including increased lactate production as a result of dysregulated tumor glycolysis. Recently, we have identified multiple tumor microenvironment (TME) factors that potentiate regulatory T (Treg) cell function in evading anti-tumor immunosurveillance. Despite the strong correlation between lactate and acidity, the potential roles of acidity in intratumoral Treg cell adaptation and underlying molecular mechanisms have gone largely unstudied. In this study, we demonstrate that acidity significantly enhances immunosuppressive functions of nTreg cells, but not iTreg cells, without altering the expression of either FoxP3 or the cell surface receptors CD25, CTLA4, or GITR in these cells. Surprisingly, the addition of lactate, often considered a major contributor to increased acidity of the TME, completely abolished the acidity-induced enhancement of nTreg suppressive functions. Consistently, metabolic flux analyses showed elevated basal mitochondrial respiratory capacity and ATP-coupled respiration in acidity-treated nTreg cells without altering glycolytic capacity. Genome-wide transcriptome and metabolomics analyses revealed alterations in multiple metabolic pathways, particularly the one-carbon folate metabolism pathway, with reduced SAM, folate, and glutathione, in nTreg cells exposed to low pH conditions. Addition of a one-carbon metabolic contributor, formate, diminished the acidity-induced enhancement in nTreg cell suppressive functions, but neither SAM nor glutathione could reverse the phenotype. Remarkably, in vitro transient treatment of nTreg cells resulted in sustained enhancement of their functions, as evidenced by more vigorous tumor growth observed in mice adoptively receiving acidity-treated nTreg cells. Further analysis of intratumoral infiltrated T cells confirmed a significant reduction in CD8+ T cell frequency and their granzyme B production. In summary, our study elucidates how acidity-mediated metabolic reprogramming leads to sustained Treg-mediated tumor immune evasion.

Biodegradable magnesium based metal materials inhibit the growth of cervical cancer cells

Traditional chemotherapy drugs for cervical cancer often cause significant toxic side effects and drug resistance problems, highlighting the urgent need for more innovative and effective treatment strategies. Magnesium alloy is known to be degradable and biocompatible. The release of degradation products Mg2+, OH-, and H2 from magnesium alloy can alter the tumor microenvironment, providing potential anti-tumor properties. We explored the innovative use of magnesium alloy biomaterials in the treatment of cervical cancer, investigating how various concentrations of Mg2+ on the proliferation and cell death of cervical cancer cells. The results revealed that varying concentrations of Mg2+ significantly inhibited cervical cancer by arresting the cell cycle in the G0/G1 phase and inducing apoptosis in SiHa cells, effectively reducing tumor cell proliferation. In vivo experiments demonstrated that 20 mM Mg2+ group had the smallest tumor volume, exhibiting a potent inhibitory effect on the biological characteristics of cervical cancer. This enhances the therapeutic potential of this biomaterial as a local anti-tumor therapy and lays a theoretical foundation for the potential application of magnesium in the treatment of cervical cancer.

Enhancing cancer immunotherapy: Nanotechnology-mediated immunotherapy overcoming immunosuppression

Immunotherapy is an important cancer treatment method that offers hope for curing cancer patients. While immunotherapy has achieved initial success, a major obstacle to its widespread adoption is the inability to benefit the majority of patients. The success or failure of immunotherapy is closely linked to the tumor's immune microenvironment. Recently, there has been significant attention on strategies to regulate the tumor immune microenvironment in order to stimulate anti-tumor immune responses in cancer immunotherapy. The distinctive physical properties and design flexibility of nanomedicines have been extensively utilized to target immune cells (including tumor-associated macrophages (TAMs), T cells, myeloid-derived suppressor cells (MDSCs), and tumor-associated fibroblasts (TAFs)), offering promising advancements in cancer immunotherapy. In this article, we have reviewed treatment strategies aimed at targeting various immune cells to regulate the tumor immune microenvironment. The focus is on cancer immunotherapy models that are based on nanomedicines, with the goal of inducing or enhancing anti-tumor immune responses to improve immunotherapy. It is worth noting that combining cancer immunotherapy with other treatments, such as chemotherapy, radiotherapy, and photodynamic therapy, can maximize the therapeutic effects. Finally, we have identified the challenges that nanotechnology-mediated immunotherapy needs to overcome in order to design more effective nanosystems.

Application of metabolomics in oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) is a prevalent malignancy affecting the head and neck region. The prognosis for OSCC patients remains unfavorable due to the absence of precise and efficient early diagnostic techniques. Metabolomics offers a promising approach for identifying distinct metabolites, thereby facilitating early detection and treatment of OSCC.

OBJECTIVE

This review aims to provide a comprehensive overview of recent advancements in metabolic marker identification for early OSCC diagnosis. Additionally, the clinical significance and potential applications of metabolic markers for the management of OSCC are discussed.

RESULTS

This review summarizes metabolic changes during the occurrence and development of oral squamous cell carcinoma and reviews prospects for the clinical application of characteristic, differential metabolites in saliva, serum, and OSCC tissue. In this review, the application of metabolomic technology in OSCC research was summarized, and future research directions were proposed.

CONCLUSION

Metabolomics, detection technology that is the closest to phenotype, can efficiently identify differential metabolites. Combined with statistical data analyses and artificial intelligence technology, it can rapidly screen characteristic biomarkers for early diagnosis, treatment, and prognosis evaluations.

Lactic acid: The culprit behind the immunosuppressive microenvironment in hepatocellular carcinoma

As a solid tumor with high glycolytic activity, hepatocellular carcinoma (HCC) produces excess lactic acid and increases extracellular acidity, thus forming a unique immunosuppressive microenvironment. L-lactate dehydrogenase (LDH) and monocarboxylate transporters (MCTs) play a very important role in glycolysis. LDH is the key enzyme for lactic acid (LA) production, and MCT is responsible for the cellular import and export of LA. The synergistic effect of the two promotes the formation of an extracellular acidic microenvironment. In the acidic microenvironment of HCC, LA can not only promote the proliferation, survival, transport and angiogenesis of tumor cells but also have a strong impact on immune cells, ultimately leading to an inhibitory immune microenvironment. This article reviews the role of LA in HCC, especially its effect on immune cells, summarizes the progress of LDH and MCT-related drugs, and highlights the potential of immunotherapy targeting lactate combined with HCC.

A predictive study of genes related to lactic acid metabolism in cervical carcinoma

OBJECTIVES

Lactic acid metabolism, a hallmark of carcinogenesis, may play potential roles in cervical carcinoma, assisting the prognosis prediction.

MATERIALS AND METHODS

A regression analysis was conducted to identify the ones with the most frequent variation in mutations and CNV changes in lactate metabolism-related (L-related) genes, after which a prognostic nomogram was built based on selected genes and clinical features by machine learning methods.

RESULTS

EGLN1, IL1, IL12RB1, ENO1, and 10 other genes had the most frequent changes and prognostic differences in overall survival (OS). The lactated associated risk (LAR) score model can distinguish the patients in OS (p = 0.046, HR = 101.9, 95%CI 1.1-9447.6), and together with clinical features has a higher AUC (AUC = 0.839). Furthermore, CD8+ T, activated CD4+ memory T and resting mast cells were significantly negatively associated with the LAR score.

CONCLUSIONS

Lactic acid metabolism is closely related to the prognosis of cervical carcinoma, where the immune microenvironment may play an important role.

Primary cilia-associated signalling in squamous cell carcinoma of head and neck region

Squamous cell carcinoma (SCC) of the head and neck originates from the mucosal lining of the upper aerodigestive tract, including the lip, tongue, nasopharynx, oropharynx, larynx and hypopharynx. In this review, we summarise what is currently known about the potential function of primary cilia in the pathogenesis of this disease. As primary cilia represent a key cellular structure for signal transduction and are related to cell proliferation, an understanding of their role in carcinogenesis is necessary for the design of new treatment approaches. Here, we introduce cilia-related signalling in head and neck squamous cell carcinoma (HNSCC) and its possible association with HNSCC tumorigenesis. From this point of view, PDGF, EGF, Wnt and Hh signalling are discussed as all these pathways were found to be dysregulated in HNSCC. Moreover, we review the clinical potential of small molecules affecting primary cilia signalling to target squamous cell carcinoma of the head and neck area.

Lactate drives the ESM1-SCD1 axis to inhibit the antitumor CD8+ T-cell response by activating the Wnt/β-catenin pathway in ovarian cancer cells and inducing cisplatin resistance

Ovarian cancer (OC) is a gynecological malignancy that results in a global threat to women's lives. Lactic acid, a key metabolite produced from the glycolytic metabolism of glucose molecules, is correlated with tumor immune infiltration and platinum resistance. In our previous study, we found that endothelial cell-specific molecule 1 (ESM1) plays a key role in OC progression. This study revealed that lactate could upregulate ESM1, which enhances SCD1 to attenuate the antitumor CD8+ T-cell response. ESM1 and SCD1 expression levels were significantly greater in OC patients with high lactic acid levels than in those with low lactic acid levels. Further mechanistic studies suggested that the Wnt/β-catenin pathway was inactivated after ESM1 knockdown and rescued by SCD1 overexpression. IC50 analysis indicated that the ESM1-SCD1 axis induces the resistance of OC cells to platinum agents, including cisplatin, carboplatin, and oxaliplatin, by upregulating P-gp. In conclusion, our study indicated that the induction of SCD1 by lactic acid-induced ESM1 can impede the CD8+ T-cell response against tumors and promote resistance to cisplatin by activating the Wnt/β-catenin pathway in ovarian cancer. Consequently, targeting ESM1 may have considerable therapeutic potential for modulating the tumor immune microenvironment and enhancing drug sensitivity in OC patients.

Multi-modal Ca2+ nanogenerator via reversing T cell exhaustion for enhanced chemo-immunotherapy

Chemo-immunotherapy holds the advantage of specific antitumor effects by activating cytotoxic lymphocyte cells (CTLs) immune response. However, multiple barriers have limited the outcomes partly due to tumor-cell-mediated exhaustion of CTLs in the immunosuppressive tumor microenvironment (iTME). Here, we rationally designed a simple-yet-versatile Ca2+ nanogenerator to modulate iTME for enhancing 2-deoxyglucose (2-DG) mediated chemo-immunotherapy. Briefly, after 2-DG chemotherapy, CaO2 nanoparticles coated with EL4 cell membrane (denoted as CaNP@ECM) could preferentially accumulate in tumor tissue via adhesion between LFA-1 on EL4 cell membrane and ICAM-1 on inflamed endothelial cell in tumor tissues and display a series of benefits for CTLs: i) Increasing glucose availability of CTLs while reducing lactic acid secretion through Ca2+ overloading mediated inhibition of tumor cell glycolysis, as well as relieving hypoxia; ii) Reversing CTLs exhaustion via TGF-β1 scavenging and PD-L1 blockade through PD-1 and TGF-β1R on EL4 cell membrane; iii) Boosting tumor immunotherapy via immunologic death (ICD) of tumor cells induced by Ca2+ overloading. We demonstrate that the multi-modal Ca2+ nanogenerator rescues T cells from exhaustion and inhibits tumor growth both in vitro and in vivo. More importantly, the study also facilitate the development of glucose metabolism inhibition-based tumor immunotherapy via Ca2+ overloading.

STAT3 drives the expression of HIF1alpha in cancer cells through a novel super-enhancer

Aerobic glycolysis is one of the major hallmarks of malignant tumors. This metabolic reprogramming benefits the rapid proliferation of cancer cells, facilitates the formation of tumor microenvironment to support their growth and survival, and impairs the efficacy of various tumor therapies. Therefore, the elucidation of the mechanisms driving aerobic glycolysis in tumors represents a pivotal breakthrough in developing therapeutic strategies for solid tumors. HIF1α serves as a central regulator of aerobic glycolysis with elevated mRNA and protein expression across multiple tumor types. However, the mechanisms contributing to this upregulation remain elusive. This study reports the identification of a novel HIF1α super enhancer (HSE) in multiple cancer cells using bioinformatics analysis, chromosome conformation capture (3C), chromatin immunoprecipitation (ChIP), and CRISPR/Cas9 genome editing techniques. Deletion of HSE in cancer cells significantly reduces the expression of HIF1α, glycolysis, cell proliferation, colony and tumor formation ability, confirming the role of HSE as the enhancer of HIF1α in cancer cells. Particularly, we demonstrated that STAT3 promotes the expression of HIF1α by binding to HSE. The discovery of HSE will help elucidate the pathways driving tumor aerobic glycolysis, offering new therapeutic targets and potentially resolving the bottleneck in solid tumor treatment.

Cancer Immunotherapy with "Vascular-Immune" Crosstalk as Entry Point: Associated Mechanisms, Therapeutic Drugs and Nano-Delivery Systems

Tumor vessels characterized by abnormal functions and structures hinder the infiltration and immune antigen presentation of immune cells by inducing the formation of an immunosuppressive microenvironment ("cold" environment). Vascular-targeted therapy has been proven to enhance immune stimulation and the effectiveness of immunotherapy by modulating the "cold" microenvironment, such as hypoxia and an acidic microenvironment. Notably, a therapeutic strategy based on "vascular-immune" crosstalk can achieve dual regulation of tumor vessels and the immune system by reprogramming the tumor microenvironment (TME), thus forming a positive feedback loop between tumor vessels and the immune microenvironment. From this perspective, we discuss the factors of tumor angiogenesis and "cold" TME formation. Building on this foundation, some vascular-targeted therapeutic drugs will be elaborated upon in detail to achieve dual regulation of tumor vessels and immunity. More importantly, we focus on cutting-edge nanotechnology in view of "vascular-immune" crosstalk and discuss the rational fabrication of tailor-made nanosystems for efficiently enhancing immunotherapy.

Translational insights into the hormetic potential of carbon dioxide: from physiological mechanisms to innovative adjunct therapeutic potential for cancer

Background

Carbon dioxide (CO2), traditionally viewed as a mere byproduct of cellular respiration, plays a multifaceted role in human physiology beyond simple elimination through respiration. CO2 may regulate the tumor microenvironment by significantly affecting the release of oxygen (O2) to tissues through the Bohr effect and by modulating blood pH and vasodilation. Previous studies suggest hypercapnia (elevated CO2 levels) might trigger optimized cellular mechanisms with potential therapeutic benefits. The role of CO2 in cellular stress conditions within tumor environments and its impact on O2 utilization offers a new investigative area in oncology.

Objectives

This study aims to explore CO2's role in the tumor environment, particularly how its physiological properties and adaptive responses can influence therapeutic strategies.

Methods

By applying a structured translational approach using the Work Breakdown Structure method, the study divided the analysis into six interconnected work packages to comprehensively analyze the interactions between carbon dioxide and the tumor microenvironment. Methods included systematic literature reviews, data analyses, data integration for identifying critical success factors and exploring extracellular environment modulation. The research used SMART criteria for assessing innovation and the applicability of results.

Results

The research revealed that the human body's adaptability to hypercapnic conditions could potentially inform innovative strategies for manipulating the tumor microenvironment. This could enhance O2 utilization efficiency and manage adaptive responses to cellular stress. The study proposed that carbon dioxide's hormetic potential could induce beneficial responses in the tumor microenvironment, prompting clinical protocols for experimental validation. The research underscored the importance of pH regulation, emphasizing CO2 and carbonic acid's role in modulating metabolic and signaling pathways related to cancer.

Conclusion

The study underscores CO2 as vital to our physiology and suggests potential therapeutic uses within the tumor microenvironment. pH modulation and cellular oxygenation optimization via CO2 manipulation could offer innovative strategies to enhance existing cancer therapies. These findings encourage further exploration of CO2's therapeutic potential. Future research should focus on experimental validation and exploration of clinical applications, emphasizing the need for interdisciplinary and collaborative approaches to tackle current challenges in cancer treatment.

Lactic acid: a narrative review of a promoter of the liver cancer microenvironment

Background and Objective

Lactic acid is a metabolite of glycolysis produced in the body, and its production is thought to be a mechanism by which cancer cells evade immune surveillance. Immune evasion and metabolic changes are well established as basic hallmarks of cancer. Although lactate has long been considered a waste product, it is now generally recognized to be a versatile small-molecule chemical that plays an important part in the tumor microenvironment (TME), with increased lactate production linked to the development of human malignancies. Metabolism in liver cancer is redirected toward glycolysis, which enhances the production of metabolic compounds used by tumor cells to produce proteins, lipids, and nucleotides, enabling them to maintain high proliferation rates and to establish the TME. Dysregulation of metabolic activity in liver cancer may impair antitumor responses owing to the immunosuppressive activity of the lactate produced by anaerobic glycolytic rates in tumor cells. This review primarily explores the link connection between lactic acid and the TME; evaluates the role of lactic acid in the occurrence, metastasis, prognosis, and treatment of liver cancer. Additionally, it investigates the associated pathways as potential targets for liver cancer treatment.

Methods

Literature searches were conducted in PubMed, Web of Science, and Google Scholar, with the publication date of the most recent article included being January 2024. After eliminating duplicate articles and less relevant articles through titles and abstracts, we selected 113 articles for this review. We categorized references into two categories. One is to classify the content into lactate-related, liver cancer-related and tumor metabolism-related. The other is to classify the article types, which are divided into reviews, research articles and clinical trials. Additionally, we consulted the reference lists of the relevant articles to ensure coverage was comprehensive and unbiased.

Key Content and Findings

The connection between lactic acid and the TME has recently become an area of intense research interest, and many related articles have been published in this field. The main finding of this review is to summarize the proven link between lactate and the TME and its possible impact on the TME of liver cancer. And analyzed the potential of lactate in liver cancer treatment and prognosis prediction.

Conclusions

Lactate may be key to developing novel approaches in the future treatment of liver cancer. Related research on the combination of classic therapies and molecular targeted drugs may provide innovative medicines that more selectively regulate immune cell activity.

Nanotherapy to Reshape the Tumor Microenvironment: A New Strategy for Prostate Cancer Treatment

Prostate cancer (PCa) is the second most common cancer in males worldwide. Androgen deprivation therapy (ADT) is the primary treatment method used for PCa. Although more effective androgen synthesis and antiandrogen inhibitors have been developed for clinical practice, hormone resistance increases the incidence of ADT-insensitive prostate cancer and poor prognoses. The tumor microenvironment (TME) has become a research hotspot with efforts to identify treatment targets based on the characteristics of the TME to improve prognosis. Herein, we introduce the basic characteristics of the PCa TME and the side effects of traditional prostate cancer treatments. We further highlight the emergence of novel nanotherapy strategies, their therapeutic mechanisms, and their effects on the PCa microenvironment. With further research, clinical applications of nanotherapy for PCa are expected in the near future. Collectively, this Review provides a valuable resource regarding the various nanotherapy types, demonstrating their broad clinical prospects to improve the quality of life in patients with PCa.

Lactate and lactylation: Behind the development of tumors

There is growing evidence that lactate can have a wide range of biological impacts in addition to being a waste product of metabolism. Because of the Warburg effect, tumors generate lots of lactate, which create a tumor microenvironment (TME) with low nutrition, hypoxia, and low pH. As a result, the immunosuppressive network is established to gain immune escape potential and regulate tumor growth. Consequently, the tumor lactate pathway is emerging as a possible therapeutic target for tumor. Importantly, Zhao et al. first discovered histone lysine lactylation (Kla) in 2019, which links gene regulation to cell metabolism through dysmetabolic activity and epigenetic modifications, influencing TME and tumor development. Therefore, the aim of this paper is to explore the effects of lactate and lactylation on the TME and tumors, and provide theoretical basis for further research on potential therapeutic targets and biomarkers, with the view to providing new ideas and methods for tumor treatment and prognosis evaluation.

A prognostic risk model based on lactate metabolism and transport-related lncRNAs for gastric adenocarcinoma

BACKGROUND

Increased lactate levels and metastasis in tumours are strongly associated with dismal outcomes. But prognostic value of lactate metabolism and transport-related lncRNAs in gastric adenocarcinoma (GA) patients remains unaddressed.

METHODS

Gene expression data of GA were provided by The Cancer Genome Atlas. Lactate metabolism and transport-related gene data were accessed from GSEA. LncRNAs related to lactate metabolism and transport were identified by correlation analysis. A prognostic model was built by regression analysis. Validity of prognostic model was confirmed through survival analysis and receiver operating characteristic (ROC) curve. Immunity of each risk group was evaluated by immune correlation analysis .LncRNA-mRNA network was built by correlation analysis using Cytoscape software.

RESULTS

A 12-gene prognostic model based on lactate metabolism and transport-related lncRNAs was built in GA. Median riskscore was utilized to classify GA samples into high- and low-risk groups. Survival analysis and ROC curves demonstrated validity of prognostic model. Most immune checkpoint molecules and TIDE scores were lower in the low-risk group. LINC01303 and LINC01545 may be the key prognostic factors in patients with GA.

CONCLUSION

This study successfully built a prognostic model of lactate metabolism and transport-related lncRNAs in GA. The findings guide prognostic management of GA patients.

Different lactate metabolism subtypes reveal heterogeneity in clinical outcomes and immunotherapy in lung adenocarcinoma patients

Background

The excessive accumulation of lactate within the tumor microenvironment (TME) has been demonstrated to facilitate tumor advancement and evade the immune system. Nonetheless, the metabolic status of lactate in lung adenocarcinoma (LUAD) remains uncertain.

Method

By analyzing the transcriptome profile of patients with LUAD, we created a lactate metabolism score (LMS) to predict survival. We then conducted a comprehensive examination of the biological functions and immune infiltration among different LMS patient groups. Moreover, we assessed the LMS predictive efficacy in chemotherapy and immunotherapy. Finally, we validated the detrimental phenotypic effects of SLC16A3 on LUAD cell lines (PC9 and A549) through in vitro experiments. We collected clinical samples to assess the prognostic impact of SLC16A3.

Results

We constructed an LMS model with 6 lactate metabolism regulatory factors using LASSO regression. The high LMS model indicates worse clinical outcomes for LUAD patients. High LMS patients are associated with metabolic dysregulation and increased infiltration of M0 and M1 macrophages. Low LMS patients are related to upregulated citric acid metabolism pathways and memory immune cells. High LMS patients are suitable for traditional chemotherapy, while patients with low LMS are more likely to benefit from immunotherapy. Lastly, downregulating SLC16A3 significantly reduces the proliferative and invasive capabilities of LUAD cell lines. Clinical cohort shows that patients with high expression of SLC16A3 have a worse prognosis.

Conclusions

The LMS model constructed based on the lactate metabolism pathway displays high effectiveness in predicting the outcome of patients with LUAD. LMS can offer direction regarding chemotherapy as well as immunotherapy in LUAD.

The cholera toxin B subunit induces trained immunity in dendritic cells and promotes CD8 T cell antitumor immunity

Introduction

Innate immune training is a metabolic, functional, and epigenetic long-term reprogramming of innate cells triggered by different stimuli. This imprinting also reaches hematopoietic precursors in the bone marrow to sustain a memory-like phenotype. Dendritic cells (DCs) can exhibit memory-like responses, enhanced upon subsequent exposure to a pathogen; however, whether this imprinting is lineage and stimulus-restricted is still being determined. Nevertheless, the functional consequences of DCs training on the adaptive and protective immune response against non-infectious diseases remain unresolved.

Methods

We evaluated the effect of the nontoxic cholera B subunit (CTB), LPS and LTA in the induction of trained immunity in murine DCs revealed by TNFa and LDH expression, through confocal microscopy. Additionally, we obtained bone marrow DCs (BMDCs) from mice treated with CTB, LPS, and LTA and evaluated training features in DCs and their antigen-presenting cell capability using multiparametric cytometry. Finally, we design an experimental melanoma mouse model to demonstrate protection induced by CTB-trained DCs in vivo.

Results

CTB-trained DCs exhibit increased expression of TNFa, and metabolic reprogramming indicated by LDH expression. Moreover, CTB training has an imprint on DC precursors, increasing the number and antigen-presenting function in BMDCs. We found that training by CTB stimulates the recruitment of DC precursors and DCs infiltration at the skin and lymph nodes. Interestingly, training-induced by CTB promotes a highly co-stimulatory phenotype in tumor-infiltrating DCs (CD86+) and a heightened functionality of exhausted CD8 T cells (Ki67+, GZMB+), which were associated with a protective response against melanoma challenge in vivo.

Conclusion

Our work indicates that CTB can induce innate immune training on DCs, which turns into an efficient adaptive immune response in the melanoma model and might be a potential immunotherapeutic approach for tumor growth control.

Immunologic tumor microenvironment modulators for turning cold tumors hot

Tumors can be classified into distinct immunophenotypes based on the presence and arrangement of cytotoxic immune cells within the tumor microenvironment (TME). Hot tumors, characterized by heightened immune activity and responsiveness to immune checkpoint inhibitors (ICIs), stand in stark contrast to cold tumors, which lack immune infiltration and remain resistant to therapy. To overcome immune evasion mechanisms employed by tumor cells, novel immunologic modulators have emerged, particularly ICIs targeting cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death protein 1/programmed death-ligand 1(PD-1/PD-L1). These agents disrupt inhibitory signals and reactivate the immune system, transforming cold tumors into hot ones and promoting effective antitumor responses. However, challenges persist, including primary resistance to immunotherapy, autoimmune side effects, and tumor response heterogeneity. Addressing these challenges requires innovative strategies, deeper mechanistic insights, and a combination of immune interventions to enhance the effectiveness of immunotherapies. In the landscape of cancer medicine, where immune cold tumors represent a formidable hurdle, understanding the TME and harnessing its potential to reprogram the immune response is paramount. This review sheds light on current advancements and future directions in the quest for more effective and safer cancer treatment strategies, offering hope for patients with immune-resistant tumors.

Advancing glioblastoma treatment by targeting metabolism

Alterations in cellular metabolism are important hallmarks of glioblastoma(GBM). Metabolic reprogramming is a critical feature as it meets the higher nutritional demand of tumor cells, including proliferation, growth, and survival. Many genes, proteins, and metabolites associated with GBM metabolism reprogramming have been found to be aberrantly expressed, which may provide potential targets for cancer treatment. Therefore, it is becoming increasingly important to explore the role of internal and external factors in metabolic regulation in order to identify more precise therapeutic targets and diagnostic markers for GBM. In this review, we define the metabolic characteristics of GBM, investigate metabolic specificities such as targetable vulnerabilities and therapeutic resistance, as well as present current efforts to target GBM metabolism to improve the standard of care.

Bridging the divide: unveiling mutual immunological pathways of cancer and pregnancy

The juxtaposition of two seemingly disparate physiological phenomena within the human body-namely, cancer and pregnancy-may offer profound insights into the intricate interplay between malignancies and the immune system. Recent investigations have unveiled striking similarities between the pivotal processes underpinning fetal implantation and successful gestation and those governing tumor initiation and progression. Notably, a confluence of features has emerged, underscoring parallels between the microenvironment of tumors and the maternal-fetal interface. These shared attributes encompass establishing vascular networks, cellular mobilization, recruitment of auxiliary tissue components to facilitate continued growth, and, most significantly, the orchestration of immune-suppressive mechanisms.Our particular focus herein centers on the phenomenon of immune suppression and its protective utility in both of these contexts. In the context of pregnancy, immune suppression assumes a paramount role in shielding the semi-allogeneic fetus from the potentially hostile immune responses of the maternal host. In stark contrast, in the milieu of cancer, this very same immunological suppression fosters the transformation of the tumor microenvironment into a sanctuary personalized for the neoplastic cells.Thus, the striking parallels between the immunosuppressive strategies deployed during pregnancy and those co-opted by malignancies offer a tantalizing reservoir of insights. These insights promise to inform novel avenues in the realm of cancer immunotherapy. By harnessing our understanding of the immunological events that detrimentally impact fetal development, a knowledge grounded in the context of conditions such as preeclampsia or miscarriage, we may uncover innovative immunotherapeutic strategies to combat cancer.

Drug repurposing for cancer therapy

Cancer, a complex and multifactorial disease, presents a significant challenge to global health. Despite significant advances in surgical, radiotherapeutic and immunological approaches, which have improved cancer treatment outcomes, drug therapy continues to serve as a key therapeutic strategy. However, the clinical efficacy of drug therapy is often constrained by drug resistance and severe toxic side effects, and thus there remains a critical need to develop novel cancer therapeutics. One promising strategy that has received widespread attention in recent years is drug repurposing: the identification of new applications for existing, clinically approved drugs. Drug repurposing possesses several inherent advantages in the context of cancer treatment since repurposed drugs are typically cost-effective, proven to be safe, and can significantly expedite the drug development process due to their already established safety profiles. In light of this, the present review offers a comprehensive overview of the various methods employed in drug repurposing, specifically focusing on the repurposing of drugs to treat cancer. We describe the antitumor properties of candidate drugs, and discuss in detail how they target both the hallmarks of cancer in tumor cells and the surrounding tumor microenvironment. In addition, we examine the innovative strategy of integrating drug repurposing with nanotechnology to enhance topical drug delivery. We also emphasize the critical role that repurposed drugs can play when used as part of a combination therapy regimen. To conclude, we outline the challenges associated with repurposing drugs and consider the future prospects of these repurposed drugs transitioning into clinical application.

Targeting metabolism of breast cancer and its implications in T cell immunotherapy

Breast cancer is a prominent health issue amongst women around the world. Immunotherapies including tumor targeted antibodies, adoptive T cell therapy, vaccines, and immune checkpoint blockers have rejuvenated the clinical management of breast cancer, but the prognosis of patients remains dismal. Metabolic reprogramming and immune escape are two important mechanisms supporting the progression of breast cancer. The deprivation uptake of nutrients (such as glucose, amino acid, and lipid) by breast cancer cells has a significant impact on tumor growth and microenvironment remodeling. In recent years, in-depth researches on the mechanism of metabolic reprogramming and immune escape have been extensively conducted, and targeting metabolic reprogramming has been proposed as a new therapeutic strategy for breast cancer. This article reviews the abnormal metabolism of breast cancer cells and its impact on the anti-tumor activity of T cells, and further explores the possibility of targeting metabolism as a therapeutic strategy for breast cancer.

Crosstalk between metabolism and cell death in tumorigenesis

It is generally recognized that tumor cells proliferate more rapidly than normal cells. Due to such an abnormally rapid proliferation rate, cancer cells constantly encounter the limits of insufficient oxygen and nutrient supplies. To satisfy their growth needs and resist adverse environmental events, tumor cells modify the metabolic pathways to produce both extra energies and substances required for rapid growth. Realizing the metabolic characters special for tumor cells will be helpful for eliminating them during therapy. Cell death is a hot topic of long-term study and targeting cell death is one of the most effective ways to repress tumor growth. Many studies have successfully demonstrated that metabolism is inextricably linked to cell death of cancer cells. Here we summarize the recently identified metabolic characters that specifically impact on different types of cell deaths and discuss their roles in tumorigenesis.

Nanoparticles in tumor microenvironment remodeling and cancer immunotherapy

Cancer immunotherapy and vaccine development have significantly improved the fight against cancers. Despite these advancements, challenges remain, particularly in the clinical delivery of immunomodulatory compounds. The tumor microenvironment (TME), comprising macrophages, fibroblasts, and immune cells, plays a crucial role in immune response modulation. Nanoparticles, engineered to reshape the TME, have shown promising results in enhancing immunotherapy by facilitating targeted delivery and immune modulation. These nanoparticles can suppress fibroblast activation, promote M1 macrophage polarization, aid dendritic cell maturation, and encourage T cell infiltration. Biomimetic nanoparticles further enhance immunotherapy by increasing the internalization of immunomodulatory agents in immune cells such as dendritic cells. Moreover, exosomes, whether naturally secreted by cells in the body or bioengineered, have been explored to regulate the TME and immune-related cells to affect cancer immunotherapy. Stimuli-responsive nanocarriers, activated by pH, redox, and light conditions, exhibit the potential to accelerate immunotherapy. The co-application of nanoparticles with immune checkpoint inhibitors is an emerging strategy to boost anti-tumor immunity. With their ability to induce long-term immunity, nanoarchitectures are promising structures in vaccine development. This review underscores the critical role of nanoparticles in overcoming current challenges and driving the advancement of cancer immunotherapy and TME modification.

Acidic/hypoxia dual-alleviated nanoregulators for enhanced treatment of tumor chemo-immunotherapy

Chemotherapy plays a crucial role in triple-negative breast cancer (TNBC) treatment as it not only directly kills cancer cells but also induces immunogenic cell death. However, the chemotherapeutic efficacy was strongly restricted by the acidic and hypoxic tumor environment. Herein, we have successfully formulated PLGA-based nanoparticles concurrently loaded with doxorubicin (DOX), hemoglobin (Hb) and CaCO3 by a CaCO3-assisted emulsion method, aiming at the effective treatment of TNBC. We found that the obtained nanomedicine (DHCaNPs) exhibited effective drug encapsulation and pH-responsive drug release behavior. Moreover, DHCaNPs demonstrated robust capabilities in neutralizing protons and oxygen transport. Consequently, DHCaNPs could not only serve as oxygen nanoshuttles to attenuate tumor hypoxia but also neutralize the acidic tumor microenvironment (TME) by depleting lactic acid, thereby effectively overcoming the resistance to chemotherapy. Furthermore, DHCaNPs demonstrated a notable ability to enhance antitumor immune responses by increasing the frequency of tumor-infiltrating effector lymphocytes and reducing the frequency of various immune-suppressive cells, therefore exhibiting a superior efficacy in suppressing tumor growth and metastasis when combined with anti-PD-L1 (αPD-L1) immunotherapy. In summary, this study highlights that DHCaNPs could effectively attenuate the acidic and hypoxic TME, offering a promising strategy to figure out an enhanced chemo-immunotherapy to benefit TNBC patients.

Lactic acid in macrophage polarization: A factor in carcinogenesis and a promising target for cancer therapy

Cancer remains a formidable challenge, continually revealing its intricate nature and demanding novel treatment approaches. Within this intricate landscape, the tumor microenvironment and its dynamic components have gained prominence, particularly macrophages that can adopt diverse polarization states, exerting a profound influence on cancer progression. Recent revelations have spotlighted lactic acid as a pivotal player in this complex interplay. This review systematically explores lactic acid's multifaceted role in macrophage polarization, focusing on its implications in carcinogenesis. We commence by cultivating a comprehensive understanding of the tumor microenvironment and the pivotal roles played by macrophages. The dynamic landscape of macrophage polarization, typified by M1 and M2 phenotypes, is dissected to reveal its substantial impact on tumor progression. Lactic acid, a metabolic byproduct, emerges as a key protagonist, and we meticulously unravel the mechanisms underpinning its generation within cancer cells, shedding light on its intimate association with glycolysis and its transformative effects on the tumor microenvironment. Furthermore, we decipher the intricate molecular framework that underlies lactic acid's pivotal role in facilitating macrophage polarization. Our review underscores lactic acid's dual role in carcinogenesis, orchestrating tumor growth and immune modulation within the tumor microenvironment, thereby profoundly influencing the balance between pro-tumor and anti-tumor immune responses. This duality highlights the therapeutic potential of selectively manipulating lactic acid metabolism for cancer treatment. Exploring strategies to inhibit lactic acid production by tumor cells, novel approaches to impede lactic acid transport in the tumor microenvironment, and the burgeoning field of immunotherapeutic cancer therapies utilizing lactic acid-induced macrophage polarization form the core of our investigation.

Current status and progress of research on the ADP-dependent glucokinase gene

ADP-dependent glucokinase (ADPGK) produces glucose-6-phosphate with adenosine diphosphate (ADP) as the phosphate group donor, in contrast to ATP-dependent hexokinases (HKs). Originally found in archaea, ADPGK is involved in glycolysis. However, its biological function in most eukaryotic organisms is still unclear, and the molecular mechanism of action requires further investigation. This paper provides a concise overview of ADPGK's origin, biological function and clinical application. It aims to furnish scientific information for the diagnosis and treatment of human metabolic diseases, neurological disorders, and malignant tumours, and to suggest new strategies for the development of targeted drugs.

Identification roles of NFE2L3 in digestive system cancers

BACKGROUND

Morbidity and mortality rates of Digestive System Cancers (DSC) continue to pose human lives and health. Nuclear factor erythroid 2-like protein 3 (NFE2L3) is aberrantly expressed in DSC. This study aimed to explore the clinical value and underlying mechanisms of NFE2L3 as a novel biomarker in DSC.

METHODS

We utilized data from databases and clinical gastric cancer specimens to validate the aberrant expression level of NFE2L3 and further assessed the clinical value of NFE2L3. To investigate the potential molecular mechanism of NFE2L3, we analyzed the correlation of NFE2L3 with immune molecular mechanisms, constructed PPI network, performed GO analysis and KEGG analysis, and finally explored the biological function of NFE2L3 in gastric cancer cells.

RESULTS

NFE2L3 expression is up-regulated in DSC and has both prognostic and diagnostic value. NFE2L3 correlates with various immune mechanisms, PPI network suggests proteins interacting with NFE2L3, GSEA analysis suggests potential molecular mechanisms for NFE2L3 to play a role in cancer promotion, and in vitro cellular experiments also confirmed the effect of NFE2L3 on the biological function of gastric cancer cells.

CONCLUSION

Our study confirms the aberrant expression and molecular mechanisms of NFE2L3 in DSC, indicating that NFE2L3 could serve as a novel biomarker for diagnosis and prognosis of DSC.

Ezrin's role in gastric cancer progression: Implications for immune microenvironment modulation and therapeutic potential

At present, surgical resection is the most effective method for the treatment of gastric cancer. However, death caused by inoperable metastasis is still very common, despite research in this area. The mechanisms underlying the occurrence, development, and metastasis of gastric cancer are not fully understood. Ezrin, a plasma membrane-microfilament junction participates in a variety of cellular activities and is closely related to tumorigenesis and development. Few studies have explored the relationship between the tumor immune microenvironment and ezrin expression in gastric cancer. In this study, we used proteomic techniques to analyze the differentially expressed proteins between the gastric cancer cell lines MKN-45 and HGC-27 and screened ezrin as the target protein. We collected patient information from The TCGA and GEO databases, and the results showed that ezrin was positively correlated with adverse clinical features. We further explored the relationship between ezrin expression levels, immune microenvironment, and genomic changes. We found that ezrin was involved in immune regulation and genomic instability in gastric cancer. When the expression of ezrin is high, immune cell infiltration also increases. We also predicted that ezrin is closely related to immunotherapy and chemosensitivity. Single-cell transcriptome data showed that the ezrin gene was mainly expressed in B cells and epithelial cells, and the expression of EZR in these epithelial cells was positively correlated with the epithelial-mesenchymal transformation pathway and Pi3k-AKT pathway score. Through functional verification of the stably transfected cell line constructed by lentivirus, the results of the liver metastasis model in nude mice suggested that high expression of ezrin leads to the formation of more metastatic foci. In summary, our results clarify the prognostic, immunological, and therapeutic value of ezrin in gastric cancer and provide a theoretical basis for more accurate treatment.

Proton-sensing ion channels, GPCRs and calcium signaling regulated by them: implications for cancer

Extracellular acidification of tumors is common. Through proton-sensing ion channels or proton-sensing G protein-coupled receptors (GPCRs), tumor cells sense extracellular acidification to stimulate a variety of intracellular signaling pathways including the calcium signaling, which consequently exerts global impacts on tumor cells. Proton-sensing ion channels, and proton-sensing GPCRs have natural advantages as drug targets of anticancer therapy. However, they and the calcium signaling regulated by them attracted limited attention as potential targets of anticancer drugs. In the present review, we discuss the progress in studies on proton-sensing ion channels, and proton-sensing GPCRs, especially emphasizing the effects of calcium signaling activated by them on the characteristics of tumors, including proliferation, migration, invasion, metastasis, drug resistance, angiogenesis. In addition, we review the drugs targeting proton-sensing channels or GPCRs that are currently in clinical trials, as well as the relevant potential drugs for cancer treatments, and discuss their future prospects. The present review aims to elucidate the important role of proton-sensing ion channels, GPCRs and calcium signaling regulated by them in cancer initiation and development. This review will promote the development of drugs targeting proton-sensing channels or GPCRs for cancer treatments, effectively taking their unique advantage as anti-cancer drug targets.

pH regulators and their inhibitors in tumor microenvironment

As an important characteristic of tumor, acidic tumor microenvironment (TME) is closely related to immune escape, invasion, migration and drug resistance of tumor. The acidity of the TME mainly comes from the acidic products produced by the high level of tumor metabolism, such as lactic acid and carbon dioxide. pH regulators such as monocarboxylate transporters (MCTs), carbonic anhydrase IX (CA IX), and Na+/H+ exchange 1 (NHE1) expel protons directly or indirectly from the tumor to maintain the pH balance of tumor cells and create an acidic TME. We review the functions of several pH regulators involved in the construction of acidic TME, the structure and structure-activity relationship of pH regulator inhibitors, and provide strategies for the development of small-molecule antitumor inhibitors based on these targets.

Identification of SLC2A1 as a predictive biomarker for survival and response to immunotherapy in lung squamous cell carcinoma

BACKGROUND

As one of the common subtypes of non-small lung cancer, lung squamous cell carcinoma (LUSC) patients with advanced stage have few choices of treatment strategies. Therefore, it is urgent to discover genes that are associated with the survival and efficacy of immunotherapies.

METHOD

Differential gene expression analyses were conducted using TCGA LUSC bulk-sequencing and single-cell RNA-sequencing data. Prognostic genes were identified from the TCGA LUSC cohort. Protein expression validation and survival analyses were performed. Experiments were conducted to explore the underlying mechanisms. In addition, the correlation between gene expression and pathological response to adjuvant immunochemotherapy was also investigated.

RESULTS

After a series of bioinformatic analyses, solute carrier family 2 member 1(SLC2A1), encoding glucose transporter-1 (GLUT1), was found to be differentially expressed between tumor and normal tissues. GLUT1 was subsequently identified as an independent prognostic factor for LUSC. GSEA analysis revealed the glycolysis metabolism pathway of KEGG enriched in SLC2A1high tumor tissues. LASSO analyses revealed that tumor tissues with high expression of SLC2A1 were associated with high levels of protein lactylation. We found that SLC2A1 was preferentially expressed by SPP1+ macrophages in the tumor microenvironment, and the expression of SLC2A1 was associated with the abundance of SPP1+ macrophages. Immunofluorescence demonstrated GLUT1 and HIF1α colocalization in tumor-infiltrating macrophages. In vitro experiments showed HIF-1α-induced macrophage polarization under hypoxia, and GLUT1 inhibition blocked this polarization. In addition, SLC2A1 was negatively associated with the common immune checkpoint molecules, such as programmed cell death 1(PD-1), T cell immunoreceptor with Ig and ITIM domains (TIGIT), cytotoxic T-lymphocyte associated protein 4 (CTLA4) and lymphocyte activating 3 (LAG3), while showed a positive association with CD44. Finally, we observed that there was a significant correlation between pre-adjuvant-treatment GLUT1 expression and the pathological response.

CONCLUSION

SLC2A1 expression was differentially upregulated in tumor tissues, and elevated GLUT1 expression was associated with worse survival and poor pathological response to adjuvant immunochemotherapy. Upregulation of GLUT1 promoted macrophage polarization into the M2 phenotype. The findings will contribute to guiding the treatment selection for LUSC patients and providing personalized immunotherapy strategies.

Recent advances in pyruvate dehydrogenase kinase inhibitors: Structures, inhibitory mechanisms and biological activities

Metabolism is reprogrammed in a variety of cancer cells to ensure their rapid proliferation. Cancer cells prefer to utilize glycolysis to produce energy as well as to provide large amounts of precursors for their division. In this process, cancer cells inhibit the activity of pyruvate dehydrogenase complex (PDC) by upregulating the expression of pyruvate dehydrogenase kinases (PDKs). Inhibiting the activity of PDKs in cancer cells can effectively block this metabolic transition in cancer cells, while also activating mitochondrial oxidative metabolism and promoting apoptosis of cancer cells. To this day, the study of PDKs inhibitors has become one of the research hotspots in the field of medicinal chemistry. Novel structures targeting PDKs are constantly being discovered, and some inhibitors have entered the clinical research stage. Here, we reviewed the research progress of PDKs inhibitors in recent years and classified them according to the PDKs binding sites they acted on, aiming to summarize the structural characteristics of inhibitors acting on different binding sites and explore their clinical application value. Finally, the shortcomings of some PDKs inhibitors and the further development direction of PDKs inhibitors are discussed.

Advances in tumor immune microenvironment of head and neck squamous cell carcinoma: A review of literature

Squamous cell carcinoma is seen as principal malignancy of head and neck. Tumor immune microenvironment plays a vital role in the occurrence, development and treatment of head and neck squamous cell carcinoma (HNSCC). The effect of immunotherapy, in particular, is closely related to tumor immune microenvironment. This review searched for high-quality literature included within PubMed, Web of Science, and Scopus using the keywords "head and neck cancers," "tumor microenvironment" and "immunotherapy," with the view to summarizing the characteristics of HNSCC immune microenvironment and how various subsets of immune cells promote tumorigenesis. At the same time, based on the favorable prospects of immunotherapy having been shown currently, the study is committed to pinpointing the latest progress of HNSCC immunotherapy, which is of great significance in not only further guiding the diagnosis and treatment of HNSCC, but also conducting its prognostic judgement.

Comparative investigation into the anticancer activity of analogs of marine coelenterazine and coelenteramine

Cancer is still one of the most challenging diseases to treat, making the pursuit for novel molecules with potential anticancer activity an important research topic. Herein, we have performed a comparative investigation into the anticancer activity of analogs of marine coelenterazine and coelenteramine. The former is a well-known bioluminescent substrate, while the latter is a metabolic product of the resulting bioluminescent reaction. While both types of analogs showed anticancer activity toward lung and gastric cancer cell lines, we have obtained data that highlight relevant differences between the activity of these two types of compounds. More specifically, we observed relevant differences in structure-activity relationships between these types of compounds. Also, coelenteramine analogs showed time-dependent activity, while coelenterazine-based compounds usually present time-independent activity. Coelenterazine analogs also appear to be relatively safer toward noncancer cells than coelenteramine analogs. There was also seen a correlation between the activity of the coelenterazine-based compounds and their light-emission properties. Thus, these results further indicate the potential of the marine coelenterazine chemi-/bioluminescent system as a source of new molecules with anticancer activity, while providing more insight into their modes of action.

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

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

The potential of aryl hydrocarbon receptor as receptors for metabolic changes in tumors

Cancer cells can alter their metabolism to meet energy and molecular requirements due to unfavorable environments with oxygen and nutritional deficiencies. Therefore, metabolic reprogramming is common in a tumor microenvironment (TME). Aryl hydrocarbon receptor (AhR) is a ligand-activated nuclear transcription factor, which can be activated by many exogenous and endogenous ligands. Multiple AhR ligands can be produced by both TME and tumor cells. By attaching to various ligands, AhR regulates cancer metabolic reprogramming by dysregulating various metabolic pathways, including glycolysis, lipid metabolism, and nucleotide metabolism. These regulated pathways greatly contribute to cancer cell growth, metastasis, and evading cancer therapies; however, the underlying mechanisms remain unclear. Herein, we review the relationship between TME and metabolism and describe the important role of AhR in cancer regulation. We also focus on recent findings to discuss the idea that AhR acts as a receptor for metabolic changes in tumors, which may provide new perspectives on the direction of AhR research in tumor metabolic reprogramming and future therapeutic interventions.

All Three AKT Isoforms Can Upregulate Oxygen Metabolism and Lactate Production in Human Hepatocellular Carcinoma Cell Lines

Hepatocellular carcinoma (HCC), the main pathological type of liver cancer, is related to risk factors such as viral hepatitis, alcohol intake, and non-alcoholic fatty liver disease (NAFLD). The constitutive activation of the PI3K/AKT signaling pathway is common in HCC and has essential involvement in tumor progression. The serine/threonine kinase AKT has several downstream substrates, which have been implicated in the regulation of cellular metabolism. However, the contribution of each of the three AKT isoforms, i.e., AKT1, AKT2 and AKT3, to HCC metabolism has not been comprehensively investigated. In this study, we analyzed the functional role of AKT1, AKT2 and AKT3 in HCC metabolism. The overexpression of activated AKT1, AKT2 and AKT3 isoforms in the human HCC cell lines Hep3B and Huh7 resulted in higher oxygen consumption rate (OCR), ATP production, maximal respiration and spare respiratory capacity in comparison to vector-transduced cells. Vice versa, lentiviral vector-mediated knockdowns of each AKT isoform reduced OCR in both cell lines. Reduced OCR rates observed in the three AKT isoform knockdowns were associated with reduced extracellular acidification rates (ECAR) and reduced lactate production in both analyzed cell lines. Mechanistically, the downregulation of OCR by AKT isoform knockdowns correlated with an increased phosphorylation of the pyruvate dehydrogenase on Ser232, which negatively regulates the activity of this crucial gatekeeper of mitochondrial respiration. In summary, our data indicate that each of the three AKT isoforms is able to upregulate OCR, ECAR and lactate production independently of each other in human HCC cells through the regulation of the pyruvate dehydrogenase.

Advancements in Preclinical Models of Pancreatic Cancer

ABSTRACT

Pancreatic cancer remains one of the deadliest of all cancer types with a 5-year overall survival rate of just 12%. Preclinical models available for understanding the disease pathophysiology have evolved significantly in recent years. Traditionally, commercially available 2-dimensional cell lines were developed to investigate mechanisms underlying tumorigenesis, metastasis, and drug resistance. However, these cells grow as monolayer cultures that lack heterogeneity and do not effectively represent tumor biology. Developing patient-derived xenografts and genetically engineered mouse models led to increased cellular heterogeneity, molecular diversity, and tissues that histologically represent the original patient tumors. However, these models are relatively expensive and very timing consuming. More recently, the advancement of fast and inexpensive in vitro models that better mimic disease conditions in vivo are on the rise. Three-dimensional cultures like organoids and spheroids have gained popularity and are considered to recapitulate complex disease characteristics. In addition, computational genomics, transcriptomics, and metabolomic models are being developed to simulate pancreatic cancer progression and predict better treatment strategies. Herein, we review the challenges associated with pancreatic cancer research and available analytical models. We suggest that an integrated approach toward using these models may allow for developing new strategies for pancreatic cancer precision medicine.

Bioresponsive and immunotherapeutic nanomaterials to remodel tumor microenvironment for enhanced immune checkpoint blockade

Immune checkpoint blockade (ICB) therapy is a revolutionary approach to treat cancers, but still have limited clinical applications. Accumulating evidence pinpoints the immunosuppressive characteristics of the tumor microenvironment (TME) as one major obstacle. The TME, characterized by acidity, hypoxia and elevated ROS levels, exerts its detrimental effects on infiltrating anti-tumor immune cells. Here, we developed a TME-responsive and immunotherapeutic catalase-loaded calcium carbonate nanoparticles (termed as CAT@CaCO3 NPs) as the simple yet versatile multi-modulator for TME remodeling. CaCO3 NPs can consume protons in the acidic TME to normalize the TME pH. CAT catalyzed the decomposition of ROS and thus generated O2. The released Ca2+ led to Ca2+ overload in the tumor cells which then triggered the release of damage-associated molecular patterns (DAMP) signals to initiate anti-tumor immune responses, including tumor antigen presentation by dendritic cells. Meanwhile, CAT@CaCO3 NPs-induced immunosupportive TME also promoted the polarization of the M2 tumor-associated macrophages to the M1 phenotype, further enhancing tumor antigen presentation. Consequently, T cell-mediated anti-tumor responses were activated, the efficacy of which was further boosted by aPD-1 immune checkpoint blockade. Our study demonstrated that local treatment of CAT@CaCO3 NPs and aPD-1 combination can effectively evoke local and systemic anti-tumor immune responses, inhibiting the growth of treated tumors and distant diseases.

Design strategies for enhancing antitumor efficacy through tumor microenvironment exploitation using albumin-based nanosystems: A review

The tumor microenvironment (TME) is a complex and dynamic system that plays a crucial role in regulating cancer progression, treatment response, and the emergence of acquired resistance mechanisms. The TME is usually featured by severe hypoxia, low pH values, high hydrogen peroxide (H2O2) concentrations, and overproduction of glutathione (GSH). The current development of intelligent nanosystems that respond to TME has shown great potential to enhance the efficacy of cancer treatment. As one of the functional macromolecules explored in this field, albumin-based nanocarriers, known for their inherent biocompatibility, serves as a cornerstone for constructing diverse therapeutic platforms. In this paper, we present a comprehensive overview of the latest advancements in the design strategies of albumin nanosystems, aiming to enhance cancer therapy by harnessing various features of solid tumors, including tumor hypoxia, acidic pH, the condensed extracellular matrix (ECM) network, excessive GSH, high glucose levels, and tumor immune microenvironment. Furthermore, we highlight representative designs of albumin-based nanoplatforms by exploiting the TME that enhance a broad range of cancer therapies, such as chemotherapy, phototherapy, radiotherapy, immunotherapy, and other tumor therapies. Finally, we discuss the existing challenges and future prospects in direction of albumin-based nanosystems for the practical applications in advancing enhanced cancer treatments.

Neuromedin U regulates the anti-tumor activity of CD8+ T cells and glycolysis of tumor cells in the tumor microenvironment of pancreatic ductal adenocarcinoma in an NMUR1-dependent manner

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer with a poor prognosis, which is lethal in approximately 90% of cases despite advanced standard therapies. A typical feature of PDAC is the immunosuppressive tumor microenvironment with multiple immunosuppressive factors including neurotransmitters. Recently, neuromedin U (NMU), a highly conserved neuropeptide with many physiological functions, has attracted attention for its roles in tumorigenesis and metastasis in several types of cancers. However, whether NMU affects PDAC progression remains unclear. In this study, using an orthotopic mouse model of PDAC in combination with bioinformatics analysis, we found that NMU was upregulated in tumor tissues from the patients with PDAC and positively correlated with a poor prognosis of the disease. Interestingly, knockout of the Nmu gene in mice enhanced the anti-tumor functions of tumor-infiltrating CD8+ T cells in an NMU receptor 1-dependent manner. Additionally, NMU promoted the glycolytic metabolism of mouse PDAC tumors. The activities of pyruvate kinase (PK) and lactate dehydrogenase (LDH), pivotal enzymes involved in the regulation of lactate production, were markedly reduced in tumor tissues from NMU-knockout mice. In vitro the presence of LDHA inhibitor can reduce the production of lactic acid stimulated by NMU, which can increase the anti-tumor activity of CD8+ T cells. Moreover, treatment of the pancreatic cancer cells with a phosphoinositide 3-kinase (PI3K) inhibitor diminished NMU-induced lactate production and the activities of PK and LDH, suggesting that NMU might regulate glycolysis via the PI3K/AKT pathway.

PA suppresses antitumor immunity of T cells by disturbing mitochondrial activity through Akt/mTOR-mediated Ca2+ flux

Deciphering the mechanisms behind how T cells become exhausted and regulatory T cells (Tregs) differentiate in a tumor microenvironment (TME) will significantly benefit cancer immunotherapy. A common metabolic alteration feature in TME is lipid accumulation, associated with T cell exhaustion and Treg differentiation. However, the regulatory role of free fatty acids (FFA) on T cell antitumor immunity has yet to be clearly illustrated. Our study observed that palmitic acid (PA), the most abundant saturated FFA in mouse plasma, enhanced T cell exhaustion and Tregs population in TME and increased tumor growth. In contrast, oleic acid (OA), a monounsaturated FFA, rescued PA-induced T cell exhaustion, decreased Treg population, and ameliorated T cell antitumor immunity in an obese mouse model. Mechanistically, mitochondrial metabolic activity is critical in maintaining T cell function, which PA attenuated. PA-induced T cell exhaustion and Treg formation depended on CD36 and Akt/mTOR-mediated calcium signaling. The study described a new mechanism of PA-induced downregulation of antitumor immunity of T cells and the therapeutic potential behind its restoration by targeting PA.

Mutant KRAS-activated circATXN7 fosters tumor immunoescape by sensitizing tumor-specific T cells to activation-induced cell death

Mutant KRAS (KRASMUT) is often exploited by cancers to shape tumor immunity, but the underlying mechanisms are not fully understood. Here we report that tumor-specific cytotoxic T lymphocytes (CTLs) from KRASMUT cancers are sensitive to activation-induced cell death (AICD). circATXN7, an NF-κB-interacting circular RNA, governs T cell sensitivity to AICD by inactivating NF-κB. Mechanistically, histone lactylation derived from KRASMUT tumor cell-produced lactic acid directly activates transcription of circATXN7, which binds to NF-κB p65 subunit and masks the p65 nuclear localization signal motif, thereby sequestering it in the cytoplasm. Clinically, circATXN7 upregulation in tumor-specific CTLs correlates with adverse clinical outcomes and immunotherapeutic resistance. Genetic ablation of circAtxn7 in CD8+ T cells leads to mutant-selective tumor inhibition, while also increases anti-PD1 efficacy in multiple tumor models in female mice. Furthermore, targeting circATXN7 in adoptively transferred tumor-reactive CTLs improves their antitumor activities. These findings provide insight into how lymphocyte-expressed circRNAs contribute to T-cell fate decisions and anticancer immunotherapies.

Protein cargo in extracellular vesicles as the key mediator in the progression of cancer

Exosomes are small vesicles of endosomal origin that are released by almost all cell types, even those that are pathologically altered. Exosomes widely participate in cell-to-cell communication via transferring cargo, including nucleic acids, proteins, and other metabolites, into recipient cells. Tumour-derived exosomes (TDEs) participate in many important molecular pathways and affect various hallmarks of cancer, including fibroblasts activation, modification of the tumour microenvironment (TME), modulation of immune responses, angiogenesis promotion, setting the pre-metastatic niche, enhancing metastatic potential, and affecting therapy sensitivity and resistance. The unique exosome biogenesis, composition, nontoxicity, and ability to target specific tumour cells bring up their use as promising drug carriers and cancer biomarkers. In this review, we focus on the role of exosomes, with an emphasis on their protein cargo, in the key mechanisms promoting cancer progression. We also briefly summarise the mechanism of exosome biogenesis, its structure, protein composition, and potential as a signalling hub in both normal and pathological conditions. Video Abstract.

Synergistic Effects of Nanoscale CaO2 Combined with PD-1 Inhibitors in the Treatment of Hepatocellular Carcinoma: A Promising Combination

Purpose

To explore the effect of calcium peroxide nanoparticles (CaO2 NPs) combined with programmed cell death protein 1 (PD-1) inhibitors in the treatment of liver cancer and its related mechanism.

Methods

Hepa1-6 cells were cultured to construct the Hepa1-6 mouse liver cancer model. In vivo mechanism study, a unilateral tumor model was established. Eighteen tumor-bearing mice were randomly divided into the control group (intra-tumoral injection of PBS solution) and the experimental group (intra-tumoral injection of CaO2 NPs). A hypoxic probe, pH probe, and micro-CT were used to evaluate the effect of CaO2 NPs on improving hypoxia, neutralizing acidity, and inducing calcium overload within the tumor. To study the effect of CaO2 NPs combined with PD-1 inhibitors on proximal and distal tumors, the bilateral tumor model was established. Forty tumor-bearing mice were randomly divided into the control group (intra-tumoral/intra-peritoneal injection of PBS solution), CaO2 NPs group (intra-tumoral injection of CaO2 NPs), PD-1 group (intra-peritoneal injection of PD-1 inhibitor), and the combination group (intra-tumoral injection of CaO2 NPs and intra-peritoneal injection of PD-1 inhibitors). The administered side was recorded as the proximal tumor. Tumor volume and body weight were measured every 2 days after treatment. On day 8, serum and tumor samples were collected. The immune factors in serum (Interferon-γ (IFN-γ), Tumour necrosis factor-α (TNF-α), Interleukin-2 (IL-2), and Interleukin-10 (IL-10)) and tumor tissue (IFN-γ and TNF-α) were detected by ELISA. H&E staining was used to detect tumor necrosis. Immunohistochemical staining was used to detect the amount of CD4+ and CD8+ T cells within the tumor. By analyzing the tumor volume, pathological indexes, and immune-related indexes, the effects of CaO2 NPs combined with PD-1 inhibitors on proximal and distal tumors were evaluated, and they mediated immunomodulatory effects (including local and systemic immunity), and their effects on tumor burden were studied. In addition, a unilateral tumor model was established to study the effect of CaO2 NPs combined with PD-1 inhibitors on survival time.

Results

The results of in vivo mechanism study showed that CaO2 NPs can improve hypoxia, neutralize acidity, and induce calcium overload within tumors. The results of the study on the effect of CaO2 NPs combined with PD-1 inhibitor on proximal and distal tumors showed that, compared with the other three groups, the bilateral tumor burden of the combination group was significantly reduced, the intra-tumoral infiltration of CD8+ and CD4+ T cells were significantly increased, the secretion of anti-tumor immune factors in tumor and serum was increased, and the secretion of pro-tumor immune factors was decreased. Mice in the combination group showed the longest survival compared with the other groups.

Conclusion

CaO2 NPs can improve hypoxia, neutralize acidity, and induce calcium overload within tumors, so as to reduce tumor burden and realize an immunosuppressive tumor transformation to a hot tumor, and play a synergistic role with PD-1 inhibitors in anti-liver cancer.