Metabolic Competition in the Tumor Microenvironment Is a Driver of Cancer Progression

Overcoming the limitations of immunotherapy in pancreatic ductal adenocarcinoma: Combining radiotherapy and metabolic targeting therapy

As a novel anticancer therapy, immunotherapy has demonstrated robust efficacy against a few solid tumors but poor efficacy against pancreatic ductal adenocarcinoma (PDAC). This poor outcome is primarily attributable to the intrinsic cancer cell resistance and T-cell exhaustion, which is also the reason for the failure of conventional therapy. The present review summarizes the current PDAC immunotherapy avenues and the underlying resistance mechanisms. Then, the review discusses synergistic combination therapies, such as radiotherapy (RT) and metabolic targeting. Research suggests that RT boosts the antigen of PDAC, which facilitates the anti-tumor immune cell infiltration and exerts function. Metabolic reprogramming contributes to restoring the exhausted T cell function. The current review will help in tailoring combination regimens to enhance the efficacy of immunotherapy. In addition, it will help provide new approaches to address the limitations of the immunosuppressive tumor microenvironment (TME) by examining the relationship among immunotherapy, RT, and metabolism targeting therapy in PDAC.

1-Pyrroline-5-carboxylate inhibit T cell glycolysis in prostate cancer microenvironment by SHP1/PKM2/LDHB axis

BACKGROUND

Our previous studies demonstrated that 1-Pyrroline-5-carboxylate (P5C) released by prostate cancer cells inhibits T cell proliferation and function by increasing SHP1 expression. We designed this study to further explore the influence of P5C on T cell metabolism, and produced an antibody for targeting P5C to restore the functions of T cells.

METHOD

We co-immunoprecipated SHP1 from T cells and analyzed the proteins that were bound to it using liquid chromatography mass spectrometry (LC/MS-MS). The influence of P5C on T cells metabolism was also detected by LC/MS-MS. Seahorse XF96 analyzer was further used to identify the effect of P5C on T cells glycolysis. We subsequently designed and produced an antibody for targeting P5C by monoclonal technique and verified its effectiveness to restore the function of T cells in vitro and in vivo.

RESULT

PKM2 and LDHB bind SHP1 in T cells, and P5C could increase the levels of p-PKM2 while having no effect on the levels of PKM2 and LDHB. We further found that P5C influences T cell energy metabolism and carbohydrate metabolism. P5C also inhibits the activity of PKM2 and decreases the content of intracellular lactic acid while increasing the activity of LDH. Using seahorse XF96 analyzer, we confirmed that P5C remarkably inhibits glycolysis in T cells. We produced an antibody for targeting P5C by monoclonal technique and verified that the antibody could oppose the influence of P5C to restore the process of glycolysis and function in T cells. Meanwhile, the antibody also inhibits the growth of prostate tumors in an animal model.

CONCLUSION

Our study revealed that P5C inhibits the process of glycolysis in T cells by targeting SHP1/PKM2/LDHB complexes. Moreover, it is important that the antibody for targeting P5C could restore the function of T cells and inhibit the growth of prostate tumors.

Glycogen metabolism-mediated intercellular communication in the tumor microenvironment influences liver cancer prognosis

Glycogen metabolism plays a key role in the development of hepatocellular carcinoma (HCC), but the function of glycogen metabolism genes in the tumor microenvironment (TME) is still to be elucidated. Single-cell RNA-seq data were obtained from ten HCC tumor samples totaling 64,545 cells, and 65 glycogen metabolism genes were analyzed by a nonnegative matrix factorization (NMF). The prognosis and immune response of new glycogen TME cell clusters were predicted by using HCC and immunotherapy cohorts from public databases. HCC single-cell analysis was divided into fibroblasts, NT T cells, macrophages, endothelial cells, and B cells, which were separately divided into new cell clusters by glycogen metabolism gene annotation. Pseudo-temporal trajectory analysis demonstrated the temporal differentiation trajectory of different glycogen subtype cell clusters. Cellular communication analysis revealed extensive interactions between endothelial cells with glycogen metabolizing TME cell-related subtypes and different glycogen subtype cell clusters. SCENIC analysis of transcription factors upstream of TME cell clusters with different glycogen metabolism. In addition, TME cell clusters of glycogen metabolism were found to be enriched in expression in CAF subtypes, CD8 depleted, M1, and M2 types. Bulk-seq analysis showed the prognostic significance of glycogen metabolism-mediated TME cell clusters in HCC, while a significant immune response was found in the immunotherapy cohort in patients treated with immune checkpoint blockade (ICB), especially for CAFs, T cells, and macrophages. In summary, our study reveals for the first time that glycogen metabolism mediates intercellular communication in the hepatocellular carcinoma microenvironment while elucidating the anti-tumor mechanisms and immune prognostic responses of different subtypes of cell clusters.

Current Status of Novel Multifunctional Targeted Pt(IV) Compounds and Their Reductive Release Properties

Platinum-based drugs are widely used in chemotherapy for various types of cancer and are considered crucial. Tetravalent platinum (Pt(IV)) compounds have gained significant attention and have been extensively researched among these drugs. Traditionally, Pt(IV) compounds are reduced to divalent platinum (Pt(II)) after entering cells, causing DNA lesions and exhibiting their anti-tumor effect. However, the available evidence indicates that some Pt(IV) derivatives may differ from the traditional mechanism and exert their anti-tumor effect through their overall structure. This review primarily focuses on the existing literature regarding targeted Pt(II) and Pt(IV) compounds, with a specific emphasis on their in vivo mode of action and the properties of reduction release in multifunctional Pt(IV) compounds. This review provides a comprehensive summary of the design and synthesis strategies employed for Pt(II) derivatives that selectively target various enzymes (glucose receptor, folate, telomerase, etc.) or substances (mitochondria, oleic acid, etc.). Furthermore, it thoroughly examines and summarizes the rational design, anti-tumor mechanism of action, and reductive release capacity of novel multifunctional Pt(IV) compounds, such as those targeting p53-MDM2, COX-2, lipid metabolism, dual drugs, and drug delivery systems. Finally, this review aims to provide theoretical support for the rational design and development of new targeted Pt(IV) compounds.

Glycolysis regulation in tumor-associated macrophages: Its role in tumor development and cancer treatment

Tumor-associated macrophages constitute the main cell population in the tumor microenvironment and play a crucial role in regulating the microenvironment composition. Emerging evidence has revealed that the metabolic profile determines the tumor-associated macrophage phenotype. Tumor-associated macrophage function is highly dependent on glucose metabolism, with glycolysis being the major metabolic pathway. Recent reports have demonstrated diversity in glucose flux of tumor-associated macrophages and complex substance communication with cancer cells. However, how the glucose flux in tumor-associated macrophages connects with glycolysis to influence tumor progression and the tumor microenvironment is still obscure. Moreover, while the development of single-cell sequencing technology allows a clearer and more accurate classification of tumor-associated macrophages, the metabolic profiles of tumor-associated macrophages from the perspective of single-cell omics has not been well summarized. Here, we review the current state of knowledge on glucose metabolism in tumor-associated macrophages and summarize the metabolic profiles of different tumor-associated macrophage subtypes from the perspective of single-cell omics. Additionally, we describe the current strategies targeting glycolysis in tumor-associated macrophages for cancer therapy.

Reprogramming endothelial cells to empower cancer immunotherapy

Cancer immunity is subject to spatiotemporal regulation by leukocyte interaction with the tumor microenvironment. Growing evidence suggests an emerging role for the vasculature in tumor immune evasion and immunotherapy resistance. Beyond the conventional functions of the tumor vasculature, such as providing oxygen and nutrients to support tumor progression, we propose multiplex mechanisms for vascular regulation of tumor immunity: The immunosuppressive vascular niche locoregionally educates circulation-derived immune cells by angiocrines, aberrant endothelial metabolism induces T cell exclusion and inactivation, and topologically and biochemically abnormal vascularity forms a pathophysiological barrier that hampers lymphocyte infiltration. We postulate that genetic and metabolic reprogramming of endothelial cells may rewire the immunosuppressive vascular microenvironment to overcome immunotherapy resistance, serving as a next-generation vascular targeting strategy for cancer treatment.

Analysis of Immune Resistance Mechanisms in TNBC: Dual Effects Inside and Outside the Tumor

Triple-negative breast cancer (TNBC) is a unique subtype of breast cancer characterized by the lack of expression of the estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. TNBC exhibits a high degree of aggressiveness, metastatic potential, and a poor prognosis. Despite the limited success of conventional treatments, immune checkpoint inhibitors (ICIs) have emerged as promising therapeutics for TNBC. Therefore, understanding the mechanisms underlying innate and acquired resistance to ICIs in TNBC is essential. Numerous studies suggest that intrinsic and extrinsic factors significantly contribute to the development of ICI resistance in TNBC. Intrinsic resistance may result from alterations in tumor-intrinsic signaling pathways, such as dysregulation of interferon (IFN) signaling or other signaling pathways. In contrast, extratumoral mechanisms may develop due to alterations in the tumor microenvironment, changes in T cell-related factors or adaptations within the immune system itself. In this paper, we endeavor to elucidate the underlying mechanisms of immune resistance by systematically examining immune mechanisms, the present state of immunotherapy, and the processes of immune resistance. Nonetheless, enhancing our understanding of the mechanisms underlying intratumoral and extratumoral resistance to ICIs in TNBC is crucial for optimizing patient outcomes in this challenging disease. Persistent efforts to identify novel targets for combination therapies, biomarkers that can predict the response to immunotherapy, and resistance mechanisms will be instrumental in achieving this objective.

Modelling cancer metabolism in vitro: current improvements and future challenges

Advances in cancer biology over the past decades have revealed that metabolic adaptation of cancer cells is an essential aspect of tumorigenesis. However, recent insights into tumour metabolism in vivo have revealed dissimilarities with results obtained in vitro. This is partly due to the reductionism of in vitro cancer models that struggle to reproduce the complexity of tumour tissues. This review describes some of the discrepancies in cancer cell metabolism between in vitro and in vivo conditions, and presents current methodological approaches and tools used to bridge the gap with the clinically relevant microenvironment. As such, these approaches should generate new knowledge that could be more effectively translated into therapeutic opportunities.

Immunosurveillance encounters cancer metabolism

Tumor cells reprogram nutrient acquisition and metabolic pathways to meet their energetic, biosynthetic, and redox demands. Similarly, metabolic processes in immune cells support host immunity against cancer and determine differentiation and fate of leukocytes. Thus, metabolic deregulation and imbalance in immune cells within the tumor microenvironment have been reported to drive immune evasion and to compromise therapeutic outcomes. Interestingly, emerging evidence indicates that anti-tumor immunity could modulate tumor heterogeneity, aggressiveness, and metabolic reprogramming, suggesting that immunosurveillance can instruct cancer progression in multiple dimensions. This review summarizes our current understanding of how metabolic crosstalk within tumors affects immunogenicity of tumor cells and promotes cancer progression. Furthermore, we explain how defects in the metabolic cascade can contribute to developing dysfunctional immune responses against cancers and discuss the contribution of immunosurveillance to these defects as a feedback mechanism. Finally, we highlight ongoing clinical trials and new therapeutic strategies targeting cellular metabolism in cancer.

Metabolic reprogramming in the tumor microenvironment of liver cancer

The liver is essential for metabolic homeostasis. The onset of liver cancer is often accompanied by dysregulated liver function, leading to metabolic rearrangements. Overwhelming evidence has illustrated that dysregulated cellular metabolism can, in turn, promote anabolic growth and tumor propagation in a hostile microenvironment. In addition to supporting continuous tumor growth and survival, disrupted metabolic process also creates obstacles for the anticancer immune response and restrains durable clinical remission following immunotherapy. In this review, we elucidate the metabolic communication between liver cancer cells and their surrounding immune cells and discuss how metabolic reprogramming of liver cancer impacts the immune microenvironment and the efficacy of anticancer immunotherapy. We also describe the crucial role of the gut-liver axis in remodeling the metabolic crosstalk of immune surveillance and escape, highlighting novel therapeutic opportunities.

Metabolic Profiling to Assess Response to Targeted and Immune Therapy in Melanoma

There is currently no consensus to determine which advanced melanoma patients will benefit from targeted therapy, immunotherapy, or a combination of both, highlighting the critical need to identify early-response biomarkers to advanced melanoma therapy. The goal of this review is to provide scientific rationale to highlight the potential role of metabolic imaging to assess response to targeted and/or immune therapy in melanoma cancer. For that purpose, a brief overview of current melanoma treatments is provided. Then, current knowledge with respect to melanoma metabolism is described with an emphasis on major crosstalks between melanoma cell metabolism and signaling pathways involved in BRAF-targeted therapy as well as in immune checkpoint inhibition therapies. Finally, preclinical and clinical studies using metabolic imaging and/or profiling to assess response to melanoma treatment are summarized with a particular focus on PET (Positron Emission Tomography) imaging and 13C-MRS (Magnetic Resonance Spectroscopy) methods.

Onco-Breastomics: An Eco-Evo-Devo Holistic Approach

Known as a diverse collection of neoplastic diseases, breast cancer (BC) can be hyperbolically characterized as a dynamic pseudo-organ, a living organism able to build a complex, open, hierarchically organized, self-sustainable, and self-renewable tumor system, a population, a species, a local community, a biocenosis, or an evolving dynamical ecosystem (i.e., immune or metabolic ecosystem) that emphasizes both developmental continuity and spatio-temporal change. Moreover, a cancer cell community, also known as an oncobiota, has been described as non-sexually reproducing species, as well as a migratory or invasive species that expresses intelligent behavior, or an endangered or parasite species that fights to survive, to optimize its features inside the host's ecosystem, or that is able to exploit or to disrupt its host circadian cycle for improving the own proliferation and spreading. BC tumorigenesis has also been compared with the early embryo and placenta development that may suggest new strategies for research and therapy. Furthermore, BC has also been characterized as an environmental disease or as an ecological disorder. Many mechanisms of cancer progression have been explained by principles of ecology, developmental biology, and evolutionary paradigms. Many authors have discussed ecological, developmental, and evolutionary strategies for more successful anti-cancer therapies, or for understanding the ecological, developmental, and evolutionary bases of BC exploitable vulnerabilities. Herein, we used the integrated framework of three well known ecological theories: the Bronfenbrenner's theory of human development, the Vannote's River Continuum Concept (RCC), and the Ecological Evolutionary Developmental Biology (Eco-Evo-Devo) theory, to explain and understand several eco-evo-devo-based principles that govern BC progression. Multi-omics fields, taken together as onco-breastomics, offer better opportunities to integrate, analyze, and interpret large amounts of complex heterogeneous data, such as various and big-omics data obtained by multiple investigative modalities, for understanding the eco-evo-devo-based principles that drive BC progression and treatment. These integrative eco-evo-devo theories can help clinicians better diagnose and treat BC, for example, by using non-invasive biomarkers in liquid-biopsies that have emerged from integrated omics-based data that accurately reflect the biomolecular landscape of the primary tumor in order to avoid mutilating preventive surgery, like bilateral mastectomy. From the perspective of preventive, personalized, and participatory medicine, these hypotheses may help patients to think about this disease as a process governed by natural rules, to understand the possible causes of the disease, and to gain control on their own health.

Unraveling T cell exhaustion in the immune microenvironment of osteosarcoma via single-cell RNA transcriptome

Osteosarcoma (OS) represents a profoundly invasive malignancy of the skeletal system. T cell exhaustion (Tex) is known to facilitate immunosuppression and tumor progression, but its role in OS remains unclear. In this study, single-cell RNA sequencing data was employed to identify exhausted T cells within the tumor immune microenvironment (TIME) of OS. We found that exhausted T cells exhibited substantial infiltration in OS samples. Pseudotime trajectory analysis revealed a progressive increase in the expression of various Tex marker genes, including PDCD1, CTLA4, LAG3, ENTPD1, and HAVCR2 in OS. GSVA showed that apoptosis, fatty acid metabolism, xenobiotic metabolism, and the interferon pathway were significantly activated in exhausted T cells in OS. Subsequently, a prognostic model was constructed using two Tex-specific genes, MYC and FCGR2B, which exhibited exceptional prognostic accuracy in two independent cohorts. Drug sensitivity analysis revealed that OS patients with a low Tex risk were responsive to Dasatinib and Pazopanib. Finally, immunohistochemistry verified that MYC and FCGR2B were significantly upregulated in OS tissues compared with adjacent tissues. This study investigates the role of Tex within the TIME of OS, and offers novel insights into the mechanisms underlying disease progression as well as the potential treatment strategies for OS.

Multi-omics reveals the role of ENO1 in bladder cancer and constructs an epithelial-related prognostic model to predict prognosis and efficacy

α-Enolase (ENO1) is a crucial molecular target for tumor therapy and has emerged as a research hotspot in recent decades. Here, we aimed to explore the role of ENO1 in bladder cancer (BLCA) and then construct a signature to predict the prognosis and treatment response of BLCA. Firstly, we found ENO1 was highly expressed in BLCA tissues, as verified by IHC, and was associated with poor prognosis. The analysis of the tumor immune microenvironment by bulk RNA-seq and scRNA-seq showed that ENO1 was associated with CD8+ T-cell exhaustion. Additionally, the results in vitro showed that ENO1 could promote the proliferation and invasion of BLCA cells. Then, the analysis of epithelial cells (ECs) revealed that ENO1 might promote BLCA progression by metabolism, the cell cycle and some carcinogenic pathways. A total of 249 hub genes were obtained from differentially expressed genes between ENO1-related ECs, and we used LASSO analysis to construct a novel signature that not only accurately predicted the prognosis of BLCA patients but also predicted the response to treatment for BLCA. Finally, we constructed a nomogram to better guide clinical application. In conclusion, through multi-omics analysis, we found that ENO1 was overexpressed in bladder cancer and associated with poor prognosis, CD8+ T-cell exhaustion and epithelial heterogeneity. Moreover, the prognosis and treatment of patients can be well predicted by constructing an epithelial-related prognostic signature.

Nasopharyngeal carcinoma: current views on the tumor microenvironment's impact on drug resistance and clinical outcomes

The incidence of nasopharyngeal carcinoma (NPC) exhibits significant variations across different ethnic groups and geographical regions, with Southeast Asia and North Africa being endemic areas. Of note, Epstein-Barr virus (EBV) infection is closely associated with almost all of the undifferentiated NPC cases. Over the past three decades, radiation therapy and chemotherapy have formed the cornerstone of NPC treatment. However, recent advancements in immunotherapy have introduced a range of promising approaches for managing NPC. In light of these developments, it has become evident that a deeper understanding of the tumor microenvironment (TME) is crucial. The TME serves a dual function, acting as a promoter of tumorigenesis while also orchestrating immunosuppression, thereby facilitating cancer progression and enabling immune evasion. Consequently, a comprehensive comprehension of the TME and its intricate involvement in the initiation, progression, and metastasis of NPC is imperative for the development of effective anticancer drugs. Moreover, given the complexity of TME and the inter-patient heterogeneity, personalized treatment should be designed to maximize therapeutic efficacy and circumvent drug resistance. This review aims to provide an in-depth exploration of the TME within the context of EBV-induced NPC, with a particular emphasis on its pivotal role in regulating intercellular communication and shaping treatment responses. Additionally, the review offers a concise summary of drug resistance mechanisms and potential strategies for their reversal, specifically in relation to chemoradiation therapy, targeted therapy, and immunotherapy. Furthermore, recent advances in clinical trials pertaining to NPC are also discussed.

Deep reinforcement learning identifies personalized intermittent androgen deprivation therapy for prostate cancer

The evolution of drug resistance leads to treatment failure and tumor progression. Intermittent androgen deprivation therapy (IADT) helps responsive cancer cells compete with resistant cancer cells in intratumoral competition. However, conventional IADT is population-based, ignoring the heterogeneity of patients and cancer. Additionally, existing IADT relies on pre-determined thresholds of prostate-specific antigen to pause and resume treatment, which is not optimized for individual patients. To address these challenges, we framed a data-driven method in two steps. First, we developed a time-varied, mixed-effect and generative Lotka-Volterra (tM-GLV) model to account for the heterogeneity of the evolution mechanism and the pharmacokinetics of two ADT drugs Cyproterone acetate and Leuprolide acetate for individual patients. Then, we proposed a reinforcement-learning-enabled individualized IADT framework, namely, I$^{2}$ADT, to learn the patient-specific tumor dynamics and derive the optimal drug administration policy. Experiments with clinical trial data demonstrated that the proposed I$^{2}$ADT can significantly prolong the time to progression of prostate cancer patients with reduced cumulative drug dosage. We further validated the efficacy of the proposed methods with a recent pilot clinical trial data. Moreover, the adaptability of I$^{2}$ADT makes it a promising tool for other cancers with the availability of clinical data, where treatment regimens might need to be individualized based on patient characteristics and disease dynamics. Our research elucidates the application of deep reinforcement learning to identify personalized adaptive cancer therapy.

Tumor cell senescence-induced macrophage CD73 expression is a critical metabolic immune checkpoint in the aging tumor microenvironment

Background: The role of senescent cells in the tumor microenvironment (TME) is usually bilateral, and diverse therapeutic approaches, such as radiotherapy and chemotherapy, can induce cellular senescence. Cellular interactions are widespread in the TME, and tumor cells reprogram immune cells metabolically by producing metabolites. However, how senescent cells remodel the metabolism of TME remains unclear. This study aimed to explore precise targets to enhance senescent cells-induced anti-tumor immunity from a metabolic perspective. Methods: The in vivo senescence model was induced by 8 Gy×3 radiotherapy or cisplatin chemotherapy, and the in vitro model was induced by 10 Gy-irradiation or cisplatin treatment. Metabonomic analysis and ELISA assay on tumor interstitial fluid were performed for metabolites screening. Marker expression and immune cell infiltration in the TME were analyzed by flow cytometry. Cell co-culture system and senescence-conditioned medium were used for crosstalk validation in vitro. RNA sequencing and rescue experiments were conducted for mechanism excavation. Immunofluorescence staining and single-cell transcriptome profiling analysis were performed for clinical validation. Results: We innovatively reveal the metabolic landscape of the senescent TME, characterized with the elevation of adenosine. It is attributed to the senescent tumor cell-induced CD73 upregulation of tumor-associated macrophages (TAMs). CD73 expression in TAMs is evoked by SASP-related pro-inflammatory cytokines, especially IL-6, and regulated by JAK/STAT3 pathway. Consistently, a positive correlation between tumor cells senescence and TAMs CD73 expression is identified in lung cancer clinical specimens and databases. Lastly, blocking CD73 in a senescent background suppresses tumors and activates CD8+ T cell-mediated antitumor immunity. Conclusions: TAMs expressed CD73 contributes significantly to the adenosine accumulation in the senescent TME, suggesting targeting CD73 is a novel synergistic anti-tumor strategy in the aging microenvironment.

Tumor cell-intrinsic PD-1 promotes Merkel cell carcinoma growth by activating downstream mTOR-mitochondrial ROS signaling

Merkel cell carcinoma (MCC) is a rare and aggressive skin cancer. Inhibitors targeting the programmed cell death 1 (PD-1) immune checkpoint have improved MCC patient outcomes by boosting antitumor T cell immunity. Here, we identify PD-1 as a growth-promoting receptor intrinsic to MCC cells. In human MCC lines and clinical tumors, RT-PCR-based sequencing, immunoblotting, flow cytometry, and immunofluorescence analyses demonstrated PD-1 gene and protein expression by MCC cells. MCC-PD-1 ligation enhanced, and its inhibition or silencing suppressed, in vitro proliferation and in vivo tumor xenograft growth. Consistently, MCC-PD-1 binding to PD-L1 or PD-L2 induced, while antibody-mediated PD-1 blockade inhibited, protumorigenic mTOR signaling, mitochondrial (mt) respiration, and ROS generation. Last, pharmacologic inhibition of mTOR or mtROS reversed MCC-PD-1:PD-L1-dependent proliferation and synergized with PD-1 checkpoint blockade in suppressing tumorigenesis. Our results identify an MCC-PD-1-mTOR-mtROS axis as a tumor growth-accelerating mechanism, the blockade of which might contribute to clinical response in patients with MCC.

Breast cancer cells and adipocytes in hypoxia: metabolism regulation

Adipocytes play a significant role in breast cancer due to the unique histological structure of the breast. These have not only been detected adjacent to breast cancer cells but they have also been implicated in cancer development. Adipocytes in obese individuals and tumor microenvironment (TME) have a common feature, that is, hypoxia. The increased expression of hypoxia-inducible factor (HIF)-1α is known to alter the metabolism and functions of adipocytes. In this study, we described the mechanism linking the hypoxia-sensing pathway manifested by HIF to adipocytes and breast cancer and discussed the mechanism underlying the role of hypoxic adipocytes in breast cancer development from the perspective of metabolic remodeling. The processes and pathways in hypoxic adipocytes could be a promising target in breast cancer therapy.

Modulating ferroptosis sensitivity: environmental and cellular targets within the tumor microenvironment

Ferroptosis, a novel form of cell death triggered by iron-dependent phospholipid peroxidation, presents significant therapeutic potential across diverse cancer types. Central to cellular metabolism, the metabolic pathways associated with ferroptosis are discernible in both cancerous and immune cells. This review begins by delving into the intricate reciprocal regulation of ferroptosis between cancer and immune cells. It subsequently details how factors within the tumor microenvironment (TME) such as nutrient scarcity, hypoxia, and cellular density modulate ferroptosis sensitivity. We conclude by offering a comprehensive examination of distinct immunophenotypes and environmental and metabolic targets geared towards enhancing ferroptosis responsiveness within the TME. In sum, tailoring precise ferroptosis interventions and combination strategies to suit the unique TME of specific cancers may herald improved patient outcomes.

Vitamin B6 Competition in the Tumor Microenvironment Hampers Antitumor Functions of NK Cells

Nutritional factors play crucial roles in immune responses. The tumor-caused nutritional deficiencies are known to affect antitumor immunity. Here, we demonstrate that pancreatic ductal adenocarcinoma (PDAC) cells can suppress NK-cell cytotoxicity by restricting the accessibility of vitamin B6 (VB6). PDAC cells actively consume VB6 to support one-carbon metabolism, and thus tumor cell growth, causing VB6 deprivation in the tumor microenvironment. In comparison, NK cells require VB6 for intracellular glycogen breakdown, which serves as a critical energy source for NK-cell activation. VB6 supplementation in combination with one-carbon metabolism blockage effectively diminishes tumor burden in vivo. Our results expand the understanding of the critical role of micronutrients in regulating cancer progression and antitumor immunity, and open new avenues for developing novel therapeutic strategies against PDAC.

SIGNIFICANCE

The nutrient competition among the different tumor microenvironment components drives tumor growth, immune tolerance, and therapeutic resistance. PDAC cells demand a high amount of VB6, thus competitively causing NK-cell dysfunction. Supplying VB6 with blocking VB6-dependent one-carbon metabolism amplifies the NK-cell antitumor immunity and inhibits tumor growth in PDAC models. This article is featured in Selected Articles from This Issue, p. 5.

HIF1α-glycolysis engages activation-induced cell death to drive IFN-γ induction in hypoxic T cells

The role of HIF1α-glycolysis in regulating IFN-γ induction in hypoxic T cells is unknown. Given that hypoxia is a common feature in a wide array of pathophysiological contexts such as tumor and that IFN-γ is instrumental for protective immunity, it is of great significance to gain a clear idea on this. Combining pharmacological and genetic gain-of-function and loss-of-function approaches, we find that HIF1α-glycolysis controls IFN-γ induction in both human and mouse T cells activated under hypoxia. Specific deletion of HIF1α in T cells (HIF1α-/-) and glycolytic inhibition significantly abrogate IFN-γ induction. Conversely, HIF1α stabilization in T cells by hypoxia and VHL deletion (VHL-/-) promotes IFN-γ production. Mechanistically, reduced IFN-γ production in hypoxic HIF1α-/- T cells is due to attenuated activation-induced cell death but not proliferative defect. We further show that depletion of intracellular acetyl-CoA is a key metabolic underlying mechanism. Hypoxic HIF1α-/- T cells are less able to kill tumor cells, and HIF1α-/- tumor-bearing mice are not responsive to immune checkpoint blockade (ICB) therapy, indicating loss of HIF1α in T cells is a major mechanism of therapeutic resistance to ICBs. Importantly, acetate supplementation restores IFN-γ production in hypoxic HIF1α-/- T cells and re-sensitizes HIF1α-/- tumor-bearing mice to ICBs, providing an effective strategy to overcome ICB resistance. Taken together, our results highlight T cell HIF1α-anaerobic glycolysis as a principal mediator of IFN-γ induction and anti-tumor immunity. Considering that acetate supplementation (i.e., glycerol triacetate (GTA)) is approved to treat infants with Canavan disease, we envision a rapid translation of our findings, justifying further testing of GTA as a repurposed medicine for ICB resistance, a pressing unmet medical need.

New sights of immunometabolism and agent progress in colitis associated colorectal cancer

Colitis associated colorectal cancer is a disease with a high incidence and complex course that develops from chronic inflammation and deteriorates after various immune responses and inflammation-induced attacks. Colitis associated colorectal cancer has the characteristics of both immune diseases and cancer, and the similarity of treatment models contributes to the similar treatment dilemma. Immunometabolism contributes to the basis of life and is the core of many immune diseases. Manipulating metabolic signal transduction can be an effective way to control the immune process, which is expected to become a new target for colitis associated colorectal cancer therapy. Immune cells participate in the whole process of colitis associated colorectal cancer development by transforming their functional condition via changing their metabolic ways, such as glucose, lipid, and amino acid metabolism. The same immune and metabolic processes may play different roles in inflammation, dysplasia, and carcinoma, so anti-inflammation agents, immunomodulators, and agents targeting special metabolism should be used in combination to prevent and inhibit the development of colitis associated colorectal cancer.

Antitumour effect of the mitochondrial complex III inhibitor Atovaquone in combination with anti-PD-L1 therapy in mouse cancer models

Immune checkpoint blockade (ICB) provides effective and durable responses for several tumour types by unleashing an immune response directed against cancer cells. However, a substantial number of patients treated with ICB develop relapse or do not respond, which has been partly attributed to the immune-suppressive effect of tumour hypoxia. We have previously demonstrated that the mitochondrial complex III inhibitor atovaquone alleviates tumour hypoxia both in human xenografts and in cancer patients by decreasing oxygen consumption and consequently increasing oxygen availability in the tumour. Here, we show that atovaquone alleviates hypoxia and synergises with the ICB antibody anti-PD-L1, significantly improving the rates of tumour eradication in the syngeneic CT26 model of colorectal cancer. The synergistic effect between atovaquone and anti-PD-L1 relied on CD8+ T cells, resulted in the establishment of a tumour-specific memory immune response, and was not associated with any toxicity. We also tested atovaquone in combination with anti-PD-L1 in the LLC (lung) and MC38 (colorectal) cancer syngeneic models but, despite causing a considerable reduction in tumour hypoxia, atovaquone did not add any therapeutic benefit to ICB in these models. These results suggest that atovaquone has the potential to improve the outcomes of patients treated with ICB, but predictive biomarkers are required to identify individuals likely to benefit from this intervention.

A Potential "Anti-Warburg Effect" in Circulating Tumor Cell-mediated Metastatic Progression?

Metabolic reprogramming is a defining hallmark of cancer metastasis, warranting thorough exploration. The tumor-promoting function of the "Warburg Effect", marked by escalated glycolysis and restrained mitochondrial activity, is widely acknowledged. Yet, the functional significance of mitochondria-mediated oxidative phosphorylation (OXPHOS) during metastasis remains controversial. Circulating tumor cells (CTCs) are considered metastatic precursors that detach from primary or secondary sites and harbor the potential to seed distant metastases through hematogenous dissemination. A comprehensive metabolic characterization of CTCs faces formidable obstacles, including the isolation of these rare cells from billions of blood cells, coupled with the complexities of ex vivo-culturing of CTC lines or the establishment of CTC-derived xenograft models (CDX). This review summarized the role of the "Warburg Effect" in both tumorigenesis and CTC-mediated metastasis. Intriguingly, bioinformatic analysis of single-CTC transcriptomic studies unveils a potential OXPHOS dominance over Glycolysis signature genes across several important cancer types. From these observations, we postulate a potential "Anti-Warburg Effect" (AWE) in CTCs-a metabolic shift bridging primary tumors and metastases. The observed AWE could be clinically important as they are significantly correlated with therapeutic response in melanoma and prostate patients. Thus, unraveling dynamic metabolic regulations within CTC populations might reveal an additional layer of regulatory complexities of cancer metastasis, providing an avenue for innovative anti-metastasis therapies.

Prostaglandin E2 controls the metabolic adaptation of T cells to the intestinal microenvironment

Immune cells must adapt to different environments during the course of an immune response. Here we study the adaptation of CD8+ T cells to the intestinal microenvironment and how this process shapes the establishment of the CD8+ T cell pool. CD8+ T cells progressively remodel their transcriptome and surface phenotype as they enter the gut wall, and downregulate expression of mitochondrial genes. Human and mouse intestinal CD8+ T cells have reduced mitochondrial mass, but maintain a viable energy balance to sustain their function. We find that the intestinal microenvironment is rich in prostaglandin E2 (PGE2), which drives mitochondrial depolarization in CD8+ T cells. Consequently, these cells engage autophagy to clear depolarized mitochondria, and enhance glutathione synthesis to scavenge reactive oxygen species (ROS) that result from mitochondrial depolarization. Impairing PGE2 sensing promotes CD8+ T cell accumulation in the gut, while tampering with autophagy and glutathione negatively impacts the T cell pool. Thus, a PGE2-autophagy-glutathione axis defines the metabolic adaptation of CD8+ T cells to the intestinal microenvironment, to ultimately influence the T cell pool.

Melatonin: a modulator in metabolic rewiring in T-cell malignancies

Melatonin, (N-acetyl-5-methoxytryptamine) an indoleamine exerts multifaced effects and regulates numerous cellular pathways and molecular targets associated with circadian rhythm, immune modulation, and seasonal reproduction including metabolic rewiring during T cell malignancy. T-cell malignancies encompass a group of hematological cancers characterized by the uncontrolled growth and proliferation of malignant T-cells. These cancer cells exhibit a distinct metabolic adaptation, a hallmark of cancer in general, as they rewire their metabolic pathways to meet the heightened energy requirements and biosynthesis necessary for malignancies is the Warburg effect, characterized by a shift towards glycolysis, even when oxygen is available. In addition, T-cell malignancies cause metabolic shift by inhibiting the enzyme pyruvate Dehydrogenase Kinase (PDK) which in turn results in increased acetyl CoA enzyme production and cellular glycolytic activity. Further, melatonin plays a modulatory role in the expression of essential transporters (Glut1, Glut2) responsible for nutrient uptake and metabolic rewiring, such as glucose and amino acid transporters in T-cells. This modulation significantly impacts the metabolic profile of T-cells, consequently affecting their differentiation. Furthermore, melatonin has been found to regulate the expression of critical signaling molecules involved in T-cell activations, such as CD38, and CD69. These molecules are integral to T-cell adhesion, signaling, and activation. This review aims to provide insights into the mechanism of melatonin's anticancer properties concerning metabolic rewiring during T-cell malignancy. The present review encompasses the involvement of oncogenic factors, the tumor microenvironment and metabolic alteration, hallmarks, metabolic reprogramming, and the anti-oncogenic/oncostatic impact of melatonin on various cancer cells.

Metabolic regulation of tumor-associated macrophage heterogeneity: insights into the tumor microenvironment and immunotherapeutic opportunities

Tumor-associated macrophages (TAMs) are a heterogeneous population that play diverse functions in tumors. Their identity is determined not only by intrinsic factors, such as origins and transcription factors, but also by external signals from the tumor microenvironment (TME), such as inflammatory signals and metabolic reprogramming. Metabolic reprogramming has rendered TAM to exhibit a spectrum of activities ranging from pro-tumorigenic to anti-tumorigenic, closely associated with tumor progression and clinical prognosis. This review implicates the diversity of TAM phenotypes and functions, how this heterogeneity has been re-evaluated with the advent of single-cell technologies, and the impact of TME metabolic reprogramming on TAMs. We also review current therapies targeting TAM metabolism and offer new insights for TAM-dependent anti-tumor immunotherapy by focusing on the critical role of different metabolic programs in TAMs.

Research progress on mitochondria regulating tumor immunity

Tumor cells adapt their metabolism to meet the demands for energy and biosynthesis. Mitochondria, pivotal organelles in the metabolic reprogramming of tumor cells, contribute to tumorigenesis and cancer progression significantly through various dysfunctions in both tumor and immune cells. Alterations in mitochondrial dynamics and metabolic signaling pathways exert crucial regulatory influence on the activation, proliferation, and differentiation of immune cells. The tumor microenvironment orchestrates the activation and functionality of tumor-infiltrating immune cells by reprogramming mitochondrial metabolism and inducing shifts in mitochondrial dynamics, thereby facilitating the establishment of a tumor immunosuppressive microenvironment. Stress-induced leakage of mitochondrial DNA contributes multifaceted regulatory effects on anti-tumor immune responses and the immunosuppressive microenvironment by activating multiple natural immune signals, including cGAS-STING, TLR9, and NLRP3. Moreover, mitochondrial DNA-mediated immunogenic cell death emerges as a promising avenue for anti-tumor immunotherapy. Additionally, mitochondrial reactive oxygen species, a crucial factor in tumorigenesis, drives the formation of tumor immunosuppressive microenvironment by changing the composition of immune cells within the tumor microenvironment. This review focuses on the intrinsic relationship between mitochondrial biology and anti-tumor immune responses from multiple angles. We explore the core role of mitochondria in the dynamic interplay between the tumor and the host to facilitate the development of targeted mitochondrial strategies for anti-tumor immunotherapy.

Developing the novel diagnostic model and potential drugs by integrating bioinformatics and machine learning for aldosterone-producing adenomas

Background: Aldosterone-producing adenomas (APA) are a common cause of primary aldosteronism (PA), a clinical syndrome characterized by hypertension and electrolyte disturbances. If untreated, it may lead to serious cardiovascular complications. Therefore, there is an urgent need for potential biomarkers and targeted drugs for the diagnosis and treatment of aldosteronism. Methods: We downloaded two datasets (GSE156931 and GSE60042) from the GEO database and merged them by de-batch effect, then screened the top50 of differential genes using PPI and enriched them, followed by screening the Aldosterone adenoma-related genes (ARGs) in the top50 using three machine learning algorithms. We performed GSEA analysis on the ARGs separately and constructed artificial neural networks based on the ARGs. Finally, the Enrich platform was utilized to identify drugs with potential therapeutic effects on APA by tARGseting the ARGs. Results: We identified 190 differential genes by differential analysis, and then identified the top50 genes by PPI, and the enrichment analysis showed that they were mainly enriched in amino acid metabolic pathways. Then three machine learning algorithms identified five ARGs, namely, SST, RAB3C, PPY, CYP3A4, CDH10, and the ANN constructed on the basis of these five ARGs had better diagnostic effect on APA, in which the AUC of the training set is 1 and the AUC of the validation set is 0.755. And then the Enrich platform identified drugs tARGseting the ARGs with potential therapeutic effects on APA. Conclusion: We identified five ARGs for APA through bioinformatic analysis and constructed Artificial neural network (ANN) based on them with better diagnostic effects, and identified drugs with potential therapeutic effects on APA by tARGseting these ARGs. Our study provides more options for the diagnosis and treatment of APA.

Prognostic value and immunological role of PD-L1 gene in pan-cancer

OBJECTIVE

PD-L1, a target of immune checkpoint blockade, has been proven to take the role of an oncogene in most human tumors. However, the role of PD-L1 in human pan-cancers has not yet been fully investigated.

MATERIALS AND METHODS

Pan-cancer analysis was conducted to analyze expression, genetic alterations, prognosis analysis, and immunological characteristics of PD-L1. Estimating the correlation between PD-L1 expression and survival involved using pooled odds ratios and hazard ratios with 95% CI. The Kaplan-Meier (K-M) technique, COX analysis, and receiver operating characteristic (ROC) curves were applied to the survival analysis. Additionally, we investigated the relationships between PD-L1 and microsatellite instability (MSI), tumor mutational burden (TMB), DNA methyltransferases (DNMTs), the associated genes of mismatch repair (MMR), and immune checkpoint biomarkers using Spearman's correlation analysis. Also, immunohistochemical analysis and qRT-PCR were employed in evaluating PD-L1's protein and mRNA expression in pan-caner.

RESULTS

PD-L1 showed abnormal mRNA and protein expression in a variety of cancers and predicted prognosis in cancer patients. Furthermore, across a variety of cancer types, the aberrant PD-L1 expression was connected to the MSI, MMR, TMB, drug sensitivity, and tumor immune microenvironment (TIME). Moreover, PD-L1 was significantly correlated with infiltrating levels of immune cells (T cell CD8 + , neutrophil, and so on).

CONCLUSION

Our study provides a better theoretical basis and guidance for the clinical treatment of PD-L1.

Mitochondrial isocitrate dehydrogenase impedes CAR T cell function by restraining antioxidant metabolism and histone acetylation

The efficacy of chimeric antigen receptor (CAR) T cell therapy is hampered by relapse in hematologic malignancies and by hyporesponsiveness in solid tumors. Long-lived memory CAR T cells are critical for improving tumor clearance and long-term protection. However, during rapid ex vivo expansion or in vivo tumor eradication, metabolic shifts and inhibitory signals lead to terminal differentiation and exhaustion of CAR T cells. Through a mitochondria-related compound screening, we find that the FDA-approved isocitrate dehydrogenase 2 (IDH2) inhibitor enasidenib enhances memory CAR T cell formation and sustains anti-leukemic cytotoxicity in vivo. Mechanistically, IDH2 impedes metabolic fitness of CAR T cells by restraining glucose utilization via the pentose phosphate pathway, which alleviates oxidative stress, particularly in nutrient-restricted conditions. In addition, IDH2 limits cytosolic acetyl-CoA levels to prevent histone acetylation that promotes memory cell formation. In combination with pharmacological IDH2 inhibition, CAR T cell therapy is demonstrated to have superior efficacy in a pre-clinical model.

Identification of Metabolism-Related Prognostic Biomarkers and Immune Features of Head and Neck Squamous Cell Carcinoma

We aimed to identify an effective metabolic subtype and risk score to predict survival and immunotherapy response in head and neck squamous cell carcinoma (HNSCC). Data were obtained from an online database. We screened significant prognostic metabolism-related genes between the normal and tumor groups using a series of bioinformatics methods. Based on the selected prognostic genes, we conducted a subtype analysis to identify significantly different subtypes in HNSCC. We then investigated survival, immune features, and hallmark differences among different subtypes. LASSO was utilized to identify optimal genes for the risk score model construction. Finally, distribution of the risk score samples was analyzed for different subtypes. A total of 32 significantly prognostic metabolism-related genes were screened, and all samples were grouped into two subtypes: cluster 1 and cluster 2. Cluster 1 had worse survival. Different immune cell infiltration (CD8 T cells, macrophages, and regulatory T cells) and immune checkpoint gene expression (PD-1 and CLAT-4) were observed between the two clusters. Twelve optimal genes were involved in risk score model, and high-risk group had poorer survival. Cluster 1 contained more high-risk samples (60%). Finally, four genes CAV1, GGT6, PYGL, and HS3ST1 were identified as significantly related to immune cells, and these genes were differentially expressed in the normal oral epithelial cells and HNSCC cells. The subtypes and risk score model in the study provide a promising biomarker for prognosis and immunotherapy response.

Transcriptome data-based status of PI3K/AKT/mTOR pathway indicates heterogeneity and immune modulation in patients with pancreatic ductal adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal cancer with limited treatment options. The PI3K/AKT/mTOR pathway is commonly activated in PDAC and plays a critical role in its progression.

METHODS AND RESULTS

In this study, the effect of taselisib (a selective PI3K inhibitor) on PDAC cell proliferation was investigated, and a significant decrease in viability was observed with increasing concentrations of taselisib. Differential analysis on samples from the Genotype-Tissue Expression and The Cancer Genome Atlas databases revealed 24 dysregulated PI3K/AKT/mTOR pathway-related genes (PRGs). Unsupervised clustering-based analysis of transcriptome cohorts revealed two clusters with high consistency between RNA-seq and microarray cohorts. Cluster B had higher enrichment of immune cells, particularly CD8+ T cells, and lower levels of immunosuppressive Treg cells. Moreover, we investigated the relationship between drug sensitivity and different clusters and found that cluster A had a better response to PI3K/AKT/mTOR pathway-related inhibitors and chemotherapy. Finally, cluster A exhibited significant activation of PI3K/AKT/mTOR and related oncogenic pathways, contributing to poor prognosis. The study also developed a risk score based on the expression profiles of PRGs and machine learning, which showed a significant increase in overall survival time among patients in the low-risk group. Importantly, the PI3K/AKT/mTOR pathway could be used to better predict individual risk scores, as evidenced by stratified survival analysis.

CONCLUSIONS

These findings suggest that targeting the PI3K/AKT/mTOR pathway may have therapeutic potential in PDAC, and distinct pathway states, immune modulation and tumor microenvironments have prognostic value.

Exhaustion, rather than lack of infiltration and persistence, of CAR-T cells hampers the efficacy of CAR-T therapy in an orthotopic PDAC xenograft model

Chimeric antigen receptor T-cell (CAR-T) therapy has demonstrated impressive success in the treatment of patients with hematologic tumors yet achieved very limited efficacy for solid tumors due to hurdles unique to solid tumors. It is also noted that the tumor microenvironment composition varies between tumor type, which again imposes unique set of hurdles in each solid tumor. Therefore, elucidation of individual hurdles is key to achieving successful CAR-T therapy for solid tumors. In the present study, we employed an orthotopic human PDAC xenograft model, in which quantitative, spatial and functional dynamics of CAR-T cells in tumor tissues were analyzed to obtain insights into ways of overcoming PDAC related hurdles. Contrary to previous studies that demonstrated a limited persistency and infiltration of CAR-T cells in many solid tumors, they persist and accumulated in PDAC tumor tissues. Ex vivo analysis revealed that CAR-T cells that had been recovered at different time points from mice bearing an orthotopic PDAC tumor exhibited a gradual loss of tumor reactivity. This loss of tumor reactivity of CAR-T cells was associated with the increased expression of AMP-activated protein kinase and Mitofusin 1/ Dynamin-related protein 1 ratio.

Harnessing the innate immune system by revolutionizing macrophage-mediated cancer immunotherapy

Immunotherapy is a promising and safer alternative to conventional cancer therapies. It involves adaptive T-cell therapy, cancer vaccines, monoclonal antibodies, immune checkpoint blockade (ICB), and chimeric antigen receptor (CAR) based therapies. However, most of these modalities encounter restrictions in solid tumours owing to a dense, highly hypoxic and immune-suppressive microenvironment as well as the heterogeneity of tumour antigens. The elevated intra-tumoural pressure and mutational rates within fastgrowing solid tumours present challenges in efficient drug targeting and delivery. The tumour microenvironment is a dynamic niche infiltrated by a variety of immune cells, most of which are macrophages. Since they form a part of the innate immune system, targeting macrophages has become a plausible immunotherapeutic approach. In this review, we discuss several versatile approaches (both at pre-clinical and clinical stages) such as the direct killing of tumour-associated macrophages, reprogramming pro-tumour macrophages to anti-tumour phenotypes, inhibition of macrophage recruitment into the tumour microenvironment, novel CAR macrophages, and genetically engineered macrophages that have been devised thus far. These strategies comprise a strong and adaptable macrophage-toolkit in the ongoing fight against cancer and by understanding their significance, we may unlock the full potential of these immune cells in cancer therapy.

Manganese Enhances the Osteogenic Effect of Silicon-Hydroxyapatite Nanowires by Targeting T Lymphocyte Polarization

Biomaterials encounter considerable challenges in extensive bone defect regeneration. The amelioration of outcomes may be attainable through the orchestrated modulation of both innate and adaptive immunity. Silicon-hydroxyapatite, for instance, which solely focuses on regulating innate immunity, is inadequate for long-term bone regeneration. Herein, extra manganese (Mn)-doping is utilized for enhancing the osteogenic ability by mediating adaptive immunity. Intriguingly, Mn-doping engenders heightened recruitment of CD4+ T cells to the bone defect site, concurrently manifesting escalated T helper (Th) 2 polarization and an abatement in Th1 cell polarization. This consequential immune milieu yields a collaborative elevation of interleukin 4, secreted by Th2 cells, coupled with attenuated interferon gamma, secreted by Th1 cells. This orchestrated interplay distinctly fosters the osteogenesis of bone marrow stromal cells and effectuates consequential regeneration of the mandibular bone defect. The modulatory mechanism of Th1/Th2 balance lies primarily in the indispensable role of manganese superoxide dismutase (MnSOD) and the phosphorylation of adenosine 5'-monophosphate-activated protein kinase (AMPK). In conclusion, this study highlights the transformative potential of Mn-doping in amplifying the osteogenic efficacy of silicon-hydroxyapatite nanowires by regulating T cell-mediated adaptive immunity via the MnSOD/AMPK pathway, thereby creating an anti-inflammatory milieu favorable for bone regeneration.

Reduced expression of secretogranin VGF in laryngeal squamous cell carcinoma

Laryngeal cancer accounts for one-third of all head and neck tumors, with squamous cell carcinoma (SCC) being the most predominant type, followed by neuroendocrine tumors. Chromogranins, are commonly used as biomarkers for neuroendocrine tumors, including laryngeal cancer. It has been reported that secretogranin VGF, a member of the chromogranin family, can be also used as a significant biomarker for neuroendocrine tumors. However, the expression and role of VGF in laryngeal carcinomas have not been previously investigated. Therefore, the present study aimed to determine the expression levels of VGF in laryngeal SCC (LSCC). The present study collected tumor tissues, as well as serum samples, from a cohort of 15 patients with LSCC. The results of reverse transcription-quantitative PCR, western blot analysis and immunofluorescence assays showed that the selective VGF precursor was downregulated in patients with LSCC. Notably, in tumor tissue, the immunoreactivity for VGF was found in vimentin-positive cells, probably corresponding to T lymphocytes. The current preliminary study suggested that the reduced expression levels of VGF observed in tumor tissue and at the systemic level could sustain LSCC phenotype. Overall, VGF could be a potential biomarker for detecting neoplastic lesions with a higher risk of tumor invasiveness, even in non-neuroendocrine tumors.

Hurdle or thruster: Glucose metabolism of T cells in anti-tumour immunity

Glucose metabolism is essential for the activation, differentiation and function of T cells and proper glucose metabolism is required to maintain effective T cell immunity. Dysregulation of glucose metabolism is a hallmark of cancer, and the tumour microenvironment (TME2) can create metabolic barriers in T cells that inhibit their anti-tumour immune function. Targeting glucose metabolism is a promising approach to improve the capacity of T cells in the TME. The efficacy of common immunotherapies, such as immune checkpoint inhibitors (ICIs3) and adoptive cell transfer (ACT4), can be limited by T-cell function, and the treatment itself can affect T-cell metabolism. Therefore, understanding the relationship between immunotherapy and T cell glucose metabolism helps to achieve more effective anti-tumour therapy. In this review, we provide an overview of T cell glucose metabolism and how T cell metabolic reprogramming in the TME regulates anti-tumour responses, briefly describe the metabolic patterns of T cells during ICI and ACT therapies, which suggest possible synergistic strategies.

Nutritional status as prognostic factor of advanced oesophageal cancer patients treated with immune checkpoint inhibitors

BACKGROUND & AIMS

Malnutrition is reported in 60%-85% of oesophageal cancer (EC) patients. Indicators commonly used in the clinic to evaluate the nutritional status of patients include haemoglobin (Hb), body mass index (BMI), albumin (ALB), prognostic nutritional index (PNI), prealbumin (PAB), transferrin (TRF), and NRS2002 scores. In this study, we explored the associations between pretreatment nutrition-related indicators and clinical outcomes in patients with advanced EC who were treated with immune checkpoint inhibitors (ICIs).

METHODS

The general clinical data of patients, NRS2002 scores, PNI, and levels of BMI, ALB, Hb, PAB, and TRF at baseline were collected. Categorical variables were compared using the chi-squared test. The chi-squared test was used to compare the differences in the objective response rate (ORR) and the disease control rate (DCR) between groups. The Kaplan-Meier method was used to compute the survival curves. Cox proportional hazard regression was performed to evaluate factors independently associated with OS and PFS.

RESULT

Of the 1340 patients diagnosed with EC at Zhejiang Cancer Hospital between June 2018 and September 2022, 354 patients with advanced EC who underwent ICI therapy were enrolled. In total, the ORR and DCR were 38.1% and 82.2%, respectively. A significantly worse response to ICI therapy was observed in the Hb-L group and the BMI-L group. The median PFS and OS among all enrolled patients were 6.0 months and 13.3 months, respectively. PFS was significantly associated with pretreatment levels of Hb, ALB, and PAB. OS was significantly associated with pretreatment levels of Hb, ALB, BMI, PNI, TRF, and PAB. The multivariate analysis further demonstrated that Hb was an independent prognostic factor of both OS (P = 0.004) and PFS (P = 0.047), and ALB was an independent prognostic factor of OS (P = 0.045). No independent relevance for OS or PFS was found in the BMI, PNI, TRF, or PAB groups. In this study, the NRS2002 scores was not significantly correlated with the therapeutic response or prognosis of ICI therapy.

CONCLUSION

Our study indicated the relevance of nutritional status to the efficacy and prognosis of advanced EC patients treated with ICIs. The pretreatment levels of Hb and BMI were significantly related to therapeutic response. The pretreatment levels of Hb, BMI, ALB, PAB, TRF, and PNI were partially associated with survival. Notably, Hb is not only related to therapeutic response but is also an independent prognostic indicator of survival outcomes.

Tumor Microenvironment Heterogeneity, Potential Therapeutic Avenues, and Emerging Therapies

OBJECTIVE

This review describes the comprehensive portrait of tumor microenvironment (TME). Additionally, we provided a panoramic perspective on the transformation and functions of the diverse constituents in TME, and the underlying mechanisms of drug resistance, beginning with the immune cells and metabolic dynamics within TME. Lastly, we summarized the most auspicious potential therapeutic strategies.

RESULTS

TME is a unique realm crafted by malignant cells to withstand the onslaught of endogenous and exogenous therapies. Recent research has revealed many small-molecule immunotherapies exhibiting auspicious outcomes in preclinical investigations. Furthermore, some pro-immune mechanisms have emerged as a potential avenue. With the advent of nanosystems and precision targeting, targeted therapy has now transcended the "comfort zone" erected by cancer cells within TME.

CONCLUSION

The ceaseless metamorphosis of TME fosters the intransigent resilience and proliferation of tumors. However, existing therapies have yet to surmount the formidable obstacles posed by TME. Therefore, scientists should investigate potential avenues for therapeutic intervention and design innovative pharmacological and clinical technologies.

The Metformin Immunoregulatory Actions in Tumor Suppression and Normal Tissues Protection

The immune system is the key player in a wide range of responses in normal tissues and tumors to anticancer therapy. Inflammatory and fibrotic responses in normal tissues are the main limitations of chemotherapy, radiotherapy, and also some newer anticancer drugs such as immune checkpoint inhibitors (ICIs). Immune system responses within solid tumors including anti-tumor and tumor-promoting responses can suppress or help tumor growth. Thus, modulation of immune cells and their secretions such as cytokines, growth factors and epigenetic modulators, pro-apoptosis molecules, and some other molecules can be suggested to alleviate side effects in normal tissues and drug-resistance mechanisms in the tumor. Metformin as an anti-diabetes drug has shown intriguing properties such as anti-inflammation, anti-fibrosis, and anticancer effects. Some investigations have uncovered that metformin can ameliorate radiation/chemotherapy toxicity in normal cells and tissues through the modulation of several targets in cells and tissues. These effects of metformin may ameliorate severe inflammatory responses and fibrosis after exposure to ionizing radiation or following treatment with highly toxic chemotherapy drugs. Metformin can suppress the activity of immunosuppressive cells in the tumor through the phosphorylation of AMP-activated protein kinase (AMPK). In addition, metformin may stimulate antigen presentation and maturation of anticancer immune cells, which lead to the induction of anticancer immunity in the tumor. This review aims to explain the detailed mechanisms of normal tissue sparing and tumor suppression during cancer therapy using adjuvant metformin with an emphasis on immune system responses.

De novo NAD+ synthesis contributes to CD8+ T cell metabolic fitness and antitumor function

The dysfunction and clonal constriction of tumor-infiltrating CD8+ T cells are accompanied by alterations in cellular metabolism; however, how the cell-intrinsic metabolic pathway specifies intratumoral CD8+ T cell features remains elusive. Here, we show that cell-autonomous generation of nicotinamide adenine dinucleotide (NAD+) via the kynurenine pathway (KP) contributes to the maintenance of intratumoral CD8+ T cell metabolic and functional fitness. De novo NAD+ synthesis is involved in CD8+ T cell metabolism and antitumor function. KP-derived NAD+ promotes PTEN deacetylation, thereby facilitating PTEN degradation and preventing PTEN-dependent metabolic defects. Importantly, impaired cell-autonomous NAD+ synthesis limits CD8+ T cell responses in human colorectal cancer samples. Our results reveal that KP-derived NAD+ regulates the CD8+ T cell metabolic and functional state by restricting PTEN activity and suggest that modulation of de novo NAD+ synthesis could restore CD8+ T cell metabolic fitness and antitumor function.

An In Situ Chemotherapy Drug Combined with Immune Checkpoint Inhibitor for Chemoimmunotherapy

Clinically, cancer chemotherapy still faces unsatisfactory efficacy due to drug resistance and severe side effects, including tiredness, hair loss, feeling sick, etc. The clinical benefits of checkpoint inhibitors have revived hope for cancer immunotherapy, but the objective response rate of immune checkpoint inhibitors remains around 10-40%. Herein, two types of copper-doped mesoporous silica nanoparticles (MS-Cu-1 with a diameter of about 30 nm and MS-Cu-2 with a diameter of about 200 nm) were synthesized using a one-pot method. Both MS-Cu-1 and MS-Cu-2 nanoparticles showed excellent tumor microenvironment regulation properties with elevated extracellular and intracellular ROS generation, extracellular and intracellular oxygenation, and intracellular GSH depletion. In particular, MS-Cu-2 nanoparticles demonstrated a better microenvironment modulation effect than MS-Cu-1 nanoparticles. The DSF/MS-Cu composites with disulfiram (DSF) and copper co-delivery characteristics were prepared by a straightforward method using chloroform as the solvent. Cell survival rate and live/dead staining results showed that DSF and MS-Cu alone were not toxic to LLC cells, while a low dose of DSF/MS-Cu (1-10 μg/mL) showed a strong cell-killing effect. In addition, MS-Cu-2 nanoparticles released more Cu2+ in a weakly acidic environment (pH = 5) than in a physiological environment (pH = 7.4), and the Cu2+ released was 41.72 ± 0.96 mg/L in 1 h under weakly acidic conditions. UV-visible absorption spectrometry confirmed the production of tumor-killing drugs (CuETs). The intratumoral injection of DSF/MS-Cu significantly inhibited tumor growth in vivo by converting nontoxic DSF/MS-Cu into toxic CuETs. The combination of DSF/MS-Cu and anti-CTLA-4 antibody further inhibited tumor growth, showing the synergistic effect of DSF/MS-Cu and immune checkpoint inhibitors.

The Role of Tumor Metabolic Reprogramming in Tumor Immunity

The occurrence and development of tumors require the metabolic reprogramming of cancer cells, namely the alteration of flux in an autonomous manner via various metabolic pathways to meet increased bioenergetic and biosynthetic demands. Tumor cells consume large quantities of nutrients and produce related metabolites via their metabolism; this leads to the remodeling of the tumor microenvironment (TME) to better support tumor growth. During TME remodeling, the immune cell metabolism and antitumor immune activity are affected. This further leads to the escape of tumor cells from immune surveillance and therefore to abnormal proliferation. This review summarizes the regulatory functions associated with the abnormal biosynthesis and activity of metabolic signaling molecules during the process of tumor metabolic reprogramming. In addition, we provide a comprehensive description of the competition between immune cells and tumor cells for nutrients in the TME, as well as the metabolites required for tumor metabolism, the metabolic signaling pathways involved, and the functionality of the immune cells. Finally, we summarize current research targeted at the development of tumor immunotherapy. We aim to provide new concepts for future investigations of the mechanisms underlying the metabolic reprogramming of tumors and explore the association of these mechanisms with tumor immunity.

Translatomics to explore dynamic differences in immunocytes in the tumor microenvironment

Protein is an essential component of all living organisms and is primarily responsible for life activities; furthermore, its synthesis depends on a highly complex and accurate translation system. For proteins, the regulation at the translation level exceeds the sum of that during transcription, mRNA degradation, and protein degradation. Therefore, it is necessary to study regulation at the translation level. Imbalance in the translation process may change the cellular landscape, which not only leads to the occurrence, maintenance, progression, invasion, and metastasis of cancer but also affects the function of immune cells and changes the tumor microenvironment. Detailed analysis of transcriptional and protein atlases is needed to better understand how gene translation occurs. However, a more rigorous direct correlation between mRNA and protein levels is needed, which somewhat limits further studies. Translatomics is a technique for capturing and sequencing ribosome-related mRNAs that can effectively identify translation changes caused by ribosome stagnation and local translation abnormalities during cancer occurrence to further understand the changes in the translation landscape of cancer cells themselves and immune cells in the tumor microenvironment, which can provide new strategies and directions for tumor treatment.

Formate Supplementation Enhances Antitumor CD8+ T-cell Fitness and Efficacy of PD-1 Blockade

The tumor microenvironment (TME) restricts antitumor CD8+ T-cell function and immunotherapy responses. Cancer cells compromise the metabolic fitness of CD8+ T cells within the TME, but the mechanisms are largely unknown. Here we demonstrate that one-carbon (1C) metabolism is enhanced in T cells in an antigen-specific manner. Therapeutic supplementation of 1C metabolism using formate enhances CD8+ T-cell fitness and antitumor efficacy of PD-1 blockade in B16-OVA tumors. Formate supplementation drives transcriptional alterations in CD8+ T-cell metabolism and increases gene signatures for cellular proliferation and activation. Combined formate and anti-PD-1 therapy increases tumor-infiltrating CD8+ T cells, which are essential for enhanced tumor control. Our data demonstrate that formate provides metabolic support to CD8+ T cells reinvigorated by anti-PD-1 to overcome a metabolic vulnerability in 1C metabolism in the TME to further improve T-cell function.

SIGNIFICANCE

This study identifies that deficiencies in 1C metabolism limit the efficacy of PD-1 blockade in B16-OVA tumors. Supplementing 1C metabolism with formate during anti-PD-1 therapy enhances CD8+ T-cell fitness in the TME and CD8+ T-cell-mediated tumor clearance. These findings demonstrate that formate supplementation can enhance exhausted CD8+ T-cell function. See related commentary by Lin et al., p. 2507. This article is featured in Selected Articles from This Issue, p. 2489.

The Influence of Metabolism on Immune Response: A Journey to Understand Immunometabolism in the Context of Viral Infection

In recent years, the emergence of the concept of immunometabolism has shed light on the pivotal role that cellular metabolism plays in both the activation of immune cells and the development of immune programs. The antiviral response, a widely distributed defense mechanism used by infected cells, serves to not only control infections but also to attenuate their deleterious effects. The exploration of the role of metabolism in orchestrating the antiviral response represents a burgeoning area of research, especially considering the escalating incidence of viral outbreaks coupled with the increasing prevalence of metabolic diseases. Here, we present a review of current knowledge regarding immunometabolism and the antiviral response during viral infections. Initially, we delve into the concept of immunometabolism by examining its application in the field of cancer-a domain that has long spearheaded inquiries into this fascinating intersection of disciplines. Subsequently, we explore examples of immune cells whose activation is intricately regulated by metabolic processes. Progressing with a systematic and cellular approach, our aim is to unravel the potential role of metabolism in antiviral defense, placing significant emphasis on the innate and canonical interferon response.

CAR-T treatment for cancer: prospects and challenges

Chimeric antigen receptor (CAR-T) cell therapy has been widely used in hematological malignancies and has achieved remarkable results, but its long-term efficacy in solid tumors is greatly limited by factors such as the tumor microenvironment (TME). In this paper, we discuss the latest research and future views on CAR-T cell cancer immunotherapy, compare the different characteristics of traditional immunotherapy and CAR-T cell therapy, introduce the latest progress in CAR-T cell immunotherapy, and analyze the obstacles that hinder the efficacy of CAR-T cell therapy, including immunosuppressive factors, metabolic energy deficiency, and physical barriers. We then further discuss the latest therapeutic strategies to overcome these barriers, as well as management decisions regarding the possible safety issues of CAR-T cell therapy, to facilitate solutions to the limited use of CAR-T immunotherapy.

Low glucose availability potentiates the effects of metformin on model T cell activation and exhaustion markers in vitro

Modulation of immune cell metabolism is one of promising strategies to improve cancer immunotherapies. Metformin is an anti-diabetic drug with potential anti-cancer effects, ranging from normalization of blood glucose and insulin levels, direct anti-proliferative effects on cancer cells to emerging immunomodulatory effects on anti-tumor immunity. Metformin can reduce tumor hypoxia and PD-L1 expression, as well as normalize or improve T cell function and potentiate the effect of immune checkpoint inhibitors, making it a promising adjuvant to immunotherapy of tumors with poor response such as triple negative breast cancer (TNBC). However, although the effects of metformin on cancer cells are glucose-dependent, the role of glucose in modulating its effect on T cells has not been systematically studied. We thus investigated the effect of metformin as a function of glucose level on Jurkat cell and PBMC T cell models in vitro. While low metformin concentrations had little effect on T cell function, high concentration reduced proliferation and IFN-γ secretion in both models and induced a shift in T cell populations from memory to effector subsets. The PD-1/CD69 ratio was improved by high metformin in T cells from PBMC. Low glucose and metformin synergistically reduced PD-1 and CD69 expression and IFN-γ secretion in T cells from PBMC. Low glucose level itself suppressed Jurkat cell function due to their limited metabolic plasticity, but had limited effects on T cells from PBMC apart from reduced proliferation. Conversely, high glucose did not strongly affect either T cell model. Metformin in combination with glycolysis inhibitor 2-deoxy-D-glucose (2DG) reduced PD-1 in Jurkat cells, but also strongly suppressed their function. However, low, physiologically achievable 2DG concentration itself reduced PD-1 while mostly maintaining IL-2 secretion and, interestingly, even strongly increased IFN-γ secretion regardless of glucose level. Overall, glucose metabolism can importantly influence some of the effects of metformin on T cell functionality in the tumor microenvironment. Additionally, we show that 2DG could potentially improve the anti-tumor T cell response.