Enhanced Lipid Accumulation and Metabolism Are Required for the Differentiation and Activation of Tumor-Associated Macrophages

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

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

Targeting lipid metabolism via nanomedicine: A prospective strategy for cancer therapy

Lipid metabolism has been increasingly recognized to play an influencing role in tumor initiation, progression, metastasis, and therapeutic drug resistance. Targeting lipid metabolic reprogramming represents a promising therapeutic strategy. Despite their structural complexity and poor targeting efficacy, lipid-metabolizing drugs, either used alone or in combination with chemotherapeutic agents, have been employed in clinical practice. The advent of nanotechnology offers new approaches to enhancing therapeutic effects, includingthe targeted delivery and integration of lipid metabolic reprogramming with chemotherapy, photodynamic therapy (PDT), and immunotherapy. The integrated nanoformulation, nanomedicine, could significantly advance the field of lipid metabolism therapy. In this review, we will briefly introduce the concept of cancer lipid metabolism reprogramming, then elaborate the latest advances in engineered nanomedicine for targeting lipid metabolism during cancer treatment, and finally provide our insights into future perspectives of nanomedicine for interference with lipid metabolism in the tumor microenvironment.

Immunometabolism of tumor-associated macrophages: A therapeutic perspective

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

EGR2 promotes liver cancer metastasis by enhancing IL-8 expression through transcription regulation of PDK4 in M2 macrophages

Liver tumor is a common digestive system tumor, and its development is closely related to complex cytokines, tumor microenvironment and immunoregulatory mechanisms. Tumor-associated macrophages play a great role in a series of liver cancer development by secreting various cytokines and transmitting multiple signals, but how macrophages regulate the various biological behaviors of liver cancer cells at the microscopic level is a challenge we still need to overcome. In this research, we first identified the Early Growth Response 2 (EGR2) gene, which exhibited significant expression in M2 macrophages in comparison to M0 and M1 cell types, utilizing RNA sequencing. Subsequently, we validated this finding through a battery of methodologies, including WB, qRT-PCR, and immunofluorescence assays. We further employed a co-culture model involving MHCC97L and macrophages to investigate the impact of EGR2 downregulation within M2 cells on the in vivo and in vitro metastatic and invasive capabilities of MHCC97L cells. Subsequently, we directed our attention to investigating the impact of EGR2 on the levels of interleukin-8 (IL-8). Through comprehensive analyses including RNA sequencing, CUT-and-Tag, and ChIP techniques, we demonstrated that EGR2 can bind to the promoter region of the Pyruvate Dehydrogenase Kinase 4 (PDK4) gene. Finally, we introduced a virus overexpressing PDK4 and demonstrated that EGR2 could regulate the transcriptional level of PDK4 to affect the expression of IL-8, and ultimately alter the metastatic ability of hepatocellular carcinoma cells. Our study demonstrates that EGR2 may be a valuable target for future intervention in the disease process of hepatocellular carcinoma and refines the mechanism at the microscopic level of Tumor-associated macrophages.

Reprogramming and targeting of cholesterol metabolism in tumor-associated macrophages

Cholesterol, as a major component of cell membranes, is closely related to the metabolic regulation of cells and organisms; tumor-associated macrophages play an important push role in tumor progression. We know that tumor-associated macrophages are polarized from macrophages, and the abnormalities of cholesterol metabolism that may be induced during their polarization are worth discussing. This manuscript focuses on metabolic abnormalities in tumor-associated macrophages, and first provides a basic summary of the regulatory mechanisms of abnormal macrophage polarization. Subsequently, it comprehensively describes the features of abnormal glucose, lipid and cholesterol metabolism in TAMs as well as the different regulatory pathways. Then, the paper also discusses the link between abnormal cholesterol metabolism in TAMs and tumors, chronic diseases and aging. Finally, the paper summarizes cancer therapeutic strategies targeting cholesterol metabolism that are already in clinical trials, as well as nanomaterials capable of targeting cholesterol metabolism that are in the research stage, in the hope of providing value for the design of targeting materials. Overall, elucidating metabolic abnormalities in tumor-associated macrophages, particularly cholesterol metabolism, could provide assistance in tumor therapy and the design of targeted drugs.

Fatty acid metabolism: The crossroads in intestinal homeostasis and tumor

Fatty acids (FAs) have various functions on cell regulation considering their abundant types and metabolic pathways. In addition, the relation between FA and other nutritional metabolism makes their functions more complex. As the first place for diet-derived FA metabolism, intestine is significantly influenced despite lack of clear conclusions due to the inconsistent findings. In this review, we discuss the regulation of fatty acid metabolism on the fate of intestinal stem cells in homeostasis and disorders, and also focus on the intestinal tumor development and treatment from the aspect of gut microbiota-epithelium-immune interaction. We summarize that the balances between FA oxidation and glycolysis, between oxidative phosphorylation and ketogenesis, between catabolism and anabolism, and the specific roles of individual FA types determine the diverse effects of intestinal FA metabolism in different cases. We hope this will inspire further dissection and suggest precise dietary/metabolic intervention for different demands related to intestinal health.

Role of Tumor-Associated Macrophages in Breast Cancer Immunotherapy

Breast cancer (BC) is the second leading cause of death among women worldwide. Immunotherapy has become an effective treatment for BC patients due to the rapid development of medical technology. Considerable breakthroughs have been made in research, marking the beginning of a new era in cancer treatment. Among them, various cancer immunotherapies such as immune checkpoint inhibitors (ICIs), cancer vaccines, and adoptive cell transfer are effective and have good prospects. The tumor microenvironment (TME) plays a crucial role in determining the outcomes of tumor immunotherapy. Tumor-associated macrophages (TAMs) are a key component of the TME, with an immunomodulatory effect closely related to the immune evasion of tumor cells, thereby affecting malignant progression. TAMs also significantly affect the therapeutic effect of ICIs (such as programmed death 1/programmed death ligand 1 (PD-1/PD-L1) inhibitors). TAMs are composed of multiple heterogeneous subpopulations, including M1 phenotypes macrophages (M1) and M2 phenotypes macrophages (M2). Furthermore, they mainly play an M2-like role and moderate a variety of harmful consequences such as angiogenesis, immunosuppression, and metastasis. Therefore, TAMs have become a key area of focus in the development of tumor therapies. However, several tumor immunotherapy studies demonstrated that ICIs are effective only in a small number of solid cancers, and tumor immunotherapy still faces relevant challenges in the treatment of solid tumors. This review explores the role of TAMs in BC immunotherapy, summarizing their involvement in BC development. It also explains the classification and functions of TAMs, outlines current tumor immunotherapy approaches and combination therapies, and discusses the challenges and potential strategies for TAMs in immuno-oncology treatments.

Loss of SPHK1 fuels inflammation to drive KRAS-mutated lung adenocarcinoma

Inflammation is a widely recognized key contributor to KRAS-driven lung adenocarcinoma (LUAD). Tumor-associated macrophages (TAM) are an integral part of the tumor microenvironment and create a supportive niche that sustains inflammation-driven tumorigenesis. In the present study, we unravel a dual role of sphingosine kinase 1 (SPHK1) in KRAS-driven LUAD. While SPHK1 promotes tumorigenesis in in vitro experimental models, it paradoxically suppresses tumorigenesis in in vivo models of KRAS-mutated LUAD. Mechanistically, tumor-intrinsic loss of SPHK1 leads to disrupted lipid homeostasis, increased inflammation and infiltration by TAM, ultimately driving tumor progression. Thus, our study suggests that clinically targeting the SPHK1/S1P axis could potentially result in increased tumor progression, possibly by rewiring the tumor microenvironment toward a more inflammatory and pro-tumorigenic state.

Immunocytes in the tumor microenvironment: recent updates and interconnections

The tumor microenvironment (TME) is a complex, dynamic ecosystem where tumor cells interact with diverse immune and stromal cell types. This review provides an overview of the TME's evolving composition, emphasizing its transition from an early pro-inflammatory, immune-promoting state to a later immunosuppressive milieu characterized by metabolic reprogramming and hypoxia. It highlights the dual roles of key immunocytes-including T lymphocytes, natural killer cells, macrophages, dendritic cells, and myeloid-derived suppressor cells-which can either inhibit or support tumor progression based on their phenotypic polarization and local metabolic conditions. The article further elucidates mechanisms of immune cell plasticity, such as the M1/M2 macrophage switch and the balance between effector T cells and regulatory T cells, underscoring their impact on tumor growth and metastasis. Additionally, emerging therapeutic strategies, including checkpoint inhibitors and chimeric antigen receptor (CAR) T and NK cell therapies, as well as approaches targeting metabolic pathways, are discussed as promising avenues to reinvigorate antitumor immunity. By integrating recent molecular insights and clinical advancements, the review underscores the importance of deciphering the interplay between immunocytes and the TME to develop more effective cancer immunotherapies.

Single-cell RNA sequencing reveals the intra-tumoral heterogeneity and immune microenvironment of small cell carcinoma of the ovary, hypercalcemic type

PURPOSE

Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) is a rare and lethal cancer lacking effective treatment. Its genomic mutations and tumor microenvironment need further exploration.

METHODS

We performed whole-exome sequencing or gene panel test to explore the SMARCA4 mutation spectrum in SCCOHT (15 samples). Single-cell RNA sequencing was conducted on one primary lesion with matched normal ovarian tissue and one recurrent lesion to investigate the intra-tumoral heterogeneity and immune microenvironment. Multiplex immunofluorescence staining validated T cell infiltration and PD-1 expression.

RESULTS

13/15 (86.7%) patients harbored SMARCA4 mutations. The loss of heterozygosity (LOH) occurred in 10/15 (66.7%) patients. Cancer cells and immune cells were observed in SCCOHT tumors. Cancer cells were further divided into seven subtypes and one from recurrent lesion exhibited the highest stemness accompanied by high expression of genes related to cell mitosis (AURKB, CHEK2, CCNB1, WEE1), DNA repair (BRCA1, RAD51) and epigenetic (EZH2, DNMT1). Immune cells mainly included macrophages and T cells. Lipid-associated tumor-associated macrophages (TAMs) was mainly in primary lesion while inflammatory cytokine-enriched TAMs in recurrent lesion. CD4+/ CD8+ T cell infiltration was observed in SCCOHT tumor and a certain proportion of T cells expressed PD-1.

CONCLUSIONS

SCCOHT exhibits universal SMARCA4 LOH and significant intra-tumoral heterogeneity, suggesting potential therapeutic targets, including CHEK2, CCNB1, and WEE1. Exhausted T cells and distinct TAM subsets infiltrate tumors. Targeting macrophage polarization or cytokine signaling may also be promising. These findings provide insights for developing novel therapies to improve outcomes in SCCOHT.

CLINICAL TRIAL NUMBER

Not applicable.

FABP5+ lipid-loaded macrophages process tumour-derived unsaturated fatty acid signal to suppress T-cell antitumour immunity

BACKGROUND & AIMS

Tumour-associated macrophages (TAMs) contribute to hepatocellular carcinoma (HCC) progression. However, while the pro-tumour and immunosuppressive roles of lipid-loaded macrophages are well established, the mechanisms by which lipid metabolism enhances the tumour-promoting effects of TAMs remain unclear.

METHODS

Single-cell RNA sequencing was performed on mouse and human HCC tumour samples to elucidate the landscape of HCC TAMs. Macrophages were stimulated with various long-chain unsaturated fatty acids (UFAs) to assess immunosuppressive molecule expression in vitro. Additionally, in vivo and in vitro studies were conducted using mice with macrophage-specific deficiencies in fatty acid-binding protein 5 (FABP5) or peroxisome proliferator-activated receptor γ (PPARγ).

RESULTS

Single-cell RNA sequencing identified a subpopulation of FABP5+ lipid-loaded TAMs characterized by enhanced immune checkpoint blocker ligands and immunosuppressive molecules in an oncogene-mutant HCC mouse model and human HCC tumours. Mechanistically, long-chain UFAs released by tumour cells activate PPARγ via FABP5, resulting in immunosuppressive properties in TAMs. FABP5 deficiency in macrophages decreases immunosuppressive molecule expression, enhances T cell-dependent antitumour immunity, diminishes HCC growth, and improves immunotherapy efficacy.

CONCLUSIONS

This study demonstrates that UFAs promote tumourigenesis by enhancing the immunosuppressive tumour microenvironment via FABP5-PPARγ signalling and provides a proof-of-concept for targeting this pathway to improve the efficacy of tumour immunotherapy.

IMPACT AND IMPLICATIONS

Despite the role of tumour-associated macrophages (TAMs) in promoting tumour progression being well established, the mechanisms by which lipid metabolism enhances the tumour-promoting effects of TAMs remain unclear. Our study reveals that FABP5-mediated unsaturated fatty acid metabolism in TAMs is crucial for modulating antitumour T-cell immunity and influencing the efficacy of immunotherapy. This finding provides novel insights into the immunomodulatory roles of FABP5+ lipid-loaded TAMs in hepatocellular carcinoma and suggests that targeting FABP5 could offer a new approach to liver cancer treatment.

Targeting lipid metabolism in regulatory T cells for enhancing cancer immunotherapy

As immunosuppressive cells, Regulatory T cells (Tregs) exert their influence on tumor immune escape within the tumor microenvironment (TME) by effectively suppressing the activity of other immune cells, thereby significantly impeding the anti-tumor immune response. In recent years, the metabolic characteristics of Tregs have become a focus of research, especially the important role of lipid metabolism in maintaining the function of Tregs. Consequently, targeted interventions aimed at modulating lipid metabolism in Tregs have been recognized as an innovative and promising approach to enhance the effectiveness of tumor immunotherapy. This review presents a comprehensive overview of the pivotal role of lipid metabolism in regulating the function of Tregs, with a specific focus on targeting Tregs lipid metabolism as an innovative approach to augment anti-tumor immune responses. Furthermore, we discuss potential opportunities and challenges associated with this strategy, aiming to provide novel insights for enhancing the efficacy of cancer immunotherapy.

Key immune cells and their crosstalk in the tumor microenvironment of bladder cancer: insights for innovative therapies

Bladder cancer (BC) is a heterogeneous disease associated with high mortality if not diagnosed early. BC is classified into non-muscle-invasive BC (NMIBC) and muscle-invasive BC (MIBC), with MIBC linked to poor systemic therapy response and high recurrence rates. Current treatments include transurethral resection with Bacillus Calmette-Guérin (BCG) therapy for NMIBC and radical cystectomy with chemotherapy and/or immunotherapy for MIBC. The tumor microenvironment (TME) plays a critical role in cancer progression, metastasis, and therapeutic efficacy. A comprehensive understanding of the TME's complex interactions holds substantial translational significance for developing innovative treatments. The TME can contribute to therapeutic resistance, particularly in immune checkpoint inhibitor (ICI) therapies, where resistance arises from tumor-intrinsic changes or extrinsic TME factors. Recent advancements in immunotherapy highlight the importance of translational research to address these challenges. Strategies to overcome resistance focus on remodeling the TME to transform immunologically "cold" tumors, which lack immune cell infiltration, into "hot" tumors that respond better to immunotherapy. These strategies involve disrupting cancer-microenvironment interactions, inhibiting angiogenesis, and modulating immune components to enhance anti-tumor responses. Key mechanisms include cytokine involvement [e.g., interleukin-6 (IL-6)], phenotypic alterations in macrophages and natural killer (NK) cells, and the plasticity of cancer-associated fibroblasts (CAFs). Identifying potential therapeutic targets within the TME can improve outcomes for MIBC patients. This review emphasizes the TME's complexity and its impact on guiding novel therapeutic approaches, offering hope for better survival in MIBC.

Myeloid cells are involved in tumor immunity, metastasis and metabolism in tumor microenvironment

Bone marrow-derived cells in the tumor microenvironment, including macrophages, neutrophils, dendritic cells, myeloid-derived suppressor cells, eosinophils and basophils, participate in the generation, development, invasion and metastasis of tumors by producing different cytokines and interacting with other cell types, and play a pro-tumor or anti-tumor role in regulating tumor immunity. Due to the complexity of cell types in the tumor microenvironment and the unknown process of tumor development and metastasis, cancer treatment to achieve better survival status remains challenging. In this article, we summarize the effects of myeloid cells in tumor microenvironment on tumor immunity, cancer migration, and crosstalk with metabolism (including glucose metabolism, lipid metabolism, and amino acid metabolism), which will help to further study the tumor microenvironment and seek targeted therapeutic strategies for patients.

Metabolites and metabolic pathway reactions links to sensitization of immunotherapy in pan-cancer

Metabolic features are crucial in tumor immune interactions, but their relationship with antitumor immune responses is not yet fully understood. This study used Mendelian randomization analysis to identify the causal relationships between blood metabolites and immune cells and to evaluate the effects of metabolic pathways and reactions on antitumor immune responses in various cancers. Levels of 156 metabolites exhibited significant associations with selected immune cells. Metabolic enrichment analysis indicated laurate, propionyl-carnitine, carnitine and l-acetylcarnitine are enriched in fatty acid (FA) metabolism pathways. These enriched pathways are significantly correlated to CD8+ T cell function signatures in tumor environment and favor better prognostic outcomes. Metabolic reactions contributing to better immunotherapy responses were identified and used to establish the immuno-metabolic reaction score (IMRS). IMRS were significantly correlated to CD8+ T cell infiltration levels and CD8+ T cell signature scores in either 10× Visium spatial transcriptomic or RNA-seq samples. Finally, IMRS could significantly predict favorable survival outcomes in different cancer patients treated with immunotherapy. Our study revealed a link between certain metabolites and their related metabolic pathways to tumor immune landscape and immune functions. These results could promote the accurate stratification of patients before treatment and improve the efficacy of immunotherapy.

Bridging epigenomics and tumor immunometabolism: molecular mechanisms and therapeutic implications

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

Lipid metabolic reprograming: the unsung hero in breast cancer progression and tumor microenvironment

Aberrant lipid metabolism is a well-recognized hallmark of cancer. Notably, breast cancer (BC) arises from a lipid-rich microenvironment and depends significantly on lipid metabolic reprogramming to fulfill its developmental requirements. In this review, we revisit the pivotal role of lipid metabolism in BC, underscoring its impact on the progression and tumor microenvironment. Firstly, we delineate the overall landscape of lipid metabolism in BC, highlighting its roles in tumor progression and patient prognosis. Given that lipids can also act as signaling molecules, we next describe the lipid signaling exchanges between BC cells and other cellular components in the tumor microenvironment. Additionally, we summarize the therapeutic potential of targeting lipid metabolism from the aspects of lipid metabolism processes, lipid-related transcription factors and immunotherapy in BC. Finally, we discuss the possibilities and problems associated with clinical applications of lipid‑targeted therapy in BC, and propose new research directions with advances in spatiotemporal multi-omics.

Zhuyu pill attenuates metabolic-associated fatty liver disease by regulating macrophage polarization through TLR4 signaling pathway

BACKGROUND

Metabolic-associated fatty liver disease (MAFLD) is the leading chronic liver disease globally, impacting a large segment of the population. The Zhuyu Pill (ZYP), a traditional Chinese remedy, has been clinically used for treating MAFLD, with its effectiveness demonstrated in both human patients and animal models. However, the underlying mechanisms of how ZYP addresses MAFLD still require further investigation.

OBJECTIVE

This study investigated the molecular mechanism of ZYP in treating MAFLD through both in vivo and vitro methods.

METHODS

A murine MAFLD model was induced by a high-fat, high-fructose diet for 12 weeks. ZYP was administered for 4 weeks, with fenofibrate serving as a positive control. Indicators of lipid metabolism in serum and liver tissue were detected by automatic biochemical analyzer and ELISA, respectively. Histopathological evaluation of liver sections was performed using HE and oil red O staining. Transcriptomics was employed to further investigate the therapeutic mechanism of ZYP in MAFLD. Additionally, macrophages and their polarization in the liver were analyzed using ELISA, flow cytometry, immunohistochemistry, and immunofluorescence (IF). Candidate proteins and pathways were validated in vivo and in vitro by western blotting and IF. Validation of the pathway was performed in vitro using inhibitors and co-culture strategies.

RESULTS

ZYP significantly improved obesity and hepatic steatosis in MAFLD mice, reducing body/liver weight and regulating lipid metabolism indicators in serum and liver tissue. Bioinformatics analysis of transcriptomic data highlighted lipid metabolism regulation and inflammation control as key effects of ZYP in treating MAFLD. The in vivo experimental results showed that ZYP inhibited M1 polarization of macrophages (pro-inflammatory) and promoted M2 polarization of macrophages (anti-inflammatory) in MAFLD mice. Further in vivo and vitro experiments indicated that ZYP competes with LPS to bind to Toll-like receptor 4 (TLR4), suppressing M1 polarization in liver macrophages, and improving MAFLD. The in vitro co-culture system also confirmed that ZYP reduces liver lipid deposition by modulating M1 macrophage polarization.

CONCLUSIONS

ZYP alleviates MAFLD by inhibiting M1 polarization of liver macrophages, indicating that ZYP may be a promising treatment for MAFLD. Its mechanism of action is to inhibit the TLR4/MyD88/TRAF6 signaling pathway, modulate macrophage polarization, and improve inflammatory response.

Follicular cytotoxic T cells is dysfunctional in chronic hepatitis B patients with non-alcoholic fatty liver disease

BACKGROUND & AIMS

Given the impact of nonalcoholic fatty liver disease (NAFLD) on T cell activation and proliferation functions, we aim to explore the heterogeneity of follicular cytotoxic T (Tfc) cells in chronic hepatitis B (CHB) patients with NAFLD.

METHODS

32 healthy controls (HCs), 36 treatment-naïve CHB patients, and 19 treatment-naïve CHB + NAFLD patients were recruited. We employed multicolor flow cytometry to assess the exhausted phenotype and functionality of Tfc cells. CD8+ T cells were subjected to single-cell RNA sequencing. Furthermore, we co-cultured peripheral blood mononuclear cells from CHB patients with HepG2.2.15 cells under different treatment to investigate the underlying mechanism.

RESULTS

We observed an increased expression of inhibitory receptors in Tfc cells compared to their counterparts in CHB patients. In CHB + NAFLD patients the memory identity and functional properties of Tfc cells were impaired. Enhanced lipid oxidation and oxidative stress were found in the Tfc of CHB + NAFLD patients. Tfc cells were predominantly present within the exhausted effector T cells in CHB + NAFLD patients, while in CHB patients, Tfc cells were mainly distributed within the precursors of exhausted T cells and central memory T cells. The effector memory phenotype of Tfc cells was diminished but could be partially restored after antioxidant treatment.

CONCLUSION

We present the phenotype of Tfc cells in CHB patients, with or without NAFLD. Our findings provide evidence that the long-term memory identity and functionality of Tfc cells are impaired in CHB + NAFLD patients. Enhancing the characteristics of effector memory cells in Tfc through maintaining the redox balance may offer innovative therapeutic strategies for CHB + NAFLD patients.

Inhibition of Kv1.3 channel restrains macrophage M2 polarization and ameliorates renal fibrosis via regulating STAT6 phosphorylation

Macrophages play crucial roles in regulating both homeostatic and inflammatory responses, with classical activated (M1) and alternatively activated (M2) subsets defined by the surrounding micro-environment. Renal fibrosis, developed from persistent inflammation, is worsened by M2 macrophages, yet the precise mechanisms underlying macrophage M2 polarization remain unclear. In this study, we investigated the role of Kv1.3, one of the primary potassium channels which is expressed in both innate and adaptive immunity, on macrophage M2 polarization and renal fibrosis. Our findings demonstrated that genetic or pharmacological inhibition of Kv1.3 significantly suppressed the expression of M2 markers and STAT6 phosphorylation. Furthermore, pharmacological inhibition of Kv1.3 by PAP-1 attenuated renal inflammation and fibrosis with decreased infiltration of macrophage infiltration and M2 polarization by employing the unilateral ureteral obstruction (UUO) renal fibrosis model. Mechanistically, we revealed that Kv1.3 was required for STAT6 phosphorylation in a mitochondria membrane potential dependent manner. Collectively, this study suggests that Kv1.3 is essential for macrophage M2 polarization and highlights the potential of Kv1.3 blockers as therapeutic agents for renal fibrosis and other M2 polarization-related diseases.

YY2-CYP51A1 signaling suppresses hepatocellular carcinoma progression by restraining de novo cholesterol biosynthesis

Lipid accumulation is a frequently observed characteristic of cancer. Lipid accumulation is closely related to tumor progression, metastasis, and drug resistance; however, the mechanism underlying lipid metabolic reprogramming in tumor cells is not fully understood. Yin yang 2 (YY2) is a C2H2‑zinc finger transcription factor that exerts tumor-suppressive effects. However, its involvement in tumor cell lipid metabolic reprogramming remains unclear. In the present study, we identified YY2 as a novel regulator of cholesterol metabolism. We showed that YY2 suppressed cholesterol accumulation in hepatocellular carcinoma (HCC) cells by downregulating the transcriptional activity of cytochrome P450 family 51 subfamily A member 1 (CYP51A1), a key enzyme in de novo cholesterol biosynthesis. Subsequently, through in vitro and in vivo experiments, we demonstrated that this downregulation is crucial for the YY2 tumor suppressive effect. Together, our findings unraveled a previously unprecedented regulation of HCC cells cholesterol metabolism, and eventually, their tumorigenic potential, through YY2 negative regulation on CYP51A1 expression. This study revealed a novel regulatory mechanism of lipid metabolic reprogramming in tumor cells and provided insights into the molecular mechanism underlying the YY2 the suppressive effect. Furthermore, our findings suggest a potential antitumor therapeutic strategy targeting cholesterol metabolic reprogramming using YY2.

The multi-faceted immune modulatory role of S100A4 in cancer and chronic inflammatory disease

S100A4 is a Ca2+-binding protein involved in multiple chronic inflammatory and neoplastic conditions. This review focuses on recent advances in the understanding of S100A4 function in immune cells, comparing and contrasting S100A4 regulation of immune responses in cancer and chronic inflammatory diseases. We provide evidence that S100A4 regulation of immune cell function has a profound role in promoting the pathogenesis of cancer and pro-inflammatory conditions. Finally, we discuss relevant future directions to target S100A4 therapeutically in different disease states.

Oxidative Stress and Redox Signaling in Gastric Cancer: From Mechanisms to Therapeutic Implications

Oxidative stress, which is characterized by an imbalance between reactive oxygen species (ROS) production and antioxidant defenses, has critical roles in the initiation, progression, and treatment of gastric cancer. On the one hand, an excessive ROS accumulation induces oxidative damage and cancer cell death. On the other hand, moderate levels of ROS cause genetic mutations and dysregulation of signaling pathways to promote proliferation, inflammation, angiogenesis, and metastasis in gastric cancer. Notably, emerging evidence has revealed that ROS also mediate oxidative post-translational modifications (oxPTMs) of redox-sensitive proteins, which can directly affect protein functions and regulate redox signaling in cancer cells. Therefore, elucidating the regulatory mechanisms of oxidative stress and redox signaling in gastric cancer holds great promise to identify novel therapeutic targets or redox-targeting strategies. This review will summarize the mechanisms of oxidative stress in regulating the hallmarks of gastric cancer and highlight the roles of ROS-mediated oxPTMs in gastric cancer. In addition, we will discuss emerging strategies targeting oxidative stress for the treatment of gastric cancer, with an emphasis on the use of bioactive natural products and nanomaterials.

Discovery of Fatty Acid Translocase CD36-Targeting Near-Infrared Fluorescent Probe Enables Visualization and Imaging-Guided Surgery for Glioma

Despite therapeutic advances in glioma, glioma-related mortality rates remain high due to its extremely poor prognosis and high recurrence. Near-infrared (NIR) fluorescence imaging technologies, using the clinically approved fluorescent probe 5-ALA, have gained prominence in facilitating visualization of glioma resection. However, the false-positive and false-negative results of 5-ALA decrease its sensitivity and specificity in detecting glioma, thereby hampering its use in glioma surgical navigation. Herein, a novel molecular probe MPA-Pip-abt-510 labeled with a NIR fluorescent dye MPA was developed, and its ability to target the CD36 protein, which is upregulated in glioma, was assessed. Fluorescent-labeled probes, conjugated to the CD36-targeting ligand abt-510, demonstrated high specificity and selectivity for CD36-positive tumor cells in vitro and tumor tissue in vivo. Biodistribution analysis of MPA-Pip-abt-510 revealed high tumor-specific accumulation in tumors, accompanied by minimal nonspecific uptake in background tissues, yielding a signal-to-noise ratio (SNR) of 6.6 ± 0.4 in a U87 subcutaneous glioma model 10 h postinjection. Meanwhile, quantitative analysis validated the high uptake of MPA-Pip-abt-510 in the U87 orthotopic tumor model, with a tumor-to-brain SNR of 5.4 ± 0.5, enabling the accurate identification of tumor tissue for surgical navigation. Moreover, pathological analysis of tumor and healthy brain tissues unveiled well-defined tumor boundaries, highlighting the capacity of the MPA-Pip-abt-510 probe to precisely visualize the CD36 protein at the molecular level. Given its rapid tumor-targeting abilities, durable retention, and accurate outlining of tumor boundaries, MPA-Pip-abt-510 emerges as a promising CD36-targeted fluorescence contrast agent and expands the toolbox of glioma fluorescent probes for surgical navigation.

Lipid Metabolism in Breast Cancer: From Basic Research to Clinical Application

Breast cancer remains the most prevalent cancer among women globally, with significant links to obesity and lipid metabolism abnormalities. This review examines the role of lipid metabolism in breast cancer progression, highlighting its multifaceted contributions to tumor biology. We discuss key metabolic processes, including fatty acid metabolism, triglyceride metabolism, phospholipid metabolism, and cholesterol metabolism, detailing the reprogramming that occurs in these pathways within breast cancer cells. Alterations in lipid metabolism are emphasized for their roles in supporting energy production, membrane biogenesis, and tumor aggressiveness. Furthermore, we examine how lipid metabolism influences immune responses in the tumor microenvironment, affecting immune cell function and therapeutic efficacy. The potential of lipid metabolism as a target for novel therapeutic strategies is also addressed, with a focus on inhibitors of key metabolic enzymes. By integrating lipid metabolism with breast cancer research, this review underscores the importance of lipid metabolism in understanding breast cancer biology and developing treatment approaches aimed at improving patient outcomes.

Characterization of canine tumor-infiltrating leukocyte transcriptomic signatures reveals conserved expression patterns with human osteosarcoma

Immune cells play key roles in host responses to malignant tumors. The selective pressure that immune cells elicit on tumors promotes immune escape, while tumor-associated modulation of immune cells creates an environment favorable to tumor growth and progression. In this study we used publicly available single-cell RNA sequencing (scRNA-seq) data from the translationally relevant canine osteosarcoma (OS) model to compare tumor-infiltrating immune cells to circulating leukocytes. Through computational analysis we investigated the differences in cell type proportions and how the OS TME impacted infiltrating immune cell transcriptomic profiles relative to circulating leukocytes. Differential abundance analysis revealed increased proportions of follicular helper T cells, regulatory T cells, and mature regulatory dendritic cells (mregDCs) in the OS TME. Differential gene expression analysis identified exhaustion markers (LAG3, HAVCR2, PDCD1) to be upregulated in CD4 and CD8 T cells within the OS TME. Comparisons of B cell gene expression profiles revealed an enrichment of protein processing and endoplasmic reticulum pathways, suggesting infiltrating B cells were activated following tumor infiltration. Gene expression changes within myeloid cells identified increased expression of immune suppressive molecules (CD274, OSM, MSR1) in the OS TME, indicating the TME skews myeloid cells toward an immunosuppressive phenotype. Comparisons to human literature and analysis of human scRNA-seq data revealed conserved transcriptomic responses to tumor infiltration, while also identifying species differences. Overall, the analysis presented here provides new insights into how the OS TME impacts the transcriptional programs of major immune cell populations in dogs and acts as a resource for comparative immuno-oncology research.

Mass spectrometry imaging reveals spatial metabolic variation and the crucial role of uridine metabolism in liver injury caused by Schistosoma japonicum

Schistosomiasis is the second most important parasitic disease worldwide. Schistosomiasis japonica is a unique species endemic to southern China, and schistosomiasis is characterized by severe liver injury, inflammation, liver granuloma, and subsequent liver fibrosis. However, the pathological mechanism of this disease remains unclear. Mass spectrometry imaging (MSI) is a versatile technique that integrates the molecular specificity of mass spectrometry (MS) with spatial imaging information, which could provide an accurate method for observing disease progression. In this study, we used an air flow-assisted desorption electrospray ionization (AFADESI-MSI) platform to detect a wide range of metabolites and visualize their distribution in the liver tissue of mice infected with Schistosoma japonicum. In the negative ion mode analysis, 21 and 25 different metabolites were detected in the early and chronic stages of infection, respectively. Thirteen characteristic metabolites and 3 metabolic pathways related to disease development may be involved in the chronicity of schistosomiasis. There were more than 32 and 40 region-specific changes in the abundance of a wide range of metabolites (including carbohydrates, amino acids, nucleotides, and fatty acids) in the livers of mice at two different infection times, which also revealed the heterogeneous metabolic characteristics of the liver egg granulomas of S. japonicum. In a chronic infection model with S. japonicum, oral treatment with praziquantel significantly alleviated most metabolic disorders, including fatty acid and pyrimidine metabolism. Surprisingly, Upase1, a key enzyme in uridine metabolism, was significantly upregulated 6 weeks after infection, and liver uridine levels were negatively correlated with the abundance of multiple lipid-associated metabolites. Further studies revealed that in vitro uridine supplementation inhibited the activation of LX-2 cells, restored the homeostasis of fatty acid metabolism through the peroxisome proliferator-activated receptor γ (PPARγ) pathway, and played an antifibrotic role. Our findings provide new insights into the molecular mechanisms of S. japonicum-induced liver fibrosis and the potential of targeting uridine metabolism in disease therapy.

Scavenger Receptor CD36 in Tumor-Associated Macrophages Promotes Cancer Progression by Dampening Type-I IFN Signaling

Tumor-associated macrophages (TAM) are a heterogeneous population of myeloid cells that dictate the inflammatory tone of the tumor microenvironment. In this study, we unveiled a mechanism by which scavenger receptor cluster of differentiation 36 (CD36) suppresses TAM inflammatory states. CD36 was upregulated in TAMs and associated with immunosuppressive features, and myeloid-specific deletion of CD36 significantly reduced tumor growth. Moreover, CD36-deficient TAMs acquired inflammatory signatures including elevated type-I IFN (IFNI) production, mirroring the inverse correlation between CD36 and IFNI response observed in patients with cancer. IFNI, especially IFNβ, produced by CD36-deficient TAMs directly induced tumor cell quiescence and delayed tumor growth. Mechanistically, CD36 acted as a natural suppressor of IFNI signaling in macrophages through p38 activation downstream of oxidized lipid signaling. These findings establish CD36 as a critical regulator of TAM function and the tumor inflammatory microenvironment, providing additional rationale for pharmacologic inhibition of CD36 to rejuvenate antitumor immunity. Significance: CD36 in tumor-associated macrophages mediates immunosuppression and can be targeted as a therapeutic avenue for stimulating interferon production and increasing the efficacy of immunotherapy.

HIG-2 promotes glioma stemness and radioresistance mediated by IGFBP2-rich microparticles in hypoxia

Hypoxia can weaken the efficacy of radiotherapy and decrease tumor immunogenicity leading to immune escape. Thus, a thorough understanding of the key signaling pathways regulated by hypoxia is vitally important to enhance the radiosensitivity and improve immunosuppressive microenvironment of glioma. In this study, we verified the crucial role of hypoxia-inducible gene 2 (HIG-2) in lipid droplet (LD) accumulation and demonstrated that HIG-2 binding to frizzled class receptor 10 (FZD10) activated Wnt/β-catenin signaling pathway and increased its downstream insulin-like growth factor binding protein 2 (IGFBP2) level in microparticles (MPs) derived from glioma stem cells (GSCs), leading to decreased radiosensitivity and immunogenicity of MPs-receiving cells via the cross-talk between GSCs and non-stem glioma cells (GCs). These findings suggest that HIG-2 may be a promising target in glioma radiotherapy and/or immunotherapy.

Targeting lipid metabolism of macrophages: A new strategy for tumor therapy

BACKGROUND

Lipid metabolism has been implicated in a variety of normal cellular processes and strongly related to the development of multiple diseases, including tumor. Tumor-associated macrophage (TAM) has emerged as a crucial regulator in tumorigenesis and promising target for tumor treatment.

AIM OF REVIEW

A thorough understanding of TAM lipid metabolism and its value in tumorigenesis may provide new ideas for TAM-based anti-tumor therapy. Key scientific concepts of review: TAMs can be divided into two main types, M1-like TAMs and M2-like TAMs, which play anti-tumor and pro-tumor functions in tumor occurrence and development, respectively. Accumulating evidence has shown that lipid metabolic reprogramming, including fatty acid uptake and utilization, cholesterol expulsion, controls the polarization of TAMs and affects the tumorgenesis. These advances in uncovering the intricacies of lipid metabolism and TAMs have yielded new insights on tumor development and treatment. In this review, we aim to provide an update on the current understanding of the lipid metabolic reprogramming made by TAMs to adapt to the harsh tumor microenvironment (TME). In particular, we emphasize that there is complex lipid metabolism connections between TAMs and distinct tumors, which influences TAM to bias from M1 to M2 phenotype in tumor progression, and ultimately promotes tumor occurrence and development. Finally, we discuss the existing issues on therapeutic strategies by reprogramming TAMs based on lipid metabolism regulation (or increasing the ratio of M1/M2-like TAMs) that could be applied in the future to clinical tumor treatment.

Linking macrophage metabolism to function in the tumor microenvironment

Macrophages are present at high frequency in most solid tumor types, and their relative abundance negatively correlates with therapy responses and survival outcomes. Tissue-resident macrophages are highly tuned to integrate tissue niche signals, and multiple factors within the idiosyncratic tumor microenvironment (TME) drive macrophages to polarization states that favor immune suppression, tumor growth and metastasis. These diverse functional states are underpinned by extensive and complex rewiring of tumor-associated macrophage (TAM) metabolism. In this Review, we link distinct and specific macrophage functional states within the TME to major, phenotype-sustaining metabolic programs and discuss the metabolic impact of macrophage-modulating therapeutic interventions.

Metabolic reprogramming and immunological changes in the microenvironment of esophageal cancer: future directions and prospects

Background

Esophageal cancer (EC) is the seventh-most prevalent cancer worldwide and is a significant contributor to cancer-related mortality. Metabolic reprogramming in tumors frequently coincides with aberrant immune function alterations, and extensive research has demonstrated that perturbations in energy metabolism within the tumor microenvironment influence the occurrence and progression of esophageal cancer. Current treatment modalities for esophageal cancer primarily include encompass chemotherapy and a limited array of targeted therapies, which are hampered by toxicity and drug resistance issues. Immunotherapy, particularly immune checkpoint inhibitors (ICIs) targeting the PD-1/PD-L1 pathway, has exhibited promising results; however, a substantial proportion of patients remain unresponsive. The optimization of these immunotherapies requires further investigation. Mounting evidence underscores the importance of modulating metabolic traits within the tumor microenvironment (TME) to augment anti-tumor immunotherapy.

Methods

We selected relevant studies on the metabolism of the esophageal cancer tumor microenvironment and immune cells based on our searches of MEDLINE and PubMed, focusing on screening experimental articles and reviews related to glucose metabolism, amino acid metabolism, and lipid metabolism, as well their interactions with tumor cells and immune cells, published within the last five years. We analyzed and discussed these studies, while also expressing our own insights and opinions.

Results

A total of 137 articles were included in the review: 21 articles focused on the tumor microenvironment of esophageal cancer, 33 delved into research related to glucose metabolism and tumor immunology, 30 introduced amino acid metabolism and immune responses, and 17 focused on the relationship between lipid metabolism in the tumor microenvironment and both tumor cells and immune cells.

Conclusion

This article delves into metabolic reprogramming and immune alterations within the TME of EC, systematically synthesizes the metabolic characteristics of the TME, dissects the interactions between tumor and immune cells, and consolidates and harnesses pertinent immunotherapy targets, with the goal of enhancing anti-tumor immunotherapy for esophageal cancer and thereby offering insights into the development of novel therapeutic strategies.

Lipid metabolism in myeloid cell function and chronic inflammatory diseases

Immune cells adapt their metabolism in response to their differentiation and activation status to meet the energy demands for an appropriate immune response. Recent studies have elucidated that during immune cell metabolic reprogramming, lipid metabolism, including lipid uptake, de novo lipid synthesis and fatty acid oxidation, undergoes significant alteration, resulting in dynamic changes in the quantity and quality of intracellular lipids. Given that lipids serve as an energy source and structural components of cellular membranes, they have important implications for physiological function. Myeloid cells, which are essential in bridging innate and adaptive immunity, are sensitive to these changes. Dysregulation of lipid metabolism in myeloid cells can result in immune dysfunction, chronic inflammation and impaired resolution of inflammation. Understanding the mechanism by which lipids regulate immune cell function might provide novel therapeutic insights into chronic inflammatory diseases, including metabolic diseases, autoimmune diseases and cancer. (143 words).

Nanomaterial-enabled metabolic reprogramming strategies for boosting antitumor immunity

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

The Impact of Metabolic Rewiring in Glioblastoma: The Immune Landscape and Therapeutic Strategies

Glioblastoma (GBM) is an aggressive brain tumor characterized by extensive metabolic reprogramming that drives tumor growth and therapeutic resistance. Key metabolic pathways, including glycolysis, lactate production, and lipid metabolism, are upregulated to sustain tumor survival in the hypoxic and nutrient-deprived tumor microenvironment (TME), while glutamine and tryptophan metabolism further contribute to the aggressive phenotype of GBM. These metabolic alterations impair immune cell function, leading to exhaustion and stress in CD8+ and CD4+ T cells while favoring immunosuppressive populations such as regulatory T cells (Tregs) and M2-like macrophages. Recent studies emphasize the role of slow-cycling GBM cells (SCCs), lipid-laden macrophages, and tumor-associated astrocytes (TAAs) in reshaping GBM's metabolic landscape and reinforcing immune evasion. Genetic mutations, including Isocitrate Dehydrogenase (IDH) mutations, Epidermal Growth Factor Receptor (EGFR) amplification, and Phosphotase and Tensin Homolog (PTEN) loss, further drive metabolic reprogramming and offer potential targets for therapy. Understanding the relationship between GBM metabolism and immune suppression is critical for overcoming therapeutic resistance. This review focuses on the role of metabolic rewiring in GBM, its impact on the immune microenvironment, and the potential of combining metabolic targeting with immunotherapy to improve clinical outcomes for GBM patients.

Targeting lipid metabolism: novel insights and therapeutic advances in pancreatic cancer treatment

Lipid metabolism in cancer is characterized by dysregulated lipid regulation and utilization, critical for promoting tumor growth, survival, and resistance to therapy. Pancreatic cancer (PC) is a highly aggressive malignancy of the gastrointestinal tract that has a dismal 5-year survival rate of less than 10%. Given the essential function of the pancreas in digestion, cancer progression severely disrupts its function. Standard treatments for PC such as surgical resection, chemotherapy, and radiotherapy. However, these therapies often face significant challenges, including biochemical recurrence and drug resistance.Given these limitations, new therapeutic approaches are being developed to target tumor metabolism. Dysregulation of cholesterol biosynthesis and alterations in fatty acids (FAs), such as palmitate, stearate, omega-3, and omega-6, have been observed in pancreatic cancer. These lipids serve as energy sources, signaling molecules, and essential components of cell membranes. Their accumulation fosters an immunosuppressive tumor microenvironment that supports cancer cell proliferation and metastasis.Moreover, lipid metabolism dysregulation within immune cells, particularly T cells, impairs immune surveillance and weakens the body's defenses against cancer. Abnormal lipid metabolism also contributes to drug resistance in PC. Despite these challenges, targeting lipid metabolism may offer a promising therapeutic strategy. By enhancing lipid peroxidation, the induction of ferroptosis-a form of regulated cell death-could impair the survival of PC cells and hinder disease progression.

Kaempferol modulates ɑ2M secretion in bone marrow-derived macrophages by downregulating GR/PER1-mediated lipid metabolism to attenuate the emotional stress-aggravated metastasis of prostate cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Prostate cancer patients often suffer from depression during androgen deprivation therapy. Chaihu-Shugan-San (CSS) can prevent prostate cancer metastasis caused by chronic unpredictable mild stress (CUMS), but its active ingredients and molecular mechanism remain unelucidated.

AIM OF STUDY

This study aims to explore the potential targets and molecular mechanisms of CSS in the treatment of emotional stress-aggravated metastasis of prostate cancer.

RESULTS

Stress induces nuclear translocation of GR, initiating the transcription of PER1, which leads to an enhanced lipid metabolism and decreased secretion of α2M in BMDMs. CSS, a classical Traditional Chinese Medicine (TCM) formula for alleviating depression, can improve prostate cancer metastasis caused by CUMS. Of the active ingredients in CSS, kaempferol demonstrated the highest potency for enhancing α2M secretion in BMDMs and inhibiting prostate cancer cell migration. Kaempferol also inhibited nuclear translocation of GR and the GR/PER1 pathway in Per1-overexpressed BMDMs.

CONCLUSIONS

These findings reveal that emotional stress-aggravated prostate cancer growth and metastasis rely on the GR/PER1 pathway and lipid metabolism, as the suppression of this pathway ultimately leads to an increase in α2M secretion in BMDMs and inhibition of PC-3 cell metastasis.

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

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

Metabolic Signaling in the Tumor Microenvironment

Cancer cells must reprogram their metabolism to sustain rapid growth. This is accomplished in part by switching to aerobic glycolysis, uncoupling glucose from mitochondrial metabolism, and performing anaplerosis via alternative carbon sources to replenish intermediates of the tricarboxylic acid (TCA) cycle and sustain oxidative phosphorylation (OXPHOS). While this metabolic program produces adequate biosynthetic intermediates, reducing agents, ATP, and epigenetic remodeling cofactors necessary to sustain growth, it also produces large amounts of byproducts that can generate a hostile tumor microenvironment (TME) characterized by low pH, redox stress, and poor oxygenation. In recent years, the focus of cancer metabolic research has shifted from the regulation and utilization of cancer cell-intrinsic pathways to studying how the metabolic landscape of the tumor affects the anti-tumor immune response. Recent discoveries point to the role that secreted metabolites within the TME play in crosstalk between tumor cell types to promote tumorigenesis and hinder the anti-tumor immune response. In this review, we will explore how crosstalk between metabolites of cancer cells, immune cells, and stromal cells drives tumorigenesis and what effects the competition for resources and metabolic crosstalk has on immune cell function.

Targeting macrophages in cancer immunotherapy: Frontiers and challenges

BACKGROUND

Cancer immunotherapy has emerged as a groundbreaking approach in cancer treatment, primarily realized through the manipulation of immune cells, notably T cell adoption and immune checkpoint blockade. Nevertheless, the manipulation of T cells encounters formidable hurdles. Macrophages, serving as the pivotal link between innate and adaptive immunity, play crucial roles in phagocytosis, cytokine secretion, and antigen presentation. Consequently, macrophage-targeted therapies have garnered significant attention.

AIM OF REVIEW

We aim to provide the most cutting-edge insights and future perspectives for macrophage-targeted therapies, fostering the development of novel and effective cancer treatments.

KEY SCIENTIFIC CONCEPTS OF REVIEW

To date, the forefront strategies for macrophage targeting encompass: altering their plasticity, harnessing CAR-macrophages, and targeting phagocytosis checkpoints. Macrophages are characterized by their remarkable diversity and plasticity, offering a unique therapeutic target. In this context, we critically analyze the innovative strategies aimed at transforming macrophages from their M2 (tumor-promoting) to M1 (tumor-suppressing) phenotype. Furthermore, we delve into the design principles, developmental progress, and advantages of CAR-macrophages. Additionally, we illuminate the challenges encountered in targeting phagocytosis checkpoints on macrophages and propose potential strategies to overcome these obstacles.

Macrophage Polarisation in the Tumour Microenvironment: Recent Research Advances and Therapeutic Potential of Different Macrophage Reprogramming

BACKGROUND

Macrophages are a critical component of the innate immune system, derived from monocytes, with significant roles in anti-inflammatory and anti-tumour activities. In the tumour microenvironment, however, macrophages are often reprogrammed into tumour-associated macrophages (TAMs), which promote tumour growth, metastasis, and therapeutic resistance.

PURPOSE

To review recent advancements in the understanding of macrophage polarisation and reprogramming, highlighting their role in tumour progression and potential as therapeutic targets.

RESEARCH DESIGN

This is a review article synthesising findings from recent studies on macrophage polarisation and reprogramming in tumour biology.

STUDY SAMPLE

Not applicable (review of existing literature).

DATA COLLECTION AND/OR ANALYSIS

Key studies were identified and summarised to explore mechanisms of macrophage polarisation and reprogramming, focusing on M1/M2 polarisation, metabolic and epigenetic changes, and pathway regulation.

RESULTS

Macrophage reprogramming in the tumour microenvironment involves complex mechanisms, including phenotypic and functional alterations. These processes are influenced by M1/M2 polarisation, metabolic and epigenetic reprogramming, and various signalling pathways. TAMs play a pivotal role in tumour progression, metastasis, and therapy resistance, making them prime targets for combination therapies.

CONCLUSIONS

Understanding the mechanisms underlying macrophage polarisation and reprogramming offers promising avenues for developing therapies to counteract tumour progression. Future research should focus on translating these insights into clinical applications for effective cancer treatment.

The influence of endothelial metabolic reprogramming on the tumor microenvironment

Endothelial cells (ECs) that line blood vessels act as gatekeepers and shape the metabolic environment of every organ system. In normal conditions, endothelial cells are relatively quiescent with organ-specific expression signatures and metabolic profiles. In cancer, ECs are metabolically reprogrammed to promote the formation of new blood vessels to fuel tumor growth and metastasis. In addition to EC's role on tumor cells, the tortuous tumor vasculature contributes to an immunosuppressive environment by limiting T lymphocyte infiltration and activity while also promoting the recruitment of other accessory pro-angiogenic immune cells. These elements aid in the metastatic spreading of cancer cells and contribute to therapeutic resistance. The concept of restoring a more stabilized vasculature in concert with cancer immunotherapy is emerging as a potential approach to overcoming barriers in cancer treatment. This review summarizes the metabolism of endothelial cells, their regulation of nutrient uptake and delivery, and their impact in shaping the tumor microenvironment and anti-tumor immunity. We highlight new therapeutic approaches that target the tumor vasculature and harness the immune response. Appreciating the integration of metabolic state and nutrient levels and the crosstalk among immune cells, tumor cells, and ECs in the TME may provide new avenues for therapeutic intervention.

Cancer knocks you out by fasting: Cachexia as a consequence of metabolic alterations in cancer

Neoplastic transformation reprograms tumor and surrounding host cell metabolism, increasing nutrient consumption and depletion in the tumor microenvironment. Tumors uptake nutrients from neighboring normal tissues or the bloodstream to meet energy and anabolic demands. Tumor-induced chronic inflammation, a high-energy process, also consumes nutrients to sustain its dysfunctional activities. These tumor-related metabolic and physiological changes, including chronic inflammation, negatively impact systemic metabolism and physiology. Furthermore, the adverse effects of antitumor therapy and tumor obstruction impair the endocrine, neural, and gastrointestinal systems, thereby confounding the systemic status of patients. These alterations result in decreased appetite, impaired nutrient absorption, inflammation, and shift from anabolic to catabolic metabolism. Consequently, cancer patients often suffer from malnutrition, which worsens prognosis and increases susceptibility to secondary adverse events. This review explores how neoplastic transformation affects tumor and microenvironment metabolism and inflammation, leading to poor prognosis, and discusses potential strategies and clinical interventions to improve patient outcomes.

Unraveling Ferroptosis: A New Frontier in Combating Renal Fibrosis and CKD Progression

Chronic kidney disease (CKD) is a global health concern caused by conditions such as hypertension, diabetes, hyperlipidemia, and chronic nephritis, leading to structural and functional kidney injury. Kidney fibrosis is a common outcome of CKD progression, with abnormal fatty acid oxidation (FAO) disrupting renal energy homeostasis and leading to functional impairments. This results in maladaptive repair mechanisms and the secretion of profibrotic factors, and exacerbates renal fibrosis. Understanding the molecular mechanisms of renal fibrosis is crucial for delaying CKD progression. Ferroptosis is a type of discovered an iron-dependent lipid peroxidation-regulated cell death. Notably, Ferroptosis contributes to tissue and organ fibrosis, which is correlated with the degree of renal fibrosis. This study aims to clarify the complex mechanisms of ferroptosis in renal parenchymal cells and explore how ferroptosis intervention may help alleviate renal fibrosis, particularly by addressing the gap in CKD mechanisms related to abnormal lipid metabolism under the ferroptosis context. The goal is to provide a new theoretical basis for clinically delaying CKD progression.

In Silico Analysis Revealed Marco (SR-A6) and Abca1/2 as Potential Regulators of Lipid Metabolism in M1 Macrophage Hysteresis

Macrophages undergo polarization, resulting in distinct phenotypes. These transitions, including de-/repolarization, lead to hysteresis, where cells retain genetic and epigenetic signatures of previous states, influencing macrophage function. We previously identified a set of interferon-stimulated genes (ISGs) associated with high lipid levels in macrophages that exhibited hysteresis following M1 polarization, suggesting potential alterations in lipid metabolism. In this study, we applied weighted gene co-expression network analysis (WGCNA) and conducted comparative analyses on 162 RNA-seq samples from de-/repolarized and lipid-loaded macrophages, followed by functional exploration. Our results demonstrate that during M1 hysteresis, the sustained high expression of Marco (SR-A6) enhances lipid uptake, while the suppression of Abca1/2 reduces lipid efflux, collectively leading to elevated intracellular lipid levels. This accumulation may compensate for reduced cholesterol biosynthesis and provide energy for sustained inflammatory responses and interferon signaling. Our findings elucidate the relationship between M1 hysteresis and lipid metabolism, contributing to understanding the underlying mechanisms of macrophage hysteresis.

Palmitic acid inhibits macrophage-mediated chemotherapy resistance in multiple myeloma via ALOX12 signaling

We previously discovered that macrophages (MΦs), especially tumor-associated MΦs (tMΦs), contribute to chemotherapy resistance in multiple myeloma (MM). However, the mechanism underlying MΦ-mediated chemotherapy resistance in MM needs further elucidation, and the identification of factors that preferentially abrogate MΦ-induced inhibition of MM chemotherapy may have important clinical significance. In this study, we showed that the expression of FASN and SCD2, the enzymes that synthesize palmitic acid and convert it to palmitoleic acid, was decreased in tMΦs compared with MΦs. Interestingly, palmitic acid abrogated the MΦ-mediated protection of MM cells from the effects of bortezomib and melphalan in vitro. Combination treatment with palmitic acid and bortezomib or melphalan further inhibited MM tumor growth in vivo. Mechanistically, palmitic acid treatment increased ALOX12 expression in MΦs. ALOX12 inhibition partially abrogated the palmitic acid-induced decrease in MΦ-mediated MM cell survival. Palmitic acid treatment inhibited AMPK signaling in MΦs, and ALOX12 knockdown activated the AMPK signaling pathway in MΦs. AMPK inhibition decreased the MΦ-mediated protection of drug-treated MM cells, and AMPK activation partially abolished the palmitic acid-induced inhibition of MΦ-mediated protection. ALOX12 converts arachidonic acid (AA) to 12-HETE. Moreover, treatment with AA but not 12-HETE partially abrogated the inhibitory effect of palmitic acid on MΦ-mediated MM cell survival in response to bortezomib or melphalan. Overall, we identified palmitic acid as a factor that inhibits MΦ-mediated resistance to bortezomib and melphalan in MM, which may have clinical significance.

Protocol for studying macrophage lipid crosstalk with murine tumor cells

Lipid accumulation has recently emerged as a key feature underlying the pro-tumorigenic role of macrophages. Here, we present a workflow to study macrophage lipid crosstalk with tumor cells. We describe steps for the identification, purification, and multi-omics characterization of lipid-laden macrophages (LLMs) from murine tumors and outline protocols to assess the functional significance of LLMs in cancer malignancy. This approach has the potential to uncover the source of lipids that drives LLM formation and its pro-tumorigenic potential in multiple cancer types. For complete details on the use and execution of this protocol, please refer to Kloosterman, Erbani, et al.1.

The Role of Innate Priming in Modifying Tumor-associated Macrophage Phenotype

Tumor-associated macrophages (TAMs) are innate immune cells that exert far reaching influence over the tumor microenvironment (TME). Depending on cues within the local environment, TAMs may promote tumor angiogenesis, cancer cell invasion and immunosuppression, or, alternatively, inhibit tumor progression via neoantigen presentation, tumoricidal reactive oxygen species generation and pro-inflammatory cytokine secretion. Therefore, TAMs have a pivotal role in determining tumor progression and response to therapy. TAM phenotypes are driven by cytokines and physical cues produced by tumor cells, adipocytes, fibroblasts, pericytes, immune cells, and other cells within the TME. Research has shown that TAMs can be primed by environmental stimuli, adding another layer of complexity to the environmental context that determines TAM phenotype. Innate priming is a functional consequence of metabolic and epigenetic reprogramming of innate cells by a primary stimulant, resulting in altered cellular response to future secondary stimulation. Innate priming offers a novel target for development of cancer immunotherapy and improved prognosis of disease, but also raises the risk of exacerbating existing inflammatory pathologies. This review will discuss the mechanisms underlying innate priming including metabolic and epigenetic modification, its relevance to TAMs and tumor progression, and possible clinical implications for cancer treatment.

Hidden features: CD36/SR-B2, a master regulator of macrophage phenotype/function through metabolism

Once thought to be in a terminally differentiated state, macrophages are now understood to be highly pliable, attuned and receptive to environmental cues that control and align responses. In development of purpose, the centrality of metabolic pathways has emerged. Thus, macrophage inflammatory or reparative phenotypes are tightly linked to catabolic and anabolic metabolism, with further fine tuning of specific gene expression patterns in specific settings. Single-cell transcriptome analyses have revealed a breadth of macrophage signatures, with some new influencers driving phenotype. CD36/Scavenger Receptor B2 has established roles in immunity and lipid metabolism. Macrophage CD36 is a key functional player in metabolic expression profiles that determine phenotype. Emerging data show that alterations in the microenvironment can recast metabolic pathways and modulate macrophage function, with the potential to be leveraged for therapeutic means. This review covers recent data on phenotypic characterization of homeostatic, atherosclerotic, lipid-, tumor- and metastatic-associated macrophages, with the integral role of CD36 highlighted.

Tumor Metabolic Reprogramming and Ferroptosis: The Impact of Glucose, Protein, and Lipid Metabolism

Ferroptosis, a novel form of cell death discovered in recent years, is typically accompanied by significant iron accumulation and lipid peroxidation during the process. This article systematically elucidates how tumor metabolic reprogramming affects the ferroptosis process in tumor cells. The paper outlines the basic concepts and physiological significance of tumor metabolic reprogramming and ferroptosis, and delves into the specific regulatory mechanisms of glucose metabolism, protein metabolism, and lipid metabolism on ferroptosis. We also explore how complex metabolic changes in the tumor microenvironment further influence the response of tumor cells to ferroptosis. Glucose metabolism modulates ferroptosis sensitivity by influencing intracellular energetic status and redox balance; protein metabolism, involving amino acid metabolism and protein synthesis, plays a crucial role in the initiation and progression of ferroptosis; and the relationship between lipid metabolism and ferroptosis primarily manifests in the generation and elimination of lipid peroxides. This review aims to provide a new perspective on how tumor cells regulate ferroptosis through metabolic reprogramming, with the ultimate goal of offering a theoretical basis for developing novel therapeutic strategies targeting tumor metabolism and ferroptosis.