Contradictory roles of lipid metabolism in immune response within the tumor microenvironment

Enhancing PD-1 blockade in NSCLC: Reprogramming tumor immune microenvironment with albumin-bound statins targeting lipid rafts and mitochondrial respiration

Non-small cell lung cancer (NSCLC) has shown limited response to immunotherapy, primarily due to an immunosuppressive tumor microenvironment characterized by hypoxia and lipid raft formation, which together inhibit T-cell infiltration and function, impeding effective immune responses. To address these challenges, we developed Abstatin, an albumin-bound fluvastatin formulation that targets lipid raft disruption and mitochondrial respiration inhibition, aiming to reduce hypoxia and destabilize lipid rafts to enhance T-cell activity within the tumor. Using bioinformatics analysis, in vitro assays, and in vivo studies in both murine and humanized PDX models, we demonstrated that Abstatin reprograms the NSCLC microenvironment by concurrently lowering hypoxia levels and lipid raft integrity, thereby restoring T-cell infiltration, enhancing cytotoxic T-cell function, and ultimately improving response to Anti-PD-1 therapy. Results showed that Abstatin significantly amplifies Anti-PD-1 efficacy with minimal toxicity, indicating a favorable safety profile for clinical use. This study highlights Abstatin as a promising immunotherapy adjuvant that addresses critical barriers in NSCLC by modulating metabolic pathways linked to immune resistance. Abstatin's approach, which combines modulation of cellular metabolism with immune sensitization, broadens the potential of immunotherapy and provides a practical, scalable strategy to enhance treatment outcomes in NSCLC and potentially other tumors, offering insights into combinatory cancer therapies.

HKDC1 promotes ovarian cancer progression through boosting lipid metabolism and immune escape by stabilizing G6PC/G6PC2

Ovarian cancer (OC) is a significant health challenge, yet the mechanisms driving its progression remain unclear. This study explored the role of hexokinase domain-containing protein 1 (HKDC1) in OC, focusing on tumor growth, lipid metabolism, and immune evasion. Human OC cell lines (SKOV3 and HEY) and the murine OC cell line (ID8) were used to knock down and overexpress HKDC1. An ID8-based epithelial OC mouse model was established to validate the in vitro findings. Our results demonstrated that HKDC1 was upregulated in OC and promoted cell proliferation, migration, and invasion. HKDC1 enhanced lipid accumulation by elevating levels of free fatty acids (FFA), triglycerides, phospholipids, cholesterol, and neutral lipid, while upregulating key enzymes (ACC1, FASN, SCD1, HMGCS1, and HMGCR). It promoted immune escape through PD-L1 upregulation, inhibiting T cell proliferation and reducing IFN-γ, granzyme B, and perforin levels while increasing PD-1 levels. HKDC1 knockdown reversed these effects, which were restored by adding FFA. Mechanistically, HKDC1 interacted with and stabilized glucose-6-phosphatase catalytic subunits (G6PC/G6PC2), supporting its tumor-promoting functions. These findings were confirmed in an OC mouse model, highlighting HKDC1 as a key driver of OC progression through lipid biosynthesis and immune suppression, offering potential therapeutic targets.

Targeting LHPP in neoadjuvant chemotherapy resistance of gastric cancer: insights from single-cell and multi-omics data on tumor immune microenvironment and stemness characteristics

Gastric cancer (GC) is a highly heterogeneous and complex malignancy, often characterized by tumor stemness and immune evasion mechanisms, which contribute to a poor response to neoadjuvant chemotherapy (NAC) and treatment resistance. In this study, we performed a comprehensive analysis using single-cell and multi-omics approaches on 375 GC samples from The Cancer Genome Atlas database, along with 141 clinical samples from patients who underwent NAC. We identified key gene modules associated with stemness and immune traits, and developed a novel stem cell-immune risk score. This score effectively distinguished responders from non-responders to chemotherapy, and was significantly associated with overall survival. Through multi-omics analysis, we further elucidated the role of phospholysine phosphohistidine inorganic pyrophosphatase (LHPP) in the tumor immune microenvironment. Our findings showed that high LHPP expression was closely linked to the increased infiltration of antitumor immune cells, such as CD8+ T cells, and significantly suppressed the development of stemness characteristics in GC. Additionally, single-cell sequencing data revealed that tumor epithelial cells with low LHPP expression exhibited heightened stemness and demonstrated the strongest communication with CD8+-exhausted T cells. We also observed that LHPP inhibited stemness and chemotherapy resistance in GC cells by regulating the phosphorylation of GSK-3β. In conclusion, LHPP plays a critical regulatory role in the stemness features and tumor immune microenvironment of GC, presenting a promising biomarker and potential therapeutic target for personalized treatment of GC.

Sesamin regulates breast cancer through reprogramming of lipid metabolism

Metabolic reprogramming is one of the hallmarks of breast cancer (BC), involving elevated synthesis and uptake of lipids, for catering to increased energy demand of cancer cells and to suppress the host immune system. Besides promoting proliferation and survival of BC cells, lipid metabolism reprogramming (LMR) is associated with stemness and chemoresistance. Recently, lignans have been reported for their therapeutic potential against different cancers, including BC. Here, we explored the potential of lignans to target LMR pathways in BC through computational approach. Initially, 88 lignans having potential anticancer activities, underwent druglikeness and pharmacokinetics analysis, displaying promising pharmacokinetic properties, except for 13 molecules with violations. Molecular docking assessed the interaction of 88 lignans (NPACT) with therapeutic targets of LMR including 3-Hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGCR), Sterol regulatory element-binding proteins 1 and 2 (SREBP1 and 2), Low-density lipoprotein receptor (LDLR), Acetyl-CoA Acetyltransferase 1 (ACAT1), ATP-binding cassette transporter (ABCA1), Liver X receptor α (LXRα), Apolipoprotein A1 (APOA1), Fatty Acid Synthase (FASN), Peroxisome proliferator-activated receptor gamma (PPARG), Stearoyl-CoA desaturase (SCD1), Acetyl-CoA carboxylase 1 and 2 (ACC1/ACACA, and ACC2/ACACB). In silico screening revealed sesamin (SE) as the best-identified hit that showed stable and consistent binding with all the selected targets of LMR. The stability of these complexes was validated by a 100 ns simulation run, and their binding free energy calculation was determined by MM-PBSA method. Interestingly, SE modulated the mRNA expression of genes involved in LMR in BC cell lines, MCF-7 and MDA-MB-231, thereby suggesting its potential as an inhibitor of LMR.

Ginsenosides modulate immunity via TLR4/MyD88/NF-κB pathway and gut microbiota

BACKGROUND

Ginsenosides, the primary active compounds in Panax ginseng C. A. Mey., are well known for their potent immunomodulatory effects. However, their precise mechanisms, particularly concerning the "intestinal-metabolism-immune axis", have yet to be fully elucidated.

PURPOSE

This study aims to investigate how ginsenosides protect immune function through the regulation of the gut-metabolism-immune axis.

STUDY DESIGN

A CTX-induced immunodeficient mouse model was established to assess the effects of ginsenosides on immune function, gut microbiota, and metabolic pathways.

METHODS

The immune organ indices (spleen and thymus), levels of immune cytokines (TNF-α, IFN-γ, IL-6, IL-1β), and immunoglobulins (IgM, IgA) were assessed. Intestinal microbial diversity was analyzed using 16S rRNA sequencing, and metabolomics was employed to identify disruptions in amino acid and lipid metabolic pathways. Spearman correlation analysis and Western blotting were conducted to explore the involvement of the TLR4/MyD88/NF-κB signaling pathway.

RESULTS

Ginsenosides significantly restored immune organ indices and enhanced cytokines and immunoglobulins. 16S rRNA sequencing revealed an increase in probiotic levels and a reduction in potentially harmful bacteria, thereby enhancing intestinal microbiota diversity. Metabolomics analysis showed that ginsenosides ameliorated CTX-induced metabolic disorders and stimulated the production of short-chain fatty acids (SCFAs) and bile acids. Western blot analysis confirmed the upregulation of TLR4, MyD88, and NF-κB p-p65 expression.

CONCLUSION

This study systematically elucidates the mechanism by which ginsenosides enhance immune function by regulating gut microbiota, restoring metabolic balance, and activating the TLR4/MyD88/NF-κB signaling pathway. These findings provide a molecular foundation for the potential use of ginsenosides in the prevention and treatment of immune-related diseases.

Cholesterol effects on the tumor immune microenvironment: from fundamental concepts to mechanisms and implications

In many cancers, the tumor microenvironment is enriched with cholesterol due to increased biosynthesis and uptake by cancer cells, resulting in the accumulation of cholesterol, cholesterol esters, oxysterols and other metabolites with various functions. These molecules serve as structural components, energy sources and intracellular signaling mediators, while their toxic by-products are secreted to suppress anti-tumor immune activity and prevent lipid peroxidation that could induce cancer cell apoptosis. Immune cells in the tumor microenvironment also contribute to cholesterol dynamics. Tumor-associated macrophages (TAMs) release cholesterol to support tumor cell metabolism, while myeloid-derived suppressor cells (MDSCs) also release cholesterol and consume essential metabolites such as L-arginine, which impairs T-cell proliferation and activation. Elevated cholesterol in dendritic cells impairs migration and tumor antigen presentation and, in lymphocytes, favors the development of a regulatory T cells (Treg) phenotype and inhibits the release of antitumor cytokines, further weakening the immune response. These findings suggest that targeting cholesterol metabolism is a promising strategy for cancer treatment, improving the efficacy of immune checkpoint blockade (ICB) therapies. In this manuscript, the molecular mechanisms underlying the effects of cholesterol on the tumor immune landscape are reviewed and the potential of cholesterol-lowering drugs to enhance antitumor immune responses is explored.

Comparison of 11C-Acetate and 18F-FDG PET/CT for Immune Infiltration and Prognosis in Hepatocellular Carcinoma

Immunotherapy has revolutionized cancer treatment, making it a challenge to noninvasively monitor immune infiltration. Metabolic reprogramming in cancers, including hepatocellular carcinoma (HCC), is closely linked to immune status. In this study, we aimed to evaluate the ability of carbon-11 acetate (11C-acetate) and fluorine-18 fluorodeoxyglucose (18F-FDG) PET/CT findings in predicting overall survival (OS) and immune infiltration in HCC patients. Totally 32 patients who underwent preoperative 18F-FDG and 11C-acetate PET/CT, followed by liver resection for HCC, were prospectively enrolled at authors' institute between January 2019 and October 2021. Tracer uptake was qualified. Densities of CD3+, CD8+, and granzyme B+ CD8+ immune cells were assessed and the Immunoscore was defined by combining the densities of CD3+ and CD8+ in tumor interior (TI) and invasion margin (IM). Patients with avid HCCs in 11C-acetate PET/CT demonstrated a longer OS. Those with only 11C-acetate-avid HCCs exhibited a longer OS compared to those with only 18F-FDG uptake. In contrast to 18F-FDG uptake, 11C-acetate uptake was positively associated with CD3+, CD8+, and granzyme B+ CD8+ cell infiltration. Patients with a higher Immunoscore exhibited a longer OS and an increased uptake of 11C-acetate rather than 18F-FDG. The sensitivity of 11C-acetate PET/CT in the detection of patients with immune infiltration was superior to that of 18F-FDG PET/CT (88% [21 of 24] vs. 58% [14 of 24]). These data show that preoperative 11C-acetate PET/CT may be a promising approach for the evaluation of immune status and postoperative outcome of HCCs.

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.

Identification and dissection of prostate cancer grounded on fatty acid metabolism-correlative features for predicting prognosis and assisting immunotherapy

BACKGROUND

Fatty acid metabolism (FAM) plays a critical role in tumor progression and therapeutic resistance by enhancing lipid biosynthesis, storage, and catabolism. Dysregulated FAM is a hallmark of prostate cancer (PCa), enabling cancer cells to adapt to extracellular signals and metabolic changes, with the tumor microenvironment (TME) playing a key role. However, the prognostic significance of FAM in PCa remains unexplored.

METHODS

We analyzed 309 FAM-related genes to develop a prognostic model using least absolute shrinkage and selection operator (LASSO) regression based on The Cancer Genome Atlas (TCGA) database. This model stratified PCa patients into high- and low-risk groups and was validated using the Gene Expression Omnibus (GEO) database. We constructed a nomogram incorporating risk score, clinical variables (T and N stage, Gleason score, age), and assessed its performance with calibration curves. The associations between risk score, tumor mutation burden (TMB), immune checkpoint inhibitors (ICIs), and TME features were also examined. Finally, a hub gene was identified via protein-protein interaction (PPI) networks and validated.

RESULTS

The risk score was an independent prognostic factor for PCa. High-risk patients showed worse survival outcomes but were more responsive to immunotherapy, chemotherapy, and targeted therapies. A core gene with high expression correlated with poor prognosis, unfavorable clinicopathological features, and immune cell infiltration.

CONCLUSION

These findings reveal the prognostic importance of FAM in PCa, providing novel insights into prognosis and potential therapeutic targets for PCa management.

FASN promotes lipid metabolism and progression in colorectal cancer via the SP1/PLA2G4B axis

Abnormal metabolic reprogramming is essential for tumorigenesis, metastasis, and the regulation of immune responses. Fatty acid synthase (FASN), a key enzyme in lipid metabolism, plays a crucial role in these processes. However, the relationship between FASN-mediated lipid reprogramming and the immune response in colorectal cancer (CRC) remains unclear. The present study demonstrated that FASN expression is elevated in CRC tissues and is significantly associated with poor prognosis. Functional experiments revealed that FASN promotes proliferation, migration, invasion, and phosphatidylcholine (PC) production in CRC cells. Additionally, in vivo experiments revealed that FASN knockdown significantly inhibits tumor growth and the spread of CRC cells to the lungs. Mechanistically, FASN, which is upregulated in CRC tissues, drives cancer cell proliferation, metastasis, and PC metabolism through the SP1/PLA2G4B axis, subsequently suppressing the antitumor response of natural killer (NK) cells in a PC-dependent manner. These findings provide new insights into lipid metabolism and the immunobiology of CRC, suggesting potential targets for the treatment and prevention of CRC. Schematic diagram showing the mechanism by which FASN promotes cancer cell proliferation, metastasis, and PC metabolism in CRC via the SP1/PLA2G4B axis, subsequently suppressing the antitumor response of NK cells in a PC-dependent manner. FFA free fatty acid, LPA lysophosphatidic acid, PA phosphatidate, DAG diglyceride, PC phosphatidylcholine, LPC lysophosphatidylcholine, CE cholesterol ester, TAG triacylglycerol.

Metabolic reprogramming of tumor microenviroment by engineered bacteria

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

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.

Exploring the role of adipokines in exercise-induced inhibition of tumor growth

The integration of exercise prescriptions into cancer adjuvant therapy presents challenges stemming from the ambiguity surrounding the precise mechanism through which exercise intervention mitigates the risk of hepatocellular carcinoma (HCC) mortality and recurrence. Elucidation of this specific mechanism has substantial social and clinical implications. In this study, tumor-bearing mice engaged in voluntary wheel running exhibited a notable decrease in tumor growth, exceeding 30%. Microarray analysis revealed an upregulation of cytokine-related pathways as a potential explanation for this effect. The inclusion of granulocyte-macrophage colony-stimulating factor (GM-CSF) was found to enhance tumor cell proliferation, while the absence of GM-CSF resulted in a marked inhibition of tumor cell growth. The findings suggest that exercise-induced serum from mice can impede the proliferation of mouse tumor cells, with the adipokine chemerin inhibiting the growth factor GM-CSF. Additionally, exercise was found to stimulate chemerin secretion by brown adipose tissue. Chemerin suppression led to a reduction in the inhibition of tumor cell proliferation. The results of this study suggest that exercise may stimulate the release of adipokines from brown adipose tissue, transport them through the blood to the distant tumor microenvironment, and downregulate GM-CSF expression, alleviating tumor immunosuppression in the tumor microenvironment, thereby inhibiting at HCC progression. These findings provide a theoretical basis for incorporating exercise prescription into cancer treatment.

127aa encoded by circSpdyA promotes FA synthesis and NK cell repression in breast cancers

Lipid metabolism reprogram plays key roles in breast cancer tumorigenesis and immune escape. The underlying mechanism and potential regulator were barely investigated. We thus established an in vivo tumorigenesis model, mice-bearing breast cancer cells were treated with an ordinary diet and high-fat diet, species were collected and subjected to circRNA sequence to scan the potential circRNAs regulating the lipid metabolism. CircSpdyA was one of the most upregulated circRNAs and had the potential to encode a 127-aa micro peptide (referred to as 127aa). 127 aa promotes tumorigenesis through promoting the fatty acid de novo synthesis by directly binding to FASN. Single-cell sequence indicated 127aa inhibited NK cell infiltration and function. This was achieved by inhibiting the transcription of NK cell activators epigenetically. Moreover, lipid-laden from 127aa positive cancer cells transferred to NK cells inhibited the cytotoxicity. Taken together, circSpdyA encoded 127aa promotes fatty acid de novo synthesis through directly binding with FASN and induced NK cell repression by inhibiting the transcription of NK cell activators.

Comprehensive analysis of lipid metabolic signatures identified CEBPD promotes breast cancer cell proliferation

Breast cancer (BRCA) remains the leading cause of cancer-related mortality worldwide, with lipid metabolism emerging as a critical factor in tumor progression that influences cell proliferation, migration, and immune response. Insights into lipid metabolism signatures and associated genes may offer new prognostic and therapeutic avenues. In this study, we leveraged scRNA-seq and bulk transcriptome data to assess the expression patterns and prognostic significance of lipid metabolism-related genes in BRCA. Through single-cell transcriptomic analysis of primary BRCA samples, we identified a specific set of lipid metabolism signature genes and constructed a prognostic risk model based on these signatures. This model enables patient stratification by risk scores, supporting an integrated analysis of lipid metabolism, immune landscape, and clinical outcomes. Importantly, we identified CEBPD, ABCA1, and CYP27A1 as independent prognostic genes linked to lipid metabolism, with functional assays revealing an inhibitory role for CEBPD in BRCA cell proliferation. Our findings underscore the influence of adipocytes in BRCA progression and propose CEBPD as a potential target for therapeutic intervention. This study provides a foundation for further exploration of metabolism-based strategies to enhance BRCA outcomes.

Investigating the causal relationship between the plasma lipidome and cholangiocarcinoma mediated by immune cells: a mediation Mendelian randomization study

The plasma lipidome and immune cells are instrumental in shaping the health profile of an organism, and their influence on diseases is profound. However, the intricate interactions between cholangiocarcinoma (CCA) and these physiological components have yet to be comprehensively explored. Employing Mendelian randomization (MR), our study delved into the causal links among immune cells, the lipidome, and CCA. The research design meticulously considered both the direct associations and the mediating roles of immune cells within the complex interplay between the lipidome and CCA. Our analysis uncovered significant correlations between the levels of Sphingomyelin (d34:1), Phosphatidylcholine (0-16:0, 22:5) and Sterol ester (27:1/16:0) and CCA. Moreover, we have pinpointed various immune cells that play a mediating role in the impact of the lipidome on CCA. For example, Sphingomyelin (d34:1) can impact CCA through the IgD on IgD+ CD38- unswitched memory (unsw mem) B cell (B cell panel), IgD on unsw mem (B cell panel) and Naive CD4+ %CD4+ (maturation stages of T cell). The proportion of mediating effects further sheds light on the intricate interplay among the lipidome, immune cells, and their cumulative influence on CCA. Our study illuminates the intricate relationship among the lipidome, immune cells, and CCA. These findings suggest that the lipidome could serve as a promising and potentially effective therapeutic target in the treatment of CCA.

Brusatol inhibits malignant phenotypes and lipid metabolism of osteosarcoma cells by regulating PI3K/AKT and MAPK pathways

BACKGROUND

Osteosarcoma (OS), the most frequent type of primary bone cancer, has a poor prognosis in metastatic cases, with overall 5-year survival rates stagnating at 20 %-30 %. This highlights the critical need for innovative therapies to address the significant survival gap between metastatic and non-metastatic cases. Brusatol (BRU), a compound extracted from Brucea javanica, has shown promising anti-tumor properties in various cancers; however, its effects on OS have yet to be investigated.

PURPOSE

To investigate the anti-tumor mechanisms of BRU in OS and evaluate its potential therapeutic efficacy, with a particular focus on its impact on lipid metabolism and related signaling pathways.

METHODS

In vitro experiments to assess the anti-tumor effects of BRU involved colony formation, CCK-8, Transwell analysis, as well as flow cytometry. RNA sequencing was conducted to identify transcriptional changes in BRU-treated cells. The mechanism of action was investigated through analysis of lipid metabolism and key signaling pathways. Therapeutic efficacy and safety were evaluated in vivo using xenograft models.

RESULTS

BRU significantly inhibited OS cell proliferation, migration, and invasion, while also inducing G2/M phase cell cycle arrest as well as promoting apoptosis. Transcriptome analysis revealed that BRU affected lipid metabolism-related genes and suppressed the PI3K/AKT and MAPK pathways. BRU treatment reduced fatty acid synthase expression and free fatty acid content in OS cells. In vivo experiments demonstrated that BRU effectively restricted xenograft growth.

CONCLUSION

This study revealed that BRU exhibits potent anti-tumor effects in OS by modulating lipid metabolism through the PI3K/AKT and MAPK pathways.

Anti-Tumor Strategies Targeting Nutritional Deprivation: Challenges and Opportunities

Higher and richer nutrient requirements are typical features that distinguish tumor cells from AU: cells, ensuring adequate substrates and energy sources for tumor cell proliferation and migration. Therefore, nutrient deprivation strategies based on targeted technologies can induce impaired cell viability in tumor cells, which are more sensitive than normal cells. In this review, nutrients that are required by tumor cells and related metabolic pathways are introduced, and anti-tumor strategies developed to target nutrient deprivation are described. In addition to tumor cells, the nutritional and metabolic characteristics of other cells in the tumor microenvironment (including macrophages, neutrophils, natural killer cells, T cells, and cancer-associated fibroblasts) and related new anti-tumor strategies are also summarized. In conclusion, recent advances in anti-tumor strategies targeting nutrient blockade are reviewed, and the challenges and prospects of these anti-tumor strategies are discussed, which are of theoretical significance for optimizing the clinical application of tumor nutrition deprivation strategies.

Serum Lipid Biomarkers and the Risk of Gastrointestinal Cancers in a Chinese Population: The Kailuan Prospective Study

BACKGROUND

Current evidence on relationships between serum lipid biomarkers and the risk of gastrointestinal cancers remains controversial, with no consensus reached.

METHODS

We conducted a prospective cohort study within the Kailuan Cohort wherein 88,225 individuals with baseline information on triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) was followed from 2006 to 2021 for the incidence of esophageal cancer (EC), gastric cancer (GC), and colorectal cancer (CRC). Cox proportional hazards models and restricted cubic spline (RCS) analysis were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Increased EC risk was associated with high HDL-C levels (HRQ4vs.Q1 = 2.50, 95% CI: 1.57-3.98), while a U-shaped relationship between HDL-C and EC risk was revealed in the RCS analysis (poverall ≤ 0.0001, pnonlinear = 0.02). No robust association was identified between lipid biomarkers and GC risk. In multivariable analysis, increased CRC risk was positively associated with high TC levels (HRQ4vs.Q1 = 1.42, 95% CI: 1.11-1.83, ptrend = 0.03), dose-responsely negatively associated with LDL-C levels over quartiles (HRQ2vs.Q1 = 0.83, 95% CI: 0.66-1.02; HRQ3vs.Q1 = 0.86, 95% CI: 0.69-1.07; HRQ4vs.Q1 = 0.68, 95% CI: 0.53-0.86, ptrend = 0.02), and showed a diminished negative association with HDL-C levels over quartiles (HRQ2vs.Q1 = 0.75, 95% CI: 0.60-0.94; HRQ3vs.Q1 = 0.76, 95% CI: 0.61-0.95; HRQ4vs.Q1 = 0.91, 95% CI 0.74-1.13, ptrend = 0.02). The subsequent RCS analysis revealed a linear negative relationship of LDL-C (poverall = 0.004, pnonlinear = 0.67) and a U-shaped relationship of HDL-C (poverall = 0.05, pnonlinear = 0.02) with CRC risk. Competitive risk analysis and sensitivity analysis confirmed the stability of our results.

CONCLUSION

We observed a U-shaped relationship regarding HDL-C levels with EC and CRC risk, and a linear inverse relationship between LDL-C levels and CRC risk. Relevant serum lipid levels should be properly managed in high-risk individuals of certain gastrointestinal cancers.

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.

Response Gene to Complement 32 is associated with poor patient survival and an inflamed tumor-immune microenvironment in clear cell renal cell carcinoma

It has been well established that tumor-infiltrating lymphocytes (TILs) play a critical role in the pathogenesis and progression of clear cell renal cell carcinoma (ccRCC). However, the mechanism on the interactions between TILs and tumor cells in the tumor-immune microenvironment remains unclear. In the present study, the expression of Response Gene to Complement 32 (RGC-32) was evaluated using immunohistochemistry. We analyzed the associations of RGC-32 expression with patient characteristics and survival. We also assessed TILs and their subsets (CD3+, CD4+, CD8+ and PD-1+) in the tumor nest. The level of RGC-32 expression was positively correlated with ISUP grade and Ki67 expression and was an independent poor prognosis factor of patients with ccRCC. RGC-32 expression was negatively correlated with the infiltration of TIL and CD3+T cells, but positively correlated with infiltration of PD-1+cells. In vitro studies showed that RGC-32 expression in renal cancer cells was downregulated by activated immune cells. Further investigation revealed that RGC-32 expression in renal cancer cells was inhibited by TNF-α and IL-1β secreted by activated immune cells. Collectively, these data indicate that RGC-32 could be a novel prognostic and druggable target related to the tumor-immune microenvironment in renal cancer.

Advances in understanding the role of squalene epoxidase in cancer prognosis and resistance

Recently, there has been burgeoning interest in the involvement of cholesterol metabolism in cancer. Squalene epoxidase (SQLE), as a critical rate-limiting enzyme in the cholesterol synthesis pathway, has garnered attention due to its overexpression in various cancer types, thereby significantly impacting tumor prognosis and resistance mechanisms. Firstly, SQLE contributes to unfavorable prognosis through diverse mechanisms, encompassing modulation of the PI3K/AKT signaling pathway, manipulation of the cancer microenvironment, and participation in ferroptosis. Secondly, directing efforts towards targeting SQLE, via mechanisms such as the PI3K/AKT pathway, presents promising avenues for overcoming resistance to conventional therapies such as endocrine cancer therapy, chemotherapy, immunotherapy, or radiotherapy. Moreover, the effectiveness of SQLE protein inhibitors in impeding cancer progression may either depend directly on SQLE inhibition or function through alternative pathways separate from SQLE. This mini-review offers insights into the intricate mechanisms through which SQLE affects the prognosis and resistance profiles across diverse cancer types, while succinctly elucidating the mechanisms underpinning the anticancer effects of SQLE protein inhibitors. Furthermore, this mini-review underscores the necessity for further investigations into the interplay between SQLE and cancer, proposing potential avenues for future research, with the aim of serving as a reference for exploring the mechanisms governing the role of SQLE in cancer regulation.

The roles of KRAS in cancer metabolism, tumor microenvironment and clinical therapy

KRAS is one of the most mutated genes, driving alternations in metabolic pathways that include enhanced nutrient uptaking, increased glycolysis, elevated glutaminolysis, and heightened synthesis of fatty acids and nucleotides. However, the beyond mechanisms of KRAS-modulated cancer metabolisms remain incompletely understood. In this review, we aim to summarize current knowledge on KRAS-related metabolic alterations in cancer cells and explore the prevalence and significance of KRAS mutation in shaping the tumor microenvironment and influencing epigenetic modification via various molecular activities. Given that cancer cells rely on these metabolic changes to sustain cell growth and survival, targeting these processes may represent a promising therapeutic strategy for KRAS-driven cancers.

Clinical significance of lipid pathway-targeted therapy in breast cancer

Globally, breast cancer represents the most common cancer and the primary cause of death by cancer in women. Lipids are crucial in human physiology, serving as vital energy reserves, structural elements of biological membranes, and essential signaling molecules. The metabolic reprogramming of lipid pathways has emerged as a critical factor in breast cancer progression, drug resistance, and patient prognosis. In this study, we delve into the clinical implications of lipid pathway-targeted therapy in breast cancer. We highlight key enzymes and potential therapeutic targets involved in lipid metabolism reprogramming, and their associations with cancer progression and treatment outcomes. Furthermore, we detail the clinical trials exploring the anticancer and cancer chemopreventive activity of therapies targeting these molecules. However, the clinical efficacy of these therapies remains controversial, highlighting the urgent need for predictive biomarkers to identify patient subpopulations likely to benefit from such treatment. We propose the Selective Lipid Metabolism Therapy Benefit Hypothesis, emphasizing the importance of personalized medicine in optimizing lipid pathway-targeted therapy for breast cancer patients.

Mechanisms of Anti-PD Therapy Resistance in Digestive System Neoplasms

Digestive system neoplasms are highly heterogeneous and exhibit complex resistance mechanisms that render anti-programmed cell death protein (PD) therapies poorly effective. The tumor microenvironment (TME) plays a pivotal role in tumor development, apart from supplying energy for tumor proliferation and impeding the body's anti-tumor immune response, the TME actively facilitates tumor progression and immune escape via diverse pathways, which include the modulation of heritable gene expression alterations and the intricate interplay with the gut microbiota. In this review, we aim to elucidate the mechanisms underlying drug resistance in digestive tumors, focusing on immune-mediated resistance, microbial crosstalk, metabolism, and epigenetics. We will highlight the unique characteristics of each digestive tumor and emphasize the significance of the tumor immune microenvironment (TIME). Furthermore, we will discuss the current therapeutic strategies that hold promise for combination with cancer immune normalization therapies. This review aims to provide a thorough understanding of the resistance mechanisms in digestive tumors and offer insights into potential therapeutic interventions.

LIX1L aggravates MASH-HCC progression by reprogramming of hepatic metabolism and microenvironment via CD36

Limb expression 1-like protein (LIX1L) is an essential player in liver disorders, but its function in metabolic dysfunction-associated steatohepatitis (MASH) and associated hepatocellular carcinoma (HCC) progression remains obscure. Here, we identify LIX1L as a key integrative regulator linking lipid metabolism and inflammation, adipose tissue and hepatic microenvironment, which promotes MASH progression. LIX1L significantly upregulates in MASH patients, mouse models, and palmitic acid-stimulated hepatocytes. Lix1l deletion inhibits hepatic lipid accumulation, inflammation, and fibrosis as well as adipocyte differentiation by downregulating CD36, alleviating MASH and associated HCC progression in mice. Mechanistically, metabolic stress promotes PARP1-mediated poly-ADP-ribosylation of LIX1L to increase stability and RNA binding ability of LIX1L. Subsequently, LIX1L binds to AU-rich element in the 3'UTR and CDS of CD36 mRNA, thus mitigating CD36 mRNA decay. Furthermore, LIX1L deficiency-mediated downregulation of CD36 reprograms the tumor-prone liver microenvironment with increased cytotoxic T lymphocytes and reduced immunosuppressive cell proportions. These data indicate a systematic function of LIX1L in the pathogenesis of MASH and underscore targeting PARP1/LIX1L/CD36 axis as a feasible strategy for treatment of MASH and associated HCC.

Ruthenium(II) Lipid-Mimics Drive Lipid Phase Separation to Arouse Autophagy-Ferroptosis Cascade for Photoimmunotherapy

Lipid-mediated phase separation is crucial for the formation of lipophilic spontaneous domain to regulate lipid metabolism and homeostasis, furtherly contributing to multiple cell death pathways. Herein, a series of Ru(II) lipid-mimics based on short chains or midchain lipids are developed. Among them, Ru-LipM with two dodecyl chains significantly induces natural lipid phase separation via hydrocarbon chain-melting phase transitions. Accompanied by the aggregation of Ru-LipM-labeled lipophilic membrane-less compartments, most polyunsaturated lipids are increased and the autophagic flux is retarded with the adaptor protein sequestosome 1 (p62). Upon low-dose irradiation, Ru-LipM further drives ferritinophagy, providing an additional source of labile iron and rendering cells more sensitive to ferroptosis. Meanwhile, the peroxidation of polyunsaturated lipids occurs due to the deactivation of glutathione peroxidase 4 (GPX4) and the overexpression of acyl-CoA synthetase long-chain family member 4 (ACSL4), leading to the immunogenic ferroptosis. Ultimately, both innate and adaptive immunity are invigorated, indicating the tremendous antitumor capability of Ru-LipM in vivo. This study presents an unprecedented discovery of small molecules capable of inducing and monitoring lipid phase separation, thereby eliciting robust immune responses in living cells. It provides a biosimulation strategy for constructing efficient metal-based immune activators.

Targeting metabolic pathway enhance CAR-T potency for solid tumor

Chimeric antigen receptor (CAR) T cells have great potential in cancer therapy, particularly in treating hematologic malignancies. However, their efficacy in solid tumors remains limited, with a significant proportion of patients failing to achieve long-term complete remission. One major challenge is the premature exhaustion of CAR-T cells, often due to insufficient metabolic energy. The survival, function and metabolic adaptation of CAR-T cells are key determinants of their therapeutic efficacy. We explore how targeting metabolic pathways in the tumor microenvironment can enhance CAR-T cell therapy by addressing metabolic competition and immunosuppression that impair CAR-T cell function. Tumors undergo metabolically reprogrammed to meet their rapid proliferation, thereby modulating metabolic pathways in immune cells to promote immunosuppression. The distinct metabolic requirements of tumors and T cells create a competitive environment, affecting the efficacy of CAR-T cell therapy. Recent research on glucose, lipid and amino acid metabolism, along with the interactions between tumor and immune cell metabolism, has revealed that targeting these metabolic processes can enhance antitumor immune responses. Combining metabolic interventions with existing antitumor therapies can fulfill the metabolic demands of immune cells, providing new ideas for tumor immunometabolic therapies. This review discusses the latest advances in the immunometabolic mechanisms underlying tumor immunosuppression, their implications for immunotherapy, and summarizes potential metabolic targets to improve the efficacy of CAR-T therapy.

SQLE-mediated squalene metabolism promotes tumor immune evasion in pancreatic cancer

Background

Squalene epoxidase (SQLE) is a key enzyme in cholesterol biosynthesis and has been shown to negatively affect tumor immunity and is associated with poor outcomes of immunotherapy in various cancers. While most research in this area has focused on the impact of cholesterol on immune functions, the influence of SQLE-mediated squalene metabolism within the tumor immune microenvironment (TIME) remains unexplored.

Methods

We established an immune-competent mouse model (C57BL/6) bearing mouse pancreatic cancer xenografts (KPC cells) with or without stable SQLE-knockdown (SQLE-KD) to evaluate the impact of SQLE-mediated metabolism on pancreatic cancer growth and immune functions. The effect of squalene on tumor growth and immune cells was tested by direct administration of squalene to C57BL/6 mice bearing KPC tumors. Flow cytometry analysis and immunohistochemical (IHC) staining of immune cells from the tumor tissues were performed to evaluate changes in immune function. We also employed RNA-sequencing to analyze the gene expression profiles in pancreatic cancer cells (PANC-1) treated with or without squalene. RT-PCR and Western blot analyses were used to investigate the relevant molecular mechanisms.

Results

We show that SQLE is significantly overexpressed in pancreatic cancer, and abrogation of SQLE results in a significant increase in squalene accumulation within tumor cells. The elevated squalene inhibits CXCL1 transcription through its impact on the NF-κB pathway via p65, and thus reduces the recruitment of myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs) into the tumor microenvironment. Silencing of SQLE also leads to an increased proportion of CD8+ T cells in the tumor tissues and suppresses tumor growth in vivo. Importantly, direct administration of squalene, the metabolic substrate of SQLE, to immune-competent mice bearing KPC pancreatic cancer tumors causes a substantial decrease in CD206+ TAMs and MDSCs, thus releasing immune suppression and inhibiting tumor growth.

Conclusion

Our study shows that squalene is an important immune-modulating metabolite that inhibits the infiltration of immune-suppressive cells in TIME, and that SQLE exerts its tumor immune evasion effect by metabolic removal of squalene. Thus, SQLE-mediated squalene metabolic pathway could be a potential target to enhance antitumor immunity in pancreatic cancer.

Integrated lipidomics and RNA-seq reveal prognostic biomarkers in well-differentiated and dedifferentiated retroperitoneal liposarcoma

BACKGROUND

Retroperitoneal liposarcoma (RLPS) is a mesenchymal malignant tumor characterized by different degrees of adipocytic differentiation. Well-differentiated liposarcoma (WDLPS) and dedifferentiated liposarcoma (DDLPS) are two of the most common subtypes of RLPS, exhibiting clear differences in biological behaviors and clinical prognosis. The metabolic features and genomic characteristics remain unclear.

METHODS

This study employed lipidomic and RNA-seq analyses of RLPS tissues from 19 WDLPS and 29 DDLPS patients. Western blot and immunohistochemistry staining were performed to verify the tumor tissue protein levels of TIMP1, FN1, MMP11, GPNMB, and ECM1. Enzyme-linked immunosorbent assay (ELISA) was performed to evaluate different serum protein levels in 128 blood samples from patients with RLPS. Multivariate analysis was performed to identify the most crucial variables associated with overall survival (OS) and recurrence-free survival (RFS) of the RLPS patients.

RESULTS

Lipidomic analysis revealed a significant difference in lipid metabolism, particularly in phosphatidylcholines and triacylglycerides metabolism. RNA sequencing analysis revealed that 1,630 differentially expressed genes (DEGs) were significantly enriched in lipid metabolism, developmental process, and extracellular matrix (ECM) pathways. Integrated lipidomic and transcriptomic analysis identified 29 genes as potential biomarkers between WDLPS and DDLPS. Among the 29 DEGs, we found that TIMP1, FN1, MMP11, GPNMB, and ECM1 were increased in DDLPS tumor tissues than in WDLPS tumor tissues. The receiver operating characteristic (ROC) curve showed high specificity and sensitivity in diagnosing patients using a five-gene combination (AUC = 0.904). ELISA revealed a significant increase in the serum levels of ECM1 and GPNMB in patients with DDLPS compared to patients with WDLPS. ECM1 increased progressively across different FNCLCC Grades, correlating negatively with RFS (P = 0.043). GPNMB levels showed a negative correlation with OS (P = 0.019).

CONCLUSIONS

Our study reveals different lipid metabolism, several transcriptional pathways between WDLPS and DDLPS, and examines several serum markers associated with the prognosis of RLPS. These findings provide a vital basis for future endeavors in diagnosing and predicting the prognosis of retroperitoneal liposarcoma with different differentiations.

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.

Metabolic reprogramming in KRAS-mutant cancers: Proven targetable vulnerabilities and potential therapeutic strategies

Kras (Ki-ras2 Kirsten rat sarcoma viral oncogene homolog), one of the most frequently mutated oncogenes in the human genome, is considered 'untargetable'. Although specific KRASG12C inhibitors have been developed, their overall impact is limited, highlighting the need for further research on targeting KRAS-mutant cancers. Metabolic abnormalities are key hallmarks of cancer, with KRAS-driven tumors exhibiting traits like glycolysis upregulation, glutamine addiction, lipid droplet accumulation, highly active macropinocytosis, and metabolic reprogramming-associated tumor microenvironment remodeling. Targeting these unique metabolic characteristics offers a promising strategy for new cancer treatments. This review summarizes recent advances in our understanding of the metabolic network in KRAS-mutated tumor cells, discusses potential targetable vulnerabilities, and outlines clinical developments in relevant therapies, while also addressing challenges to improve strategies against these aggressive cancers.

Precise targeting of lipid metabolism in the era of immuno-oncology and the latest advances in nano-based drug delivery systems for cancer therapy

Over the past decade, research has increasingly identified unique dysregulations in lipid metabolism within the tumor microenvironment (TME). Lipids, diverse biomolecules, not only constitute biological membranes but also function as signaling molecules and energy sources. Enhanced synthesis or uptake of lipids in the TME significantly promotes tumorigenesis and proliferation. Moreover, lipids secreted into the TME influence tumor-resident immune cells (TRICs), thereby aiding tumor survival against chemotherapy and immunotherapy. This review aims to highlight recent advancements in understanding lipid metabolism in both tumor cells and TRICs, with a particular emphasis on exogenous lipid uptake and endogenous lipid de novo synthesis. Targeting lipid metabolism for intervention in anticancer therapies offers a promising therapeutic avenue for cancer treatment. Nano-drug delivery systems (NDDSs) have emerged as a means to maximize anti-tumor effects by rewiring tumor metabolism. This review provides a comprehensive overview of recent literature on the development of NDDSs targeting tumor lipid metabolism, particularly in the context of tumor immunotherapy. It covers four key aspects: reprogramming lipid uptake, reprogramming lipolysis, reshaping fatty acid oxidation (FAO), and reshuffling lipid composition on the cell membrane. The review concludes with a discussion of future prospects and challenges in this burgeoning field of research.

Integration of transcriptomics and machine learning for insights into breast cancer: exploring lipid metabolism and immune interactions

Background

Breast cancer (BRCA) represents a substantial global health challenge marked by inadequate early detection rates. The complex interplay between the tumor immune microenvironment and fatty acid metabolism in BRCA requires further investigation to elucidate the specific role of lipid metabolism in this disease.

Methods

We systematically integrated nine machine learning algorithms into 184 unique combinations to develop a consensus model for lipid metabolism-related prognostic genes (LMPGS). Additionally, transcriptomics analysis provided a comprehensive understanding of this prognostic signature. Using the ESTIMATE method, we evaluated immune infiltration among different risk subgroups and assessed their responsiveness to immunotherapy. Tailored treatments were screened for specific risk subgroups. Finally, we verified the expression of key genes through in vitro experiments.

Results

We identified 259 differentially expressed genes (DEGs) related to lipid metabolism through analysis of the cancer genome atlas program (TCGA) database. Subsequently, via univariate Cox regression analysis and C-index analysis, we developed an optimal machine learning algorithm to construct a 21-gene LMPGS model. We used optimal cutoff values to divide the lipid metabolism prognostic gene scores into two groups according to high and low scores. Our study revealed distinct biological functions and mutation landscapes between high-scoring and low-scoring patients. The low-scoring group presented a greater immune score, whereas the high-scoring group presented enhanced responses to both immunotherapy and chemotherapy drugs. Single-cell analysis highlighted significant upregulation of CPNE3 in epithelial cells. Moreover, by employing molecular docking, we identified niclosamide as a potential targeted therapeutic drug. Finally, our experiments demonstrated high expression of MTMR9 and CPNE3 in BRCA and their significant correlation with prognosis.

Conclusion

By employing bioinformatics and diverse machine learning algorithms, we successfully identified genes associated with lipid metabolism in BRCA and uncovered potential therapeutic agents, thereby offering novel insights into the mechanisms and treatment strategies for BRCA.

Drug resistance and tumor immune microenvironment: An overview of current understandings (Review)

The use of antitumor drugs represents a reliable strategy for cancer therapy. Unfortunately, drug resistance has become increasingly common and contributes to tumor metastasis and local recurrence. The tumor immune microenvironment (TME) consists of immune cells, cytokines and immunomodulators, and collectively they influence the response to treatment. Epigenetic changes including DNA methylation and histone modification, as well as increased drug exportation have been reported to contribute to the development of drug resistance in cancers. In the past few years, the majority of studies on tumors have only focused on the development and progression of a tumor from a mechanistic standpoint; few studies have examined whether the changes in the TME can also affect tumor growth and drug resistance. Recently, emerging evidence have raised more concerns regarding the role of TME in the development of drug resistance. In the present review, it was discussed how the suppressive TME adapts to drug resistance characterized by the cooperation of immune cells, cytokines, immunomodulators, stromal cells and extracellular matrix. Furthermore, it was reviewed how these immunological or metabolic changes alter immuno‑surveillance and thus facilitate tumor drug resistance. In addition, potential targets present in the TME for developing novel therapeutic strategies to improve individualized therapy for cancer treatment were revealed.

miR-504 knockout regulates tumor cell proliferation and immune cell infiltration to accelerate oral cancer development

miR-504 plays a pivotal role in the progression of oral cancer. However, the underlying mechanism remains elusive in vivo. Here, we find that miR-504 is significantly down-regulated in oral cancer patients. We generate miR-504 knockout mice (miR-504-/-) using CRISPR/Cas9 technology to investigate its impact on the malignant progression of oral cancer under exposure to 4-Nitroquinoline N-oxide (4NQO). We show that the deletion of miR-504 does not affect phenotypic characteristics, body weight, reproductive performance, and survival in mice, but results in changes in the blood physiological and biochemical indexes of the mice. Moreover, with 4NQO treatment, miR-504-/- mice exhibit more pronounced pathological changes characteristic of oral cancer. RNA sequencing shows that the differentially expressed genes observed in samples from miR-504-/- mice with oral cancer are involved in regulating cell metabolism, cytokine activation, and lipid metabolism-related pathways. Additionally, these differentially expressed genes are significantly enriched in lipid metabolism pathways that influence immune cell infiltration within the tumor microenvironment, thereby accelerating tumor development progression. Collectively, our results suggest that knockout of miR-504 accelerates malignant progression in 4NQO-induced oral cancer by regulating tumor cell proliferation and lipid metabolism, affecting immune cell infiltration.

Metal complex lipid-based nanoparticles deliver metabolism-regulating lomitapide to overcome CTC immune evasion via activating STING pathway

Activating the cGAS-STING pathway of circulating tumor cell clusters (CTC clusters) represents a promising strategy to mitigate metastases. To fully exploit the potential of cholesterol-regulating agents in activating CTCs' STING levels, we developed a nanoparticle (NP) composed of metal complex lipid (MCL). This design includes MCL-miriplatin to increase NP stiffness and loads lomitapide (lomi) modulating cholesterol levels, resulting in the creation of PLTs@Pt-lipid@lomi NPs. MCL-miriplatin not only enhances lomi's eliciting efficacy on STING pathway but also increases NPs' stiffness, thus a vital factor affecting the penetration into CTC clusters to further boost lomi's ability. Demonstrated by cy5 tracking experiments, PLTs@Pt-lipid@lomi NPs quickly attach to cancer cell via platelet membrane anchorage, penetrate deep into the spheres, and reach the subcellular endoplasmic reticulum where lomi regulates cholesterol. Additionally, these NPs have been shown to track CTCs in the bloodstream, a capability not demonstrated by the free drug. PLTs@Pt-lipid@lomi NPs more efficiently activate the STING pathway and reduce CTC stemness compared to free lomi. Ultimately, PLTs@Pt-lipid@lomi NPs reduce metastasis in a post-surgery animal model. While cholesterol-regulating agents are limited in efficacy when being repositioned as immunomodulatory agents, this MCL-composing NP strategy demonstrates the potential to effectively deliver these agents to target CTC clusters.

Lipids in the tumor microenvironment: immune modulation and metastasis

Tumor cells can undergo metabolic adaptations that support their growth, invasion, and metastasis, such as reprogramming lipid metabolism to meet their energy demands and to promote survival in harsh microenvironmental conditions, including hypoxia and acidification. Metabolic rewiring, and especially alterations in lipid metabolism, not only fuel tumor progression but also influence immune cell behavior within the tumor microenvironment (TME), leading to immunosuppression and immune evasion. These processes, in turn, may contribute to the metastatic spread of cancer. The diverse metabolic profiles of immune cell subsets, driven by the TME and tumor-derived signals, contribute to the complex immune landscape in tumors, affecting immune cell activation, differentiation, and effector functions. Understanding and targeting metabolic heterogeneity among immune cell subsets will be crucial for developing effective cancer immunotherapies that can overcome immune evasion mechanisms and enhance antitumor immunity.

PD-1 signaling limits expression of phospholipid phosphatase 1 and promotes intratumoral CD8+ T cell ferroptosis

The tumor microenvironment (TME) promotes metabolic reprogramming and dysfunction in immune cells. Here, we examined the impact of the TME on phospholipid metabolism in CD8+ T cells. In lung cancer, phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were lower in intratumoral CD8+ T cells than in circulating CD8+ T cells. Intratumoral CD8+ T cells exhibited decreased expression of phospholipid phosphatase 1 (PLPP1), which catalyzes PE and PC synthesis. T cell-specific deletion of Plpp1 impaired antitumor immunity and promoted T cell death by ferroptosis. Unsaturated fatty acids in the TME stimulated ferroptosis of Plpp1-/- CD8+ T cells. Mechanistically, programmed death-1 (PD-1) signaling in CD8+ T cells induced GATA1 binding to the promoter region Plpp1 and thereby suppressed Plpp1 expression. PD-1 blockade increased Plpp1 expression and restored CD8+ T cell antitumor function but did not rescue dysfunction of Plpp1-/- CD8+ T cells. Thus, PD-1 signaling regulates phospholipid metabolism in CD8+ T cells, with therapeutic implications for immunotherapy.

Serum PCSK9 is a novel serological biomarker for the diagnosis and prognosis of pancreatic cancer

Background

Although CA19-9 is an essential blood biomarker of pancreatic cancer (PC), its sensitivity and specificity are limited for early detection.

Methods

We analyzed the serum proprotein convertase subtilisin/kexin type 9 (sPCSK9) in PC patients, benign disease groups (BDG), and healthy controls (HC) by ELISA.

Results

Consistently, sPCSK9 was considerably lower in PC patients than in HC (Z = -2.546, P < 0.05), and sPCSK9 in PC patients was statistically significantly higher than in BDG (Z = -5.457, P < 0.001). sPCSK9 was linked to the invasion of lymph nodes (χ2 = 6.846, P < 0.01). According to ROC curves, combining sPCSK9 with CA19-9 could potentially enhance the diagnostic capability of CA19-9 in early-stage PC patients. Furthermore, the low sPCSK9 group (n = 41) exhibited statistically significantly prolonged overall survival compared to the high sPCSK9 group (n = 15), with median survival times of 27 months (95% CI [17.59-36.41]) and 11 months (95% CI [7.21-14.79]), respectively (P = 0.022).

Conclusion

The diagnostic performance of CA19-9 for early-stage PC patients could be improved by combining sPCSK9 with CA19-9. Moreover, the higher sPCSK9 group has a significantly shorter overall survival rate.

Cellular senescence and metabolic reprogramming: Unraveling the intricate crosstalk in the immunosuppressive tumor microenvironment

The intrinsic oncogenic mechanisms and properties of the tumor microenvironment (TME) have been extensively investigated. Primary features of the TME include metabolic reprogramming, hypoxia, chronic inflammation, and tumor immunosuppression. Previous studies suggest that senescence-associated secretory phenotypes that mediate intercellular information exchange play a role in the dynamic evolution of the TME. Specifically, hypoxic adaptation, metabolic dysregulation, and phenotypic shifts in immune cells regulated by cellular senescence synergistically contribute to the development of an immunosuppressive microenvironment and chronic inflammation, thereby promoting the progression of tumor events. This review provides a comprehensive summary of the processes by which cellular senescence regulates the dynamic evolution of the tumor-adapted TME, with focus on the complex mechanisms underlying the relationship between senescence and changes in the biological functions of tumor cells. The available findings suggest that components of the TME collectively contribute to the progression of tumor events. The potential applications and challenges of targeted cellular senescence-based and combination therapies in clinical settings are further discussed within the context of advancing cellular senescence-related research.

Biomaterials-Boosted Immunotherapy for Osteosarcoma

Osteosarcoma (OS) is a primary malignant bone tumor that emanates from mesenchymal cells, commonly found in the epiphyseal end of long bones. The highly recurrent and metastatic nature of OS poses significant challenges to the efficacy of treatment and negatively affects patient prognosis. Currently, available clinical treatment strategies primarily focus on maximizing tumor resection and reducing localized symptoms rather than the complete eradication of malignant tumor cells to achieve ideal outcomes. The biomaterials-boosted immunotherapy for OS is characterized by high effectiveness and a favorable safety profile. This therapeutic approach manipulates the tumor microenvironments at the cellular and molecular levels to impede tumor progression. This review delves into the mechanisms underlying the treatment of OS, emphasizing biomaterials-enhanced tumor immunity. Moreover, it summarizes the immune cell phenotype and tumor microenvironment regulation, along with the ability of immune checkpoint blockade to activate the autoimmune system. Gaining a profound comprehension of biomaterials-boosted OS immunotherapy is imperative to explore more efficacious immunotherapy protocols and treatment options in this setting.

Lipid metabolism associated crosstalk: the bidirectional interaction between cancer cells and immune/stromal cells within the tumor microenvironment for prognostic insight

Cancer is closely related to lipid metabolism, with the tumor microenvironment (TME) containing numerous lipid metabolic interactions. Cancer cells can bidirectionally interact with immune and stromal cells, the major components of the TME. This interaction is primarily mediated by fatty acids (FAs), cholesterol, and phospholipids. These interactions can lead to various physiological changes, including immune suppression, cancer cell proliferation, dissemination, and anti-apoptotic effects on cancer cells. The physiological modulation resulting from this lipid metabolism-associated crosstalk between cancer cells and immune/stromal cells provides valuable insights into cancer prognosis. A comprehensive literature review was conducted to examine the function of the bidirectional lipid metabolism interactions between cancer cells and immune/stromal cells within the TME, particularly how these interactions influence cancer prognosis. A novel autophagy-extracellular vesicle (EV) pathway has been proposed as a mediator of lipid metabolism interactions between cancer cells and immune cells/stromal cells, impacting cancer prognosis. As a result, different forms of lipid metabolism interactions have been described as being linked to cancer prognosis, including those mediated by the autophagy-EV pathway. In conclusion, understanding the bidirectional lipid metabolism interactions between cancer cells and stromal/immune cells in the TME can help develop more advanced prognostic approaches for cancer patients.

Tumor Metabolism: A New Field for the Treatment of Glioma

The clinical treatment of glioma remains relatively immature. Commonly used clinical treatments for gliomas are surgery combined with chemotherapy and radiotherapy, but there is a problem of drug resistance. In addition, immunotherapy and targeted therapies also suffer from the problem of immune evasion. The advent of metabolic therapy holds immense potential for advancing more efficacious and tolerable therapies against this aggressive disease. Metabolic therapy alters the metabolic processes of tumor cells at the molecular level to inhibit tumor growth and spread, and lead to better outcomes for patients with glioma that are insensitive to conventional treatments. Moreover, compared with conventional therapy, it has less impact on normal cells, less toxicity and side effects, and higher safety. The objective of this review is to examine the changes in metabolic characteristics throughout the development of glioma, enumerate the current methodologies employed for studying tumor metabolism, and highlight the metabolic reprogramming pathways of glioma along with their potential molecular mechanisms. Importantly, it seeks to elucidate potential metabolic targets for glioblastoma (GBM) therapy and summarize effective combination treatment strategies based on various studies.

The role of metabolic reprogramming in immune escape of triple-negative breast cancer

Triple-negative breast cancer (TNBC) has become a thorny problem in the treatment of breast cancer because of its high invasiveness, metastasis and recurrence. Although immunotherapy has made important progress in TNBC, immune escape caused by many factors, especially metabolic reprogramming, is still the bottleneck of TNBC immunotherapy. Regrettably, the mechanisms responsible for immune escape remain poorly understood. Exploring the mechanism of TNBC immune escape at the metabolic level provides a target and direction for follow-up targeting or immunotherapy. In this review, we focus on the mechanism that TNBC affects immune cells and interstitial cells through hypoxia, glucose metabolism, lipid metabolism and amino acid metabolism, and changes tumor metabolism and tumor microenvironment. This will help to find new targets and strategies for TNBC immunotherapy.

Strategies to enhance the therapeutic efficacy of anti-PD-1 antibody, anti-PD-L1 antibody and anti-CTLA-4 antibody in cancer therapy

Although immune checkpoint inhibitors (anti-PD-1 antibody, anti-PD-L1 antibody, and anti-CTLA-4 antibody) have displayed considerable success in the treatment of malignant tumors, the therapeutic effect is still unsatisfactory for a portion of patients. Therefore, it is imperative to develop strategies to enhance the effect of these ICIs. Increasing evidence strongly suggests that the key to this issue is to transform the tumor immune microenvironment from a state of no or low immune infiltration to a state of high immune infiltration and enhance the tumor cell-killing effect of T cells. Therefore, some combination strategies have been proposed and this review appraise a summary of 39 strategies aiming at enhancing the effectiveness of ICIs, which comprise combining 10 clinical approaches and 29 foundational research strategies. Moreover, this review improves the comprehensive understanding of combination therapy with ICIs and inspires novel ideas for tumor immunotherapy.

Elucidating the role of S100A10 in CD8+ T cell exhaustion and HCC immune escape via the cPLA2 and 5-LOX axis

Hepatocellular carcinoma (HCC) is a common malignant tumor with a complex immune evasion mechanism posing a challenge to treatment. The role of the S100A10 gene in various cancers has garnered significant attention. This study aims to elucidate the impact of S100A10 on CD8+ T cell exhaustion via the cPLA2 and 5-LOX axis, thereby elucidating its role in immune evasion in HCC. By analyzing the HCC-related data from the GEO and TCGA databases, we identified differentially expressed genes associated with lipid metabolism and developed a prognostic risk model. Subsequently, through RNA-seq and PPI analyses, we determined vital lipid metabolism genes and downstream factors S100A10, ACOT7, and SMS, which were significantly correlated with CD8+ T cell infiltration. Given the most significant expression differences, we selected S100A10 for further investigation. Both in vitro and in vivo experiments were conducted, including co-culture experiments of CD8+ T cells with MHCC97-L cells, Co-IP experiments, and validation in an HCC mouse model. S100A10 was significantly overexpressed in HCC tissues and potentially regulates CD8+ T cell exhaustion and lipid metabolism reprogramming through the cPLA2 and 5-LOX axis. Silencing S100A10 could inhibit CD8+ T cell exhaustion, further suppressing immune evasion in HCC. S100A10 may activate the cPLA2 and 5-LOX axis, initiating lipid metabolism reprogramming and upregulating LTB4 levels, thus promoting CD8+ T cell exhaustion in HCC tissues, facilitating immune evasion by HCC cells, ultimately impacting the growth and migration of HCC cells. This research highlights the critical role of S100A10 via the cPLA2 and 5-LOX axis in immune evasion in HCC, providing new theoretical foundations and potential targets for diagnosing and treating HCC.

Differential impact of lipid profile according to neutrophil-to-lymphocyte ratio status in patients with advanced cancer treated with immunotherapy

Aim: To investigate the different impact of each component of lipid profile in advanced cancer patients treated with immune checkpoints inhibitors (ICIs) according to neutrophil-to-lymphocyte ratio (NLR) value.Methods: We retrospectively collected total cholesterol (TC), triglycerides (TGs), low-density lipoproteins (LDL), high-density lipoproteins (HDL).Results: 407 patients were enrolled. In NLR <4 subgroup, TGs <150 mg/dl led to longer PFS (p = 0.01) and OS (p = 0.02) compared with TGs ≥150 mg/dl; LDL <100 mg/dl led to longer PFS (p = 0.004) and OS (p = 0.007) compared with LDL ≥100 mg/dl. In NLR ≥4 subgroup, TC >200 mg/dl led to longer PFS (p = 0.008) and OS (p = 0.004) compared with TC <200 mg/dl.Conclusion: We showed a distinct prognostic impact of lipid profile according to NLR.

The immunosuppressive landscape in tumor microenvironment

Recent advances in cancer immunotherapy, especially immune checkpoint inhibitors (ICIs), have revolutionized the clinical outcome of many cancer patients. Despite the fact that impressive progress has been made in recent decades, the response rate remains unsatisfactory, and many patients do not benefit from ICIs. Herein, we summarized advanced studies and the latest insights on immune inhibitory factors in the tumor microenvironment. Our in-depth discussion and updated landscape of tumor immunosuppressive microenvironment may provide new strategies for reversing tumor immune evasion, enhancing the efficacy of ICIs therapy, and ultimately achieving a better clinical outcome.

Loss of STK11 Suppresses Lipid Metabolism and Attenuates KRAS-Induced Immunogenicity in Patients with Non-Small Cell Lung Cancer

As many as 30% of the patients with non-small cell lung cancer harbor oncogenic KRAS mutations, which leads to extensive remodeling of the tumor immune microenvironment. Although co-mutations in several genes have prognostic relevance in KRAS-mutated patients, their effect on tumor immunogenicity are poorly understood. In the present study, a total of 189 patients with non-small cell lung cancer underwent a standardized analysis including IHC, whole-exome DNA sequencing, and whole-transcriptome RNA sequencing. Patients with activating KRAS mutations demonstrated a significant increase in PDL1 expression and CD8+ T-cell infiltration. Both were increased in the presence of a co-occurring TP53 mutation and lost with STK11 co-mutation. Subsequent genomic analysis demonstrated that KRAS/TP53 co-mutated tumors had a significant decrease in the expression of glycolysis-associated genes and an increase in several genes involved in lipid metabolism, notably lipoprotein lipase, low-density lipoprotein receptor, and LDLRAD4. Conversely, in the immune-excluded KRAS/STK11 co-mutated group, we observed diminished lipid metabolism and no change in anaerobic glycolysis. Interestingly, in patients with low expression of lipoprotein lipase, low-density lipoprotein receptor, or LDLRAD4, KRAS mutations had no effect on tumor immunogenicity. However, in patients with robust expression of these genes, KRAS mutations were associated with increased immunogenicity and associated with improved overall survival. Our data further suggest that the loss of STK11 may function as a metabolic switch, suppressing lipid metabolism in favor of glycolysis, thereby negating KRAS-induced immunogenicity. Hence, this concept warrants continued exploration, both as a predictive biomarker and potential target for therapy in patients receiving ICI-based immunotherapy.

SIGNIFICANCE

In patients with lung cancer, we demonstrate that KRAS mutations increase tumor immunogenicity; however, KRAS/STK11 co-mutated patients display an immune-excluded phenotype. KRAS/STK11 co-mutated patients also demonstrated significant downregulation of several key lipid metabolism genes, many of which were associated with increased immunogenicity and improved overall survival in KRAS-mutated patients. Hence, alteration to lipid metabolism warrants further study as a potential biomarker and target for therapy in patients with KRAS-mutated lung cancer.