Lactate in the tumour microenvironment: From immune modulation to therapy

Influence of lactate in resistance to anti‑PD‑1/PD‑L1 therapy: Mechanisms and clinical applications (Review)

Metabolic reprogramming is a prominent characteristic of tumor cells, evidenced by heightened secretion of lactate, which is linked to tumor progression. Furthermore, the accumulation of lactate in the tumor microenvironment (TME) influences immune cell activity, including the activity of macrophages, dendritic cells and T cells, fostering an immunosuppressive milieu. Anti‑programmed cell death protein 1 (PD‑1)/programmed death‑ligand 1 (PD‑L1) therapy is associated with a prolonged survival time of patients with non‑small cell lung cancer. However, some patients still develop resistance to anti‑PD‑1/PD‑L1 therapy. Lactate is associated with resistance to anti‑PD‑1/PD‑L1 therapy. The present review summarizes what is known about lactate metabolism in tumor cells and how it affects immune cell function. In addition, the present review emphasizes the relationship between lactate secretion and immunotherapy resistance. The present review also explores the potential for targeting lactate within the TME to enhance the efficacy of immunotherapy.

Untargeted metabolomics of 3xTg-AD neurotoxic astrocytes

Alzheimer's disease (AD) is the most common form of dementia, affecting approximately 47 M people worldwide. Histological features and genetic risk factors, among other evidence, supported the amyloid hypothesis of the disease. This neuronocentric paradigm is currently undergoing a shift, considering evidence of the role of other cell types, such as microglia and astrocytes, in disease progression. Previously, we described a particular astrocyte subtype obtained from the 3xTg-AD murine model that displays neurotoxic properties in vitro. We continue here our exploratory analysis through the lens of metabolomics to identify potentially altered metabolites and biological pathways. Cell extracts from neurotoxic and control astrocytes were compared using high-resolution mass spectrometry-based metabolomics. Around 12 % of metabolic features demonstrated significant differences between neurotoxic and control astrocytes, including alterations in the key metabolite glutamate. Consistent with our previous transcriptomic study, the present results illustrate many homeostatic and regulatory functions of metabolites, suggesting that neurotoxic 3xTg-AD astrocytes exhibit alterations in the Krebs cycle as well as the prostaglandin pathway. This is the first metabolomic study performed in 3xTg-AD neurotoxic astrocytes. These results provide insight into metabolic alterations potentially associated with neurotoxicity and pathology progression in the 3xTg-AD mouse model and strengthen the therapeutic potential of astrocytes in AD. BIOLOGICAL SIGNIFICANCE: Our study is the first high-resolution metabolomic characterization of the novel neurotoxic 3xTg-AD astrocytes. We propose key metabolites and pathway alterations, as well as possible associations with gene expression alterations in the model. Our results are in line with recent hypotheses beyond the amyloid cascade, considering the involvement of several stress response cascades during the development of Alzheimer's disease. This work could inspire other researchers to initiate similar studies in related models. Furthermore, this work illustrates a powerful workflow for metabolite annotation and selection that can be implemented in other studies.

Lactate and lactylation in gastrointestinal cancer: Current progress and perspectives (Review)

Gastrointestinal (GI) cancers, which have notable incidence and mortality, are impacted by metabolic reprogramming, especially the increased production and accumulation of lactate. Lactylation, a post‑translational modification driven by lactate, is a crucial regulator of gene expression and cellular function in GI cancer. The present review aimed to examine advancements in understanding lactate and lactylation in GI cancer. The mechanisms of lactate production, its influence on the tumor microenvironment and the clinical implications of lactate levels as potential biomarkers were explored. Furthermore, lactylation was investigated, including its biochemical foundation, primary targets and functional outcomes. The present review underscored potential therapeutic strategies targeting lactate metabolism and lactylation. Challenges and future directions emphasize the potential of lactate and lactylation as innovative therapeutic targets in GI cancer to improve clinical outcomes.

Metabolic Reprogramming in Cancer: Implications for Immunosuppressive Microenvironment

Cancer is a complex and heterogeneous disease characterised by uncontrolled cell growth and proliferation. One hallmark of cancer cells is their ability to undergo metabolic reprogramming, which allows them to sustain their rapid growth and survival. This metabolic reprogramming creates an immunosuppressive microenvironment that facilitates tumour progression and evasion of the immune system. In this article, we review the mechanisms underlying metabolic reprogramming in cancer cells and discuss how these metabolic alterations contribute to the establishment of an immunosuppressive microenvironment. We also explore potential therapeutic strategies targeting metabolic vulnerabilities in cancer cells to enhance immune-mediated anti-tumour responses. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02044861, NCT03163667, NCT04265534, NCT02071927, NCT02903914, NCT03314935, NCT03361228, NCT03048500, NCT03311308, NCT03800602, NCT04414540, NCT02771626, NCT03994744, NCT03229278, NCT04899921.

Comprehensive analysis of lysine lactylation and its potential biological significance in clear cell renal cell carcinoma

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) is a common histological subtype of malignant renal neoplasm. Protein lysine lactylation (Kla) plays a crucial role in tumor metabolic reprogramming. However, little is known regarding the distribution and potential biological functions of Kla in ccRCC. This study aimed to systematically investigate the role of Kla in ccRCC.

METHODS

A total of 12 ccRCC samples were collected from 6 patients. Western blotting was performed to determine the trend of Kla-modified proteins in ccRCC. Liquid chromatography-tandem mass spectrometry was used to quantitatively analyze Kla in ccRCC. Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein-protein interaction (PPI) network analyses were conducted to clarify the biological functions and interactional relationships of differentially lactylated proteins (DLPs).

RESULTS

In total, 239 DLPs, including 441 lactylated sites, were identified by comparing ccRCC tissues with adjacent normal tissues. Kla-related enzymes have a higher affinity for alanine than for other amino acid residues in ccRCC. Subcellular localization analysis revealed that most DLPs were localized in the cytoplasm and mitochondria. GO enrichment analysis showed that most of the DLPs were enriched in metabolism-associated biological processes, including the purine ribonucleotide, monocarboxylic acid, ribonucleoside triphosphate, purine nucleoside triphosphate, and ATP metabolic processes. KEGG analysis indicated that most DLPs were also enriched in metabolism-related pathways, including glycolysis, amino acid (valine, leucine, and isoleucine) degradation, pyruvate metabolism, fatty acid degradation, and the citrate cycle. The top 20 hub proteins were screened from the PPI network based on their degree ranks.

CONCLUSIONS

This study revealed the role of Kla in ccRCC, which will extend our understanding of the potential molecular mechanisms underlying ccRCC formation and progression. These key Kla-modified proteins may be promising therapeutic targets for the treatment of ccRCC. However, further molecular experiments are required to validate these findings.

Cancer specific up-regulated lactate genes associated with immunotherapy resistance in a pan-cancer analysis

Background

Although the lactate pathway has been reported to lead to immune escape through the inhibition of effector T cells, the cancer-intrinsic lactate signature has not been identified, and the immunotherapeutic efficacy and potential mechanism of the lactate signature are still unclear.

Methods

We defined a pan-cancer up-lactate score by comparing malignant tissues and normal tissues in the TCGA cohort. The immunotherapeutic efficacy was evaluated in non-small cell lung cancer (NSCLC), metastatic renal cancer (mRCC), bladder cancer (BLCA) and melanoma cohorts. The cancer cell-intrinsic mechanism to immune checkpoint inhibitors (ICIs) resistance was measured using single cell sequencing (scRNA-seq) data. Pathway activation was evaluated in the TCGA cohort and CPTAC cohort with transcriptomics and proteomics. The co-occurrence of up-lactate signature and mTOR signaling was determined by spatial transcriptomics of the tissue samples. Immunotherapy resistance and pathway regulation were validated in the in-house NSCLC cohort.

Results

Patients with the high up-lactate scores had significantly short overall survival (OS) than those with the low up-lactate scores (p < 0.001) across multiple types of cancers. The up-regulated lactate signature exhibited higher expression in the malignant cells compared with stromal cells and immune cells in multiple scRNA-seq datasets. A high up-lactate score was associated with poor OS in NSCLC, mRCC, BLCA and melanoma patients who received anti-PD(L)1 antibody. The up-lactate score was higher in the responders of cancer cells, but not in immune cells and stromal cells compared with the non-responders (p < 0.05). Moreover, up-lactate score was positively correlated with mTOR signaling across multiple cancers. In patients with NSCLC who received anti-PD-1 antibody, higher up-lactate scores were associated with significantly shorter PFS compared to lower up-lactate scores (p < 0.001). Additionally, the up-lactate score was associated with cold tumor, and was positively correlated with mTOR signaling.

Conclusion

Collectively, we defined a pan-cancer up-lactate signature, which is a feature of malignant cells and is associated with ICIs resistance. This reveals a coherent program with prognostic and predictive value that may be therapeutically targeted.

Evaluating lactate metabolism for prognostic assessment and therapy response prediction in gastric cancer with emphasis on the oncogenic role of SLC5A12

BACKGROUND

Gastric cancer remains a common malignancy with poor prognosis. While lactate metabolism is recognized as a significant factor in tumor progression, its potential as a predictive tool for treatment response remains unexplored. This study introduces a novel Lactate-Related Gene Signature (LRGS) designed to predict both survival outcomes and therapy responses in gastric cancer patients.

METHODS

We comprehensively analyzed 335 lactate-related genes from 11 metabolic pathways using MSigDB, identifying 278 differentially expressed genes between gastric cancer and normal tissues. Employing the LASSO Cox regression model, we developed an innovative LRGS formula based on the expression of 16 key lactate-related genes. The impact of Solute Carrier Family 5 Member 12 (SLC5A12), a gene of particular interest, on gastric cancer cell functions was evaluated using in vitro assays and an in vivo zebrafish model.

RESULTS

Our newly established LRGS demonstrated robust capability in stratifying gastric cancer patients by survival risk. Notably, the LRGS-low subtype showed significantly improved overall and disease-free survival rates compared to the LRGS-high subtype. A key finding was LRGS's ability to predict patient responses to both adjuvant chemotherapy and immunotherapy. Random forest analysis identified SLC5A12 as the most significant gene differentiating gastric cancer from normal tissues. Functional experiments confirmed SLC5A12's role in promoting gastric cancer cell proliferation, invasion, and migration both in vitro and in vivo.

CONCLUSION

The LRGS is a dependable and efficient prognostic tool for assessing the survival outcomes in individuals with gastric cancer, as well as a predictor of patient response to adjuvant chemotherapy and immunotherapy.

Antitumoral Activity and Metabolic Signatures of Dichloroacetate, 6-Aminonicotinamide and Etomoxir in Breast-Tumor-Educated Macrophages

Pharmacological targeting of metabolic pathways represents an appealing strategy to selectively kill cancer cells while promoting antitumor functions of stromal cells. In this study, we assessed the effectiveness of 13 metabolic drugs (MDs) in steering in vitro generated breast tumor-educated macrophages (TEMs) toward an antitumoral phenotype. For that, the production of vascular endothelial growth factor (VEGF) and tumor necrosis factor α (TNF-α), two important regulators of tumor progression, was evaluated. Notably, dichloroacetate (DCA), 6-aminonicotinamide (6-AN), and etomoxir decreased VEGF production and enhanced TNF-α release. Hence, we further clarified their impact on TEM metabolism using an untargeted NMR-based metabolomics approach. DCA downregulated glycolysis and enhanced the utilization of extracellular substrates like lactate while reconfiguring lipid metabolism. Several DCA-induced changes significantly correlated with heightened TNF-α production in response to pro-inflammatory stimulation. The inhibition of the pentose phosphate pathway by 6-AN was accompanied by enhanced glutaminolysis, which correlated with a decreased level of VEGF production. In etomoxir-treated TEM, inhibition of fatty acid oxidation was compensated through upregulation of glycolysis, catabolism of intracellular amino acids, and consumption of extracellular branched chain alpha-ketoacids (BCKA) and citrate. Overall, our results offer a comprehensive view of the metabolic signature of each MD in breast TEM and highlight putative correlations with phenotypic effects.

Tumor microenvironment: Nurturing cancer cells for immunoevasion and druggable vulnerabilities for cancer immunotherapy

The tumor microenvironment (TME) is an intricate ecosystem where cancer cells thrive, encompassing a wide array of cellular and non-cellular components. The TME co-evolves with tumor progression in a spatially and temporally dynamic manner, which endows cancer cells with the adaptive capability of evading immune surveillance. To this end, diverse cancer-intrinsic mechanisms were exploited to dampen host immune system, such as upregulating immune checkpoints, impairing antigens presentation and competing for nutrients. In this review, we discuss how cancer immunoevasion is tightly regulated by hypoxia, one of the hallmark biochemical features of the TME. Moreover, we comprehensively summarize how immune evasiveness of cancer cells is facilitated by the extracellular matrix, as well as soluble components of TME, including inflammatory factors, lactate, nutrients and extracellular vesicles. Given their important roles in dictating cancer immunoevasion, various strategies to target TME components are proposed, which holds promising translational potential in developing novel therapeutics to sensitize anti-cancer immunotherapy such as immune checkpoint blockade.

Mitochondrial metabolic reprogramming of macrophages and T cells enhances CD47 antibody-engineered oncolytic virus antitumor immunity

BACKGROUND

Although immunotherapy can reinvigorate immune cells to clear tumors, the response rates are poor in some patients. Here, CD47 antibody-engineered oncolytic viruses (oAd-αCD47) were employed to lyse tumors and activate immunity. The oAd-αCD47 induced comprehensive remodeling of the tumor microenvironment (TME). However, whether the acidic TME affects the antitumor immunotherapeutic effects of oncolytic viruses-αCD47 has not been clarified.

METHODS

To assess the impact of oAd-αCD47 treatment on the TME, we employed multicolor flow cytometry. Glucose uptake was quantified using 2NBDG, while mitochondrial content was evaluated with MitoTracker FM dye. pH imaging of tumors was performed using the pH-sensitive fluorophore SNARF-4F. Moreover, changes in the calmodulin-dependent protein kinase II (CaMKII)/cyclic AMP activates-responsive element-binding proteins (CREB) and peroxisome proliferator-activated receptor gamma coactivator-1α (PGC1α) signaling pathway were confirmed through western blotting and flow cytometry.

RESULTS

Here, we identified sodium bicarbonate (NaBi) as the potent metabolic reprogramming agent that enhanced antitumor responses in the acidic TME. The combination of NaBi and oAd-αCD47 therapy significantly inhibited tumor growth and produced complete immune control in various tumor-bearing mouse models. Mechanistically, combination therapy mainly reduced the number of regulatory T cells and enriched the ratio of M1-type macrophages TAMs (M1.TAMs) to M2-type macrophages TAMs (M2.TAMs), while decreasing the abundance of PD-1+TIM3+ expression and increasing the expression of CD107a in the CD8+ T cells. Furthermore, the combination therapy enhanced the metabolic function of T cells and macrophages by upregulating PGC1α, a key regulator of mitochondrial biogenesis. This metabolic improvement contributed to a robust antitumor response. Notably, the combination therapy also promoted the generation of memory T cells, suggesting its potential as an effective neoadjuvant treatment for preventing postoperative tumor recurrence and metastasis.

CONCLUSIONS

Tumor acidic microenvironment impairs mitochondrial energy metabolism in macrophages and T cells inducing oAd-αCD47 immunotherapeutic resistance. NaBi improves the acidity of the TME and activates the CaMKII/CREB/PGC1α mitochondrial biosynthesis signaling pathway, which reprograms the energy metabolism of macrophages and T cells in the TME, and oral NaBi enhances the antitumor effect of oAd-αCD47.

Cytochrome c and cancer cell metabolism: A new perspective

Cytochrome c is a vital electron carrier in the mitochondrial respiratory chain. When the outer membrane of mitochondria becomes permeable, cytochrome c is discharged into the cytoplasm, where it initiates the intrinsic apoptosis pathway. The complex interaction between cytochrome c and apoptosis protease-activating factor-1 (Apaf-1) leads to the formation of the apoptosome and activation of a cascade of caspases, highlighting the critical role of cytochrome c in controlling cell death mechanisms. Additionally, cytochrome c undergoes post-translational modifications, especially phosphorylation, which intricately regulate its roles in both respiration and apoptosis. These modifications add layers of complexity to how cytochrome c effectively controls cellular functions. cytochrome c becomes a lighthouse in the intricate web of cancer, its expression patterns providing hints about prognosis and paths toward treatment. Reduced levels of cytochrome c have been observed in cancer tissues, indicating a potential inhibition of apoptosis. For instance, in glioma tissues, cytochrome c levels were lower compared to healthy tissues, and this reduction became more pronounced in advanced stages of the disease. However, the role of cytochrome c in cancer becomes more intricate as it becomes intertwined with the metabolic reprogramming of cancer cells. This suggests that cytochrome c plays a crucial role in tumor progression and resistance to treatment. Viewing cytochrome c as a molecular mosaic reveals that it is not merely a protein, but also a central player in determining cellular fate. This realization opens up exciting avenues for potential advancements in cancer diagnosis and treatment strategies. Despite the advancements made, the narrative surrounding cytochrome c remains incomplete, urging further exploration into its complexities and the biological implications linked to cancer. cytochrome c stands as a beacon of hope and a promising target for therapy in the battle against cancer, particularly due to its significant involvement in tumor metabolism. It holds the potential for a future where innovative solutions can be developed to address the intricate challenges of cellular fate. In this review, we have endeavored to illuminate the multifaceted domain of cytochrome c drawing connections among apoptosis, metabolic reprogramming, and the Warburg effect in the context of cancer.

Understanding Metabolic Pathway Rewiring by Oncogenic Gamma Herpesvirus

Gamma herpesviruses, including Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV), are key contributors to the development of various cancers through their ability to manipulate host cellular pathways. This review explores the intricate ways these viruses rewire host metabolic pathways to sustain viral persistence and promote tumorigenesis. We look into how EBV and KSHV induce glycolytic reprogramming, alter mitochondrial function, and remodel nucleotide and amino acid metabolism, highlighting the crucial role of lipid metabolism in these oncogenic processes. By understanding these metabolic alterations, which confer proliferative and survival advantages to the virus-infected cells, we can identify potential therapeutic targets and develop innovative treatment strategies for gamma herpesvirus-associated malignancies. Ultimately, this review underscores the critical role of metabolic reprogramming in gamma herpesvirus oncogenesis and its implications for precision medicine in combating virus-driven cancers.

Prediction of prognosis and immune response in lung adenocarcinoma based on mitophagy and lactate-related gene signatures

BACKGROUND

Lung adenocarcinoma (LUAD) causes leading death worldwide. Mitophagy and lactate metabolism accumulation are distinctive features of LUAD. We aimed to identify lactate-related genes (LRGs) signatures based on mitophagy for predicting prognosis and immune response in LUAD.

METHODS

The gene expression and clinical data were downloaded from TCGA and GEO database. First, the subtype analysis was analyzed based on 29 mitophagy genes. Survival, immune, and function differences between the different subtypes were analyzed. Then, based on mitophagy genes and 14 LRGs, the best LRGs were screened to construct a risk score model and combined with clinical factors to establish a nomogram for predicting patient survival. Finally, the expression level and molecular function of the key candidate gene OGDH were verified by in vitro experiments.

RESULTS

All the LUAD samples were divided into 2 subtypes: sub1 and sub2. The sub2 possessed worse survival. Immune score, immune checkpoint genes, and human leucocyte antigen genes in sub1 were higher than in sub2. Six optimal mitophagy-related LRGs were used to construct a risk score model. A high-risk score indicates poorer survival, higher tumor mutation burden, and higher drug sensitivity. The nomogram was robust in predicting LUAD survival. The experiments in vitro showed that knockdown of OGDH inhibited the proliferation, migration and invasion in LUAD cells.

CONCLUSIONS

A nomogram based on the construction of the mitophagy-related lactate genes predicts prognosis and immune response in LUAD. These results could help with risk stratification and targeted therapy for LUAD.

Intrathecal lactate dehydrogenase A inhibitors FX11 and oxamate alleviate chronic constriction injury-induced nociceptive sensitization through neuroinflammation and angiogenesis

BACKGROUND

Neuropathic pain involves neuroinflammation and upregulation of glycolysis in the central nervous system. Unfortunately, few effective treatments are available for managing this type of pain. The overactivation of lactate dehydrogenase A (LDHA), an essential enzyme in glycolysis, can cause neuroinflammation and nociception. This study investigated the spinal role of LDHA in neuropathic pain.

METHOD

Using immunohistochemical analysis, nociceptive behavior, and western blotting, we evaluated the cellular mechanisms of intrathecal administration of LDHA inhibitors, including FX11 and oxamate, in chronic constriction injury (CCI)-induced neuropathic rats.

RESULT

FX11 and oxamate attenuated CCI-induced neuronal LDHA upregulation and nociceptive sensitization. Moreover, CCI-induced neuroinflammation, microglial polarization, and angiogenesis were attenuated by LDHA inhibitors. These inhibitors regulate the TANK binding kinase-1 (TBK1)/hypoxia-inducible factor 1 subunit alpha (HIF-1α) axis, crucial for controlling inflammation and new blood vessel growth. Additionally, CCI-induced nuclear LDHA translocation, as associated with oxidative stress resistance, was attenuated by LDHA inhibitors.

CONCLUSION

In conclusion, LDHA may be a potential therapeutic target for treating neuropathic pain by regulating neuroinflammation and angiogenesis.

From metabolic byproduct to immune modulator: the role of lactate in tumor immune escape

Lactic acid, a key metabolic byproduct within the tumor microenvironment, has garnered significant attention for its role in immune evasion mechanisms. Tumor cells produce and release large amounts of lactic acid into the tumor microenvironment through aberrant glycolysis via the Warburg effect, leading to a drop in pH. Elevated lactic acid levels profoundly suppress proliferation capacity, cytotoxic functions, and migratory abilities of immune effector cells such as macrophages and natural killer cells at the tumor site. Moreover, lactic acid can modulate the expression of surface molecules on immune cells, interfering with their recognition and attack of tumor cells, and it regulates signaling pathways that promote the expansion and enhanced function of immunosuppressive cells like regulatory T cells, thereby fostering immune tolerance within the tumor microenvironment. Current research is actively exploring strategies targeting lactic acid metabolism to ameliorate tumor immune evasion. Key approaches under investigation include inhibiting the activity of critical enzymes in lactic acid production to reduce its synthesis or blocking lactate transporters to alter intracellular and extracellular lactate distribution. These methods hold promise when combined with existing immunotherapies such as immune checkpoint inhibitors and chimeric antigen receptor T-cell therapies to enhance the immune system's ability to eliminate tumor cells. This could pave the way for novel combinatorial treatment strategies in clinical cancer therapy, effectively overcoming tumor immune evasion phenomena, and ultimately improving overall treatment efficacy.

Metabolic reprogramming and therapeutic resistance in primary and metastatic breast cancer

Metabolic alterations, a hallmark of cancer, enable tumor cells to adapt to their environment by modulating glucose, lipid, and amino acid metabolism, which fuels rapid growth and contributes to treatment resistance. In primary breast cancer, metabolic shifts such as the Warburg effect and enhanced lipid synthesis are closely linked to chemotherapy failure. Similarly, metastatic lesions often display distinct metabolic profiles that not only sustain tumor growth but also confer resistance to targeted therapies and immunotherapies. The review emphasizes two major aspects: the mechanisms driving metabolic resistance in both primary and metastatic breast cancer, and how the unique metabolic environments in metastatic sites further complicate treatment. By targeting distinct metabolic vulnerabilities at both the primary and metastatic stages, new strategies could improve the efficacy of existing therapies and provide better outcomes for breast cancer patients.

Emerging Role of Extracellular pH in Tumor Microenvironment as a Therapeutic Target for Cancer Immunotherapy

Identifying definitive biomarkers that predict clinical response and resistance to immunotherapy remains a critical challenge. One emerging factor is extracellular acidosis in the tumor microenvironment (TME), which significantly impairs immune cell function and contributes to immunotherapy failure. However, acidic conditions in the TME disrupt the interaction between cancer and immune cells, driving tumor-infiltrating T cells and NK cells into an inactivated, anergic state. Simultaneously, acidosis promotes the recruitment and activation of immunosuppressive cells, such as myeloid-derived suppressor cells and regulatory T cells (Tregs). Notably, tumor acidity enhances exosome release from Tregs, further amplifying immunosuppression. Tumor acidity thus acts as a "protective shield," neutralizing anti-tumor immune responses and transforming immune cells into pro-tumor allies. Therefore, targeting lactate metabolism has emerged as a promising strategy to overcome this barrier, with approaches including buffer agents to neutralize acidic pH and inhibitors to block lactate production or transport, thereby restoring immune cell efficacy in the TME. Recent discoveries have identified genes involved in extracellular pH (pHe) regulation, presenting new therapeutic targets. Moreover, ongoing research aims to elucidate the molecular mechanisms driving extracellular acidification and to develop treatments that modulate pH levels to enhance immunotherapy outcomes. Additionally, future clinical studies are crucial to validate the safety and efficacy of pHe-targeted therapies in cancer patients. Thus, this review explores the regulation of pHe in the TME and its potential role in improving cancer immunotherapy.

Analysis of immune status and prognostic model incorporating lactic acid metabolism-associated genes

BACKGROUND

Cancer development is intricately linked with metabolic dysregulation, including lactic acid metabolism, which plays a pivotal role in tumor progression and immune evasion. However, its specific implications in gastric adenocarcinoma (STAD) remain unclear. This study introduces a novel methodology to evaluate lactic acid metabolism comprehensively in STAD, aiming to elucidate its prognostic significance and impact on immunotherapy efficacy. Targeted therapies directed at key lactic acid metabolism genes (LMGs) identified within the tumor microenvironment (TME) hold promise for personalized treatment strategies.

METHODS

Lactic acid metabolism patterns were assessed in 415 STAD patients using a panel of 21 LMGs. Cox regression and Lasso regression analyses were employed to develop a predictive risk model based on differentially expressed genes (DEGs). Validation of the model was conducted using independent cohorts from the GEO and TCGA databases, as well as additional datasets focused on immunotherapy responses. Further investigations into TME dynamics of lactic acid metabolism included functional assays targeting SLC16A3, a pivotal gene identified through our analyses.

RESULTS

Patients were stratified into distinct risk groups based on their lactic acid metabolism profiles. Low-risk patients exhibited attenuated lactic acid metabolism, correlating with favorable clinical outcomes characterized by prolonged survival and enhanced responsiveness to immunotherapy. Notably, tumor cells within the TME demonstrated heightened levels of active lactic acid metabolism, particularly impacting tumor-infiltrating lymphocytes such as CD8 + T cells and regulatory T cells. Mechanistically, SLC16A3 emerged as a critical regulator promoting STAD cell proliferation, invasion, and migration while modulating the metabolic landscape.

CONCLUSION

This study underscores the prognostic value of a lactic acid metabolism-based model in STAD, providing insights into its potential as a predictive biomarker for patient stratification and therapeutic targeting. The findings highlight SLC16A3 as a promising candidate for therapeutic intervention aimed at modulating lactic acid metabolism in the TME, thereby advancing personalized treatment strategies in gastric cancer management.

Engineered Biomimetic Cancer Cell Membrane Nanosystems Trigger Gas-Immunometabolic Therapy for Spinal-Metastasized Tumors

Despite great progress in enhancing tumor immunogenicity, conventional gas therapy cannot effectively reverse the tumor immunosuppressive microenvironment (TIME), limiting immunotherapy. The development of therapeutic gases that are tumor microenvironment responsive and efficiently reverse the TIME for precisely targeted tumor gas-immunometabolic therapy remains a great challenge. In this study, a novel cancer cell membrane-encapsulated pH-responsive nitric oxide (NO)-releasing biomimetic nanosystem (MP@AL) is prepared. Lactate oxidase (Lox) in MP@AL consumed oxygen to promote the decomposition of lactate, a metabolic by-product of tumor glycolysis, and the generation of H2O2, while L-arginine (L-Arg) in MP@AL is oxidized by H2O2 to generate nitric oxide (NO). For one thing, NO led to mitochondrial dysfunction in tumor cells to reduce oxygen consumption and promote the efficiency of Lox in lactate decomposition, thus reversing lactate-induced TIME; for another, NO effectively triggered immunogenic cell death, activated anti-tumor immune response and long-term immune memory, and ensured a favorable effect in the synergistic interaction with PD-L1 antibody for inhibiting tumor growth and recurrence. Therefore, a novel gas-immunometabolic therapy dual closed-loop nanosystem for enhancing tumor immunogenicity and remodeling lactate-induced TIME is established. Overall, this work will provide new ideas for gas therapy to effectively remodel the TIME to enhance cancer immunotherapy.

Targeting Disulfidptosis with Potentially Bioactive Natural Products in Metabolic Cancer Therapy

BACKGROUND

Metabolic cancers are defined by metabolic reprogramming. Although this reprograming drives rapid tumour growth and invasion, it also reveals specific metabolic vulnerabilities that can be therapeutically exploited in cancer therapy. A novel form of programmed cell death, known as disulfidptosis, was identified last year; tumour cells with high SLC7A11 expression undergo disulfidptosis when deprived of glucose. Natural products have attracted increasing attention and have shown potential to treat metabolic cancers through diverse mechanisms.

METHODS

We systematically searched electronic databases involving PubMed, Web of Science, Gooale Scholar. To ensue comprehensive exploration, keywords including metabolic reprogramming, metabolic cancer, disulfidptosis, natural products and some other words were employed.

RESULTS

In this review, we focus on the shared characteristics and metabolic vulnerabilities of metabolic cancers. Additionally, we discuss the molecular mechanisms underlying disulfidptosis and highlight key regulatory genes. Furthermore, we predict bioactive natural products that target disulfidptosis-related genes, offering new perspectives for anticancer strategies through the modulation of disulfidptosis.

CONCLUSIONS

By summarizing current research progress, this review mainly analyzed the potential mechanisms of natural products in the treatment of metabolic cancer.

Emerging Mechanisms of Physical Exercise Benefits in Adjuvant and Neoadjuvant Cancer Immunotherapy

The primary factors that can be modified in one's lifestyle are the most influential determinants and significant preventable causes of various types of cancer. Exercise has demonstrated numerous advantages in preventing cancer and aiding in its treatment. However, the precise mechanisms behind these effects are still not fully understood. To contribute to our comprehension of exercise's impact on cancer immunotherapy and provide recommendations for future research in exercise oncology, we will examine the roles and underlying mechanisms of exercise on immune cells. In addition to reducing the likelihood of developing cancer, exercise can also improve the effectiveness of certain approved anticancer treatments, such as targeted therapy, immunotherapy, and radiotherapy. Exercise is a pivotal modulator of the immune response, and thus, it can play an emerging important role in new immunotherapies. The mechanisms responsible for these effects involve the regulation of intra-tumoral angiogenesis, myokines, adipokines, their associated pathways, cancer metabolism, and anticancer immunity. Our review assesses the potential of physical exercise as an adjuvant/neoadjuvant tool, reducing the burden of cancer relapse, and analyzes emerging molecular mechanisms predicting favorable adjuvanticity effects.

Old concepts, new tricks: How peptide vaccines are reshaping cancer immunotherapy?

Over the past few decades, research on cancer immunotherapy has firmly established immune cells as key players in effective cancer treatment. Peptide vaccines directly targeting immune cells have demonstrated immense potential due to their specificity and applicability. However, developing peptide vaccines to generate tumor-reactive T cells remains challenging, primarily due to suboptimal immunogenicity and overcoming the immunosuppressive tumor microenvironment (TME). In this review, we discuss various elements of effective peptide vaccines, including antigen selection, peptide epitope optimization, vaccine adjuvants, and the combination of multiple immunotherapies, in addition to recent advances in tumor neoantigens as well as epitopes bound by non-classical human leukocyte antigen (HLA) molecules, to increase the understanding of cancer peptide vaccines and provide multiple references for the design of subsequent T cell-based peptide vaccines.

Mechanism of 5-fluorouracil induced resistance and role of piperine and curcumin as chemo-sensitizers in colon cancer

Among cancer-related deaths worldwide, colorectal cancer ranks second, accounting for 1.2% of deaths in those under 50 years and 0.6% of deaths in those between 50 and 54 years. The anticancer drug 5-fluorouracil is widely used to treat colorectal cancer. Due to a better understanding of the drug's mechanism of action, its anticancer activity has been increased through a variety of therapeutic alternatives. Clinical use of 5-FU has been severely restricted due to drug resistance. The chemoresistance mechanism of 5-FU is challenging to overcome because of the existence of several drug efflux transporters, DNA repair enzymes, signaling cascades, classical cellular processes, cancer stem cells, metastasis, and angiogenesis. Curcumin, a potent phytocompound derived from Curcuma longa, functions as a nuclear factor (NF)-κB inhibitor and sensitizer to numerous chemotherapeutic drugs. Piperine, an alkaloid found in Piper longum, inhibits cancer cell growth, causing cell cycle arrest and apoptosis. This review explores the mechanism of 5-FU-induced chemoresistance in colon cancer cells and the role of curcumin and piperine in enhancing the sensitivity of 5-FU-based chemotherapy. CLINICAL TRIAL REGISTRATION: Not applicable.

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

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

Copper homeostasis and copper-induced cell death in tumor immunity: implications for therapeutic strategies in cancer immunotherapy

Copper is an important trace element for maintaining key biological functions such as cellular respiration, nerve conduction, and antioxidant defense. Maintaining copper homeostasis is critical for human health, and its imbalance has been linked to various diseases, especially cancer. Cuproptosis, a novel mechanism of copper-induced cell death, provides new therapeutic opportunities for metal ion regulation to interact with cell fate. This review provides insights into the complex mechanisms of copper metabolism, the molecular basis of cuproptosis, and its association with cancer development. We assess the role of cuproptosis-related genes (CRGs) associated with tumorigenesis, their importance as prognostic indicators and therapeutic targets, and the impact of copper homeostasis on the tumor microenvironment (TME) and immune response. Ultimately, this review highlights the complex interplay between copper, cuproptosis, and cancer immunotherapy.

Harnessing the Power of Sugar-Based Nanoparticles: A Drug-Free Approach to Enhance Immune Checkpoint Inhibition against Glioblastoma and Pancreatic Cancer

Cancer cells have a high demand for sugars and express diverse carbohydrate receptors, offering opportunities to improve delivery with multivalent glycopolymer materials. However, effectively delivering glycopolymers to tumors while inhibiting cancer cell activity, altering cellular metabolism, and reversing tumor-associated macrophage (TAM) polarization to overcome immunosuppression remains a challenging area of research due to the lack of reagents capable of simultaneously achieving these objectives. Here, the glycopolymer-like condensed nanoparticle (∼60 nm) was developed by a one-pot carbonization reaction with a single precursor, promoting multivalent interactions for the galactose-related receptors of the M2 macrophage (TAM) and thereby regulating the STAT3/NF-κB pathways. The subsequently induced M2-to-M1 transition was increased with the condensed level of glycopolymer-like nanoparticles. We found that the activation of the glycopolymer-like condensed galactose (CG) nanoparticles influenced monocarboxylate transporter 4 (MCT-4) function, which caused inhibited lactate efflux (similar to inhibitor effects) from cancer cells. Upon internalization via galactose-related endocytosis, CG NPs induced cellular reactive oxygen species (ROS), leading to dual functionalities of cancer cell death and M2-to-M1 macrophage polarization, thereby reducing the tumor's acidic microenvironment and immunosuppression. Blocking the nanoparticle-MCT-4 interaction with antibodies reduced their toxicity in glioblastoma (GBM) and affected macrophage polarization. In orthotopic GBM and pancreatic cancer models, the nanoparticles remodeled the tumor microenvironment from "cold" to "hot", enhancing the efficacy of anti-PD-L1/anti-PD-1 therapy by promoting macrophage polarization and activating cytotoxic T lymphocytes (CTLs) and dendritic cells (DCs). These findings suggest that glycopolymer-like nanoparticles hold promise as a galactose-elicited adjuvant for precise immunotherapy, particularly in targeting hard-to-treat cancers.

The signature of extracellular vesicles in hypoxic breast cancer and their therapeutic engineering

Breast cancer (BC) currently ranks second in the global cancer incidence rate. Hypoxia is a common phenomenon in BC. Under hypoxic conditions, cells in the tumor microenvironment (TME) secrete numerous extracellular vesicles (EVs) to achieve intercellular communication and alter the metabolism of primary and metastatic tumors that shape the TME. In addition, emerging studies have indicated that hypoxia can promote resistance to tumor treatment. Engineered EVs are expected to become carriers for cancer treatment due to their high biocompatibility, low immunogenicity, high drug delivery efficiency, and ease of modification. In this review, we summarize the mechanisms of EVs in the primary TME and distant metastasis of BC under hypoxic conditions. Additionally, we highlight the potential applications of engineered EVs in mitigating the malignant phenotypes of BC cells under hypoxia.

Targeting PLCG2 Suppresses Tumor Progression, Orchestrates the Tumor Immune Microenvironment and Potentiates Immune Checkpoint Blockade Therapy for Colorectal Cancer

Background: Tumor progression and limited benefits of immune checkpoint blockade (ICB) therapy have been two major challenges in the clinical management of colorectal cancer (CRC). The objective of our research was to explore the role of PLCG2 in CRC progression, tumor microenvironment, and potentiating ICB therapy. Methods: Based on bioinformatics analysis and a prospective clinical observational study, the expression, prognostic significance, and clinical relevance of PLCG2 in CRC were unveiled. The single-cell and spatial transcriptome revealed the role of PLCG2 in shaping the heterogeneity of the CRC tumor microenvironment. The biological function of PLCG2 was validated by in vivo and in vitro experiments. The underlying mechanisms were elucidated by RNA-seq, western blotting, qRT-PCR, and multicolor immunofluorescence. The multiplex immunohistochemistry and flow cytometry were adopted to clarify the immunomodulatory role of PLCG2 in facilitating CRC immune escape. The translational value of targeting PLCG2 to potentiate the efficacy of ICB therapy and synergistic therapy to improve prognosis was explored in the preclinical animal models. Results: In CRC, PLCG2 exhibited high expression levels and was strongly associated with poor prognosis and advanced clinicopathological characteristics of patients. The single-cell transcriptome shed light on its important role in cell communication and the development and differentiation of immune cells. The spatial transcriptome described the spatial distribution of PLCG2 in CRC tissues. Further mechanistic analysis demonstrated that PLCG2 could promote proliferation, invasion, metastasis, epithelial-mesenchymal transition, and cell cycle regulation and inhibit apoptosis of CRC cells via the Akt-mTOR pathway activation. Furthermore, PLCG2 was found to contribute greatly to the immunosuppressive microenvironment and enhanced immune escape as it significantly suppressed the infiltration and functional activation of CD8+ T cells and promoted the infiltration of Treg cells as well as PD-1 and PD-L1 expression. Meanwhile, knockdown of PLCG2 could potentiate the efficacy of ICB therapy. Conclusion: In summary, we have identified for the first time that PLCG2 could be considered a precise biomarker and promising therapeutic target for predicting CRC prognosis, optimizing individualized treatment, reversing CRC immune escape, and overcoming resistance to ICB therapy.

Metabolic regulation of the immune system in health and diseases: mechanisms and interventions

Metabolism, including glycolysis, oxidative phosphorylation, fatty acid oxidation, and other metabolic pathways, impacts the phenotypes and functions of immune cells. The metabolic regulation of the immune system is important in the pathogenesis and progression of numerous diseases, such as cancers, autoimmune diseases and metabolic diseases. The concept of immunometabolism was introduced over a decade ago to elucidate the intricate interplay between metabolism and immunity. The definition of immunometabolism has expanded from chronic low-grade inflammation in metabolic diseases to metabolic reprogramming of immune cells in various diseases. With immunometabolism being proposed and developed, the metabolic regulation of the immune system can be gradually summarized and becomes more and more clearer. In the context of many diseases including cancer, autoimmune diseases, metabolic diseases, and many other disease, metabolic reprogramming occurs in immune cells inducing proinflammatory or anti-inflammatory effects. The phenotypic and functional changes of immune cells caused by metabolic regulation further affect and development of diseases. Based on experimental results, targeting cellular metabolism of immune cells becomes a promising therapy. In this review, we focus on immune cells to introduce their metabolic pathways and metabolic reprogramming, and summarize how these metabolic pathways affect immune effects in the context of diseases. We thoroughly explore targets and treatments based on immunometabolism in existing studies. The challenges of translating experimental results into clinical applications in the field of immunometabolism are also summarized. We believe that a better understanding of immune regulation in health and diseases will improve the management of most diseases.

Nanobiotechnology boosts ferroptosis: opportunities and challenges

Ferroptosis, distinct from apoptosis, necrosis, and autophagy, is a unique type of cell death driven by iron-dependent phospholipid peroxidation. Since ferroptosis was defined in 2012, it has received widespread attention from researchers worldwide. From a biochemical perspective, the regulation of ferroptosis is strongly associated with cellular metabolism, primarily including iron metabolism, lipid metabolism, and redox metabolism. The distinctive regulatory mechanism of ferroptosis holds great potential for overcoming drug resistance-a major challenge in treating cancer. The considerable role of nanobiotechnology in disease treatment has been widely reported, but further and more systematic discussion on how nanobiotechnology enhances the therapeutic efficacy on ferroptosis-associated diseases still needs to be improved. Moreover, while the exciting therapeutic potential of ferroptosis in cancer has been relatively well summarized, its applications in other diseases, such as neurodegenerative diseases, cardiovascular and cerebrovascular diseases, and kidney disease, remain underreported. Consequently, it is necessary to fill these gaps to further complete the applications of nanobiotechnology in ferroptosis. In this review, we provide an extensive introduction to the background of ferroptosis and elaborate its regulatory network. Subsequently, we discuss the various advantages of combining nanobiotechnology with ferroptosis to enhance therapeutic efficacy and reduce the side effects of ferroptosis-associated diseases. Finally, we analyze and discuss the feasibility of nanobiotechnology and ferroptosis in improving clinical treatment outcomes based on clinical needs, as well as the current limitations and future directions of nanobiotechnology in the applications of ferroptosis, which will not only provide significant guidance for the clinical applications of ferroptosis and nanobiotechnology but also accelerate their clinical translations.

Potentiated Calcium Carbonate with Enhanced Calcium Overload Induction and Acid Neutralization Capabilities to Boost Chemoimmunotherapy against Liver Cancer

Unfavorable phenotypes characterized by low immunogenicity and acidity within the tumor microenvironment (TME) contribute to immunosuppression and therapeutic resistance. Herein, we rationally synthesized a multifunctional nanoregulator by encapsulating DOX and erianin into calcium carbonate (CaCO3)-based nanoparticles using a modified double emulsion method. The DOX and erianin-loaded CaCO3-based nanoparticles, termed DECaNPs, could effectively induce the calcium overload by triggering calcium influx and absorbing CaCO3 nanoparticles. Additionally, DECaNPs also neutralize the acidic TME by interacting with extracellular protons and limiting lactic acid production, a result of metabolic remodeling in cancer cells. As a result, DECaNPs elicit cellular oxidative stress damage, which mediates the activation of ferroptosis/apoptosis hybrid pathways, and profound immunogenic cell death. Treatment with DECaNPs could inhibit the growth of tumors by promoting oxidative stress, acid neutralization, metabolic remodeling, and protective antitumor immunity in vivo. In addition, DECaNPs could synergistically amplify the antitumor effects of αPD-L1 in a bilateral tumor model by eliciting systemic immune responses. In all, our work presents the preparation of CaCO3-based nanoregulators designed to reverse the unfavorable TME and enhance αPD-L1 immunotherapy through multiple mechanisms.

Prognostic Analysis of Lactic Acid Metabolism Genes in Oral Squamous Cell Carcinoma

OBJECTIVES

Oral squamous cell carcinoma (OSCC) is the most common malignant tumour in the oral and maxillofacial region. Lactic acid accumulation in the tumour microenvironment (TME) has gained attention for its dual role as an energy source for cancer cells and an activator of signalling pathways crucial to tumour progression. This study aims to reveal the impact of lactate-related genes (LRGs) on the prognosis, TME, and immune characteristics of OSCC, with the ultimate goal of developing a novel prognostic model.

METHODS

Unsupervised clustering analysis of LRGs in OSCC patients from The Cancer Genome Atlas database was conducted to evaluate and compare TME, immune features, and clinical characteristics across various lactate subtypes. A refined prognostic model was developed through the application of Cox and Least absolute shrinkage and selection operator (LASSO) regression techniques. External validation sets were then utilised to improve model accuracy, along with a detailed correlation analysis of drug sensitivity.

RESULTS

The Cancer Genome Atlas-OSCC patients were categorised into 4 distinct lactate subtypes based on LRGs. Notably, patients in subtype 1 and subtype 2 exhibited the least and most favourable prognoses, respectively. Subtype 1 patients showed elevated expression levels of immune checkpoint genes. Further analysis identified 1086 genes with significant expression differences between cancer and noncancer tissues, as well as between subtype 1 and subtype 2 patients. Selected genes for the prognostic model included ZNF662, CGNL1, VWCE, and ZFP42. The high-risk group defined by this model had a significantly poorer prognosis (P < .0001) and functioned as an independent prognostic factor (P < .001), accurately predicting 1-, 3-, and 5-year survival rates. Additionally, individuals in the high-risk category exhibited heightened sensitivity to chemotherapy drugs such as AZ6102 and Venetoclax.

CONCLUSIONS

The predictive model based on the genes ZNF662, CGNL1, VWCE, and ZFP42 can serve as a reliable biomarker, providing accurate prognostic predictions for OSCC patients and potential opportunities for pharmaceutical interventions.

The Use of Patient-Derived Organoids in the Study of Molecular Metabolic Adaptation in Breast Cancer

Around 13% of women will likely develop breast cancer during their lifetime. Advances in cancer metabolism research have identified a range of metabolic reprogramming events, such as altered glucose and amino acid uptake, increased reliance on glycolysis, and interactions with the tumor microenvironment (TME), all of which present new opportunities for targeted therapies. However, studying these metabolic networks is challenging in traditional 2D cell cultures, which often fail to replicate the three-dimensional architecture and dynamic interactions of real tumors. To address this, organoid models have emerged as powerful tools. Tumor organoids are 3D cultures, often derived from patient tissue, that more accurately mimic the structural and functional properties of actual tumor tissues in vivo, offering a more realistic model for investigating cancer metabolism. This review explores the unique metabolic adaptations of breast cancer and discusses how organoid models can provide deeper insights into these processes. We evaluate the most advanced tools for studying cancer metabolism in three-dimensional culture models, including optical metabolic imaging (OMI), matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI), and recent advances in conventional techniques applied to 3D cultures. Finally, we explore the progress made in identifying and targeting potential therapeutic targets in breast cancer metabolism.

Targeting Lactate: An Emerging Strategy for Macrophage Regulation in Chronic Inflammation and Cancer

Lactate accumulation and macrophage infiltration are pivotal features of both chronic inflammation and cancer. Lactate, once regarded merely as an aftereffect of glucose metabolism, is now gaining recognition for its burgeoning spectrum of biological roles and immunomodulatory significance. Recent studies have evidenced that macrophages display divergent immunophenotypes in different diseases, which play a pivotal role in disease management by modulating macrophage polarization within the disease microenvironment. The specific polarization patterns of macrophages in a high-lactate environment and their contribution to the progression of chronic inflammation and cancer remain contentious. This review presents current evidence on the crosstalk of lactate and macrophage in chronic inflammation and cancer. Additionally, we provide an in-depth exploration of the pivotal yet enigmatic mechanisms through which lactate orchestrates disease pathogenesis, thereby offering novel perspectives to the development of targeted therapeutic interventions for chronic inflammation and cancer.

Lactate's impact on immune cells in sepsis: unraveling the complex interplay

Lactate significantly impacts immune cell function in sepsis and septic shock, transcending its traditional view as just a metabolic byproduct. This review summarizes the role of lactate as a biomarker and its influence on immune cell dynamics, emphasizing its critical role in modulating immune responses during sepsis. Mechanistically, key lactate transporters like MCT1, MCT4, and the receptor GPR81 are crucial in mediating these effects. HIF-1α also plays a significant role in lactate-driven immune modulation. Additionally, lactate affects immune cell function through post-translational modifications such as lactylation, acetylation, and phosphorylation, which alter enzyme activities and protein functions. These interactions between lactate and immune cells are central to understanding sepsis-associated immune dysregulation, offering insights that can guide future research and improve therapeutic strategies to enhance patient outcomes.

Roles of the tumor microenvironment in the resistance to programmed cell death protein 1 inhibitors in patients with gastric cancer

Despite the continuous developments and advancements in the treatment of gastric cancer (GC), which is one of the most prevalent types of cancer in China, the overall survival is still poor for most patients with advanced GC. In recent years, with the progress in tumor immunology research, attention has shifted toward immunotherapy as a therapeutic approach for GC. Programmed cell death protein 1 (PD-1) inhibitors, as novel immunosuppressive medications, have been widely utilized in the treatment of GC. However, many patients are still resistant to PD-1 inhibitors and experience recurrence in the advanced stages of PD-1 immunotherapy. To reduce the occurrence of drug resistance and recurrence in GC patients receiving PD-1 immunotherapy, to maximize the clinical activity of immunosuppressive drugs, and to elicit a lasting immune response, it is essential to research the tumor microenvironment mechanisms leading to PD-1 inhibitor resistance in GC patients. This article reviews the progress in studying the factors influencing the resistance to PD-1 inhibitors in the GC tumor microenvironment, aiming to provide insights and a basis for reducing resistance to PD-1 inhibitors for GC patients in the future.

Metabolic reprogramming and immune evasion: the interplay in the tumor microenvironment

Tumor cells possess complex immune evasion mechanisms to evade immune system attacks, primarily through metabolic reprogramming, which significantly alters the tumor microenvironment (TME) to modulate immune cell functions. When a tumor is sufficiently immunogenic, it can activate cytotoxic T-cells to target and destroy it. However, tumors adapt by manipulating their metabolic pathways, particularly glucose, amino acid, and lipid metabolism, to create an immunosuppressive TME that promotes immune escape. These metabolic alterations impact the function and differentiation of non-tumor cells within the TME, such as inhibiting effector T-cell activity while expanding regulatory T-cells and myeloid-derived suppressor cells. Additionally, these changes lead to an imbalance in cytokine and chemokine secretion, further enhancing the immunosuppressive landscape. Emerging research is increasingly focusing on the regulatory roles of non-tumor cells within the TME, evaluating how their reprogrammed glucose, amino acid, and lipid metabolism influence their functional changes and ultimately aid in tumor immune evasion. Despite our incomplete understanding of the intricate metabolic interactions between tumor and non-tumor cells, the connection between these elements presents significant challenges for cancer immunotherapy. This review highlights the impact of altered glucose, amino acid, and lipid metabolism in the TME on the metabolism and function of non-tumor cells, providing new insights that could facilitate the development of novel cancer immunotherapies.

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

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

Unlocking the potential: Targeting metabolic pathways in the tumor microenvironment for Cancer therapy

Cancer incidence and mortality are increasing and impacting global life expectancy. Metabolic reprogramming in the tumor microenvironment (TME) is intimately related to tumorigenesis, progression, metastasis and drug resistance. Tumor cells drive metabolic reprogramming of other cells in the TME through metabolic induction of cytokines and metabolites, and metabolic substrate competition. Consequently, this boosts tumor cell growth by providing metabolic support and facilitating immunosuppression and angiogenesis. The metabolic interplay in the TME presents potential therapeutic targets. Here, we focus on the metabolic reprogramming of four principal cell subsets in the TME: CAFs, TAMs, TILs and TECs, and their interaction with tumor cells. We also summarize medications and therapies targeting these cells' metabolic pathways, particularly in the context of immune checkpoint blockade therapy.

New Metabolomic Insights Into Cancer

ABSTRACT

Cancer has been marked by metabolic irregularities that fuel various aggressive activities such as rapid cell proliferation, evasion of the immune system, and spread to distant organs. Therefore, exploiting cancer metabolism for diagnosis, monitoring, or treatment has been extensively studied in the past couple of decades with various molecular and cellular techniques. More recently, investigating cancer diagnostics and treatments through advanced metabolomics has emerged, and these comprehensive approaches provide a holistic understanding of cancer metabolism, which supported the discovery of metabolic targets relevant across multiple cancer types and the development of more effective treatments. This study offers highlights of new knowledge on cancer metabolism enabled by recent metabolomics studies and their potential applications in aiding cancer research and predicting cancer treatment outcomes. Specifically, we discussed the use of advanced metabolomics in cancer metabolism, tumor microenvironment, and cancer immunotherapy studies to provide valuable insights that can shape future research efforts in the dynamic field of cancer metabolism research.

Metabolic vulnerabilities in cancer: A new therapeutic strategy

Cancer metabolism is now a key area for therapeutic intervention, targeting unique metabolic reprogramming crucial for tumor growth and survival. This article reviews the therapeutic potential of addressing metabolic vulnerabilities through glycolysis and glutaminase inhibitors, which disrupt cancer cell metabolism. Challenges such as tumor heterogeneity and adaptive resistance are discussed, with strategies including personalized medicine and predictive biomarkers to enhance treatment efficacy. Additionally, integrating diet and lifestyle changes with metabolic targeting underscores a holistic approach to improving therapy outcomes. The article also examines the benefits of incorporating these strategies into standard care, highlighting the potential for more tailored, safer treatments. In conclusion, exploiting metabolic vulnerabilities promises a new era in oncology, positioning metabolic targeting at the forefront of personalized cancer therapy and transforming patient care.

Glioblastoma stem cell metabolism and immunity

Despite enormous efforts being invested in the development of novel therapies for brain malignancies, there remains a dire need for effective treatments, particularly for pediatric glioblastomas. Their poor prognosis has been attributed to the fact that conventional therapies target tumoral cells, but not glioblastoma stem cells (GSCs). GSCs are characterized by self-renewal, tumorigenicity, poor differentiation, and resistance to therapy. These characteristics represent the fundamental tools needed to recapitulate the tumor and result in a relapse. The mechanisms by which GSCs alter metabolic cues and escape elimination by immune cells are discussed in this article, along with potential strategies to harness effector immune cells against GSCs. As cellular immunotherapy is making significant advances in a variety of cancers, leveraging this underexplored reservoir may result in significant improvements in the treatment options for brain malignancies.

From Crypts to Cancer: A Holistic Perspective on Colorectal Carcinogenesis and Therapeutic Strategies

Colorectal cancer (CRC) represents a significant global health burden, with high incidence and mortality rates worldwide. Recent progress in research highlights the distinct clinical and molecular characteristics of colon versus rectal cancers, underscoring tumor location's importance in treatment approaches. This article provides a comprehensive review of our current understanding of CRC epidemiology, risk factors, molecular pathogenesis, and management strategies. We also present the intricate cellular architecture of colonic crypts and their roles in intestinal homeostasis. Colorectal carcinogenesis multistep processes are also described, covering the conventional adenoma-carcinoma sequence, alternative serrated pathways, and the influential Vogelstein model, which proposes sequential APC, KRAS, and TP53 alterations as drivers. The consensus molecular CRC subtypes (CMS1-CMS4) are examined, shedding light on disease heterogeneity and personalized therapy implications.

Recent developments in immunotherapy for gastrointestinal tract cancers

The past few decades have witnessed the rise of immunotherapy for Gastrointestinal (GI) tract cancers. The role of immune checkpoint inhibitors (ICIs), particularly programmed death protein 1 (PD-1) and PD ligand-1 antibodies, has become increasingly pivotal in the treatment of advanced and perioperative GI tract cancers. Currently, anti-PD-1 plus chemotherapy is considered as first-line regimen for unselected advanced gastric/gastroesophageal junction adenocarcinoma (G/GEJC), mismatch repair deficient (dMMR)/microsatellite instability-high (MSI-H) colorectal cancer (CRC), and advanced esophageal cancer (EC). In addition, the encouraging performance of claudin18.2-redirected chimeric antigen receptor T-cell (CAR-T) therapy in later-line GI tract cancers brings new hope for cell therapy in solid tumour treatment. Nevertheless, immunotherapy for GI tumour remains yet precise, and researchers are dedicated to further maximising and optimising the efficacy. This review summarises the important research, latest progress, and future directions of immunotherapy for GI tract cancers including EC, G/GEJC, and CRC.

ALDH1A1 promotes immune escape of tumor cells through ZBTB7B-glycolysis pathway

The primary impediment to the success of immunotherapy lies in the immune evasion orchestrated by tumors, contributing to the suboptimal overall response rates observed. Despite this recognition, the intricacies of the underlying mechanisms remain incompletely understood. Through preliminary detection of clinical patient tissues, we have found that ALDH1A1 was a key gene for the prognosis of cancer patients and tumor glycolysis. In vitro experiments and tumor formation in nude mice suggested that targeting ALDH1A1 could inhibit tumor growth. Through further analysis of xenograft tumor models in immune-normal mice and flow cytometry, we found that deficiency in ALDH1A1 could promote immune system suppression of tumors in vivo. Specifically, RNA-seq analysis, combined with qPCR and western blot, identified the transcription factor ZBTB7B as downstream of ALDH1A1. The binding sites of the transcription factor ZBTB7B on the LDHA promoter region, which is responsible for regulating the rate-limiting enzyme gene LDHA in glycolysis, were determined using luciferase reporter gene detection and Chip-qPCR, respectively. In addition, the increased SUMOylation of ZBTB7B stabilized its transcriptional activity. Further in vivo and in vitro experiments confirmed that the combination of targeting ALDH1A1 and ZBTB7B with immune checkpoint inhibitors could synergistically inhibit tumors in vivo. Finally, after conducting additional verification of patient tissue and clinical data, we have confirmed the potential translational value of targeting ALDH1A1 and ZBTB7B for tumor immunotherapy. These results emphasize the potential translational significance of targeting ALDH1A1 and ZBTB7B in the realm of tumor immunotherapy. The convergence of ALDH1A1 inhibition and immune checkpoint blockade, particularly with PD-L1/PD-1 mAb, presents a compelling avenue for curtailing tumor immune escape.

Biomimetic gold nanocages incorporating copper-human serum albumin for tumor immunotherapy via cuproptosis-lactate regulation

Cancer immunotherapy remains a significant challenge due to insufficient proliferation of immune cells and the sturdy immunosuppressive tumor microenvironment. Herein, we proposed the hypothesis of cuproptosis-lactate regulation to provoke cuproptosis and enhance anti-tumor immunity. For this purpose, copper-human serum albumin nanocomplex loaded gold nanocages with bacterial membrane coating (BAu-CuNCs) were developed. The targeted delivery and disassembly of BAu-CuNCs in tumor cells initiated a cascade of reactions. Under near infrared (NIR) laser irradiation, the release of copper-human serum albumin (Cu-HSA) was enhanced that reacted with intratumoral glutathione (GSH) via a disulfide exchange reaction to liberate Cu2+ ions and exert cuproptosis. Subsequently, the cuproptosis effect triggered immunogenic cell death (ICD) in tumor by the release of damage associated molecular patterns (DAMPs) to realize anti-tumor immunity via robust production of cytotoxic T cells (CD8+) and helper T cells (CD4+). Meanwhile, under NIR irradiation, gold nanocages (AuNCs) promoted excessive reactive oxygen species (ROS) generation that played a primary role in inhibiting glycolysis, reducing the lactate and ATP level. The combine action of lower lactate level, ATP reduction and GSH depletion further sensitized the tumor cells to cuproptosis. Also, the lower lactate production led to the significant blockage of immunosuppressive T regulatory cells (Tregs) and boosted the anti-tumor immunity. Additionally, the effective inhibition of breast cancer metastasis to the lungs enhanced the anti-tumor therapeutic impact of BAu-CuNCs + NIR treatment. Hence, BAu-CuNCs + NIR concurrently induced cuproptosis, ICD and hindered lactate production, leading to the inhibition of tumor growth, remodeling of the immunosuppressive tumor microenvironment and suppression of lung metastasis. Therefore, leveraging cuproptosis-lactate regulation, this approach presents a novel strategy for enhanced tumor immunotherapy.

The Interplay between Metabolic Adaptations and Diet in Cancer Immunotherapy

Over the past decade, cancer immunotherapy has significantly advanced through the introduction of immune checkpoint inhibitors and the augmentation of adoptive cell transfer to enhance the innate cancer defense mechanisms. Despite these remarkable achievements, some cancers exhibit resistance to immunotherapy, with limited patient responsiveness and development of therapy resistance. Metabolic adaptations in both immune cells and cancer cells have emerged as central contributors to immunotherapy resistance. In the last few years, new insights emphasized the critical role of cancer and immune cell metabolism in animal models and patients. During therapy, immune cells undergo important metabolic shifts crucial for their acquired effector function against cancer cells. However, cancer cell metabolic rewiring and nutrient competition within tumor microenvironment (TME) alters many immune functions, affecting their fitness, polarization, recruitment, and survival. These interactions have initiated the development of novel therapies targeting tumor cell metabolism and favoring antitumor immunity within the TME. Furthermore, there has been increasing interest in comprehending how diet impacts the response to immunotherapy, given the demonstrated immunomodulatory and antitumor activity of various nutrients. In conclusion, recent advances in preclinical and clinical studies have highlighted the capacity of immune-based cancer therapies. Therefore, further exploration into the metabolic requirements of immune cells within the TME holds significant promise for the development of innovative therapeutic approaches that can effectively combat cancer in patients.

7-amino carboxycoumarin 2 inhibits lactate induced epithelial-to-mesenchymal transition via MPC1 in oral and breast cancer cells

Lactate is an oncometabolite that play important role in tumor aggressiveness. Lactate from the tumor microenvironment (TME) is taken up by cancer cells as an energy resource via mitochondrial oxidative phosphorylation (or OXPHOS). In the present study, by using an online meta-analysis tool we demonstrated that in oral squamous cancer cells (OSCCs) glycolytic and OXPHOS governing genes are overexpressed, like in breast cancer. For experimental demonstration, we treated the OSCC cell line (SCC4) and breast cancer cells (MDA-MB-231) with sodium L-lactate and analyzed its effects on changes in EMT and migration. For the therapeutic intervention of lactate metabolism, we used AZD3965 (an MCT1 inhibitor), and 7ACC2 (an MPC inhibitor). Like breast cancer, oral cancer tissues showed increased transcripts of 12 genes that were previously shown to be associated with glycolysis and OXPHOS. We experimentally demonstrated that L-lactate treatment induced mesenchymal markers and migration of cancer cells, which was significantly neutralized by MPC inhibitor that is, 7ACC2. Such an effect on EMT status was not observed with AZD3965. Furthermore, we showed that lactate treatment increases the MPC1 expression in both cancer cells, and this might be the reason why cancer cells in the high lactate environment are more sensitive to 7ACC2. Overall, our present findings demonstrate that extracellular lactate positively regulates the MPC1 protein expression in cancer cells, thereby putting forward the notion of using 7ACC2 as a potential therapeutic alternative to inhibit malignant oxidative cancers. Future preclinical studies are warranted to validate the present findings.

The role of immune metabolism in skin cancers: implications for pathogenesis and therapy

The skin is a complex organ that serves as a critical barrier against external pathogens and environmental impact. Recent advances in immunometabolism have highlighted the intricate link between cellular metabolism and immune function, particularly in the context of skin cancers. This review aims to provide a comprehensive overview of the key metabolic pathways and adaptations that occur in immune cells during homeostasis and activation, and explore how metabolic reprogramming contributes to the pathogenesis of specific skin cancers. We discuss the complex interplay between tumor cells and infiltrating immune cells, which shapes the tumor microenvironment and influences disease outcomes. The review delves into the role of various metabolic pathways, such as glycolysis, oxidative phosphorylation, and lipid metabolism, in the regulation of immune cell function and their impact on the development and progression of skin cancers. Furthermore, we examine the potential of targeting metabolic pathways as a therapeutic strategy in skin cancers and discuss the challenges and future perspectives in this rapidly evolving field. By understanding the metabolic basis of skin immune responses, we can develop novel, personalized therapies for the treatment of skin cancers, ultimately improving patient outcomes and quality of life. The insights gained from this review will contribute to the growing body of knowledge in immunometabolism and its application in the management of skin cancers, paving the way for more effective and targeted interventions in the future.

Hallmarks of perineural invasion in pancreatic ductal adenocarcinoma: new biological dimensions

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignant tumor with a high metastatic potential. Perineural invasion (PNI) occurs in the early stages of PDAC with a high incidence rate and is directly associated with a poor prognosis. It involves close interaction among PDAC cells, nerves and the tumor microenvironment. In this review, we detailed discuss PNI-related pain, six specific steps of PNI, and treatment of PDAC with PNI and emphasize the importance of novel technologies for further investigation.