Dietary restriction of cysteine and methionine sensitizes gliomas to ferroptosis and induces alterations in energetic metabolism

Neuroferroptosis in health and diseases

Ferroptosis is a type of cell death process defined by iron-dependent peroxidation of phospholipids leading to the destruction of cellular membranes and death of the cell. Ferroptosis occurs throughout the body, but a considerable research focus on ferroptosis in the brain - neuroferroptosis - has been driven by the rich lipid and iron content of the brain as well as its high oxygen consumption. Neurons also have an exceptionally large surface area and metabolic demand, which necessitates specific mechanisms (such as lipid antioxidants) to engage constantly to protect the plasma membrane against lipid peroxidation. Ferroptosis has been extensively linked to neurodegeneration and ischaemia and is increasingly implicated in physiological processes such as neuronal reprogramming. Astrocytes provide metabolic support to neurons, enabling them to defend against ferroptosis, yet ferroptotic signals in microglia can propagate damage to astrocytes and neurons, highlighting the complex intercellular (patho)physiology of neuroferroptosis.

Therapeutic and prognostic values of ferroptosis signature in glioblastoma

Ferroptosis is a regulated cell death process that results in decreased tumor growth and aggressiveness when targeted in various cancer cells. Studying the impact of ferroptosis in glioblastoma (GBM) will provide important knowledge about tumor biology and potential treatment strategies. The high metabolic activity resulting in ROS production, iron content and active lipid metabolism of glioblastoma cells make them particularly susceptible to ferroptosis. Single-cell RNA sequencing reveals the molecular signature of GBM and its tumor microenvironment, introducing ferroptosis-related biomarkers pathways and drug resistance mechanisms to enhance treatment outcomes for GBM patients. The relationship between ferroptosis and the immune landscape in GBM is complex and can have either positive or negative effects. These effects can be identified through single-cell RNA sequencing to develop targeted chemo-, radio- and immuno- therapies against glioma stem cells and tumor-supportive immune cells. Additionally, the implication of oncolytic virotherapy in combination with ferroptosis induction can lead to improved treatment of GBM in a clinical setting.

Walnut oil as a dietary intervention for atherosclerosis: Efficacy and mechanistic pathways

BACKGROUND AND AIMS

Walnut oil (WO) and peanut oil (PO) are common vegetable oils rich in unsaturated fatty acids, known to alleviate atherosclerosis (AS) and reduce the risk of cardiovascular diseases (CVD). WO contains a higher proportion of polyunsaturated fatty acids (PUFAs) compared to PO. This study aimed to explore the influence of WO on AS and elucidate its potential mechanisms, providing a theoretical basis for enhancing the application of WO in functional foods and pharmaceuticals.

METHODS

AS was established in rats using a high-fat diet and vitamin D3 injections. Rats with AS were administered WO or PO via gavage at a dose of 1.2 g/kg for 4 weeks. Serum lipid levels and arterial injury were assessed, and transcriptomic and metabolomic analyses of the rat vasculature were performed.

RESULTS

Both WO and PO significantly lowered serum lipid levels and the atherogenic index (AI) in rats, reducing arterial wall injury and plaque formation. WO exhibited a more pronounced effect, particularly in decreasing serum levels of TG, TC, HDLC, and LDL-C. Transcriptomic analysis indicated that fatty acid, amino acid metabolism were crucial in AS development due to a high-fat diet. Metabolomic analysis indicated significant changes in the metabolism of arginine, proline, cysteine, methionine, glycine, serine and threonine in rats treated with WO.

CONCLUSION

WO and PO help alleviate AS by regulating lipid metabolism and influencing pivotal metabolic pathways like TCA cycle and cysteine-methionine metabolism. The more significant impact of WO indicates its potential as a dietary supplement for preventing and treating AS.

Sarcosine sensitizes lung adenocarcinoma to chemotherapy by dual activation of ferroptosis via PDK4/PDHA1 signaling and NMDAR-mediated iron export

BACKGROUND

Ferroptosis, a regulated cell death driven by iron-dependent lipid peroxidation, is associated with chemoresistance in lung adenocarcinoma (LUAD). This study aims to investigate the role of sarcosine in ferroptosis and its underlying mechanisms.

METHODS

An RSL3-induced ferroptosis model was used to screen a library of 889 human endogenous metabolites and metabolomic profiling was harnessed to identify metabolites associated with ferroptosis. Cell viability, lipid-reactive oxygen species (ROS), ferrous iron, malondialdehyde (MDA), and mitochondrial integrity were assessed to evaluate sarcosine's effects on ferroptosis. Metabolic fate was studied using 15N-labeled sarcosine. Next, we used untargeted metabolomic profiling and next-generation sequencing to dissect metabolic and transcriptomic changes upon sarcosine supplementation. The effects of sarcosine on ferroptosis and chemotherapy were further validated in patient-derived organoids (PDOs), xenograft models, and LUAD tissues.

RESULTS

Sarcosine emerged as a potent ferroptosis inducer in the metabolic library screening, which was further confirmed via cell viability, lipid-ROS, ferrous iron, and MDA measurements. Metabolic flux analysis showed limited conversion of sarcosine to other metabolites in LUAD cells, while untargeted metabolomic profiling and seahorse assays indicated a metabolic shift from glycolysis to oxidative phosphorylation. Sarcosine enhanced pyruvate dehydrogenase activity to generate more ROS by interacting with PDK4, reducing PDHA1 phosphorylation. As a co-activator of N-methyl-D-aspartate receptor (NMDAR), sarcosine also exerted its pro-ferroptosis effect via regulating ferrous export through the NMDAR/MXD3/SLC40A1 axis. Given the significance of ferroptosis in chemotherapy, we validated that sarcosine enhanced the sensitization of cisplatin by promoting ferroptosis in LUAD cells, PDOs, and xenograft models.

CONCLUSION

Sarcosine promotes ferroptosis and enhances chemosensitivity, suggesting its potential as a therapeutic agent in treating LUAD.

IDH status dictates oHSV mediated metabolic reprogramming affecting anti-tumor immunity

Identification of isocitrate dehydrogenase (IDH) mutations has uncovered the crucial role of metabolism in gliomagenesis. Oncolytic herpes virus (oHSV) initiates direct tumor debulking by tumor lysis and activates anti-tumor immunity, however, little is known about the role of glioma metabolism in determining oHSV efficacy. Here we identify that oHSV rewires central carbon metabolism increasing glucose utilization towards oxidative phosphorylation and shuttling glutamine towards reductive carboxylation in IDH wildtype glioma. The switch in metabolism results in increased lipid synthesis and cellular ROS. PKC induces ACSL4 in oHSV treated cells leading to lipid peroxidation and ferroptosis. Ferroptosis is critical to launch an anti-tumor immune response which is important for viral efficacy. Mutant IDH (IDHR132H) gliomas are incapable of reductive carboxylation and hence ferroptosis. Pharmacological blockade of IDHR132H induces ferroptosis and anti-tumor immunity. This study provides a rationale to use an IDHR132H inhibitor to treat high grade IDH-mutant glioma patients undergoing oHSV treatment.

Glutathione-specific gamma-glutamylcyclotransferase 1 (CHAC1) increases kidney disease risk by modulating ferroptosis

Genome-wide association studies (GWASs) have identified more than 1000 loci where genetic variants correlate with kidney function. However, the specific genes, cell types, and mechanisms influenced by these genetic variants remain largely uncharted. Here, we identified glutathione-specific gamma-glutamylcyclotransferase 1 (CHAC1) on chromosome 15 as affected by GWAS variants by analyzing human kidney gene expression and methylation information. Both CHAC1 RNA and protein were expressed in the loop of Henle region in mouse and human kidneys, and CHAC1 expression was higher in patients carrying disease risk variants. Using CRISPR technology, we created mice with a single functional copy of the Chac1 gene (Chac1+/-) that displayed no baseline phenotypic alterations in kidney structure or function. These mice demonstrated resilience to kidney disease in multiple models, including folic acid-induced nephropathy, adenine-induced chronic kidney disease, and uninephrectomy-streptozotocin-induced diabetic nephropathy. We further showed that CHAC1 plays a critical role in degrading the cellular antioxidant glutathione. Tubule cells isolated from Chac1+/- mice showed increased glutathione, decreased lipid peroxidation, improved cell viability, and protection against ferroptosis. Expression of ferroptosis-associated genes was also lower in mice with only one copy of Chac1. Higher CHAC1 protein also correlated with ferroptosis-related protein abundance in kidney biopsies from patients with kidney disease. This study positions CHAC1 as an important mediator of kidney disease that influences glutathione concentrations and ferroptosis, suggesting potential avenues to explore for the treatment of kidney diseases.

Iron, lipid peroxidation, and ferroptosis play pathogenic roles in atherosclerosis

Oxidation of lipids, excessive cell death, and iron deposition are prominent features of human atherosclerotic plaques. While extensive research has established the detrimental roles of lipid oxidation and apoptosis in atherosclerosis development, the involvement of iron in atherogenesis is not yet fully understood. With the emergence of an iron-dependent form of cell death termed ferroptosis, new attention has been brought to the complex inter-play among iron, ferroptosis, and atherosclerosis. Mechanistically, ferroptosis is caused by the lethal accumulation of iron-mediated lipid peroxides. Emerging studies have underscored ferroptosis as a contributor to worsened atherosclerosis. Herein, we review the evidence that oxidative damage and iron overload in the context of atherosclerosis may promote ferroptosis within plaques. Furthermore, we summarize recent findings of lipid peroxidation, thereby potentially ferroptosis, in various plaque cell types-such as endothelial cells, macrophages, dendritic cells, T cells, and vascular smooth muscle cells-across different stages of atherosclerosis. Understanding how these processes influence atherosclerotic plaque progression may permit targeting stage-dependent ferroptosis in each cell population and could provide a rationale for developing cell type-specific intervention strategies to mitigate atherogenic ferroptosis effectively.

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.

Mechanisms of ferroptosis sensitization and resistance

Ferroptosis is an iron-dependent and oxidative form of non-apoptotic cell death with roles in development, homeostasis, and disease. Ferroptosis sensitivity can vary between cells, often for reasons that are not well understood. In this perspective, we describe the core ferroptosis mechanism and outline how changes in iron, redox, and lipid metabolism can alter ferroptosis sensitivity. We propose the concept of a ferroptosis sensitivity-resistance continuum to describe how different intrinsic and extrinsic factors interact to push cells toward a more ferroptosis-sensitive or ferroptosis-resistant state, with effects on development and diseases such as cancer.

PRMT5-mediated arginine methylation stabilizes GPX4 to suppress ferroptosis in cancer

The activation of ferroptosis has shown great potential for cancer therapy from an unconventional perspective, but revealing the mechanisms underlying the suppression of tumour-intrinsic ferroptosis to promote tumorigenesis remains a challenging task. Here we report that methionine is metabolized into S-adenosylmethionine, which functions as a methyl-group donor to trigger symmetric dimethylation of glutathione peroxidase 4 (GPX4) at the conserved arginine 152 (R152) residue, along with a prolonged GPX4 half-life. Inhibition of protein arginine methyltransferase 5 (PRMT5), which catalyses GPX4 methylation, decreases GPX4 protein levels by impeding GPX4 methylation and increasing ferroptosis inducer sensitivity in vitro and in vivo. This methylation prevents Cullin1-FBW7 E3 ligase binding to GPX4, thereby abrogating the ubiquitination-mediated GPX4 degradation. Notably, combining PRMT5 inhibitor treatment with ferroptotic therapies markedly suppresses tumour progression in mouse tumour models. In addition, the levels of GPX4 are negatively correlated with the levels of FBW7 and a poor prognosis in patients with human carcinoma. In summary, we found that PRMT5 functions as a target for improving cancer therapy efficacy, by acting to reduce the counteraction of ferroptosis by tumour cells by means of PRMT5-enhanced GPX4 stability.

Adaptation mechanisms in cancer: Lipid metabolism under hypoxia and nutrient deprivation as a target for novel therapeutic strategies (Review)

Tumor tissues generally exist in a relatively hypovascular state, and cancer cells must adapt to severe tissue conditions with a limited molecular oxygen and nutrient supply for their survival. Lipid metabolism serves a role in this adaptation. Lipids are supplied not only through the bloodstream but also through autonomous synthesis by cancer cells, and they function as sources of adenosine triphosphate and cell components. Although cancer‑associated lipid metabolism has been widely reviewed, how this metabolism responds to the tumor environment with poor molecular oxygen and nutrient supply remains to be fully discussed. The main aim of the present review was to summarize the findings on this issue and to provide insights into how cancer cells adapt to better cope with metabolic stresses within tumors. It may be suggested that diverse types of lipid metabolism have a role in enabling cancer cells to adapt to both hypoxia and nutrient‑poor conditions. Gaining a deeper understanding of these molecular mechanisms may reveal novel possibilities of exploration for cancer treatment.

Methionine cycle inhibition disrupts antioxidant metabolism and reduces glioblastoma cell survival

Glioblastoma (GBM) is a highly aggressive primary malignant adult brain tumor that inevitably recurs with a fatal prognosis. This is due in part to metabolic reprogramming that allows tumors to evade treatment. Therefore, we must uncover the pathways mediating these adaptations to develop novel and effective treatments. We searched for genes that are essential in GBM cells as measured by a whole-genome pan-cancer CRISPR screen available from DepMap and identified the methionine metabolism genes MAT2A and AHCY. We conducted genetic knockdown, evaluated mitochondrial respiration, and performed targeted metabolomics to study the function of these genes in GBM. We demonstrate that MAT2A or AHCY knockdown induces oxidative stress, hinders cellular respiration, and reduces the survival of GBM cells. Furthermore, selective MAT2a or AHCY inhibition reduces GBM cell viability, impairs oxidative metabolism, and shifts the cellular metabolic profile towards oxidative stress and cell death. Mechanistically, MAT2a and AHCY regulate spare respiratory capacity, the redox buffer cystathionine, lipid and amino acid metabolism, and prevent oxidative damage in GBM cells. Our results point to the methionine metabolic pathway as a novel vulnerability point in GBM.

Glioma-induced alterations in excitatory neurons are reversed by mTOR inhibition

Gliomas are aggressive neoplasms that diffusely infiltrate the brain and cause neurological symptoms, including cognitive deficits and seizures. Increased mTOR signaling has been implicated in glioma-induced neuronal hyperexcitability, but the molecular and functional consequences have not been identified. Here, we show three types of changes in tumor-associated neurons: (1) downregulation of transcripts encoding excitatory and inhibitory postsynaptic proteins and dendritic spine development and upregulation of cytoskeletal transcripts via neuron-specific profiling of ribosome-bound mRNA, (2) marked decreases in dendritic spine density via light and electron microscopy, and (3) progressive functional alterations leading to neuronal hyperexcitability via in vivo calcium imaging. A single acute dose of AZD8055, a combined mTORC1/2 inhibitor, reversed these tumor-induced changes. These findings reveal mTOR-driven pathological plasticity in neurons at the infiltrative margin of glioma and suggest new strategies for treating glioma-associated neurological symptoms.

Amino acid metabolism in glioblastoma pathogenesis, immune evasion, and treatment resistance

Glioblastoma (GBM) ranks among the most lethal primary tumors of the central nervous system. This is partly due to its complex intracellular metabolism and interactions with the surrounding tumor microenvironment (TME). Compelling evidence represents that altered amino acids (AAs) metabolism plays a crucial role in both areas. The role of AAs and their metabolites in glioma biology is an emerging topic. Therefore, this review was conducted to summarize the current knowledge about the molecular mechanisms by which AAs participate in the GBM pathogenesis. AAs can directly influence tumor progression by affecting tumor cell metabolism or indirectly by releasing bioactive agents through particular metabolic pathways. This review begins by examining the metabolic pathways of essential AAs, such as tryptophan, tyrosine, and phenylalanine, which contribute to synthesizing critical neurotransmitters and shape tumor metabolism signatures. We explore how these pathways impact tumor growth and immune modulation, focusing on how AAs and their metabolites can promote malignant properties in GBM cells. AAs also play a pivotal role in reprogramming the TME, contributing to immune evasion and resistance to therapy. The review further discusses how tumor metabolism signatures, influenced by AA metabolism, can enhance the immunosuppressive microenvironment, providing new avenues for targeted immunotherapies. Finally, we outline potential therapeutic strategies to modulate AA metabolism and emphasize critical opportunities for future research to improve GBM management.

Exploiting the gut microbiome for brain tumour treatment

Increasing evidence suggests that the gut microbiome plays a key role in a host of pathological conditions, including cancer. Indeed, the bidirectional communication that occurs between the gut and the brain, known as the 'gut-brain axis,' has recently been implicated in brain tumour pathology. Here, we focus on current research that supports a gut microbiome-brain tumour link with emphasis on high-grade gliomas, the most aggressive of all brain tumours, and the impact on the glioma tumour microenvironment. We discuss the potential use of gut-brain axis signals to improve responses to current and future therapeutic approaches. We highlight that the success of novel treatment strategies may rely on patient-specific microbiome profiles, and these should be considered for personalised treatment approaches.

Emerging role of ferroptosis in ultraviolet radiation-driven skin photoaging: a narrative review

Photoaging is characterized by chronic inflammation in response to ultraviolet (UV) radiation. UV radiation causes skin cells to produce reactive oxygen species (ROS), which causes oxidative stress and inflammation. ROS can reversibly or irreversibly destroy different cellular compounds, including nucleic acids, proteins, free amino acids, lipids, lipoproteins, carbohydrates, and connective tissue macromolecules. Ferroptosis is a kind of programmed cell death caused by iron dependence and lipid peroxidation and has been recently discovered. Its occurrence is primarily related to iron metabolism, antioxidants, lipid peroxidation, and other processes. In addition, high levels of ROS can trigger oxidative stress, altering the redox balance within cells and thus initiating ferroptosis. Ferroptosis has been implicated in UV-driven skin photoaging. Moreover, UV radiation from sunlight can regulate numerous ferroptosis-linked genes. This review will focus on the function of ferroptosis in UV radiation-damaged skin cells. We hope to draw attention to the significance of ferroptosis regulation in the prevention and treatment of skin photoaging.

Inhibition of glutathione peroxidase 4 suppresses gastric cancer peritoneal metastasis via regulation of RCC2 homeostasis

Gastric cancer (GC) is one of the most lethal malignancies due to high metastatic rate, making the identification of new therapeutic targets critical for developing effective anti-GC treatments. Glutathione peroxidase 4 (GPx4), a key regulator of ferroptosis and redox homeostasis, contributes to progression and influences patient survival. However, the molecular mechanism by which GPx4 drives GC progression has not been fully illuminated. In this study, we found that GPx4 was overexpressed and negatively associated with poor prognosis and distant metastasis, as confirmed by single-cell RNA sequencing (scRNA-seq) and validation with retrospective clinical samples. GPx4 knockdown suppressed GC invasion, migration and peritoneal metastasis in vitro and in vivo. Proteomic analysis revealed that GPx4 expression regulated the Homeostasis of RCC2, an oncogene link to epithelial-mesenchymal transition (EMT). Furthermore, we demonstrated that the reactive oxygen species (ROS) accumulation induced by GPx4 inhibition or knockdown activated aurora A phosphorylation, leading to RCC2 ubiquitination and degradation, thereby suppressing peritoneal metastasis in GC. We also identified that the Thr418 phosphorylation site is crucial for RCC2 ubiquitination at the K377, initiating its degradation in response to ROS. In conclusion, our results indicate that GPx4 acts as an oncogene in GC, and that suppressing GPx4 prevents GC progression and metastasis by promoting ROS-induced RCC2 ubiquitination and degradation.

Inactivation of necroptosis-promoting protein MLKL creates a therapeutic vulnerability in colorectal cancer cells

Mortality from colorectal cancer (CRC) is significant, and novel CRC therapies are needed. A pseudokinase MLKL typically executes necroptotic cell death, and MLKL inactivation protects cells from such death. However, we found unexpectedly that MLKL gene knockout enhanced CRC cell death caused by a protein synthesis inhibitor homoharringtonine used for chronic myeloid leukemia treatment. In an effort to explain this finding, we observed that MLKL gene knockout reduces the basal CRC cell autophagy and renders such autophagy critically dependent on the presence of VPS37A, a component of the ESCRT-I complex. We further found that the reason why homoharringtonine enhances CRC cell death caused by MLKL gene knockout is that homoharringtonine activates p38 MAP kinase and thereby prevents VPS37A from supporting autophagy in MLKL-deficient cells. We observed that the resulting inhibition of the basal autophagy in CRC cells triggers their parthanatos, a cell death type driven by poly(ADP-ribose) polymerase hyperactivation. Finally, we discovered that a pharmacological MLKL inhibitor necrosulfonamide strongly cooperates with homoharringtonine in suppressing CRC cell tumorigenicity in mice. Thus, while MLKL promotes cell death during necroptosis, MLKL supports the basal autophagy in CRC cells and thereby protects them from death. MLKL inactivation reduces such autophagy and renders the cells sensitive to autophagy inhibitors, such as homoharringtonine. Hence, MLKL inhibition creates a therapeutic vulnerability that could be utilized for CRC treatment.

Targeting pancreatic cancer glutamine dependency confers vulnerability to GPX4-dependent ferroptosis

Pancreatic ductal adenocarcinoma (PDAC) relies heavily on glutamine (Gln) utilization to meet its metabolic and biosynthetic needs. How epigenetic regulators contribute to the metabolic flexibility and PDAC's response and adaptation to Gln scarcity in the tumor milieu remains largely unknown. Here, we elucidate that prolonged Gln restriction or treatment with the Gln antagonist, 6-diazo-5-oxo-L-norleucine (DON), leads to growth inhibition and ferroptosis program activation in PDAC. A CRISPR-Cas9 screen identifies an epigenetic regulator, Paxip1, which promotes H3K4me3 upregulation and Hmox1 transcription upon DON treatment. Additionally, ferroptosis-related repressors (e.g., Slc7a11 and Gpx4) are increased as an adaptive response, thereby predisposing PDAC cells to ferroptosis upon Gln deprivation. Moreover, DON sensitizes PDAC cells to GPX4 inhibitor-induced ferroptosis, both in vitro and in patient-derived xenografts (PDXs). Taken together, our findings reveal that targeting Gln dependency confers susceptibility to GPX4-dependent ferroptosis via epigenetic remodeling and provides a combination strategy for PDAC therapy.

Dietary and nutritional interventions for human diseases: their modulatory effects on ferroptosis

A balanced diet is essential for maintaining human health. Increasing evidence suggests that dietary and nutritional interventions contribute to disease management and are associated with reduced healthcare costs and economic burden. Ferroptosis, a novel type of regulated cell death (RCD) driven by lipid peroxidation, has been shown to be involved in various pathological conditions, including diabetes, ischemia/reperfusion (I/R) injury, inflammation-related diseases, and cancer. Therefore, specifically targeting the uncontrolled ferroptosis process may offer new therapeutic opportunities. Of note, certain interventions, such as small-molecule compounds, natural products, herbal medicines, and non-pharmacological approaches, have been reported to prevent and treat multiple human diseases by reversing the dysregulation of ferroptosis. In this review, we present the key molecular mechanisms that regulate ferroptosis. Importantly, interventions targeting ferroptosis are summarized from the perspective of dietary patterns, food and nutrients. By understanding these advances, innovative ideas can be provided for individualized dietary interventions and treatment strategies.

Global research landscape and hotspots for ferroptosis in glioma: A comprehensive bibliometric and visual analysis

Studying ferroptosis is crucial for understanding the mechanisms underlying the onset and progression of glioblastoma, identifying therapeutic targets, and improving prognosis assessment and diagnostic methods. While recent research has explored the link between ferroptosis and glioblastoma, there is a lack of comprehensive bibliometric analyses specifically addressing this relationship and its connection to glioblastoma. To address this gap, we conducted a thorough analysis of 225 relevant articles on glioma and ferroptosis obtained from the Web of Science database covering the period from 2012 to 2023, employing rigorous exclusion criteria. Visual and statistical analyses were performed using CiteSpace, VOSviewer, R Studio Plotting, and Scimago Graphica Beta. Our findings revealed a significant exponential growth in the number of studies during the last decade. China, the United States, and Germany made the most substantial contributions to research in this field, collectively accounting for 76.2 % of the total research output. Notably, Central South University, Shandong University, and Zhejiang University emerged as leaders in both literature production and research collaboration. Frontiers in Oncology stood out as the most prolific journal, encompassing a wide array of topics from molecular mechanisms to potential therapeutic strategies. Visual keyword analysis highlighted "tumor biology" "cell death mechanisms" and "gene expression and metabolic processes" as central themes in the research network. This study offers a comprehensive visual perspective on the global publication landscape of ferroptosis in glioma, providing valuable insights for researchers seeking to understand the current state of the field and identify potential directions for future studies.

Targeting amino acid metabolism to inhibit gastric cancer progression and promote anti-tumor immunity: a review

The incidence of gastric cancer remains high and poses a serious threat to human health. Recent comprehensive investigations into amino acid metabolism and immune system components within the tumor microenvironment have elucidated the functional interactions between tumor cells, immune cells, and amino acid metabolism. This study reviews the characteristics of amino acid metabolism in gastric cancer, with a particular focus on the metabolism of methionine, cysteine, glutamic acid, serine, taurine, and other amino acids. It discusses the relationship between these metabolic processes, tumor development, and the body's anti-tumor immunity, and analyzes the importance of targeting amino acid metabolism in gastric cancer for chemotherapy and immunotherapy.

Multifaceted interplays between the essential players and lipid peroxidation in ferroptosis

Ferroptosis, a type of programmed cell death, represents a distinct paradigm in cell biology. It is characterized by the iron-dependent accumulation of reactive oxygen species, which induce lipid peroxidation (LPO), and is orchestrated by the interplay between iron, lipid peroxides, and glutathione. In this review, we emphasize the frequently overlooked role of iron in LPO beyond the classical iron-driven Fenton reaction in several crucial processes that regulate cellular iron homeostasis, including iron intake and export as well as ferritinophagy, and the emerging roles of endoplasmic reticulum-resident flavoprotein oxidoreductases, especially P450 oxidoreductases, in modulating LPO. We summarize how various types of fatty acids (FAs), including saturated, monounsaturated, and polyunsaturated FAs, differentially influence ferroptosis when incorporated into phospholipids. Furthermore, we highlight the therapeutic potential of targeting LPO to mitigate ferroptosis and discuss the regulatory mechanisms of endogenous lipophilic radical-trapping antioxidants that confer resistance to ferroptosis, shedding light on therapeutic avenues for ferroptosis-associated diseases.

Nanomaterial-enabled metabolic reprogramming strategies for boosting antitumor immunity

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

Angelic acid triggers ferroptosis in colorectal cancer cells via targeting and impairing NRF2 protein stability

Ferroptosis is a unique programmed cell death driven by iron-dependent phospholipid peroxidation. Tumor cells that escape from the conventional therapies appear more sensitive to ferroptosis. Therefore, it is extremely urgent to find safe and efficient active ingredients that induce ferroptosis in tumor cells. Herein, we identified that angelic acid, as a potent anti-tumor active ingredient in Angelica sinensis, profoundly sensitizes CRC cells to ferroptosis via a natural compound library screen. We revealed that angelic acid treatment is sufficient to predispose CRC cells to ferroptosis phenotype, evidenced by malondialdehyde (MDA) accumulation, lipid peroxidation, and upregulation of ferroptosis-associated markers CHAC1 and PTGS2, which is abolished by ferroptosis inhibitor Fer-1. Moreover, the results of network pharmacology showed that NRF2 is critical for angelic acid-mediated CRC cell ferroptosis. Mechanistically, angelic acid exerted its ferroptosis induction via directly binding and facilitating the degradation of NRF2. In addition, the syngeneic mouse models revealed that angelic acid boosts CRC cell sensitivity to ferroptosis inducer sulfasalazine with essentially no toxicity in vivo. Collectively, our findings highlighted a previously unrecognized anti-tumor mechanism of angelic acid and represented an appealing therapeutic strategy for CRC treatment.

Enhanced protection for interfacial lipid ozonolysis by sulfur-containing amino acids

Sulfur-containing amino acids have been proposed as drugs for lipid oxidation associated with diseases for a long time, but the molecular-level mechanism on the effectiveness of sulfur-containing amino acids against lipid oxidation remains elusive. In this work, with the interfacial sensitivity mass spectrometry method, oxidation of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylglycerol (POPG), a widely used model lipid, was significantly inhibited on hung droplet surface in presence of sulfur-containing amino acids, such as cysteine (Cys) and methionine (Met). Both the Cys and Met showed a self-sacrificing protection. The amino acids with -S-R tails (R referring to methyl or t-butyl group) showed more effective against POPG oxidation than those with -SH tails, and this process was not related to the conformations of amino acids. The low effectiveness of Cys during the interfacial chemistry was proved to arise from the formation of disulfide bond. This study extends the current understanding of chemistry of sulfur-containing amino acids and provides insights to aid the sulfur-containing amino acids against cell oxidation.

Potential involvement of cuproptosis induced by m6A-modified autophagy gene ATG10 in KICH : Cuproptosis induced by m6A-modified ATG10 in KICH

Kidney Chromophobe (KICH) is the third most prevalent renal malignancy, with research challenges due to a dearth of cell lines and clinical samples. There is no specific treatment regimen tailored exclusively for KICH. This study employed gene expression analysis, immunohistochemistry (IHC), Spearman's correlation, immune cell infiltration assessment, and molecular network construction to investigate the autophagy gene ATG10 in KICH. ATG10 was uniquely downregulated in KICH, predominantly regulated by RNA m6A methylation. This downregulation correlated with patient survival, suggesting a potential tumor-regulatory role. ATG10's involvement in the protein lipidation pathway, essential for cuproptosis, was identified. B cells and CD8 + T cells were key immune cells in KICH tumorigenesis associated with ATG10. Examination of molecular networks identified several key molecules and mechanisms, including ceRNA, interplaying proteins, and transcription factors. Additionally, drug targeting analysis pointed to specific amino acids and metabolites as potential therapeutic agents. This study elucidates the significance of ATG10 in KICH, implicating m6A methylation and cuproptosis as novel targets for therapeutic intervention. The identification of B cells and CD8 + T cells as key immune components, along with specific amino acids, suggests that a combination of targeted immune therapies and dietary interventions could provide a multifaceted approach to KICH treatment. Given the limited understanding of KICH pathogenesis, our analysis has unveiled new theoretical insights and potential clinical significances for KICH, expected to broaden the research horizon in this field.

A whole food, plant-based diet reduces amino acid levels in patients with metastatic breast cancer

BACKGROUND

Amino acids are critical to tumor survival. Tumors can acquire amino acids from the surrounding microenvironment, including the serum. Limiting dietary amino acids is suggested to influence their serum levels. Further, a plant-based diet is reported to contain fewer amino acids than an animal-based diet. The extent to which a plant-based diet lowers the serum levels of amino acids in patients with cancer is unclear.

METHODS

Patients with metastatic breast cancer (n = 17) were enrolled in a clinical trial with an ad libitum whole food, plant-based diet for 8 weeks without calorie or portion restriction. Dietary changes by participants were monitored using a three-day food record. Serum was collected from participants at baseline and 8 weeks. Food records and serum were analyzed for metabolic changes.

RESULTS

We found that a whole food, plant-based diet resulted in a lower intake of calories, fat, and amino acids and higher levels of fiber. Additionally, body weight, serum insulin, and IGF were reduced in participants. The diet contained lower levels of essential and non-essential amino acids, except for arginine (glutamine and asparagine were not measured). Importantly, the lowered dietary intake of amino acids translated to reduced serum levels of amino acids in participants (5/9 essential amino acids; 4/11 non-essential amino acids).

CONCLUSIONS

These findings provide a tractable approach to limiting amino acid levels in persons with cancer. This data lays a foundation for studying the relationship between amino acids in patients and tumor progression. Further, a whole-food, plant-based diet has the potential to synergize with cancer therapies that exploit metabolic vulnerabilities.

TRIAL REGISTRATION

The clinical trial was registered with ClinicalTrials.gov identifier NCT03045289 on 2017-02-07.

Coumarin-aurone based fluorescence probes for cysteine sensitive in-situ identification in living cells

The quantification of cysteine (Cys) levels in the organisms holds paramount significance in biological research and disease diagnosis, which can give the correlation between abnormal Cys levels and diseases. In this study, two fluorescent probes, designated as DEA-OH and DEA-AC, featuring a coumarin-aurone backbone specifically engineered for Cys detection, were meticulously designed and synthesized. The diethylamino coumarin-aurone probe DEA-OH and the acrylate-substituted probe DEA-AC demonstrated remarkable sensitivity in detecting cysteine by means of copper displacement (DEA-OH) and acrylate hydrolysis mechanisms (DEA-AC) with fluorescence detection limits of 7.25 μM and 1.65 μM, respectively. Moreover, the fluorescence peak wavelength of the two probes displayed a linear relationship with solvent polarity in the ET (30) range of 30-65 kcal•mol-1, indicating the potential for monitoring changes in environmental polarity within this ET (30) range. The outstanding attributes exhibited by DEA-AC including superior photostability, remarkable selectivity, and swift response (kinetic rate constant: 0.00747 s-1), coupled with the exceptional anti-interference ability, have significantly broadened its scope of applications, for example detecting alterations in Cys within biological systems.

Postoperative Injection of a Triptolide-Preloaded Hydrogel Prevents the Recurrence of Glioblastoma by Dual-Pathway Activation of Ferroptosis

Glioblastoma (GBM) recurrence leads to high mortality, which remains a major concern in clinical therapy. Herein, an injectable triptolide (TP)-preloaded hydrogel (TP@DNH) accompanied by a postoperative injection strategy is developed to prevent the recurrence of GBM. With a potential inhibitor of the NRF2/SLC7A11/GPX4 axis, it is demonstrated that TP can deactivate glutathione peroxidase 4 (GPX4) from the source of glutathione (GSH) biosynthesis, thereby activating ferroptosis in GBM cells by blocking the neutralization of intracellular lipid peroxide (LPO). Based on acid-sensitive Fe3+/tannic acid (TA) metal-phenolic networks (MPNs), the TP@DNH hydrogel can induce the effective generation of reactive oxygen species (ROS) through Fe3+/TA-mediated Fenton reaction and achieve controllable release of TP in resected GBM cavity. Due to ROS generation and GPX4 deactivation, postoperative injection of TP@DNH can achieve high-level ferroptosis through dual-pathway LPO accumulation, remarkably suppressing the growth of recurrent GBM and prolonging the overall survival in orthotopic GBM relapse mouse model. This work provides an alternative paradigm for regulating ferroptosis in the postoperative treatment of GBM.

MAT2a and AHCY inhibition disrupts antioxidant metabolism and reduces glioblastoma cell survival

Glioblastoma (GBM) is a highly aggressive primary malignant adult brain tumor that inevitably recurs with a fatal prognosis. This is due in part to metabolic reprogramming that allows tumors to evade treatment. We therefore must uncover the pathways mediating these adaptations to develop novel and effective treatments. We searched for genes that are essential in GBM cells as measured by a whole-genome pan-cancer CRISPR screen available from DepMap and identified the methionine metabolism genes MAT2A and AHCY. We conducted genetic knockdown, evaluated mitochondrial respiration, and performed targeted metabolomics to study the function of these genes in GBM. We demonstrate that MAT2A or AHCY knockdown induces oxidative stress, hinders cellular respiration, and reduces the survival of GBM cells. Furthermore, selective MAT2a or AHCY inhibition reduces GBM cell viability, impairs oxidative metabolism, and changes the metabolic profile of these cells towards oxidative stress and cell death. Mechanistically, MAT2a or AHCY regulates spare respiratory capacity, the redox buffer cystathionine, lipid and amino acid metabolism, and prevents DNA damage in GBM cells. Our results point to the methionine metabolic pathway as a novel vulnerability point in GBM.

Methionine deprivation inhibits glioma proliferation and EMT via the TP53TG1/miR-96-5p/STK17B ceRNA pathway

Recent research highlights the significant impact of methionine metabolism on glioma progression. An increasing amount of compelling evidence bridges long non-coding RNAs to abnormal metabolism in gliomas. However, the specific role of long non-coding RNAs in methionine metabolism regulating glioma progression remains unclear. This study reveals that methionine deprivation inhibits the proliferation, migration, and invasion capabilities of gliomas. Interestingly, the expression of TP53TG1, a long non-coding RNA, is also suppressed. TP53TG1 is highly expressed in gliomas and associated with poor patient outcomes. Subsequently, our data proves that inhibition of TP53TG1 suppresses glioma cell proliferation and the epithelial-mesenchymal transition process both in vitro and in vivo. Ultimately, we found that the underlying mechanism involves a competing endogenous RNA regulating network, in which TP53TG1 modulates the target protein STK17B by competitively binding to miR-96-5p, thus regulating glioma progression. These findings suggest that targeting methionine deprivation could be a promising approach for the clinical treatment of glioma.

Borneol-Functionalized Macrophage Membrane-Encapsulated Mesoporous Selenium Nanoparticles Loaded with Resveratrol for the Treatment of Spinal Cord Injury

Spinal cord injury (SCI) is a serious neurological disease that can result in paralysis. After SCI occurs, the blood-spinal cord barrier (BSCB) is disrupted, and permeability is transiently elevated. However, the permeability of the BSCB returns to normal over time, which prevents many drugs from being used in subsequent treatments. In this study, we designed a borneol-functionalized macrophage membrane encapsulating mesoporous selenium nanoparticles loaded with resveratrol (MSe-Res-BMMs) for SCI treatment. In vivo animal experiments and in vitro cell experiments demonstrated that MSe-Res-BMMs were able to protect neurons from ferroptosis by reducing ROS levels and increasing glutathione peroxidase-4 (GPx-4) activity. In addition, this treatment also reduced ROS-induced inflammation and apoptosis by decreasing the expression of inflammatory factor IL-1β and apoptotic factor Cleaved Caspase-3 at the site of injury. Therefore, MSe-Res-BMMs are expected to provide new therapeutic options for SCI treatment.

Metabolic regulation of the glioblastoma stem cell epitranscriptome by malate dehydrogenase 2

Tumors reprogram their metabolism to generate complex neoplastic ecosystems. Here, we demonstrate that glioblastoma (GBM) stem cells (GSCs) display elevated activity of the malate-aspartate shuttle (MAS) and expression of malate dehydrogenase 2 (MDH2). Genetic and pharmacologic targeting of MDH2 attenuated GSC proliferation, self-renewal, and in vivo tumor growth, partially rescued by aspartate. Targeting MDH2 induced accumulation of alpha-ketoglutarate (αKG), a critical co-factor for dioxygenases, including the N6-methyladenosine (m6A) RNA demethylase AlkB homolog 5, RNA demethylase (ALKBH5). Forced expression of MDH2 increased m6A levels and inhibited ALKBH5 activity, both rescued by αKG supplementation. Reciprocally, targeting MDH2 reduced global m6A levels with platelet-derived growth factor receptor-β (PDGFRβ) as a regulated transcript. Pharmacological inhibition of MDH2 in GSCs augmented efficacy of dasatinib, an orally bioavailable multi-kinase inhibitor, including PDGFRβ. Collectively, stem-like tumor cells reprogram their metabolism to induce changes in their epitranscriptomes and reveal possible therapeutic paradigms.

Mechanism of CXCL8 regulation of methionine metabolism to promote angiogenesis in gliomas

BACKGROUND

Gliomas are the most common malignant brain tumors characterized by angiogenesis and invasive growth. A detailed understanding of its molecular characteristics could provide potential therapeutic targets. In the present study, we sought to explore the key gene CXCL8 in methionine metabolism in gliomas and its potential role in angiogenesis.

METHODS

U251 glioma cells were divided into control and methionine-restriction tolerant (constructed with 1/4 of the standard level of methionine in the culture medium) groups for transcriptome and metabolome analysis. To confirm the functions and mechanism of CXCL8 in glioma, heat map, volcano map, Go enrichment, gene set enrichment analysis (GSEA), protein-protein interaction network analysis, RT-PCR, western blotting assays, chicken embryo chorioallantoic membrane (CAM) test, chicken embryo yolk sac membrane (YSM) test and transplantation tumor nude mice model were performed. The TCGA database, CGGA database and clinical tissue samples were used to analyze CXCL8's significance on prognosis for patients with glioma.

RESULTS

CXCL8 expression was significantly up-regulated in methionine-restricted tolerance cells, it also activated vascular system development and triggered angiogenesis. CXCL8 expression is negatively correlated with survival prognosis in gliomas.

CONCLUSIONS

Glioma cells promote angiogenesis in methionine-restricted environments through the activation of CXCL8, compensating for nutrient deprivation, and possibly contributing to the failure of antiangiogenic therapy.

The role of short-chain fatty acids in cancer prevention and cancer treatment

Short-chain fatty acids (SCFAs) are microbial metabolites in the gut that may play a role in cancer prevention and treatment. They affect the metabolism of both normal and cancer cells, regulating various cellular energetic processes. SCFAs also inhibit histone deacetylases, which are targets for cancer therapy. The three main SCFAs are acetate, propionate, and butyrate, which are transported into cells through specific transporters. SCFAs may enhance the efficacy of chemotherapeutic agents and modulate immune cell metabolism, potentially reprogramming the tumor microenvironment. Although SCFAs and SCFA-generating microbes enhance therapeutic efficacy of several forms of cancer therapy, published data also support the opposing viewpoint that SCFAs mitigate the efficacy of some cancer therapies. Therefore, the relationship between SCFAs and cancer is more complex, and this review discusses some of these aspects. Clearly, further research is needed to understand the role of SCFAs, their mechanisms, and applications in cancer prevention and treatment.

One-carbon metabolism shapes T cell immunity in cancer

One-carbon metabolism (1CM), comprising folate metabolism and methionine metabolism, serves as an important mechanism for cellular energy provision and the production of vital signaling molecules, including single-carbon moieties. Its regulation is instrumental in sustaining the proliferation of cancer cells and facilitating metastasis; in addition, recent research has shed light on its impact on the efficacy of T cell-mediated immunotherapy. In this review, we consolidate current insights into how 1CM affects T cell activation, differentiation, and functionality. Furthermore, we delve into the strategies for modulating 1CM in both T cells and tumor cells to enhance the efficacy of adoptively transferred T cells, overcome metabolic challenges in the tumor microenvironment (TME), and maximize the benefits of T cell-mediated immunotherapy.

PDGF-BB overexpression in p53 null oligodendrocyte progenitors increases H3K27me3 and induces transcriptional changes which favor proliferation

Proneural gliomas are brain tumors characterized by enrichment of oligodendrocyte progenitor cell (OPC) transcripts and genetic alterations. In this study we sought to identify transcriptional and epigenetic differences between OPCs with Trp53 deletion and PDGF-BB overexpression (BB-p53n) and those carrying only p53 deletion (p53n). In culture, the BB-p53n OPCs display growth characteristics more similar to glioma cells than p53n OPCs. When injected in mouse brains, BB-p53n OPC form tumors, while the p53n OPCs do not. Unbiased histone proteomics and transcriptomic analysis on these OPC populations identified higher levels of the histone H3K27me3 mark and lower levels of the histone H4K20me3. The transcriptome of the BB-p53n OPCs was characterized by higher levels of transcripts related to proliferation and cell adhesion compared to p53n OPCs. Pharmacological inhibition of the enzyme responsible for histone H3K27 trimethylation (EZH2i) in BB-p53n OPCs, reduced cell cycle transcripts and increased the expression of differentiation markers, but was not sufficient to restore their growth characteristics. This suggests that PDGF-BB overexpression in p53n OPCs favors the early stages of transformation, by promoting proliferation and halting differentiation in a H3K27me3-dependent pathway, and favoring growth characteristics in a H3K27me3 independent manner.

Amino Acid Deprivation in Glioblastoma: The Role in Survival and the Tumour Microenvironment-A Narrative Review

BACKGROUND

Glioblastoma is the most common and aggressive primary brain tumour, characterised by its invasive nature and complex metabolic profile. Emerging research highlights the role of amino acids (AAs) in glioblastoma metabolism, influencing tumour growth and the surrounding microenvironment.

METHODS

This narrative review synthesises recent pre-clinical studies focusing on the metabolic functions of AAs in glioblastoma. Key areas include the effects of AA deprivation on tumour growth, adaptive mechanisms, and the tumour microenvironment.

RESULTS

The effects related to arginine, glutamine, methionine, and cysteine deprivation have been more extensively reported. Arginine deprivation in arginine-auxotrophic glioblastomas induces apoptosis and affects cell adhesion, while glutamine deprivation disrupts metabolic pathways and enhances autophagy. Methionine and cysteine deprivation impact lipid metabolism and ferroptosis. Tumour adaptive mechanisms present challenges, and potential compensatory responses have been identified. The response of the microenvironment to AA deprivation, including immune modulation, is critical to determining therapeutic outcomes.

CONCLUSIONS

Targeting AA metabolism offers a promising approach for glioblastoma treatment, with potential targeted drugs showing clinical promise. However, the complexity of tumour adaptive mechanisms and their impact on the microenvironment necessitates further research to optimise combination therapies and improve therapeutic efficacy.

Porphyrin-engineered nanoscale metal-organic frameworks: enhancing photodynamic therapy and ferroptosis in oncology

Photodynamic therapy and ferroptosis induction have risen as vanguard oncological interventions, distinguished by their precision and ability to target vulnerabilities in cancer cells. Photodynamic therapy's non-invasive profile and selective cytotoxicity complement ferroptosis' unique mode of action, which exploits iron-dependent lipid peroxidation, offering a pathway to overcome chemoresistance with lower systemic impact. The synergism between photodynamic therapy and ferroptosis is underscored by the depletion of glutathione and glutathione peroxidase four inhibitions by photodynamic therapy-induced reactive oxygen species, amplifying lipid peroxidation and enhancing ferroptotic cell death. This synergy presents an opportunity to refine cancer treatment by modulating redox homeostasis. Porphyrin-based nanoscale metal-organic frameworks have unique hybrid structures and exceptional properties. These frameworks can serve as a platform for integrating photodynamic therapy and ferroptosis through carefully designed structures and functions. These nanostructures can be engineered to deliver multiple therapeutic modalities simultaneously, marking a pivotal advance in multimodal cancer therapy. This review synthesizes recent progress in porphyrin-modified nanoscale metal-organic frameworks for combined photodynamic therapy and ferroptosis, delineating the mechanisms that underlie their synergistic effects in a multimodal context. It underscores the potential of porphyrin-based nanoscale metal-organic frameworks as advanced nanocarriers in oncology, propelling the field toward more efficacious and tailored cancer treatments.

A whole food, plant-based diet reduces amino acid levels in patients with metastatic breast cancer

Background

Amino acids are critical to tumor survival. Tumors can acquire amino acids from the surrounding microenvironment, including the serum. Limiting dietary amino acids is suggested to influence their serum levels. Further, a plant-based diet is reported to contain fewer amino acids than an animal-based diet. The extent to which a plant-based diet lowers the serum levels of amino acids in patients with cancer is unclear.

Methods

Patients with metastatic breast cancer (n=17) were enrolled in a clinical trial with an ad libitum whole food, plant-based diet for 8 weeks without calorie or portion restriction. Dietary changes by participants were monitored using a three-day food record. Serum was collected from participants at baseline and 8 weeks. Food records and serum were analyzed for metabolic changes.

Results

We found that a whole food, plant-based diet resulted in a lower intake of calories, fat, and amino acids and higher levels of fiber. Additionally, body weight, serum insulin, and IGF were reduced in participants. The diet contained lower levels of essential and non-essential amino acids, except for arginine (glutamine and asparagine were not measured). Importantly, the lowered dietary intake of amino acids translated to reduced serum levels of amino acids in participants (5/9 essential amino acids; 4/11 non-essential amino acids).

Conclusions

These findings provide a tractable approach to limiting amino acid levels in persons with cancer. This data lays a foundation for studying the relationship between amino acids in patients and tumor progression. Further, a whole-food, plant-based diet has the potential to synergize with cancer therapies that exploit metabolic vulnerabilities.

Trial Registration

The clinical trial was registered with ClinicalTrials.gov identifier NCT03045289 on 2017-02-07.

Oncogenic accumulation of cysteine promotes cancer cell proliferation by regulating the translation of D-type cyclins

Malignant cells exhibit a high demand for amino acids to sustain their abnormal proliferation. Particularly, the intracellular accumulation of cysteine is often observed in cancer cells. Previous studies have shown that deprivation of intracellular cysteine in cancer cells results in the accumulation of lipid peroxides in the plasma membrane and induction of ferroptotic cell death, indicating that cysteine plays a critical role in the suppression of ferroptosis. Herein, we found that the oncogenic accumulation of cysteine also contributes to cancer cell proliferation by promoting the cell cycle progression, which is independent of its suppressive effect on ferroptosis. The growth ability of four types of cancer cells, including murine hepatocarcinoma cells, but not of primary hepatocytes, were dependent on the exogenous supply of cysteine. Deprivation of intracellular cysteine in cancer cells induced cell cycle arrest at the G0/G1 phase, accompanied by a decrease in the expression of cyclin D1 and D2 proteins. The cysteine deprivation-induced decrease in D-type cyclin expression was associated with the upregulation of eukaryotic translation initiation factor 4E binding protein 1, which represses the translation of cyclin D1 and D2 proteins by binding to eukaryotic translation initiation factor 4E. Similar results were observed in hepatocarcinoma cells treated with erastin, an inhibitor of cystine/glutamate antiporter, xCT. These findings reveal an unappreciated role of cysteine in regulating the growth of malignant cancer cells and deepen our understanding of the cytotoxic effect of xCT inhibitor to prevent cancer cell proliferation.

Catabolism of extracellular glutathione supplies amino acids to support tumor growth

Restricting amino acids from tumors is an emerging therapeutic strategy with significant promise. While typically considered an intracellular antioxidant with tumor-promoting capabilities, glutathione (GSH) is a tripeptide of cysteine, glutamate, and glycine that can be catabolized, yielding amino acids. The extent to which GSH-derived amino acids are essential to cancers is unclear. Here, we find that GSH catabolism promotes tumor growth. We show that depletion of intracellular GSH does not perturb tumor growth, and extracellular GSH is highly abundant in the tumor microenvironment, highlighting the potential importance of GSH outside of tumors. We find supplementation with GSH can rescue cancer cell survival and growth in cystine-deficient conditions, and this rescue is dependent on the catabolic activity of γ-glutamyltransferases (GGTs). Finally, pharmacologic targeting of GGTs' activity prevents the breakdown of circulating GSH, lowers tumor cysteine levels, and slows tumor growth. Our findings indicate a non-canonical role for GSH in supporting tumors by acting as a reservoir of amino acids. Depriving tumors of extracellular GSH or inhibiting its breakdown is potentially a therapeutically tractable approach for patients with cancer. Further, these findings change our view of GSH and how amino acids, including cysteine, are supplied to cells.

Unlocking ferroptosis in prostate cancer - the road to novel therapies and imaging markers

Ferroptosis is a distinct form of regulated cell death that is predominantly driven by the build-up of intracellular iron and lipid peroxides. Ferroptosis suppression is widely accepted to contribute to the pathogenesis of several tumours including prostate cancer. Results from some studies reported that prostate cancer cells can be highly susceptible to ferroptosis inducers, providing potential for an interesting new avenue of therapeutic intervention for advanced prostate cancer. In this Perspective, we describe novel molecular underpinnings and metabolic drivers of ferroptosis, analyse the functions and mechanisms of ferroptosis in tumours, and highlight prostate cancer-specific susceptibilities to ferroptosis by connecting ferroptosis pathways to the distinctive metabolic reprogramming of prostate cancer cells. Leveraging these novel mechanistic insights could provide innovative therapeutic opportunities in which ferroptosis induction augments the efficacy of currently available prostate cancer treatment regimens, pending the elimination of major bottlenecks for the clinical translation of these treatment combinations, such as the development of clinical-grade inhibitors of the anti-ferroptotic enzymes as well as non-invasive biomarkers of ferroptosis. These biomarkers could be exploited for diagnostic imaging and treatment decision-making.

A cell state-specific metabolic vulnerability to GPX4-dependent ferroptosis in glioblastoma

Glioma cells hijack developmental programs to control cell state. Here, we uncover a glioma cell state-specific metabolic liability that can be therapeutically targeted. To model cell conditions at brain tumor inception, we generated genetically engineered murine gliomas, with deletion of p53 alone (p53) or with constitutively active Notch signaling (N1IC), a pathway critical in controlling astrocyte differentiation during brain development. N1IC tumors harbored quiescent astrocyte-like transformed cell populations while p53 tumors were predominantly comprised of proliferating progenitor-like cell states. Further, N1IC transformed cells exhibited increased mitochondrial lipid peroxidation, high ROS production and depletion of reduced glutathione. This altered mitochondrial phenotype rendered the astrocyte-like, quiescent populations more sensitive to pharmacologic or genetic inhibition of the lipid hydroperoxidase GPX4 and induction of ferroptosis. Treatment of patient-derived early-passage cell lines and glioma slice cultures generated from surgical samples with a GPX4 inhibitor induced selective depletion of quiescent astrocyte-like glioma cell populations with similar metabolic profiles. Collectively, these findings reveal a specific therapeutic vulnerability to ferroptosis linked to mitochondrial redox imbalance in a subpopulation of quiescent astrocyte-like glioma cells resistant to standard forms of treatment.

Fluoride exposure-induced gut microbiota alteration mediates colonic ferroptosis through N6-methyladenosine (m6A) mediated silencing of SLC7A11

Fluoride exposure is widespread worldwide and poses a significant threat to organisms, particularly to their gastrointestinal tracts. However, due to limited knowledge of the mechanism of fluoride induced intestinal injury, it has been challenging to develop an effective treatment. To address this issue, we used a series of molecular biology in vitro and in vivo experiments. NaF triggered m6A mediated ferroptosis to cause intestinal damage. Mechanistically, NaF exposure increased the m6A level of SLC7A11 mRNA, promoted YTHDF2 binding to m6A-modified SLC7A11 mRNA, drove the degradation of SLC7A11 mRNA, and led to a decrease in its protein expression, which eventually triggers ferroptosis. Moreover, NaF aggravated ferroptosis of the colon after antibiotics destroyed the composition of gut microbiota. 16 S rRNA sequencing and SPEC-OCCU plots, Zi-Pi relationships, and Spearman correlation coefficients verified that Lactobacillus murinus (ASV54, ASV58, and ASV82) plays a key role in the response to NaF-induced ferroptosis. Collectively, NaF-induced gut microbiota alteration mediates severe intestinal cell injury by inducing m6A modification-mediated ferroptosis. Our results highlight a key mechanism of the gut in response to NaF exposure and suggest a valuable theoretical basis for its prevention and treatment.

Regulatory mechanisms of amino acids in ferroptosis

Ferroptosis, an iron-dependent non-apoptotic regulated cell death process, is associated with the pathogenesis of various diseases. Amino acids, which are indispensable substrates of vital activities, significantly regulate ferroptosis. Amino acid metabolism is involved in maintaining iron and lipid homeostasis and redox balance. The regulatory effects of amino acids on ferroptosis are complex. An amino acid may exert contrasting effects on ferroptosis depending on the context. This review systematically and comprehensively summarized the distinct roles of amino acids in regulating ferroptosis and highlighted the emerging opportunities to develop clinical therapeutic strategies targeting amino acid-mediated ferroptosis.

Study of Plasma Biochemistry and Plasma Metabolomics Differences in Montbéliard and Holstein Backcross and Holstein Heifers

Holstein cattle are the main breed of dairy cattle in China. However, given the high degree of purebred selection of Holstein cattle, Chinese dairy cattle are increasingly being characterized by poor disease resistance, poor quality, and declining fertility. In this study, using Montbéliard × Holstein cattle as females and Montbéliard bulls as males for backcross breeding, we sought to provide a reference for improving the quality and performance of Holstein cattle and enhancing the efficiency of dairy farming. On the basis of similar physiological status and age, we selected 24 Montbéliard and Holstein backcross heifers and 11 Holstein heifers fed the same formula for comparative analyses. Plasma samples collected for plasma biochemical index analyses revealed that the content of ALB and BUN in the Montbéliard and Holstein backcross heifers was 20.83% (31.62 g/L to 26.17 g/L) and 42.36% (6.89 mmol/L to 4.84 mmol/L) higher than in the Holsteins (p < 0.01). The ALB/GLB (0.90 to 0.60, p < 0.05) was significantly higher in Montbéliard and Holstein backcross heifers than in Holstein heifers. Similarly, the activity of CAT in the backcross heifers was 61.28% (4.29 U/mL to 2.66 U/mL) higher than that in the Holstein heifers (p < 0.05). Although the activity of GSH-Px in the backcross heifers also showed an increasing trend, the difference did not reach the level of statistical significance (p = 0.052). Compared with Holstein heifers, the concentrations of IgA, IgG, and IL-4 were elevated by 32.52% (24.90 μg/mL to 18.79 μg/mL, p < 0.01), 13.46% (234.32 μg/mL to 206.53 μg/mL, p < 0.01), and 14.59% (306.27 pg/mL to 267.28 pg/mL, p < 0.05), and the contents of IL-6 and TNF-α were decreased by 15.92% (215.71 pg/mL to 256.55 pg/mL, p < 0.01) and 32.17% (7.17 ng/mL to 10.57 ng/mL, p < 0.01) in the plasma of Montbéliard and Holstein backcross heifers. Among the experimental heifers, five animals from each of the two groups were selected for plasma metabolomic analysis based on untargeted liquid chromatography-mass spectrometry. A comparison of the differential metabolites between the two heifer breeds revealed an up-regulation of d-glucuronic acid, s-glutathionyl-l-cysteine, and oleic acid levels in the backcross cattle compared with those in the Holstein heifers. We speculate that changes in the levels of these metabolites may be associated with an enhancement of the anti-inflammatory, antioxidant, and immune systems in these backcross heifers. Collectively, our findings in this study indicate that compared with 12-month-old purebred Holstein heifers, Montbéliard and Holstein backcross heifers of the same age are characterized by higher antioxidant capacity and immunity.

Cancer organoids 2.0: modelling the complexity of the tumour immune microenvironment

The development of neoplasia involves a complex and continuous interplay between malignantly transformed cells and the tumour microenvironment (TME). Cancer immunotherapies targeting the immune TME have been increasingly validated in clinical trials but response rates vary substantially between tumour histologies and are often transient, idiosyncratic and confounded by resistance. Faithful experimental models of the patient-specific tumour immune microenvironment, capable of recapitulating tumour biology and immunotherapy effects, would greatly improve patient selection, target identification and definition of resistance mechanisms for immuno-oncology therapeutics. In this Review, we discuss currently available and rapidly evolving 3D tumour organoid models that capture important immune features of the TME. We highlight diverse opportunities for organoid-based investigations of tumour immunity, drug development and precision medicine.

Current advances in cancer energy metabolism under dietary restriction: a mini review

The manipulation of the energy or source of food for cancer cells has attracted significant attention in oncology research. Metabolic reprogramming of the immune system allows for a deeper understanding of cancer cell mechanisms, thereby impeding their progression. A more targeted approach is the restriction of cancer cells through dietary restriction (CR), which deprives cancer cells of the preferred energy sources within the tumor microenvironment, thereby enhancing immune cell efficacy. Although there is a plethora of CR strategies that can be employed to impede cancer progression, there is currently no comprehensive review that delineates the specific dietary restrictions that target the diverse metabolic pathways of cancer cells. This mini-review introduces amino acids as anti-cancer agents and discusses the role of dietary interventions in cancer prevention and treatment. It highlights the potential of a ketogenic diet as a therapeutic approach for cancer, elucidating its distinct mechanisms of action in tumor progression. Additionally, the potential of plant-based diets as anti-cancer agents and the role of polyphenols and vitamins in anti-cancer therapy were also discussed, along with some prospective interventions for CR as anti-tumor progression.