Differential Glutamate Metabolism in Proliferating and Quiescent Mammary Epithelial Cells

Reductive stress and mitochondrial dysfunction: The hidden link in chronic disease

Conventional theories of oxidative stress have long focused on the deleterious consequences of excessive reactive oxygen species (ROS) formation. However, growing evidence reveals that an overload of reducing equivalents-termed reductive stress-may be equally pivotal in driving mitochondrial dysfunction and chronic disease. In this paradigm, abnormally high concentrations of NADH and NADPH create an electron "traffic jam" in the mitochondrial electron transport chain (ETC), leading to partial inhibition or reverse electron flow at upstream complexes. Paradoxically, this hyper-reduced environment promotes ROS generation by increasing electron leakage to molecular oxygen, thereby intensifying oxidative damage to lipids, proteins, and mitochondrial DNA. This review explores the intertwined nature of reductive and oxidative stress, showing how a surplus of reducing equivalents can potentiate metabolic derangements in conditions such as type 2 diabetes, nonalcoholic fatty liver disease, and neurodegenerative disorders. The review discusses common drivers of reductive overload, including chronic hyperglycemia, high-fat diets, and specific dietary patterns-particularly those enriched in polyunsaturated omega-6 fatty acids-that inundate mitochondria with electron donors. The review also highlights emerging evidence that targeted assessment of redox biomarkers (e.g., lactate:pyruvate, β-hydroxybutyrate:acetoacetate ratios) can provide clinically relevant indicators of reductive stress. Finally, the review examines how novel therapeutic strategies can address the underlying reductive imbalance, from rational nutrient modulation to pharmacologic interventions that restore NAD+ levels or optimize ETC flux. Recognizing reductive stress as a critical inflection point in mitochondrial pathophysiology underscores the need for a refined redox framework, one that moves beyond conventional oxidative paradigms to embrace the full spectrum of redox dysregulation in chronic degenerative disease.

Metabolic landscape of disseminated cancer dormancy

Cancer dormancy is a phenomenon defined by the entry of cancer cells into a reversible quiescent, nonproliferative state, and represents an essential part of the metastatic cascade responsible for cancer recurrence and mortality. Emerging evidence suggests that metabolic reprogramming plays a pivotal role in enabling entry, maintenance, and exit from dormancy in the face of the different environments of the metastatic cascade. Here, we review the current literature to understand the dynamics of metabolism during dormancy, highlighting its fine-tuning by the host micro- and macroenvironment, and put forward the importance of identifying metabolic vulnerabilities of the dormant state as therapeutic targets to eradicate recurrent disease.

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

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

Analysis of nitrogen metabolism-related gene expression in hepatocellular carcinoma to establish relevant indicators for prediction of prognosis and guidance of immunotherapy

BACKGROUND

The prognosis of cancers is strongly connected with nitrogen metabolism (NM), which plays a critical role in the microenvironment and growth of tumors. It is unsubstantiated, however, how important NM-related genes are for the prognosis of hepatocellular carcinoma (HCC).

METHODS

Using publicly available data, we examined potential mechanisms of NM-related genes in HCC, created a predictive model, and assessed immune infiltration and medication sensitivity.

RESULTS

A prognostic model, which included 12 NM genes (COLQ, GNE, ISCU, MSRA, SARS2, SPHK1, CBS, GOT2, CHST1, EXTL2, GCLM, YARS1), was constructed based on regression analysis. The robustness of the model was validated using multiple methods. The high-risk (HR) and low-risk (LR) groups had varying degrees of immune infiltration, according to an immunology-related study. Of these, B cells and Type_II_IFN_Response were greatly infiltrated in the LR group, whereas aCDs, Macrophages, and Treg were heavily infiltrated in the HR group (p < 0.05). Because of higher immunophenoscore, the low-risk group could benefit from immunotherapy more. Drug sensitivity predictions indicated that people with high CBS expression and low GOT2 and ISCU expression may benefit more from treatment with SCH-772984, Pimasertib, Cobimetinib (isomer1), TAK-733, LY-3214996, ARRY-162, Cladribine, Fludarabine, and Hydroxyurea.

CONCLUSION

This work created a 12-gene signature based on NM, preliminary investigated immune infiltration in two risk categories, and discovered some possible anti-tumor medications. To sum up, our study findings offer fresh perspectives on the roles played by NM-associated genes in HCC development, prognosis, immunological response, and medication screening.

Microenvironmental G protein-coupled estrogen receptor-mediated glutamine metabolic coupling between cancer-associated fibroblasts and triple-negative breast cancer cells governs tumour progression

BACKGROUND

Triple-negative breast cancer (TNBC) is a particularly aggressive type of breast cancer, known for its lack of effective treatments and unfavorable prognosis. The G protein-coupled estrogen receptor (GPER), a novel estrogen receptor, is linked to increased malignancy in various cancers. However, its involvement in the metabolic regulation of cancer-associated fibroblasts (CAFs), a key component in the tumour microenvironment, remains largely unexplored. This study investigates how GPER influences the metabolic interaction between CAFs and TNBC cells, aiming to identify potential therapeutic targets.

METHODS

The co-culture system is performed to examine the interaction between CAFs and TNBC cells, with a focus on GPER-mediated glutamine production and release by CAFs and its subsequent uptake and utilization by TNBC cells. The definite roles of microenvironmental GPER/cAMP/PKA/CREB signalling in regulating the expression of glutamine synthetase (GLUL) and lactate dehydrogenase B (LDHB) are further investigated.

RESULTS

Our findings reveal that estrogen-activated GPER in CAFs significantly upregulates the expression of GLUL and LDHB, leading to increased glutamine production. This glutamine is then secreted into the extracellular matrix and absorbed by TNBC cells, enhancing their viability, motility, and chemoresistance both in vitro and in vivo. TNBC cells further metabolize the glutamine through the glutamine transporter (ASCT2) and glutaminase (GLS1) axes, which, in turn, promote mitochondrial activity and tumour progression.

CONCLUSIONS

The study identifies GPER as a critical mediator of metabolic coupling between CAFs and TNBC cells, primarily through glutamine metabolism. Targeting the estrogen/GPER/glutamine signalling axis in CAFs offers a promising therapeutic strategy to inhibit TNBC progression and improve patient outcomes. This novel insight into the tumour microenvironment highlights the potential of metabolic interventions in treating TNBC.

KEY POINTS

Estrogen-activated GPER in CAFs enhances GLUL and LDHB expression via the cAMP/PKA/CREB signalling, facilitating glutamine production and utilization. Microenvironmental GPER-induced glutamine serves as a crucial mediator of metabolic coupling between CAFs and TNBC cells, boosting tumour progression by enhancing mitochondrial function. Targeting the glutamine metabolic coupling triggered by estrogen/GPER/GLUL signalling in CAFs is a promising therapeutic strategy for TNBC treatment.

Targeting the glutamine-arginine-proline metabolism axis in cancer

Metabolic abnormalities are an important feature of tumours. The glutamine-arginine-proline axis is an important node of cancer metabolism and plays a major role in amino acid metabolism. This axis also acts as a scaffold for the synthesis of other nonessential amino acids and essential metabolites. In this paper, we briefly review (1) the glutamine addiction exhibited by tumour cells with accelerated glutamine transport and metabolism; (2) the methods regulating extracellular glutamine entry, intracellular glutamine synthesis and the fate of intracellular glutamine; (3) the glutamine, proline and arginine metabolic pathways and their interaction; and (4) the research progress in tumour therapy targeting the glutamine-arginine-proline metabolic system, with a focus on summarising the therapeutic research progress of strategies targeting of one of the key enzymes of this metabolic system, P5CS (ALDH18A1). This review provides a new basis for treatments targeting the metabolic characteristics of tumours.

Aberrant Energy Metabolism in Tumors and Potential Therapeutic Targets

Energy metabolic reprogramming is frequently observed during tumor progression as tumor cells necessitate adequate energy production for rapid proliferation. Although current medical research shows promising prospects in studying the characteristics of tumor energy metabolism and developing anti-tumor drugs targeting energy metabolism, there is a lack of systematic compendiums and comprehensive reviews in this field. The objective of this study is to conduct a systematic review on the characteristics of tumor cells' energy metabolism, with a specific focus on comparing abnormalities between tumor and normal cells, as well as summarizing potential targets for tumor therapy. Additionally, this review also elucidates the aberrant mechanisms underlying four major energy metabolic pathways (glucose, lipid, glutamine, and mitochondria-dependent) during carcinogenesis and tumor progression. Through the utilization of graphical representations, we have identified anomalies in crucial energy metabolism pathways, encompassing transporter proteins (glucose transporter, CD36, and ASCT2), signaling molecules (Ras, AMPK, and PTEN), as well as transcription factors (Myc, HIF-1α, CREB-1, and p53). The key molecules responsible for aberrant energy metabolism in tumors may serve as potential targets for cancer therapy. Therefore, this review provides an overview of the distinct energy-generating pathways within tumor cells, laying the groundwork for developing innovative strategies for precise cancer treatment.

Glutamate Transport Proteins and Metabolic Enzymes are Poor Prognostic Factors in Invasive Lobular Carcinoma

Invasive Lobular Carcinoma (ILC) is a subtype of breast cancer characterized by distinct biological features, and limited glucose uptake coupled with increased reliance on amino acid and lipid metabolism. Our prior studies highlight the importance of glutamate as a key regulator of ILC tumor growth and therapeutic response. Here we examine the expression of four key proteins involved in glutamate transport and metabolism - SLC3A2, SLC7A11, GPX4, and GLUD1/2 - in a racially diverse cohort of 72 estrogen receptor-positive (ER+) ILC and 50 ER+ invasive ductal carcinoma, no special type (IDC/NST) patients with primary disease. All four proteins are associated with increased tumor size in ILC, but not IDC/NST, with SLC3A2 also specifically linked to shorter overall survival and the presence of comorbidities in ILC. Notably, GLUD1/2 expression is associated with ER expression in ILC, and is most strongly associated with increased tumor size and stage in Black women with ILC from our cohort and TCGA. We further explore the effects of GLUD1 inhibition in endocrine therapy-resistant ILC cells using the small-molecule inhibitor R162, which reduces ER protein levels, increases reactive oxygen species, and inhibits oxidative phosphorylation. These findings highlight a potentially important role for glutamate metabolism in ILC, particularly for Black women, and position several of these glutamate-handling proteins as potential targets for therapeutic intervention in ILC.

Energy metabolism-related GLUD1 contributes to favorable clinical outcomes of IDH-mutant glioma

BACKGROUND

Glioma is the most common brain tumor. IDH mutations occur frequently in glioma, indicating a more favorable prognosis. We aimed to explore energy metabolism-related genes in glioma to promote the research and treatment.

METHODS

Datasets were obtained from TCGA and GEO databases. Candidate genes were screened by differential gene expression analysis, then functional enrichment analysis was conducted on the candidate genes. PPI was also carried out to help determine the target gene. GSEA and DO analysis were conducted in the different expression level groups of the target gene. Survival analysis and immune cell infiltrating analysis were performed as well.

RESULTS

We screened 34 candidate genes and selected GLUD1 as the target gene. All candidate genes were significantly enriched in 10 KEGG pathways and 330 GO terms. GLUD1 expression was higher in IDH-mutant samples than IDH-wildtype samples, and higher in normal samples than tumor samples. Low GLUD1 expression was related to poor prognosis according to survival analysis. Most types of immune cells were negatively related to GLUD1 expression, but monocytes and activated mast cells exhibited significantly positive correlation with GLUD1 expression. GLUD1 expression was significantly related to 119 drugs and 6 immune checkpoint genes. GLUD1 was able to serve as an independent prognostic indicator of IDH-mutant glioma.

CONCLUSION

In this study, we identified an energy metabolism-related gene GLUD1 potentially contributing to favorable clinical outcomes of IDH-mutant glioma. In glioma, GLUD1 related clinical outcomes and immune landscape were clearer, and more valuable information was provided for immunotherapy.

The tRNA Gm18 methyltransferase TARBP1 promotes hepatocellular carcinoma progression via metabolic reprogramming of glutamine

Cancer cells rely on metabolic reprogramming to sustain the prodigious energetic requirements for rapid growth and proliferation. Glutamine metabolism is frequently dysregulated in cancers and is being exploited as a potential therapeutic target. Using CRISPR/Cas9 interference (CRISPRi) screening, we identified TARBP1 (TAR (HIV-1) RNA Binding Protein 1) as a critical regulator involved in glutamine reliance of cancer cell. Consistent with this discovery, TARBP1 amplification and overexpression are frequently observed in various cancers. Knockout of TARBP1 significantly suppresses cell proliferation, colony formation and xenograft tumor growth. Mechanistically, TARBP1 selectively methylates and stabilizes a small subset of tRNAs, which promotes efficient protein synthesis of glutamine transporter-ASCT2 (also known as SLC1A5) and glutamine import to fuel the growth of cancer cell. Moreover, we found that the gene expression of TARBP1 and ASCT2 are upregulated in combination in clinical cohorts and their upregulation is associated with unfavorable prognosis of HCC (hepatocellular carcinoma). Taken together, this study reveals the unexpected role of TARBP1 in coordinating the tRNA availability and glutamine uptake during HCC progression and provides a potential target for tumor therapy.

BET inhibition induces GDH1-dependent glutamine metabolic remodeling and vulnerability in liver cancer

Bromodomain and extra-terminal domain (BET) proteins, which function partly through MYC proto-oncogene (MYC), are critical epigenetic readers and emerging therapeutic targets in cancer. Whether and how BET inhibition simultaneously induces metabolic remodeling in cancer cells remains unclear. Here we find that even transient BET inhibition by JQ-1 and other pan-BET inhibitors (pan-BETis) blunts liver cancer cell proliferation and tumor growth. BET inhibition decreases glycolytic gene expression but enhances mitochondrial glucose and glutamine oxidative metabolism revealed by metabolomics and isotope labeling analysis. Specifically, BET inhibition downregulates miR-30a to upregulate glutamate dehydrogenase 1 (GDH1) independent of MYC, which produces α-ketoglutarate for mitochondrial oxidative phosphorylation (OXPHOS). Targeting GDH1 or OXPHOS is synthetic lethal to BET inhibition, and combined BET and OXPHOS inhibition therapeutically prevents liver tumor growth in vitro and in vivo. Together, we uncover an important epigenetic-metabolic crosstalk whereby BET inhibition induces MYC-independent and GDH1-dependent glutamine metabolic remodeling that can be exploited for innovative combination therapy of liver cancer.

Curcumin synergistically enhances the efficacy of gemcitabine against gemcitabine-resistant cholangiocarcinoma via the targeting LAT2/glutamine pathway

Cholangiocarcinoma (CCA) is often diagnosed late, leading to incomplete tumor removal, drug resistance and reduced chemotherapy efficacy. Curcumin has the potential for anti-cancer activity through various therapeutic properties and can improve the efficacy of chemotherapy. We aimed to investigate the synergistic effect of a combination of curcumin and gemcitabine against CCA, targeting the LAT2/glutamine pathway. This combination synergistically suppressed proliferation in gemcitabine-resistant CCA cells (KKU-213BGemR). It also resulted in a remarkable degree of CCA cell apoptosis and cell cycle arrest, characterized by a high proportion of cells in the S and G2/M phases. Knockdown of SLC7A8 decreased the expressions of glutaminase and glutamine synthetase, resulting in inhibited cell proliferation and sensitized CCA cells to gemcitabine treatment. Moreover, in vivo experiments showed that a combination curcumin and gemcitabine significantly reduced tumor size, tumor growth rate and LAT2 expression in a gemcitabine-resistant CCA xenograft mouse model. Suppression of tumor progression in an orthotopic CCA hamster model provided strong support for clinical application. In conclusion, curcumin synergistically enhances gemcitabine efficacy against gemcitabine-resistant CCA by induction of apoptosis, partly via inhibiting LAT2/glutamine pathway. This approach may be an alternative strategy for the treatment of gemcitabine-resistant in CCA patients.

Metabolism-dependent secondary effect of anti-MAPK cancer therapy on DNA repair

Amino acid bioavailability impacts mRNA translation in a codon-dependent manner. Here, we report that the anti-cancer MAPK inhibitors (MAPKi) decrease the intracellular concentration of aspartate and glutamate in melanoma cells. This coincides with the accumulation of ribosomes on codons corresponding to these amino acids and triggers the translation-dependent degradation of mRNAs encoding aspartate- and glutamate-rich proteins, involved in DNA metabolism such as DNA replication and repair. Consequently, cells that survive MAPKi degrade aspartate and glutamate likely to generate energy, which simultaneously decreases their requirement for amino acids due to the downregulation of aspartate- and glutamate-rich proteins involved in cell proliferation. Concomitantly, the downregulation of aspartate- and glutamate-rich proteins involved in DNA repair increases DNA damage loads. Thus, DNA repair defects, and therefore mutations, are at least in part a secondary effect of the metabolic adaptation of cells exposed to MAPKi.

IDH1 mutation inhibits differentiation of astrocytes and glioma cells with low oxoglutarate dehydrogenase expression by disturbing α-ketoglutarate-related metabolism and epigenetic modification

Isocitrate dehydrogenase (IDH) mutations frequently occur in lower-grade gliomas and secondary glioblastomas. Mutant IDHs exhibit a gain-of-function activity, leading to the production of D-2-hydroxyglutarate (D-2HG) by reducing α-ketoglutarate (α-KG), a central player in metabolism and epigenetic modifications. However, the role of α-KG homeostasis in IDH-mutated gliomagenesis remains elusive. In this study, we found that low expression of oxoglutarate dehydrogenase (OGDH) was a common feature in IDH-mutated gliomas, as well as in astrocytes. This low expression of OGDH resulted in the accumulation of α-KG and promoted astrocyte maturation. However, IDH1 mutation significantly reduced α-KG levels and increased glutaminolysis and DNA/histone methylation in astrocytes. These metabolic and epigenetic alterations inhibited astrocyte maturation and led to cortical dysplasia in mice. Moreover, our results also indicated that reduced OGDH expression can promote the differentiation of glioma cells, while IDH1 mutations impeded the differentiation of glioma cells with low OGDH by reducing the accumulation of α-KG and increasing glutaminolysis. Finally, we found that l-glutamine increased α-KG levels and augmented the differentiation-promoting effects of AGI5198, an IDH1-mutant inhibitor, in IDH1-mutant glioma cells. Collectively, this study reveals that low OGDH expression is a crucial metabolic characteristic of IDH-mutant gliomas, providing a potential strategy for the treatment of IDH-mutant gliomas by targeting α-KG homeostasis.

Integration of pan-omics technologies and three-dimensional in vitro tumor models: an approach toward drug discovery and precision medicine

Despite advancements in treatment protocols, cancer is one of the leading cause of deaths worldwide. Therefore, there is a need to identify newer and personalized therapeutic targets along with screening technologies to combat cancer. With the advent of pan-omics technologies, such as genomics, transcriptomics, proteomics, metabolomics, and lipidomics, the scientific community has witnessed an improved molecular and metabolomic understanding of various diseases, including cancer. In addition, three-dimensional (3-D) disease models have been efficiently utilized for understanding disease pathophysiology and as screening tools in drug discovery. An integrated approach utilizing pan-omics technologies and 3-D in vitro tumor models has led to improved understanding of the intricate network encompassing various signalling pathways and molecular cross-talk in solid tumors. In the present review, we underscore the current trends in omics technologies and highlight their role in understanding genotypic-phenotypic co-relation in cancer with respect to 3-D in vitro tumor models. We further discuss the challenges associated with omics technologies and provide our outlook on the future applications of these technologies in drug discovery and precision medicine for improved management of cancer.

The bidirectional relationship between metabolism and cell cycle control

The relationship between metabolism and cell cycle progression is complex and bidirectional. Cells must rewire metabolism to meet changing biosynthetic demands across cell cycle phases. In turn, metabolism can influence cell cycle progression through direct regulation of cell cycle proteins, through nutrient-sensing signaling pathways, and through its impact on cell growth, which is linked to cell division. Furthermore, metabolism is a key player in mediating quiescence-proliferation transitions in physiologically important cell types, such as stem cells. How metabolism impacts cell cycle progression, exit, and re-entry, as well as how these processes impact metabolism, is not fully understood. Recent advances uncovering mechanistic links between cell cycle regulators and metabolic processes demonstrate a complex relationship between metabolism and cell cycle control, with many questions remaining.

MET Oncogene Enhances Pro-Migratory Functions by Counteracting NMDAR2B Cleavage

The involvement of the N-methyl-D-aspartate receptor (NMDAR), a glutamate-gated ion channel, in promoting the invasive growth of cancer cells is an area of ongoing investigation. Our previous findings revealed a physical interaction between NMDAR and MET, the hepatocyte growth factor (HGF) receptor. However, the molecular mechanisms underlying this NMDAR/MET interaction remain unclear. In this study, we demonstrate that the NMDAR2B subunit undergoes proteolytic processing, resulting in a low-molecular-weight form of 100 kDa. Interestingly, when the NMDAR2B and MET constructs were co-transfected, the full-size high-molecular-weight NMDAR2B form of 160 kDa was predominantly observed. The protection of NMDAR2B from cleavage was dependent on the kinase activity of MET. We provide the following evidence that MET opposes the autophagic lysosomal proteolysis of NMDAR2B: (i) MET decreased the protein levels of lysosomal cathepsins; (ii) treatment with either an inhibitor of autophagosome formation or the fusion of the autophagosome and lysosome elevated the proportion of the NMDAR2B protein's uncleaved form; (iii) a specific mTOR inhibitor hindered the anti-autophagic effect of MET. Finally, we demonstrate that MET coopts NMDAR2B to augment cell migration. This implies that MET harnesses the functionality of NMDAR2B to enhance the ability of cancer cells to migrate.

Vector-borne Trypanosoma brucei parasites develop in artificial human skin and persist as skin tissue forms

Transmission of Trypanosoma brucei by tsetse flies involves the deposition of the cell cycle-arrested metacyclic life cycle stage into mammalian skin at the site of the fly's bite. We introduce an advanced human skin equivalent and use tsetse flies to naturally infect the skin with trypanosomes. We detail the chronological order of the parasites' development in the skin by single-cell RNA sequencing and find a rapid activation of metacyclic trypanosomes and differentiation to proliferative parasites. Here we show that after the establishment of a proliferative population, the parasites enter a reversible quiescent state characterized by slow replication and a strongly reduced metabolism. We term these quiescent trypanosomes skin tissue forms, a parasite population that may play an important role in maintaining the infection over long time periods and in asymptomatic infected individuals.

Machine learning-based analysis of cancer cell-derived vesicular proteins revealed significant tumor-specificity and predictive potential of extracellular vesicles for cell invasion and proliferation - A meta-analysis

BACKGROUND

Although interest in the role of extracellular vesicles (EV) in oncology is growing, not all potential aspects have been investigated. In this meta-analysis, data regarding (i) the EV proteome and (ii) the invasion and proliferation capacity of the NCI-60 tumor cell lines (60 cell lines from nine different tumor types) were analyzed using machine learning methods.

METHODS

On the basis of the entire proteome or the proteins shared by all EV samples, 60 cell lines were classified into the nine tumor types using multiple logistic regression. Then, utilizing the Least Absolute Shrinkage and Selection Operator, we constructed a discriminative protein panel, upon which the samples were reclassified and pathway analyses were performed. These panels were validated using clinical data (n = 4,665) from Human Protein Atlas.

RESULTS

Classification models based on the entire proteome, shared proteins, and discriminative protein panel were able to distinguish the nine tumor types with 49.15%, 69.10%, and 91.68% accuracy, respectively. Invasion and proliferation capacity of the 60 cell lines were predicted with R2 = 0.68 and R2 = 0.62 (p < 0.0001). The results of the Reactome pathway analysis of the discriminative protein panel suggest that the molecular content of EVs might be indicative of tumor-specific biological processes.

CONCLUSION

Integrating in vitro EV proteomic data, cell physiological characteristics, and clinical data of various tumor types illuminates the diagnostic, prognostic, and therapeutic potential of EVs. Video Abstract.

The Role of Amino Acids in the Diagnosis, Risk Assessment, and Treatment of Breast Cancer: A Review

This review summarizes the role of amino acids in the diagnosis, risk assessment, imaging, and treatment of breast cancer. It was shown that the content of individual amino acids changes in breast cancer by an average of 10-15% compared with healthy controls. For some amino acids (Thr, Arg, Met, and Ser), an increase in concentration is more often observed in breast cancer, and for others, a decrease is observed (Asp, Pro, Trp, and His). The accuracy of diagnostics using individual amino acids is low and increases when a number of amino acids are combined with each other or with other metabolites. Gln/Glu, Asp, Arg, Leu/Ile, Lys, and Orn have the greatest significance in assessing the risk of breast cancer. The variability in the amino acid composition of biological fluids was shown to depend on the breast cancer phenotype, as well as the age, race, and menopausal status of patients. In general, the analysis of changes in the amino acid metabolism in breast cancer is a promising strategy not only for diagnosis, but also for developing new therapeutic agents, monitoring the treatment process, correcting complications after treatment, and evaluating survival rates.

Relationship between Bladder Cancer, Nutritional Supply, and Treatment Strategies: A Comprehensive Review

Bladder cancer (BC) is the predominant neoplasm affecting the urinary system and ranks among the most widespread malignancies globally. The causes of bladder cancer include genetic factors; age; sex; and lifestyle factors, such as imbalanced nutrition, obesity, and metabolic disorders. The lack of proper nutrient intake leads to the development of bladder cancer because insufficient nutrients are consumed to prevent this disease. The purpose of this review was to analyze the nutrients closely linked to the onset and advancement of bladder cancer and to explore the relationship between dietary nutrients and bladder cancer. Particular emphasis was placed on nutrients that are frequently ingested in daily life, including sugar, fat, protein, and others. The focus of this research was to analyze how nutritional intake before and after surgery affects the recovery process of patients who have been diagnosed with bladder cancer. This article seeks to increase awareness among both society and the medical community about the significance of implementing appropriate dietary nutrition to reduce the chances of developing bladder cancer, enhance perioperative care for patients with bladder cancer, and aid in their recuperation.

Cancer 3D Models for Metallodrug Preclinical Testing

Despite being standard tools in research, the application of cellular and animal models in drug development is hindered by several limitations, such as limited translational significance, animal ethics, and inter-species physiological differences. In this regard, 3D cellular models can be presented as a step forward in biomedical research, allowing for mimicking tissue complexity more accurately than traditional 2D models, while also contributing to reducing the use of animal models. In cancer research, 3D models have the potential to replicate the tumor microenvironment, which is a key modulator of cancer cell behavior and drug response. These features make cancer 3D models prime tools for the preclinical study of anti-tumoral drugs, especially considering that there is still a need to develop effective anti-cancer drugs with high selectivity, minimal toxicity, and reduced side effects. Metallodrugs, especially transition-metal-based complexes, have been extensively studied for their therapeutic potential in cancer therapy due to their distinctive properties; however, despite the benefits of 3D models, their application in metallodrug testing is currently limited. Thus, this article reviews some of the most common types of 3D models in cancer research, as well as the application of 3D models in metallodrug preclinical studies.

The diagnostic significance of circulating miRNAs and metabolite profiling in early prediction of breast cancer in Egyptian women

OBJECTIVE

Breast cancer (BC) is one of the most commonly diagnosed solid malignancies in women worldwide.

PURPOSE

Finding new non-invasive circulating diagnostic biomarkers will facilitate the early prediction of BC and provide valuable insight into disease progression and response to therapy using a safe and more accessible approach available every inspection time. Therefore, our present study aimed to investigate expression patterns of potentially circulating biomarkers that can differentiate well between benign, malignant, and healthy subjects.

METHODS

To achieve our target, quantitative analyses were performed for some circulating biomarkers which have a role in the proliferation and tumor growth, as well as, glutamic acid, and human epidermal growth receptor 2 (HER2) in blood samples of BC patients in comparison to healthy controls using qRT-PCR, liquid chromatography/mass spectrometry (LC/MS/MS), and ELISA.

RESULTS

Our findings showed that the two miRNAs (miRNA-145, miRNA-382) were expressed at lower levels in BC sera than healthy control group, while miRNA-21 was expressed at higher levels in BC patients than control subjects. Area under ROC curves of BC samples revealed that AUC of miRNA-145, miRNA-382, miRNA-21, and glutamic acid was evaluated to equal 0.99, 1.00, 1.00 and 1.00, respectively. Besides, there was a significantly positive correlation between miRNA-145 and miRNA-382 (r = 0.737), and a highly significant positive correlation between miRNA-21 and glutamic acid (r = 0.385).

CONCLUSION

Based on our results, we conclude that the detection of serum miRNA-145, -382 and -21 as a panel along with glutamic acid, and circulating HER2 concentrations could be useful as a non-invasive diagnostic profiling for early prediction of breast cancer in Egyptian patients. It can provide an insight into disease progression, discriminate between malignancy and healthy control, and overcome the use limitations (low sensitivity and specificity, repeated risky exposure, and high cost) of other detecting tools, including mammography, magnetic resonance imaging, and ultrasound.

In Situ Spatial Analysis of Metabolic Heterogeneity in Single Living Tumor Spheroids Using Nanocapillary-Based Electrospray Ionization Mass Spectroscopy

Spatial metabolomic analysis of individual tumor spheroids can help investigate metabolic rearrangements in different cellular regions of a spheroid. In this work, a nanocapillary-based electrospray ionization mass spectroscopy (ESI-MS) method is established that could realize the spatial sampling of cellular components in different regions of a single living tumor spheroid and the subsequent MS analysis for a metabolic study. During the penetration of the nanocapillary into the spheroid for sampling, this "wound surface" at the outer layer of the spheroid takes only 0.1% of the whole area that maximally maintains the cellular activity inside the spheroid for the metabolic analysis. Using the ESI-MS analysis, different metabolic activities in the inner and outer (upper and lower) layers of a single spheroid are revealed, giving a full investigation of the metabolic heterogeneity inside one living tumor spheroid for the first time. In addition, the metabolic activities between the outer layer of the spheroid and two-dimensional (2D)-cultured cells show obvious differences, which suggests more frequent cell-cell and cell-extracellular environment interactions during the culture of the spheroid. This observation not only establishes a powerful tool for the in situ spatial analysis of the metabolic heterogeneity in single living tumor spheroids but also provides molecular information to elucidate the metabolic heterogeneity in this three-dimensional (3D)-cultured cell model.

Noncanonical role of singleminded-2s in mitochondrial respiratory chain formation in breast cancer

Dysregulation of cellular metabolism is a hallmark of breast cancer progression and is associated with metastasis and therapeutic resistance. Here, we show that the breast tumor suppressor gene SIM2 promotes mitochondrial oxidative phosphorylation (OXPHOS) using breast cancer cell line models. Mechanistically, we found that SIM2s functions not as a transcription factor but localizes to mitochondria and directly interacts with the mitochondrial respiratory chain (MRC) to facilitate functional supercomplex (SC) formation. Loss of SIM2s expression disrupts SC formation through destabilization of MRC Complex III, leading to inhibition of electron transport, although Complex I (CI) activity is retained. A metabolomic analysis showed that knockout of SIM2s leads to a compensatory increase in ATP production through glycolysis and accelerated glutamine-driven TCA cycle production of NADH, creating a favorable environment for high cell proliferation. Our findings indicate that SIM2s is a novel stabilizing factor required for SC assembly, providing insight into the impact of the MRC on metabolic adaptation and breast cancer progression.

What is cancer metabolism?

The uptake and metabolism of nutrients support fundamental cellular process from bioenergetics to biomass production and cell fate regulation. While many studies of cell metabolism focus on cancer cells, the principles of metabolism elucidated in cancer cells apply to a wide range of mammalian cells. The goal of this review is to discuss how the field of cancer metabolism provides a framework for revealing principles of cell metabolism and for dissecting the metabolic networks that allow cells to meet their specific demands. Understanding context-specific metabolic preferences and liabilities will unlock new approaches to target cancer cells to improve patient care.

Metabolic reprogramming in cancer: Mechanisms and therapeutics

Cancer cells characterized by uncontrolled growth and proliferation require altered metabolic processes to maintain this characteristic. Metabolic reprogramming is a process mediated by various factors, including oncogenes, tumor suppressor genes, changes in growth factors, and tumor-host cell interactions, which help to meet the needs of cancer cell anabolism and promote tumor development. Metabolic reprogramming in tumor cells is dynamically variable, depending on the tumor type and microenvironment, and reprogramming involves multiple metabolic pathways. These metabolic pathways have complex mechanisms and involve the coordination of various signaling molecules, proteins, and enzymes, which increases the resistance of tumor cells to traditional antitumor therapies. With the development of cancer therapies, metabolic reprogramming has been recognized as a new therapeutic target for metabolic changes in tumor cells. Therefore, understanding how multiple metabolic pathways in cancer cells change can provide a reference for the development of new therapies for tumor treatment. Here, we systemically reviewed the metabolic changes and their alteration factors, together with the current tumor regulation treatments and other possible treatments that are still under investigation. Continuous efforts are needed to further explore the mechanism of cancer metabolism reprogramming and corresponding metabolic treatments.

Metabolic rewiring in keratinocytes by miR-31-5p identifies therapeutic intervention for psoriasis

Besides genetic alterations, the cellular environment also determines disease onset and progression. When different cell types contribute to disease outcome, this imposes environmental challenges as different cell types likely differ in their extracellular dependencies. Hsa-microRNA-31-5p (miR-31) is highly expressed in keratinocytes of psoriatic skin, and we show that expression in keratinocytes is induced by limited glucose availability and enables increased survival under limiting glucose conditions by increasing glutamine metabolism. In addition, miR-31 expression results in not only secretion of specific metabolites (aspartate and glutamate) but also secretion of immunomodulatory factors. We show that this miR-31-induced secretory phenotype is sufficient to induce Th17 cell differentiation, a hallmark of psoriasis. Inhibitors of miR31-induced metabolic rewiring and metabolic crosstalk with immune cells alleviate psoriasis pathology in a mouse model of psoriasis. Together our data illustrate an emerging concept of metabolic interaction across cell compartments that characterizes disease development, which can be employed to design effective treatment options for disease, as shown here for psoriasis.

Effects of glutamate oxaloacetate transaminase on reactive oxygen species in Ganoderma lucidum

Nitrogen metabolism can regulate mycelial growth and secondary metabolism in Ganoderma lucidum. As an important enzyme in intracellular amino acid metabolism, glutamate oxaloacetate transaminase (GOT) has many physiological functions in animals and plants, but its function in fungi has been less studied. In the present study, two GOT isoenzymes were found in G. lucidum; one is located in the mitochondria (GOT1), and the other is located in the cytoplasm (GOT2). The reactive oxygen species (ROS) level was increased in got1 silenced strains and was approximately 1.5-fold higher than that in the wild-type (WT) strain, while silencing got2 did not affect the ROS level. To explore how GOT affects ROS in G. lucidum, experiments related to the generation and elimination of intracellular ROS were conducted. First, compared with that in the WT strain, the glutamate content, one of the substrates of GOT, decreased when got1 or got2 was knocked down, and the glutathione (l-γ-glutamyl-l-cysteinylglycine) (GSH) content decreased by approximately 38.6%, 19.3%, and 40.1% in got1 silenced strains, got2 silenced strains, and got1/2 co-silenced strains respectively. Second, GOT also affects glucose metabolism. The pyruvate (PA), acetyl-CoA and α-ketoglutarate (α-KG) contents decreased in got1 and got2 silenced strains, and the transcription levels of most genes involved in the glycolytic pathway and the tricarboxylic acid cycle increased. The NADH content was increased in got1 silenced strains and got2 silenced strains, and the NAD⁺/NADH ratio was decreased, which might result in mitochondrial ROS production. Compared with the WT strain, the mitochondrial ROS level was approximately 1.5-fold higher in the got1 silenced strains. In addition, silencing of got1 or got2 resulted in a decrease in antioxidant enzymes, including superoxide dismutase, catalase, glutathione reductase, and ascorbate peroxidase. Finally, ganoderic acid (GA) was increased by approximately 40% in got1 silenced strains compared with the WT strain, while silencing of got2 resulted in a 10% increase in GA biosynthesis. These findings provide new insights into the effect of GOT on ROS and secondary metabolism in fungi. KEY POINTS: • GOT plays important roles in ROS level in Ganoderma lucidum. • Silencing of got1 resulted in decrease in GSH content and antioxidant enzymes activities, but an increase in mitochondrial ROS level in G. lucidum. • Silencing of got1 and got2 resulted in an increase in ganoderic acid biosynthesis in G. lucidum.

Mitochondrial Metabolism in Pancreatic Ductal Adenocarcinoma: From Mechanism-Based Perspectives to Therapy

Pancreatic ductal adenocarcinoma (PDAC), the fourteenth most common malignancy, is a major contributor to cancer-related death with the utmost case fatality rate among all malignancies. Functional mitochondria, regardless of their complex ecosystem relative to normal cells, are essential in PDAC progression. Tumor cells' potential to produce ATP as energy, despite retaining the redox potential optimum, and allocating materials for biosynthetic activities that are crucial for cell growth, survival, and proliferation, are assisted by mitochondria. The polyclonal tumor cells with different metabolic profiles may add to carcinogenesis through inter-metabolic coupling. Cancer cells frequently possess alterations in the mitochondrial genome, although they do not hinder metabolism; alternatively, they change bioenergetics. This can further impart retrograde signaling, educate cell signaling, epigenetic modifications, chromatin structures, and transcription machinery, and ultimately satisfy cancer cellular and nuclear demands. To maximize the tumor microenvironment (TME), tumor cells remodel nearby stromal cells and extracellular matrix. These changes initiate polyclonality, which is crucial for growth, stress response, and metastasis. Here, we evaluate all the intrinsic and extrinsic pathways drawn by mitochondria in carcinogenesis, emphasizing the perspectives of mitochondrial metabolism in PDAC progression and treatment.

Platycodin D induces neutrophil apoptosis by downregulating PD-L1 expression to inhibit breast cancer pulmonary metastasis

During breast cancer development, programmed cell death 1 ligand 1 (PD-L1) overexpression in neutrophils leads to delayed apoptosis and promotes neutrophil hyperproliferation in the lung to form a premetastatic niche, which is beneficial for pulmonary metastasis. Platycodin D (PlaD), a triterpenoid saponin with known anti-inflammatory and antitumor effects, has been reported to downregulate PD-L1 expression. This study aimed to investigate the inhibitory effect of PlaD on neutrophil PD-L1 in 4 T1 tumor-bearing mice and the potential mechanism of breast cancer pulmonary metastasis. In this study, the orthotopic 4 T1 murine mammary carcinoma model was administered 10 and 20 mg/kg PlaD by gavage. PlaD reduced the excess neutrophils and decreased their high migratory capacity in bone marrow, peripheral blood and lung tissue in the premetastatic period, thereby effectively inhibiting tumor growth and pulmonary metastasis. Moreover, PlaD inhibited the phosphatidylinositol-3-kinase (PI3K)/Akt pathway by decreasing the expression of PD-L1 in neutrophils and promoted neutrophil apoptosis. In vitro, PlaD treatment decreased the viability and inhibited migration of neutrophil-like dHL-60 in a dose-dependent manner. Similarly, PlaD inhibited the increase in PD-L1 induced by IFN-γ stimulation and subsequently induced apoptosis in dHL-60 cells. In conclusion, the administration of PlaD inhibited the PI3K/Akt signaling pathway by reducing the expression of PD-L1 in neutrophils. PlaD promoted neutrophil apoptosis, thereby inhibiting the establishment of a premetastatic niche and ultimately blocking the development of pulmonary metastasis.

Microfluidic Mixer for In Situ Ammonia Analysis of Single Cells in Mass Spectrometry

Mass spectrometry (MS) is a powerful tool for exploring single-cell heterogeneity. However, due to the ultralow absolute content of most substances in a single cell, existing methods can only analyze high-content substances; conventional methods are incompetent for quantitative analysis of important trace-amount small-molecule metabolites such as ammonia and sulfide. Herein, a method integrating single-cell extraction, online derivatization, and MS for multifunctional and more accurate MS analysis is reported. For application, ammonia content in a single cell was analyzed, where the cellular heterogeneity in ammonia metabolism was revealed. First, the extraction room of a microfluidic probe was covered on the target single cell, and the extraction fluid was allowed to flow through a single cell and dissolve cellular ammonia. Then, the ammonia was mixed and reacted with the pretreatment reagent input from another inlet to achieve the derivatization and signal amplification, enhancing the analysis sensitivity on MS. Finally, the sample was sent to MS, and the ammonia content was successfully quantitatively evaluated by analyzing its derivative urotropine, demonstrating the potential of this method to advance single-cell mass spectrometry analysis to higher sensitivity.

GOT1 regulates CD8+ effector and memory T cell generation

T cell activation, proliferation, function, and differentiation are tightly linked to proper metabolic reprogramming and regulation. By using [U-¹³C]glucose tracing, we reveal a critical role for GOT1 in promoting CD8⁺ T cell effector differentiation and function. Mechanistically, GOT1 enhances proliferation by maintaining intracellular redox balance and serine-mediated purine nucleotide biosynthesis. Further, GOT1 promotes the glycolytic programming and cytotoxic function of cytotoxic T lymphocytes via posttranslational regulation of HIF protein, potentially by regulating the levels of α-ketoglutarate. Conversely, genetic deletion of GOT1 promotes the generation of memory CD8⁺ T cells.

NMDA Receptor and Its Emerging Role in Cancer

Glutamate is a key player in excitatory neurotransmission in the central nervous system (CNS). The N-methyl-D-aspartate receptor (NMDAR) is a glutamate-gated ion channel which presents several unique features and is involved in various physiological and pathological neuronal processes. Thanks to great efforts in neuroscience, its structure and the molecular mechanisms controlling its localization and functional regulation in neuronal cells are well known. The signaling mediated by NMDAR in neurons is very complex as it depends on its localization, composition, Ca²⁺ influx, and ion flow-independent conformational changes. Moreover, NMDA receptors are highly diffusive in the plasma membrane of neurons, where they form heterocomplexes with other membrane receptors and scaffold proteins which determine the receptor function and activation of downstream signaling. Interestingly, a recent paper demonstrates that NMDAR signaling is involved in epithelial cell competition, an evolutionary conserved cell fitness process influencing cancer initiation and progress. The idea that NMDAR signaling is limited to CNS has been challenged in the past two decades. A large body of evidence suggests that NMDAR is expressed in cancer cells outside the CNS and can respond to the autocrine/paracrine release of glutamate. In this review, we survey research on NMDAR signaling and regulation in neurons that can help illuminate its role in tumor biology. Finally, we will discuss existing data on the role of the glutamine/glutamate metabolism, the anticancer action of NMDAR antagonists in experimental models, NMDAR synaptic signaling in tumors, and clinical evidence in human cancer.

Glutamine Metabolism in Cancer Stem Cells: A Complex Liaison in the Tumor Microenvironment

In this review we focus on the role of glutamine in control of cancer stem cell (CSC) fate. We first provide an overview of glutamine metabolism, and then summarize relevant studies investigating how glutamine metabolism modulates the CSC compartment, concentrating on solid tumors. We schematically describe how glutamine in CSC contributes to several metabolic pathways, such as redox metabolic pathways, ATP production, non-essential aminoacids and nucleotides biosynthesis, and ammonia production. Furthermore, we show that glutamine metabolism is a key regulator of epigenetic modifications in CSC. Finally, we briefly discuss how cancer-associated fibroblasts, adipocytes, and senescent cells in the tumor microenvironment may indirectly influence CSC fate by modulating glutamine availability. We aim to highlight the complexity of glutamine's role in CSC, which supports our knowledge about metabolic heterogeneity within the CSC population.

Metabonomic analysis of tumor microenvironments: a mini-review

Metabolomic analysis is a vital part of studying cancer progression. Metabonomic crosstalk, such as nutrient availability, physicochemical transformation, and intercellular interactions can affect tumor metabolism. Many original studies have demonstrated that metabolomics is important in some aspects of tumor metabolism. In this mini-review, we summarize the definition of metabolomics and how it can help change a tumor microenvironment, especially in pathways of three metabonomic tumors. Just as non-invasive biofluids have been identified as early biomarkers of tumor development, metabolomics can also predict differences in tumor drug response, drug resistance, and efficacy. Therefore, metabolomics is important for tumor metabolism and how it can affect oncology drugs in cancer therapy.

SPTBN1 abrogates renal clear cell carcinoma progression via glycolysis reprogramming in a GPT2-dependent manner

BACKGROUND

Renal clear cell carcinoma (ccRCC) is the most prevalent tumors worldwide. Discovering effective biomarkers is essential to monitor the prognosis and provide alternative clinical options. SPTBN1 is implicated in various cancerous processes. However, its role in ccRCC remains unelucidated. This study intends to explore the biological function and mechanism of SPTBN1 in ccRCC.

METHODS

Single-cell and bulk RNA-seq, tissue microarray, real-time quantitative PCR, and western blotting were applied to verify the expression and predictive value of SPTBN1 in ccRCC. Gain or loss of functional ccRCC cell line models were constructed, and in vitro and in vivo assays were performed to elucidate its tumorigenic phenotypes. Actinomycin D experiment, RNA immunoprecipitation (RIP), specific inhibitors, and rescue experiments were carried out to define the molecular mechanisms.

RESULTS

SPTBN1 was down-regulated in ccRCC and knockdown of SPTBN1 displayed a remarkably oncogenic role both in vitro and in vivo; while overexpressing SPTBN1 reversed this effect. SPTBN1 mediated ccRCC progression via the pathway of glutamate pyruvate transaminase 2 (GPT2)-dependent glycolysis. The expression of GPT2 was significantly negatively correlated with that of SPTBN1. As an RNA binding protein SPTBN1, regulated the mRNA stability of GPT2.

CONCLUSION

Our research demonstrated that SPTBN1 is significantly down-regulated in ccRCC. SPTBN1 knockdown promotes ccRCC progression via activating GPT2-dependent glycolysis. SPTBN1 may serve as a therapeutic target for the treatment of ccRCC.

Glutamine synthetase limits β-catenin-mutated liver cancer growth by maintaining nitrogen homeostasis and suppressing mTORC1

Glutamine synthetase (GS) catalyzes de novo synthesis of glutamine that facilitates cancer cell growth. In the liver, GS functions next to the urea cycle to remove ammonia waste. As a dysregulated urea cycle is implicated in cancer development, the impact of GS's ammonia clearance function has not been explored in cancer. Here, we show that oncogenic activation of β-catenin (encoded by CTNNB1) led to a decreased urea cycle and elevated ammonia waste burden. While β-catenin induced the expression of GS, which is thought to be cancer promoting, surprisingly, genetic ablation of hepatic GS accelerated the onset of liver tumors in several mouse models that involved β-catenin activation. Mechanistically, GS ablation exacerbated hyperammonemia and facilitated the production of glutamate-derived nonessential amino acids, which subsequently stimulated mechanistic target of rapamycin complex 1 (mTORC1). Pharmacological and genetic inhibition of mTORC1 and glutamic transaminases suppressed tumorigenesis facilitated by GS ablation. While patients with hepatocellular carcinoma, especially those with CTNNB1 mutations, have an overall defective urea cycle and increased expression of GS, there exists a subset of patients with low GS expression that is associated with mTORC1 hyperactivation. Therefore, GS-mediated ammonia clearance serves as a tumor-suppressing mechanism in livers that harbor β-catenin activation mutations and a compromised urea cycle.

Tumor Cell Derived Exosomal GOT1 Suppresses Tumor Cell Ferroptosis to Accelerate Pancreatic Cancer Progression by Activating Nrf2/HO-1 Axis via Upregulating CCR2 Expression

Recently, evidence has shown that GOT1 expression is upregulated in pancreatic cancer tissues and promotes cancer development, but the specific mechanism remains unclear. We found that GOT1 expression was upregulated in pancreatic cancer cell-derived exosomes. When PANC-1 cells were incubated with exosomes alone or transfected together with si-GOT1, we found that exosomes enhanced cell proliferation, invasion and migration, promoted ferroptosis, and si-GOT1 reversed the effects of exosomes. The results of online bioinformatics database analysis indicated that CCR2 was a potential binding protein of GOT1 and is highly expressed in pancreatic cancer tissues. PANC-1 cells were transfected with pcDNA-CCR2 or si-CCR2, and it was found that pcDNA-CCR2 enhanced cell proliferation, invasion and migration, promoted ferroptosis, and si-CCR2 had an opposite effect. Next, exosome-treated cells were transfected with si-GOT1 alone or together with pcDNA-CCR2, and we found that exosomes promoted CCR2 expression, promoted cell proliferation and invasion, and inhibited ferroptosis, the transfection of si-GOT1 abolished the effect of exosomes, and the transfection of pcDNA-CCR2 again reversed the effect of si-GOT1. Furthermore, when exosome-treated cells were transfected with si-GOT1 alone or co-incubated with Nrf2 activator NK-252, we found that si-GOT1 reversed the promoting effect of exosomes on Nrf2 and HO-1 expression, as well as its inhibitory effect on ferroptosis, but this effect was abrogated by NK-252. In vivo studies showed that knockdown of GOT1 expression inhibited tumor formation compared with tumor tissues formed upon exosome induction, which was mediated by promoting ferroptosis via suppressing the protein expression of GOT1, CCR2, Nrf2 and HO-1 in tumor tissues.

A central role for STAT5 in the transcriptional programing of T helper cell metabolism

Activated lymphocytes adapt their metabolism to meet the energetic and biosynthetic demands imposed by rapid growth and proliferation. Common gamma chain (cγ) family cytokines are central to these processes, but the role of downstream signal transducer and activator of transcription 5 (STAT5) signaling, which is engaged by all cγ members, is poorly understood. Using genome-, transcriptome-, and metabolome-wide analyses, we demonstrate that STAT5 is a master regulator of energy and amino acid metabolism in CD4+ T helper cells. Mechanistically, STAT5 localizes to an array of enhancers and promoters for genes encoding essential enzymes and transporters, where it facilitates p300 recruitment and epigenetic remodeling. We also find that STAT5 licenses the activity of two other key metabolic regulators, the mTOR signaling pathway and the MYC transcription factor. Building on the latter, we present evidence for transcriptome-wide cooperation between STAT5 and MYC in both normal and transformed T cells. Together, our data provide a molecular framework for transcriptional programing of T cell metabolism downstream of cγ cytokines and highlight the JAK-STAT pathway in mediating cellular growth and proliferation.

Transcriptome Analysis of Goat Mammary Gland Tissue Reveals the Adaptive Strategies and Molecular Mechanisms of Lactation and Involution

To understand how genes precisely regulate lactation physiological activity and the molecular genetic mechanisms underlying mammary gland involution, this study investigated the transcriptome characteristics of goat mammary gland tissues at the late gestation (LG), early lactation (EL), peak lactation (PL), late lactation (LL), dry period (DP), and involution (IN) stages. A total of 13,083 differentially expressed transcripts were identified by mutual comparison of mammary gland tissues at six developmental stages. Genes related to cell growth, apoptosis, immunity, nutrient transport, synthesis, and metabolism make adaptive transcriptional changes to meet the needs of mammary lactation. Notably, platelet derived growth factor receptor beta (PDGFRB) was screened as a hub gene of the mammary gland developmental network, which is highly expressed during the DP and IN. Overexpression of PDGFRB in vitro could slow down the G1/S phase arrest of goat mammary epithelial cell cycle and promote cell proliferation by regulating the PI3K/Akt signaling pathway. In addition, PDGFRB overexpression can also affect the expression of genes related to apoptosis, matrix metalloproteinase family, and vascular development, which is beneficial to the remodeling of mammary gland tissue during involution. These findings provide new insights into the molecular mechanisms involved in lactation and mammary gland involution.

Amino Acids in Cancer and Cachexia: An Integrated View

Rapid tumor growth requires elevated biosynthetic activity, supported by metabolic rewiring occurring both intrinsically in cancer cells and extrinsically in the cancer host. The Warburg effect is one such example, burning glucose to produce a continuous flux of biomass substrates in cancer cells at the cost of energy wasting metabolic cycles in the host to maintain stable glycemia. Amino acid (AA) metabolism is profoundly altered in cancer cells, which use AAs for energy production and for supporting cell proliferation. The peculiarities in cancer AA metabolism allow the identification of specific vulnerabilities as targets of anti-cancer treatments. In the current review, specific approaches targeting AAs in terms of either deprivation or supplementation are discussed. Although based on opposed strategies, both show, in vitro and in vivo, positive effects. Any AA-targeted intervention will inevitably impact the cancer host, who frequently already has cachexia. Cancer cachexia is a wasting syndrome, also due to malnutrition, that compromises the effectiveness of anti-cancer drugs and eventually causes the patient's death. AA deprivation may exacerbate malnutrition and cachexia, while AA supplementation may improve the nutritional status, counteract cachexia, and predispose the patient to a more effective anti-cancer treatment. Here is provided an attempt to describe the AA-based therapeutic approaches that integrate currently distant points of view on cancer-centered and host-centered research, providing a glimpse of several potential investigations that approach cachexia as a unique cancer disease.

Tumor glycolysis, an essential sweet tooth of tumor cells

Cancer cells undergo metabolic alterations to meet the immense demand for energy, building blocks, and redox potential. Tumors show glucose-avid and lactate-secreting behavior even in the presence of oxygen, a process known as aerobic glycolysis. Glycolysis is the backbone of cancer cell metabolism, and cancer cells have evolved various mechanisms to enhance it. Glucose metabolism is intertwined with other metabolic pathways, making cancer metabolism diverse and heterogeneous, where glycolysis plays a central role. Oncogenic signaling accelerates the metabolic activities of glycolytic enzymes, mainly by enhancing their expression or by post-translational modifications. Aerobic glycolysis ferments glucose into lactate which supports tumor growth and metastasis by various mechanisms. Herein, we focused on tumor glycolysis, especially its interactions with the pentose phosphate pathway, glutamine metabolism, one-carbon metabolism, and mitochondrial oxidation. Further, we describe the role and regulation of key glycolytic enzymes in cancer. We summarize the role of lactate, an end product of glycolysis, in tumor growth, and the metabolic adaptations during metastasis. Lastly, we briefly discuss limitations and future directions to improve our understanding of glucose metabolism in cancer.

Limiting glutamine utilization activates a GCN2/TRAIL-R2/Caspase-8 apoptotic pathway in glutamine-addicted tumor cells

Oncogenic transformation leads to changes in glutamine metabolism that make transformed cells highly dependent on glutamine for anabolic growth and survival. Herein, we investigated the cell death mechanism activated in glutamine-addicted tumor cells in response to the limitation of glutamine metabolism. We show that glutamine starvation triggers a FADD and caspase-8-dependent and mitochondria-operated apoptotic program in tumor cells that involves the pro-apoptotic TNF-related apoptosis-inducing ligand receptor 2 (TRAIL-R2), but is independent of its cognate ligand TRAIL. In glutamine-depleted tumor cells, activation of the amino acid-sensing general control nonderepressible-2 kinase (GCN2) is responsible for TRAIL-R2 upregulation, caspase-8 activation, and apoptotic cell death. Interestingly, GCN2-dependent ISR signaling induced by methionine starvation also leads to TRAIL-R2 upregulation and apoptosis. Moreover, pharmacological inhibition of transaminases activates a GCN2 and TRAIL-R2-dependent apoptotic mechanism that is inhibited by non-essential amino acids (NEAA). In addition, metabolic stress upon glutamine deprivation also results in GCN2-independent FLICE-inhibitory protein (FLIP) downregulation facilitating caspase-8 activation and apoptosis. Importantly, downregulation of the long FLIP splice form (FLIP_L) and apoptosis upon glutamine deprivation are inhibited in the presence of a membrane-permeable α-ketoglutarate. Collectively, our data support a model in which limiting glutamine utilization in glutamine-addicted tumor cells triggers a previously unknown cell death mechanism regulated by GCN2 that involves the TRAIL-R2-mediated activation of the extrinsic apoptotic pathway.

GLUD1 suppresses renal tumorigenesis and development via inhibiting PI3K/Akt/mTOR pathway

Growing cancer cells are addicted to glutamine. Glutamate dehydrogenase 1 (GLUD1) is one of key enzymes in glutamine metabolism and plays a critical role in the malignancy of diverse tumors. However, its role and molecular mechanism in clear cell renal cell carcinoma (ccRCC) development and progression remain unknown. In this study, analysis results of the GEO/TCGA/UALCAN database showed that GLUD1 level was downregulated in ccRCC tissues. Immunohistochemistry and western blotting results further validated the downregulation of GLUD1 level in ccRCC tissues. GLUD1 level was gradually decreased as ccRCC stage and grade progressed. Low GLUD1 level was associated with a shorter survival and higher IC50 value for tyrosine kinase inhibitors (TKIs) in ccRCC, reminding that GLUD1 level could predict the prognosis and TKIs sensitivity of ccRCC patients. High level of methylation in GLUD1 promoter was positively correlated with the downregulation of GLUD1 level and was negatively correlated with survival of ccRCC patients. GLUD1 overexpression suppressed RCC cell proliferation, colony formation and migration by inhibiting PI3K/Akt/mTOR pathway activation. Low GLUD1 level correlated with suppressive immune microenvironment (TIME) in ccRCC. Together, we found a novel tumor-suppressing role of GLUD1 in ccRCC which was different from that in other tumors and a new mechanism for inhibiting PI3K/Akt/mTOR activation and TIME in ccRCC. These results provide a theoretical basis for GLUD1 as a therapeutic target and prognostic marker in ccRCC.

Hormone-Glutamine Metabolism: A Critical Regulatory Axis in Endocrine-Related Cancers

The endocrine-related cancers and hormones are undoubtedly highly interconnected. How hormones support or repress tumor induction and progression has been extensively profiled. Furthermore, advances in understanding the role of glutamine metabolism in mediating tumorigenesis and development, coupled with these in-depth studies on hormone (e.g., estrogen, progesterone, androgen, prostaglandin, thyroid hormone, and insulin) regulation of glutamine metabolism, have led us to think about the relationship between these three factors, which remains to be elucidated. Accordingly, in this review, we present an updated overview of glutamine metabolism traits and its influence on endocrine oncology, as well as its upstream hormonal regulation. More importantly, this hormone/glutamine metabolism axis may help in the discovery of novel therapeutic strategies for endocrine-related cancer.

Sorting-free metabolic profiling uncovers the vulnerability of fatty acid β-oxidation in in vitro quiescence models

Quiescent cancer cells are rare nondiving cells with the unique ability to evade chemotherapies and resume cell division after treatment. Despite the associated risk of cancer recurrence, how cells can reversibly switch between rapid proliferation and quiescence remains a long-standing open question. By developing a unique methodology for the cell sorting-free separation of metabolic profiles in cell subpopulations in vitro, we unraveled metabolic characteristics of quiescent cells that are largely invariant to basal differences in cell types and quiescence-inducing stimuli. Consistent with our metabolome-based analysis, we show that impairing mitochondrial fatty acid β-oxidation (FAO) can induce apoptosis in quiescence-induced cells and hamper their return to proliferation. Our findings suggest that in addition to mediating energy and redox balance, FAO can play a role in preventing the buildup of toxic intermediates during transitioning to quiescence. Uncovering metabolic strategies to enter, maintain, and exit quiescence can reveal fundamental principles in cell plasticity and new potential therapeutic targets beyond cancer.

LC-qTOF-MS analysis of fish immune organs reveals the distribution of amino acids in response to metabolic adaptation of the survival phenotype in grouper against Vibrio infection

Epinephelus fuscoguttatus is economically crucial to various Southeast Asia countries where they are reared in fish farms to meet the demand for supply. However, a systemic infectious disease known as vibriosis has steadily and extensively affected the fish farming industry. The disease is caused by Vibrio spp., which are pathogenic gram-negative bacteria. This study focused on understanding the host's metabolic adaptation against Vibrio vulnificus infection, which features a survival phenotype, by profiling the metabolites in grouper fingerlings that survived the experimental infection. Mapping of the pathways is crucial to explain the roles of metabolites in fish immunity. A solvent extraction method was used on the grouper's immune organs (gills, liver and spleen) prior to Liquid Chromatography-Quadrupole Time-of-Flight Mass Spectrometry (LC-qTOF-MS) analysis. The metabolites identified in fingerlings that survived experimental infections were mostly amino acids (primary metabolites). Glutamine (0.44%), alanine (0.68%), phenylalanine (2.63%) and tyrosine (2.60%) were highly abundant in survived-infected gills. Aspartic acid (13.57%) and leucine (4.01%) were highly abundant in the livers of the survived-infected fish and lysine was highly abundant in both gills (2.94%) and liver (3.64%) of the survived-infected fish. Subsequent bioinformatics analysis revealed the involvement of the identified functional amino acids in various immune-related pathways. The current findings facilitate the comprehension of the metabolic adaptation of grouper fingerlings that exhibited a survival phenotype against Vibrio infection.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03269-1.