bims-glucam 2024-01-21 papers

bims-glucam

Biomed News

on Glutamine cancer metabolism

Issue of 2024‒01‒21
eighteen papers selected by
Sreeparna Banerjee, Middle East Technical University

Glutamine metabolism-related genes and immunotherapy in nonspecific orbital inflammation were validated using bioinformatics and machine learning.
GLS and GOT2 as prognostic biomarkers associated with dendritic cell and immunotherapy response in breast cancer.
Modulation of macrophage metabolism as an emerging immunotherapy strategy for cancer.
Evodiamine inhibits EPRS expression to regulate glutamate metabolism and proliferation of oral squamous cell carcinoma cells.
Discovery of Novel Aminobutanoic Acid-Based ASCT2 Inhibitors for the Treatment of Non-Small-Cell Lung Cancer.
Glucose-derived glutamate drives neuronal terminal differentiation in vitro.
Amino acid metabolism in tumor biology and therapy.
Short-term autophagy inhibition by autophinib or SAR405 does not alter the effect of cisplatin on ATP production in prostate cancer cells.
Development of a mouse model expressing a bifunctional glutathione synthesizing enzyme to study glutathione limitation in vivo.
Changes in glutamate and glutamine distributions in the retinas of cystine/glutamate antiporter knockout mice.
Metabolism in Hematopoiesis and Its Malignancy.
Cellular metabolism: a key player in cancer ferroptosis.
α-Ketoglutarate supplementation and NAD+ modulation enhance metabolic rewiring and radiosensitization in SLC25A1 inhibited cancer cells.
Investigations of potential non-amino acid SNAT2 inhibitors.
Electrophilic metabolites targeting the KEAP1/NRF2 partnership.
Glutamine enhances sucrose taste through a gut microbiota-gut-brain axis in Drosophila.
Residual Complex I activity and amphidirectional Complex II operation support glutamate catabolism through mtSLP in anoxia.
Thiol starvation triggers melanoma state switching in an ATF4 and NRF2-dependent manner.

BMC Genomics. 2024 Jan 17. 25(1): 71

Glutamine metabolism-related genes and immunotherapy in nonspecific orbital inflammation were validated using bioinformatics and machine learning.

Zixuan Wu, Na Li, Yuan Gao, Liyuan Cao, Xiaolei Yao, Qinghua Peng.

  BACKGROUND: Nonspecific orbital inflammation (NSOI) is an idiopathic, persistent, and proliferative inflammatory condition affecting the orbit, characterized by polymorphous lymphoid infiltration. Its pathogenesis and progression have been linked to imbalances in tumor metabolic pathways, with glutamine (Gln) metabolism emerging as a critical aspect in cancer. Metabolic reprogramming is known to influence clinical outcomes in various malignancies. However, comprehensive research on glutamine metabolism's significance in NSOI is lacking.METHODS: This study conducted a bioinformatics analysis to identify and validate potential glutamine-related molecules (GlnMgs) associated with NSOI. The discovery of GlnMgs involved the intersection of differential expression analysis with a set of 42 candidate GlnMgs. The biological functions and pathways of the identified GlnMgs were analyzed using GSEA and GSVA. Lasso regression and SVM-RFE methods identified hub genes and assessed the diagnostic efficacy of fourteen GlnMgs in NSOI. The correlation between hub GlnMgs and clinical characteristics was also examined. The expression levels of the fourteen GlnMgs were validated using datasets GSE58331 and GSE105149.
RESULTS: Fourteen GlnMgs related to NSOI were identified, including FTCD, CPS1, CTPS1, NAGS, DDAH2, PHGDH, GGT1, GCLM, GLUD1, ART4, AADAT, ASNSD1, SLC38A1, and GFPT2. Biological function analysis indicated their involvement in responses to extracellular stimulus, mitochondrial matrix, and lipid transport. The diagnostic performance of these GlnMgs in distinguishing NSOI showed promising results.
CONCLUSIONS: This study successfully identified fourteen GlnMgs associated with NSOI, providing insights into potential novel biomarkers for NSOI and avenues for monitoring disease progression.

Keywords:  Bioinformatics; Gln-Metabolism genes (GlnMgs); Lasso regression; Nonspecific orbital inflammation (NSOI); SVM-RFE

DOI:  https://doi.org/10.1186/s12864-023-09946-6
Heliyon. 2024 Jan 15. 10(1): e24163

GLS and GOT2 as prognostic biomarkers associated with dendritic cell and immunotherapy response in breast cancer.

Ruifang Yang, Shuo Cheng, Jie Xiao, Yujie Pei, Zhonglin Zhu, Jifa Zhang, Jing Feng, Jing Li.

  Breast cancer is the females' most common cancer. Targeting the immune microenvironment is a new and promising treatment method for breast cancer. Nevertheless, only a small section of patients can profit by immunotherapy, and improving the ability to accurately predict the potential for immunotherapy response is still awaiting further exploration. In this study, we found that the key factors of glutamine metabolism, glutaminase 1 (GLS) and mitochondrial aspartate transaminase (GOT2), showed opposite expression patterns in breast cancer samples. Based on the expression level of GLS and GOT2, we divided the breast cancer samples into two clusters: Cluster 2 showed GLS expressed higher and GOT2 expressed lower, whereas Cluster 1 showed GOT2 expressed higher and GLS expressed lower. GSEA showed that the clusters were related to pathways of immunity. Further analysis showed that Cluster 2 was positively associated with immunity infiltration. Through WGCNA, we identified a module strongly correlated with glutamine metabolism and immunity and identified 11 dendritic cell-associated genes involved in dendritic cell development, maturation, activation and other functions. In addition, Cluster 2 also showed higher immune checkpoint gene expression, which suggest the Cluster 2 had even better response to immunotherapy. The validation dataset could also be clustered into two groups. Cluster 2 (GLS expressed higher and GOT2 expressed lower) of the validation dataset was also positively associated with dendritic cells and a better immunotherapy response. Thus, these data indicate that GLS and GOT2 are prognostic biomarkers which closely related to dendritic cells and better reacted to immunotherapy in breast cancer.

Keywords:  Breast cancer; Dendritic cell; GLS1; GOT2; Immune checkpoint

DOI:  https://doi.org/10.1016/j.heliyon.2024.e24163
J Clin Invest. 2024 Jan 16. pii: e175445. [Epub ahead of print]134(2):

Modulation of macrophage metabolism as an emerging immunotherapy strategy for cancer.

Corey Dussold, Kaylee Zilinger, Jillyn Turunen, Amy B Heimberger, Jason Miska.

Immunometabolism is a burgeoning field of research that investigates how immune cells harness nutrients to drive their growth and functions. Myeloid cells play a pivotal role in tumor biology, yet their metabolic influence on tumor growth and antitumor immune responses remains inadequately understood. This Review explores the metabolic landscape of tumor-associated macrophages, including the immunoregulatory roles of glucose, fatty acids, glutamine, and arginine, alongside the tools used to perturb their metabolism to promote antitumor immunity. The confounding role of metabolic inhibitors on our interpretation of myeloid metabolic phenotypes will also be discussed. A binary metabolic schema is currently used to describe macrophage immunological phenotypes, characterizing inflammatory M1 phenotypes, as supported by glycolysis, and immunosuppressive M2 phenotypes, as supported by oxidative phosphorylation. However, this classification likely underestimates the variety of states in vivo. Understanding these nuances will be critical when developing interventional metabolic strategies. Future research should focus on refining drug specificity and targeted delivery methods to maximize therapeutic efficacy.

DOI: https://doi.org/10.1172/JCI175445
Kaohsiung J Med Sci. 2024 Jan 19.

Evodiamine inhibits EPRS expression to regulate glutamate metabolism and proliferation of oral squamous cell carcinoma cells.

Li-Qi Lin, Si-Yi Lv, Hao-Zhe Ren, Rong-Rong Li, Lin Li, Yun-Qing Pang, Jing Wang.

  The effects of evodiamine (EVO) on oral squamous cell carcinoma (OSCC) are not yet understood. Based on our earlier findings, we hypothesized that evodiamine may affect OSCC cell proliferation and glutamate metabolism by modulating the expression of EPRS (glutamyl-prolyl-tRNA synthetase 1). From GEPIA, we obtained EPRS expression data in patients with OSCC as well as survival prognosis data. An animal model using Cal27 cells in BALB/c nude mice was established. The expression of EPRS was assessed by immunofluorescence, Western blotting, and quantitative PCR. Glutamate measurements were performed to evaluate the impact of evodiamine on glutamate metabolism of Cal27 and SAS tumor cells. transient transfection techniques were used to knock down and modulate EPRS in these cells. EPRS is expressed at higher levels in OSCC than in normal tissues, and it predicts poor prognosis in patients. In a nude mouse xenograft model, evodiamine inhibited tumor growth and the expression of EPRS. Evodiamine impacted cell proliferation, glutamine metabolism, and EPRS expression on Cal27 and SAS cell lines. In EPRS knockdown cell lines, both cell proliferation and glutamine metabolism are suppressed. EPRS's overexpression partially restores evodiamine's inhibitory effects on cell proliferation and glutamine metabolism. This study provides crucial experimental evidence supporting the potential therapeutic application of evodiamine in treating OSCC. Evodiamine exhibits promising anti-tumor effects by targeting EPRS to regulate glutamate metabolism.

Keywords:  evodiamine; glutamate metabolism; glutamyl-prolyl-tRNA synthetase 1 (EPRS); oral squamous cell carcinoma; proliferation

DOI:  https://doi.org/10.1002/kjm2.12803
J Med Chem. 2024 Jan 13.

Discovery of Novel Aminobutanoic Acid-Based ASCT2 Inhibitors for the Treatment of Non-Small-Cell Lung Cancer.

Lian Qin, Xinying Cheng, Shijiao Wang, Guangyue Gong, Huiyan Su, Huidan Huang, Tian Chen, Davaadagva Damdinjav, Buyankhishig Dorjsuren, Zhiyu Li, Zhixia Qiu, Jinlei Bian.

Alanine-serine-cysteine transporter 2 (ASCT2) is up-regulated in lung cancers, and inhibiting it could potentially lead to nutrient deprivation, making it a viable strategy for cancer treatment. In this study, we present a series of ASCT2 inhibitors based on aminobutanoic acids, which exhibit potent inhibitory activity. Two compounds, 20k and 25e, were identified as novel and potent ASCT2 inhibitors, with IC50 values at the micromolar level in both A549 and HEK293 cells, effectively blocking glutamine (Gln) uptake. Additionally, these compounds regulated amino acid metabolism, suppressed mTOR signaling, inhibited non-small-cell lung cancer (NSCLC) growth, and induced apoptosis. In vivo, experiments showed that 20k and 25e suppressed tumor growth in an A549 xenograft model, with tumor growth inhibition (TGI) values of 65 and 70% at 25 mg/kg, respectively, while V9302 only achieved a TGI value of 29%. Furthermore, both compounds demonstrated promising therapeutic potential in patient-derived organoids. Therefore, these ASCT2 inhibitors based on aminobutanoic acids are promising therapeutic agents for treating NSCLC by targeting cancer Gln metabolism.

DOI: https://doi.org/10.1021/acs.jmedchem.3c01093
EMBO Rep. 2024 Jan 19.

Glucose-derived glutamate drives neuronal terminal differentiation in vitro.

Laura D'Andrea, Matteo Audano, Silvia Pedretti, Silvia Pelucchi, Ramona Stringhi, Gabriele Imperato, Giulia De Cesare, Clara Cambria, Marine H Laporte, Nicola Zamboni, Flavia Antonucci, Monica Di Luca, Nico Mitro, Elena Marcello.

  Neuronal maturation is the phase during which neurons acquire their final characteristics in terms of morphology, electrical activity, and metabolism. However, little is known about the metabolic pathways governing neuronal maturation. Here, we investigate the contribution of the main metabolic pathways, namely glucose, glutamine, and fatty acid oxidation, during the maturation of primary rat hippocampal neurons. Blunting glucose oxidation through the genetic and chemical inhibition of the mitochondrial pyruvate transporter reveals that this protein is critical for the production of glutamate, which is required for neuronal arborization, proper dendritic elongation, and spine formation. Glutamate supplementation in the early phase of differentiation restores morphological defects and synaptic function in mitochondrial pyruvate transporter-inhibited cells. Furthermore, the selective activation of metabotropic glutamate receptors restores the impairment of neuronal differentiation due to the reduced generation of glucose-derived glutamate and rescues synaptic local translation. Fatty acid oxidation does not impact neuronal maturation. Whereas glutamine metabolism is important for mitochondria, it is not for endogenous glutamate production. Our results provide insights into the role of glucose-derived glutamate as a key player in neuronal terminal differentiation.

Keywords:  Glutamate; Local Protein Translation in Neurons; Metabolism; Mitochondrial Pyruvate Carrier

DOI:  https://doi.org/10.1038/s44319-023-00048-8
Cell Death Dis. 2024 Jan 13. 15(1): 42

Amino acid metabolism in tumor biology and therapy.

Jie Chen, Likun Cui, Shaoteng Lu, Sheng Xu.

Amino acid metabolism plays important roles in tumor biology and tumor therapy. Accumulating evidence has shown that amino acids contribute to tumorigenesis and tumor immunity by acting as nutrients, signaling molecules, and could also regulate gene transcription and epigenetic modification. Therefore, targeting amino acid metabolism will provide new ideas for tumor treatment and become an important therapeutic approach after surgery, radiotherapy, and chemotherapy. In this review, we systematically summarize the recent progress of amino acid metabolism in malignancy and their interaction with signal pathways as well as their effect on tumor microenvironment and epigenetic modification. Collectively, we also highlight the potential therapeutic application and future expectation.

DOI: https://doi.org/10.1038/s41419-024-06435-w
Bratisl Lek Listy. 2024 ;124(2): 84-91

Short-term autophagy inhibition by autophinib or SAR405 does not alter the effect of cisplatin on ATP production in prostate cancer cells.

Monika Kratochvilova, Petr Stepka, Martina Raudenska, Jan Balvan, Lukas Richtera, Natalia Cernei, Dagmar Sterbova Skopalova, Ondrej Zitka, Petr Filipensky, Petr Babula, Michal Masarik.

  OBJECTIVES: Cisplatin is a widely used anticancer drug for the treatment of many solid cancers. DNA damage is thought to be the key mechanism of cisplatin's anticancer activity. However, cisplatin may also affect cellular metabolism. The aim of this study was to determine the effect of cisplatin on the types of ATP production (OXPHOS versus glycolysis) and their rate in prostate cancer cells and to determine the potentially protective effect of autophagy and amino acids during cisplatin treatment. We also wanted to investigate the potential synergy between the metabolic effects of cisplatin on ATP production and the inhibition of autophagy.METHODS: Cisplatin treatment can significantly affect the metabolism of cancer cells. Important metabolic pathways can be altered, leading to changes in energy production and nutrient utilization. Autophagy and amino acid pool modulations can serve as protective mechanisms significantly affecting tumor cell survival under metabolic stress caused by anticancer treatment. By enabling the recycling of amino acids, autophagy helps cancer cells maintain cellular homeostasis and overcome nutrient limitations. Thus, inhibition of autophagy could have a supportive effect on the metabolic effects of cisplatin.
RESULTS: After cisplatin treatment, ATP production by way of OXPHOS was significantly decreased in 22Rv1 and PC-3 cells. On the other hand, ATP production by glycolysis was not significantly affected in 22Rv1 cells. DU145 cells with dysfunctional autophagy were the most sensitive to cisplatin treatment and showed the lowest ATP production. However, short-term autophagy inhibition (24h) by autophinib or SAR405 in 22Rv1 and PC-3 cells did not alter the effect of cisplatin on ATP production. Levels of some amino acids (arginine, methionine) significantly affected the fitness of cancer cells.
CONCLUSION: Persistent defects of autophagy can affect the metabolic sensitivity of cancer cells due to interference with arginine metabolism. Amino acids contained in the culture medium had an impact on the overall effect of cisplatin (Fig. 3, Ref. 38).

Keywords:  amino acids prostate cancer.; autophagy inhibition; cisplatin

DOI:  https://doi.org/10.4149/BLL_2024_013
J Biol Chem. 2024 Jan 11. pii: S0021-9258(24)00021-8. [Epub ahead of print] 105645

Development of a mouse model expressing a bifunctional glutathione synthesizing enzyme to study glutathione limitation in vivo.

Rebecca C Timson, Artem Khan, Beste Uygur, Marwa Saad, Hsi-Wen Yeh, Nicole L DelGaudio, Ross Weber, Hanan Alwaseem, Jing Gao, Chingwen Yang, Kıvanç Birsoy.

Glutathione (GSH) is a highly abundant tripeptide thiol that performs diverse protective and biosynthetic functions in cells. While changes in GSH availability are associated with inborn errors of metabolism, cancer and neurodegenerative disorders, studying the limiting role of GSH in physiology and disease has been challenging due to its tight regulation. To address this, we generated cell and mouse models that express a bifunctional glutathione-synthesizing enzyme from Streptococcus thermophilus (GshF), which possesses both glutamate-cysteine ligase and glutathione synthase activities. GshF expression allows efficient production of GSH in the cytosol and mitochondria and prevents cell death in response to GSH depletion, but not ferroptosis induction, indicating that GSH is not a limiting factor under lipid peroxidation. CRISPR screens using engineered enzymes further revealed genes required for cell proliferation under cellular and mitochondrial GSH depletion. Among these, we identified the glutamate-cysteine ligase modifier subunit, Gclm, as a requirement for cellular sensitivity to buthionine sulfoximne, a glutathione synthesis inhibitor. Finally, GshF expression in mice is embryonically lethal but sustains postnatal viability when restricted to adulthood. Overall, our work identifies a conditional mouse model to investigate the limiting role of GSH in physiology and disease.

DOI: https://doi.org/10.1016/j.jbc.2024.105645
Mol Vis. 2023 ;29 274-288

Changes in glutamate and glutamine distributions in the retinas of cystine/glutamate antiporter knockout mice.

Luis J Knight, Renita M Martis, Paul J Donaldson, Monica L Acosta, Julie C Lim.

Purpose: The cystine/glutamate antiporter is involved in the export of intracellular glutamate in exchange for extracellular cystine. Glutamate is the main neurotransmitter in the retina and plays a key metabolic role as a major anaplerotic substrate in the tricarboxylic acid cycle to generate adenosine triphosphate (ATP). In addition, glutamate is also involved in the outer plexiform glutamate-glutamine cycle, which links photoreceptors and supporting Müller cells and assists in maintaining photoreceptor neurotransmitter supply. In this study, we investigated the role of xCT, the light chain subunit responsible for antiporter function, in glutamate pathways in the mouse retina using an xCT knockout mouse. As xCT is a glutamate exporter, we hypothesized that loss of xCT function may influence the presynaptic metabolism of photoreceptors and postsynaptic levels of glutamate.Methods: Retinas of C57BL/6J wild-type (WT) and xCT knockout (KO) mice of either sex were analyzed from 6 weeks to 12 months of age. Biochemical assays were used to determine the effect of loss of xCT on glycolysis and energy metabolism by measuring lactate dehydrogenase activity and ATP levels. Next, biochemical assays were used to measure whole-tissue glutamate and glutamine levels, while silver-intensified immunogold labeling was performed on 6-week and 9-month-old retinas to visualize and quantify the distribution of glutamate, glutamine, and related neurochemical substrates gamma-aminobutyric acid (GABA) and glycine in the different layers of the retina.
Results: Biochemical analysis revealed that loss of xCT function did not alter the lactate dehydrogenase activity, ATP levels, or glutamate and glutamine contents in whole retinas in any age group. However, at 6 weeks of age, the xCT KO retinas revealed altered glutamate distribution compared with the age-matched WT retinas, with accumulation of glutamate in the photoreceptors and outer plexiform layer. In addition, at 6 weeks and 9 months of age, the xCT KO retinas also showed altered glutamine distribution compared with the WT retinas, with glutamine labeling significantly decreased in Müller cell bodies. No significant difference in GABA or glycine distribution were found between the WT and xCT KO retinas at 6 weeks or 9 months of age.
Conclusion: Loss of xCT function results in glutamate metabolic disruption through the accumulation of glutamate in photoreceptors and a reduced uptake of glutamate by Müller cells, which in turn decreases glutamine production. These findings support the idea that xCT plays a role in the presynaptic metabolism of photoreceptors and postsynaptic levels of glutamate and derived neurotransmitters in the retina.
Adv Exp Med Biol. 2023 ;1442 45-64

Metabolism in Hematopoiesis and Its Malignancy.

Xiaoyuan Zeng, Yi-Ping Wang, Cheuk-Him Man.

  Hematopoietic stem cells (HSCs) are multipotent stem cells that can self-renew and generate all blood cells of different lineages. The system is under tight control in order to maintain a precise equilibrium of the HSC pool and the effective production of mature blood cells to support various biological activities. Cell metabolism can regulate different molecular activities, such as epigenetic modification and cell cycle regulation, and subsequently affects the function and maintenance of HSC. Upon malignant transformation, oncogenic drivers in malignant hematopoietic cells can remodel the metabolic pathways for supporting the oncogenic growth. The dysregulation of metabolism results in oncogene addiction, implying the development of malignancy-specific metabolism-targeted therapy. In this chapter, we will discuss the significance of different metabolic pathways in hematopoiesis, specifically, the distinctive metabolic dependency in hematopoietic malignancies and potential metabolic therapy.

Keywords:  Hematopoiesis; Hematopoietic malignancy; Metabolism; Metabolism-targeted therapy; Nutrient metabolism

DOI:  https://doi.org/10.1007/978-981-99-7471-9_4
Cancer Commun (Lond). 2024 Jan 13.

Cellular metabolism: a key player in cancer ferroptosis.

Xianjie Jiang, Qiu Peng, Mingjing Peng, Linda Oyang, Honghan Wang, Qiang Liu, Xuemeng Xu, Nayiyuan Wu, Shiming Tan, Wenjuan Yang, Yaqian Han, Jinguan Lin, Longzheng Xia, Yanyan Tang, Xia Luo, Jie Dai, Yujuan Zhou, Qianjin Liao.

  Cellular metabolism is the fundamental process by which cells maintain growth and self-renewal. It produces energy, furnishes raw materials, and intermediates for biomolecule synthesis, and modulates enzyme activity to sustain normal cellular functions. Cellular metabolism is the foundation of cellular life processes and plays a regulatory role in various biological functions, including programmed cell death. Ferroptosis is a recently discovered form of iron-dependent programmed cell death. The inhibition of ferroptosis plays a crucial role in tumorigenesis and tumor progression. However, the role of cellular metabolism, particularly glucose and amino acid metabolism, in cancer ferroptosis is not well understood. Here, we reviewed glucose, lipid, amino acid, iron and selenium metabolism involvement in cancer cell ferroptosis to elucidate the impact of different metabolic pathways on this process. Additionally, we provided a detailed overview of agents used to induce cancer ferroptosis. We explained that the metabolism of tumor cells plays a crucial role in maintaining intracellular redox homeostasis and that disrupting the normal metabolic processes in these cells renders them more susceptible to iron-induced cell death, resulting in enhanced tumor cell killing. The combination of ferroptosis inducers and cellular metabolism inhibitors may be a novel approach to future cancer therapy and an important strategy to advance the development of treatments.

Keywords:  cancer therapy; cellular metabolism; ferroptosis; ferroptosis inducer

DOI:  https://doi.org/10.1002/cac2.12519
Cell Death Discov. 2024 Jan 15. 10(1): 27

α-Ketoglutarate supplementation and NAD+ modulation enhance metabolic rewiring and radiosensitization in SLC25A1 inhibited cancer cells.

Kexu Xiang, Mikhail Kunin, Safa Larafa, Maike Busch, Nicole Dünker, Verena Jendrossek, Johann Matschke.

Metabolic rewiring is the result of the increasing demands and proliferation of cancer cells, leading to changes in the biological activities and responses to treatment of cancer cells. The mitochondrial citrate transport protein SLC25A1 is involved in metabolic reprogramming offering a strategy to induce metabolic bottlenecks relevant to radiosensitization through the accumulation of the oncometabolite D-2-hydroxyglutarate (D-2HG) upon SLC25A1 inhibition (SLC25A1i). Previous studies have revealed the comparative effects of SLC25A1i or cell-permeable D-2HG (octyl-D-2HG) treatments on DNA damage induction and repair, as well as on energy metabolism and cellular function, which are crucial for the long-term survival of irradiated cells. Here, α-ketoglutarate (αKG), the precursor of D-2HG, potentiated the effects observed upon SLC25A1i on DNA damage repair, cell function and long-term survival in vitro and in vivo, rendering NCI-H460 cancer cells more vulnerable to ionizing radiation. However, αKG treatment alone had little effect on these phenotypes. In addition, supplementation with nicotinamide (NAM), a precursor of NAD (including NAD+ and NADH), counteracted the effects of SLC25A1i or the combination of SLC25A1i with αKG, highlighting a potential importance of the NAD+/NADH balance on cellular activities relevant to the survival of irradiated cancer cells upon SLC25A1i. Furthermore, inhibition of histone lysine demethylases (KDMs), as a major factor affected upon SLC25A1i, by JIB04 treatment alone or in combination with αKG supplementation phenocopied the broad effects on mitochondrial and cellular function induced by SLC25A1i. Taken together, αKG supplementation potentiated the effects on cellular processes observed upon SLC25A1i and increased the cellular demand for NAD to rebalance the cellular state and ensure survival after irradiation. Future studies will elucidate the underlying metabolic reprogramming induced by SLC25A1i and provide novel therapeutic strategies for cancer treatment.

DOI: https://doi.org/10.1038/s41420-024-01805-x
Front Pharmacol. 2023 ;14 1302445

Investigations of potential non-amino acid SNAT2 inhibitors.

Sebastian Jakobsen, Emilie Fynbo Petersen, Carsten Uhd Nielsen.

  The sodium-coupled neutral amino acid transporter 2 (SNAT2, SLC38A2) has been implicated in cancer for its ability to supply cancer cells with glutamine and sarcosine. A recent high-throughput screen published by Gauthier-Coles et al. identified the non-amino acid 3-(N-methyl (4-methylphenyl)sulfonamido)-N-(2-trifluoromethylbenzyl)thiophene-2-carboxamide (MMTC or 57E) as a potent and selective SNAT2 inhibitor. Here we have investigated the ability of MMTC and four other compounds selected from the screen by Gauthier-Coles et al. to decrease 3H-Gly uptake in hyperosmotically treated human prostate cancer PC-3 cells. In these cells, SNAT2 is highly upregulated when the cells are hyperosmotically stressed for 24 h and is the primary contributor to glycine uptake. The five compounds were investigated at concentrations of 1-50 µM based on their equilibrium solubility. At 37°C the equilibrium solubility in HEPES buffered HBSS at pH 7.4 was measured to be 24.9 (53B), 56.1 (54F), 13.3 (55B), and 27.5 (57B) µM, respectively. The equilibrium solubility of MMTC was below the detection limit of the HPLC-UV method, thus less than 1.8 µM. However, a kinetic solubility of approximately 2.5-10 µM could be achieved during the course of the uptake study. In contrast to the previous publication, MMTC showed no inhibition of SNAT2-mediated 3H-Gly uptake in PC-3 cells at a concentration of 1 or 5 μM, despite a published IC50 of 0.8 µM. Similarly, 53B, 55B, and 57B showed no inhibition at soluble conditions, whereas 54F showed approximately 20% inhibition at 50 µM. In our experimental setup, the investigated compounds showed limited potential as SNAT2 inhibitors.

Keywords:  PC-3 cells; SNAT2; amino acid transport; cancer; inhibitor

DOI:  https://doi.org/10.3389/fphar.2023.1302445
Curr Opin Chem Biol. 2024 Jan 18. pii: S1367-5931(24)00001-2. [Epub ahead of print]78 102425

Electrophilic metabolites targeting the KEAP1/NRF2 partnership.

Albena T Dinkova-Kostova, Henriikka Hakomäki, Anna-Liisa Levonen.

Numerous electrophilic metabolites are formed during cellular activity, particularly under conditions of oxidative, inflammatory and metabolic stress. Among them are lipid oxidation and nitration products, and compounds derived from amino acid and central carbon metabolism. Here we focus on one cellular target of electrophiles, the Kelch-like ECH associated protein 1 (KEAP1)/nuclear factor erythroid 2 p45-related factor 2 (NRF2) partnership. Many of these reactive compounds modify C151, C273 and/or C288 within KEAP1. Other types of modifications include S-lactoylation of C273, N-succinylation of K131, and formation of methylimidazole intermolecular crosslink between two KEAP1 monomers. Modified KEAP1 relays the initial signal to transcription factor NRF2 and its downstream targets, the ultimate effectors that provide means for detoxification, adaptation and survival. Thus, by non-enzymatically covalently modifying KEAP1, the electrophilic metabolites discussed here serve as chemical signals connecting metabolism with stress responses.

DOI: https://doi.org/10.1016/j.cbpa.2024.102425
Life Sci. 2024 Jan 11. pii: S0024-3205(24)00004-3. [Epub ahead of print]339 122415

Glutamine enhances sucrose taste through a gut microbiota-gut-brain axis in Drosophila.

Sha-Sha Li, An-Qi Li, Zhi-Ying Liu, Xin-Yuan Zhao, Ge-Run Wang, Yinyue Deng, Qiao-Ping Wang.

  AIMS: Amino acids (AAs) are known to play important roles in various physiological functions. However, their effect on sweet taste perception remains largely unknown.MAIN METHODS: We used Drosophila to evaluate the effect of each AA on sucrose taste perception. Individual AA was supplemented into diets and male flies were fed on these diets for 6 days. The proboscis extension response (PER) assay was applied to assess the sucrose taste sensitivity of treated flies. We further utilized the RNA-seq and germ-free (GF) flies to reveal the underlying mechanisms of sucrose taste sensitization induced by glutamine (Gln).
KEY FINDINGS: We found that supplementation of Gln into diets significantly enhances sucrose taste sensitivity. This sucrose taste sensitization is dependent on gut microbiota and requires a specific gut bacterium Acetobacter tropicalis (A. tropicalis). We further found that CNMamide (CNMa) in the gut and CNMa receptor (CNMaR) in dopaminergic neurons are required for increased sucrose taste sensitivity by Gln diet. Finally, we demonstrated that a gut microbiota-gut-brain axis is required for Gln-induced sucrose taste sensitization.
SIGNIFICANCE: These findings can advance understanding of the complex interplay between host physiology, dietary factors, and gut microbiota.

Keywords:  Amino acid; CNMaR; CNMamide; Glutamine; Gut microbiota; Sucrose taste sensitivity

DOI:  https://doi.org/10.1016/j.lfs.2024.122415
Sci Rep. 2024 Jan 19. 14(1): 1729

Residual Complex I activity and amphidirectional Complex II operation support glutamate catabolism through mtSLP in anoxia.

Dora Ravasz, David Bui, Sara Nazarian, Gergely Pallag, Noemi Karnok, Jennie Roberts, Bryan P Marzullo, Daniel A Tennant, Bennett Greenwood, Alex Kitayev, Collin Hill, Timea Komlódi, Carolina Doerrier, Kristyna Cunatova, Erika Fernandez-Vizarra, Erich Gnaiger, Michael A Kiebish, Alexandra Raska, Krasimir Kolev, Bence Czumbel, Niven R Narain, Thomas N Seyfried, Christos Chinopoulos.

Anoxia halts oxidative phosphorylation (OXPHOS) causing an accumulation of reduced compounds in the mitochondrial matrix which impedes dehydrogenases. By simultaneously measuring oxygen concentration, NADH autofluorescence, mitochondrial membrane potential and ubiquinone reduction extent in isolated mitochondria in real-time, we demonstrate that Complex I utilized endogenous quinones to oxidize NADH under acute anoxia. 13C metabolic tracing or untargeted analysis of metabolites extracted during anoxia in the presence or absence of site-specific inhibitors of the electron transfer system showed that NAD+ regenerated by Complex I is reduced by the 2-oxoglutarate dehydrogenase Complex yielding succinyl-CoA supporting mitochondrial substrate-level phosphorylation (mtSLP), releasing succinate. Complex II operated amphidirectionally during the anoxic event, providing quinones to Complex I and reducing fumarate to succinate. Our results highlight the importance of quinone provision to Complex I oxidizing NADH maintaining glutamate catabolism and mtSLP in the absence of OXPHOS.

DOI: https://doi.org/10.1038/s41598-024-51365-4
Redox Biol. 2023 Dec 27. pii: S2213-2317(23)00412-3. [Epub ahead of print]70 103011

Thiol starvation triggers melanoma state switching in an ATF4 and NRF2-dependent manner.

Madlen Meinert, Christina Jessen, Anita Hufnagel, Julia Katharina Charlotte Kreß, Mychal Burnworth, Theo Däubler, Till Gallasch, Thamara Nishida Xavier da Silva, Ancély Ferreira Dos Santos, Carsten Patrick Ade, Werner Schmitz, Susanne Kneitz, José Pedro Friedmann Angeli, Svenja Meierjohann.

The cystine/glutamate antiporter xCT is an important source of cysteine for cancer cells. Once taken up, cystine is reduced to cysteine and serves as a building block for the synthesis of glutathione, which efficiently protects cells from oxidative damage and prevents ferroptosis. As melanomas are particularly exposed to several sources of oxidative stress, we investigated the biological role of cysteine and glutathione supply by xCT in melanoma. xCT activity was abolished by genetic depletion in the Tyr::CreER; BrafCA; Ptenlox/+ melanoma model and by acute cystine withdrawal in melanoma cell lines. Both interventions profoundly impacted melanoma glutathione levels, but they were surprisingly well tolerated by murine melanomas in vivo and by most human melanoma cell lines in vitro. RNA sequencing of human melanoma cells revealed a strong adaptive upregulation of NRF2 and ATF4 pathways, which orchestrated the compensatory upregulation of genes involved in antioxidant defence and de novo cysteine biosynthesis. In addition, the joint activation of ATF4 and NRF2 triggered a phenotypic switch characterized by a reduction of differentiation genes and induction of pro-invasive features, which was also observed after erastin treatment or the inhibition of glutathione synthesis. NRF2 alone was capable of inducing the phenotypic switch in a transient manner. Together, our data show that cystine or glutathione levels regulate the phenotypic plasticity of melanoma cells by elevating ATF4 and NRF2.

DOI: https://doi.org/10.1016/j.redox.2023.103011