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Cell Nov 2023Metabolic reprogramming is a hallmark of cancer. However, mechanisms underlying metabolic reprogramming and how altered metabolism in turn enhances tumorigenicity are...
Metabolic reprogramming is a hallmark of cancer. However, mechanisms underlying metabolic reprogramming and how altered metabolism in turn enhances tumorigenicity are poorly understood. Here, we report that arginine levels are elevated in murine and patient hepatocellular carcinoma (HCC), despite reduced expression of arginine synthesis genes. Tumor cells accumulate high levels of arginine due to increased uptake and reduced arginine-to-polyamine conversion. Importantly, the high levels of arginine promote tumor formation via further metabolic reprogramming, including changes in glucose, amino acid, nucleotide, and fatty acid metabolism. Mechanistically, arginine binds RNA-binding motif protein 39 (RBM39) to control expression of metabolic genes. RBM39-mediated upregulation of asparagine synthesis leads to enhanced arginine uptake, creating a positive feedback loop to sustain high arginine levels and oncogenic metabolism. Thus, arginine is a second messenger-like molecule that reprograms metabolism to promote tumor growth.
Topics: Animals; Humans; Mice; Arginine; Carcinoma, Hepatocellular; Cell Line, Tumor; Lipid Metabolism; Liver Neoplasms
PubMed: 37804830
DOI: 10.1016/j.cell.2023.09.011 -
Cell Death and Differentiation Aug 2023Pancreatic ductal adenocarcinoma (PDAC) remains a highly fatal malignancy partially due to the acquired alterations related to aberrant protein glycosylation that...
Pancreatic ductal adenocarcinoma (PDAC) remains a highly fatal malignancy partially due to the acquired alterations related to aberrant protein glycosylation that pathologically remodel molecular biological processes and protect PDAC cells from death. Ferroptosis driven by lethal lipid peroxidation provides a targetable vulnerability for PDAC. However, the crosstalk between glycosylation and ferroptosis remains unclear. Here, we identified 4F2hc, a subunit of the glutamate-cystine antiporter system X, and its asparagine (N)-glycosylation is involved in PDAC ferroptosis by N- and O-linked glycoproteomics. Knockdown of SLC3A2 (gene name of 4F2hc) or blocking the N-glycosylation of 4F2hc potentiates ferroptosis sensitization of PDAC cells by impairing the activity of system X manifested by a marked decrease in intracellular glutathione. Mechanistically, we found that the glycosyltransferase B3GNT3 catalyzes the glycosylation of 4F2hc, stabilizes the 4F2hc protein, and enhances the interaction between 4F2hc and xCT. Knockout of B3GNT3 or deletion of enzymatically active B3GNT3 sensitizes PDAC cells to ferroptosis. Reconstitution of 4F2hc-deficient cells with wildtype 4F2hc restores ferroptosis resistance while glycosylation-mutated 4F2hc does not. Additionally, upon combination with a ferroptosis inducer, treatment with the classical N-glycosylation inhibitor tunicamycin (TM) markedly triggers the overactivation of lipid peroxidation and enhances the sensitivity of PDAC cells to ferroptosis. Notably, we confirmed that genetic perturbation of SLC3A2 or combination treatment with TM significantly augments ferroptosis-induced inhibition of orthotopic PDAC. Clinically, high expression of 4F2hc and B3GNT3 contributes to the progression and poor survival of PDAC patients. Collectively, our findings reveal a previously unappreciated function of N-glycosylation of 4F2hc in ferroptosis and suggest that dual targeting the vulnerabilities of N-glycosylation and ferroptosis may be an innovative therapeutic strategy for PDAC.
Topics: Humans; Glycosylation; Ferroptosis; Glycosyltransferases; Cell Line, Tumor; Pancreatic Neoplasms; Carcinoma, Pancreatic Ductal; N-Acetylglucosaminyltransferases
PubMed: 37479744
DOI: 10.1038/s41418-023-01188-z -
Nature Communications Aug 2023KRAS is an important tumor intrinsic factor driving immune suppression in colorectal cancer (CRC). In this study, we demonstrate that SLC25A22 underlies mutant...
KRAS is an important tumor intrinsic factor driving immune suppression in colorectal cancer (CRC). In this study, we demonstrate that SLC25A22 underlies mutant KRAS-induced immune suppression in CRC. In immunocompetent male mice and humanized male mice models, SLC25A22 knockout inhibits KRAS-mutant CRC tumor growth with reduced myeloid derived suppressor cells (MDSC) but increased CD8 T-cells, implying the reversion of mutant KRAS-driven immunosuppression. Mechanistically, we find that SLC25A22 plays a central role in promoting asparagine, which binds and activates SRC phosphorylation. Asparagine-mediated SRC promotes ERK/ETS2 signaling, which drives CXCL1 transcription. Secreted CXCL1 functions as a chemoattractant for MDSC via CXCR2, leading to an immunosuppressive microenvironment. Targeting SLC25A22 or asparagine impairs KRAS-induced MDSC infiltration in CRC. Finally, we demonstrate that the targeting of SLC25A22 in combination with anti-PD1 therapy synergizes to inhibit MDSC and activate CD8 T cells to suppress KRAS-mutant CRC growth in vivo. We thus identify a metabolic pathway that drives immunosuppression in KRAS-mutant CRC.
Topics: Male; Mice; Animals; Cell Line, Tumor; CD8-Positive T-Lymphocytes; Proto-Oncogene Proteins p21(ras); Colorectal Neoplasms; Asparagine; Immunotherapy; Tumor Microenvironment
PubMed: 37542037
DOI: 10.1038/s41467-023-39571-6 -
Nature Metabolism Aug 2023Robust and effective T cell immune surveillance and cancer immunotherapy require proper allocation of metabolic resources to sustain energetically costly processes,...
Robust and effective T cell immune surveillance and cancer immunotherapy require proper allocation of metabolic resources to sustain energetically costly processes, including growth and cytokine production. Here, we show that asparagine (Asn) restriction on CD8 T cells exerted opposing effects during activation (early phase) and differentiation (late phase) following T cell activation. Asn restriction suppressed activation and cell cycle entry in the early phase while rapidly engaging the nuclear factor erythroid 2-related factor 2 (NRF2)-dependent stress response, conferring robust proliferation and effector function on CD8 T cells during differentiation. Mechanistically, NRF2 activation in CD8 T cells conferred by Asn restriction rewired the metabolic program by reducing the overall glucose and glutamine consumption but increasing intracellular nucleotides to promote proliferation. Accordingly, Asn restriction or NRF2 activation potentiated the T cell-mediated antitumoral response in preclinical animal models, suggesting that Asn restriction is a promising and clinically relevant strategy to enhance cancer immunotherapy. Our study revealed Asn as a critical metabolic node in directing the stress signaling to shape T cell metabolic fitness and effector functions.
Topics: Animals; CD8-Positive T-Lymphocytes; NF-E2-Related Factor 2; Asparagine; Glucose; Neoplasms
PubMed: 37550596
DOI: 10.1038/s42255-023-00856-1 -
Nature Cancer Jan 2024In pancreatic ductal adenocarcinoma (PDAC), glutamine is a critical nutrient that drives a wide array of metabolic and biosynthetic processes that support tumor growth....
In pancreatic ductal adenocarcinoma (PDAC), glutamine is a critical nutrient that drives a wide array of metabolic and biosynthetic processes that support tumor growth. Here, we elucidate how 6-diazo-5-oxo-L-norleucine (DON), a glutamine antagonist that broadly inhibits glutamine metabolism, blocks PDAC tumor growth and metastasis. We find that DON significantly reduces asparagine production by inhibiting asparagine synthetase (ASNS), and that the effects of DON are rescued by asparagine. As a metabolic adaptation, PDAC cells upregulate ASNS expression in response to DON, and we show that ASNS levels are inversely correlated with DON efficacy. We also show that L-asparaginase (ASNase) synergizes with DON to affect the viability of PDAC cells, and that DON and ASNase combination therapy has a significant impact on metastasis. These results shed light on the mechanisms that drive the effects of glutamine mimicry and point to the utility of cotargeting adaptive responses to control PDAC progression.
Topics: Humans; Glutamine; Asparagine; Cell Line, Tumor; Asparaginase; Pancreatic Neoplasms; Carcinoma, Pancreatic Ductal; Neoplastic Processes
PubMed: 37814011
DOI: 10.1038/s43018-023-00649-1 -
Nutrients Sep 2023Aspartic acid exists in L- and D-isoforms (L-Asp and D-Asp). Most L-Asp is synthesized by mitochondrial aspartate aminotransferase from oxaloacetate and glutamate... (Review)
Review
Aspartic acid exists in L- and D-isoforms (L-Asp and D-Asp). Most L-Asp is synthesized by mitochondrial aspartate aminotransferase from oxaloacetate and glutamate acquired by glutamine deamidation, particularly in the liver and tumor cells, and transamination of branched-chain amino acids (BCAAs), particularly in muscles. The main source of D-Asp is the racemization of L-Asp. L-Asp transported via aspartate-glutamate carrier to the cytosol is used in protein and nucleotide synthesis, gluconeogenesis, urea, and purine-nucleotide cycles, and neurotransmission and via the malate-aspartate shuttle maintains NADH delivery to mitochondria and redox balance. L-Asp released from neurons connects with the glutamate-glutamine cycle and ensures glycolysis and ammonia detoxification in astrocytes. D-Asp has a role in brain development and hypothalamus regulation. The hereditary disorders in L-Asp metabolism include citrullinemia, asparagine synthetase deficiency, Canavan disease, and dicarboxylic aminoaciduria. L-Asp plays a role in the pathogenesis of psychiatric and neurologic disorders and alterations in BCAA levels in diabetes and hyperammonemia. Further research is needed to examine the targeting of L-Asp metabolism as a strategy to fight cancer, the use of L-Asp as a dietary supplement, and the risks of increased L-Asp consumption. The role of D-Asp in the brain warrants studies on its therapeutic potential in psychiatric and neurologic disorders.
PubMed: 37764806
DOI: 10.3390/nu15184023 -
Philosophical Transactions of the Royal... Nov 2023Citrullination is an important post-translational modification (PTM) of arginine, known to play a role in autoimmune disorders, innate immunity response and maintenance... (Review)
Review
Citrullination is an important post-translational modification (PTM) of arginine, known to play a role in autoimmune disorders, innate immunity response and maintenance of stem cell potency. However, citrullination remains poorly characterized and not as comprehensively understood compared to other PTMs, such as phosphorylation and ubiquitylation. High-resolution mass spectrometry (MS)-based proteomics offers a valuable approach for studying citrullination in an unbiased manner, allowing confident identification of citrullination modification sites and distinction from deamidation events on asparagine and glutamine. MS efforts have already provided valuable insights into peptidyl arginine deaminase targeting along with site-specific information of citrullination in for example synovial fluids derived from rheumatoid arthritis patients. Still, there is unrealized potential for the wider citrullination field by applying MS-based mass spectrometry approaches for proteome-wide investigations. Here we will outline contemporary methods and current challenges for studying citrullination by MS, and discuss how the development of neoteric citrullination-specific proteomics approaches still may improve our understanding of citrullination networks. This article is part of the Theo Murphy meeting issue 'The virtues and vices of protein citrullination'.
Topics: Humans; Arginine; Citrullination; Mass Spectrometry; Protein Processing, Post-Translational; Proteome; Proteomics
PubMed: 37778389
DOI: 10.1098/rstb.2022.0237 -
Neural Regeneration Research Apr 2024Proteolytic cleavage of tau by asparagine endopeptidase (AEP) creates tau-N368 fragments, which may drive the pathophysiology associated with synaptic dysfunction and...
Proteolytic cleavage of tau by asparagine endopeptidase (AEP) creates tau-N368 fragments, which may drive the pathophysiology associated with synaptic dysfunction and memory deterioration in the brain of Alzheimer's disease patients. Nonetheless, the molecular mechanisms of truncated tau-induced cognitive deficits remain unclear. Evidence suggests that signal transduction and activator of transcription-3 (STAT3) is associated with modulating synaptic plasticity, cell apoptosis, and cognitive function. Using luciferase reporter assays, electrophoretic mobility shift assays, western blotting, and immunofluorescence, we found that human tau-N368 accumulation inhibited STAT3 activity by suppressing STAT3 translocation into the nucleus. Overexpression of STAT3 improved tau-N368-induced synaptic deficits and reduced neuronal loss, thereby improving the cognitive deficits in tau-N368 mice. Moreover, in tau-N368 mice, activation of STAT3 increased N-methyl-D-aspartic acid receptor levels, decreased Bcl-2 levels, reversed synaptic damage and neuronal loss, and thereby alleviated cognitive deficits caused by tau-N368. Taken together, STAT3 plays a critical role in truncated tau-related neuropathological changes. This indicates a new mechanism behind the effect of tau-N368 on synapses and memory deficits. STAT3 can be used as a new molecular target to treat tau-N368-induced protein pathology.
PubMed: 37843229
DOI: 10.4103/1673-5374.382253 -
Trends in Molecular Medicine Jun 2024Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive form of pancreatic cancer, known for its challenging diagnosis and limited treatment options. The focus on... (Review)
Review
Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive form of pancreatic cancer, known for its challenging diagnosis and limited treatment options. The focus on metabolic reprogramming as a key factor in tumor initiation, progression, and therapy resistance has gained prominence. In this review we focus on the impact of metabolic changes on the interplay among stromal, immune, and tumor cells, as glutamine and branched-chain amino acids (BCAAs) emerge as pivotal players in modulating immune cell functions and tumor growth. We also discuss ongoing clinical trials that explore metabolic modulation for PDAC, targeting mitochondrial metabolism, asparagine and glutamine addiction, and autophagy inhibition. Overcoming challenges in understanding nutrient effects on immune-stromal-tumor interactions holds promise for innovative therapeutic strategies.
Topics: Humans; Pancreatic Neoplasms; Animals; Carcinoma, Pancreatic Ductal; Glutamine; Tumor Microenvironment; Mitochondria; Amino Acids, Branched-Chain; Autophagy; Energy Metabolism
PubMed: 38604929
DOI: 10.1016/j.molmed.2024.03.008