bims-glucam 2022-11-20 papers

bims-glucam

Biomed News

on Glutamine cancer metabolism

Issue of 2022–11–20
fiveteen papers selected by
Sreeparna Banerjee, Middle East Technical University

α-ketoglutarate suppresses immediate early gene expression in cancer cells.
Loss of vascular endothelial glutaminase inhibits tumor growth and metastasis, and increases sensitivity to chemotherapy.
Targeting glutamine metabolism in hepatic stellate cells alleviates liver fibrosis.
Multiomics analysis couples mRNA turnover and translational control of glutamine metabolism to the differentiation of the activated CD4+ T cell.
Metabolic reprogramming in the immunosuppression of tumor-associated macrophages.
Cellular and computational models reveal environmental and metabolic interactions in MMUT-type methylmalonic aciduria.
Cancer cell survival depends on collagen uptake into tumor-associated stroma.
Proteomics revealed the crosstalk between copper stress and cuproptosis, and explored the feasibility of curcumin as anticancer copper ionophore.
Tracing the electron flow in redox metabolism: The appropriate distribution of electrons is essential to maintain redox balance in cancer cells.
Relevance of the TRIAP1/p53 axis in colon cancer cell proliferation and adaptation to glutamine deprivation.
Disorders of cancer metabolism: The therapeutic potential of cannabinoids.
Discovery of DRP-104, a tumor-targeted metabolic inhibitor prodrug.
Anti-tumor effects of P-LPK-CPT, a peptide-camptothecin conjugate, in colorectal cancer.
Identification and validation in a novel quantification system of the glutamine metabolism patterns for the prediction of prognosis and therapy response in hepatocellular carcinoma.
O-GlcNAcylation Coordinates Glutaminolysis by Regulating the Stability and Membrane Trafficking of ASCT2 in Hepatic Stellate Cells.

Biochem Biophys Res Commun. 2022 Nov 11. pii: S0006-291X(22)01562-5. [Epub ahead of print]637 144-152

α-ketoglutarate suppresses immediate early gene expression in cancer cells.

Sungmin Joo, Seungwoo Baek, Jaehyeon Kang, Dong Soo Seo, Taeg Kyu Kwon, Younghoon Jang.

  Cancer cells exhibit increased glutamine consumption compared to normal cells, supporting cell survival and proliferation. Glutamine is converted to α-ketoglutarate (αKG), which then enters the tricarboxylic acid cycle to generate ATP. Recently, therapeutic modulation of glutamine metabolism has become an attractive metabolic anti-cancer strategy. However, how synergistic combination therapy is required to overcome glutamine metabolism drug resistance remains elusive. To address this issue, we first investigated the role of αKG in regulating gene expression in several cancer cell lines. Using RNA-seq analysis and histone modification screening, we demonstrated that αKG reduced the expression of the immediate early gene (IEG) in cancer cells in an H3K27 acetylation-dependent manner. Conversely, glutaminase (GLS) inhibitors induce IEG expression in cancer cells. Furthermore, we showed that siRNA knockdown of orphan nuclear receptor subfamily 4 group A member 1 (NR4A1) induces IEG expression. Notably, the NR4A1 agonist cytosporone B sensitizes GLS inhibitor resistance to cancer cell death. Together, these findings indicate that therapeutic targeting of IEG dysregulation by αKG can be a potentially effective anti-cancer therapeutic strategy for glutamine metabolism inhibitors.

Keywords:  Cancer cells; GLS inhibitor; IEG; NR4A; αKG

DOI:  https://doi.org/10.1016/j.bbrc.2022.11.021
Cancer Res Commun. 2022 Jul;2(7): 694-705

Loss of vascular endothelial glutaminase inhibits tumor growth and metastasis, and increases sensitivity to chemotherapy.

Verra M Ngwa, Deanna N Edwards, Yoonha Hwang, Breelyn Karno, Xiaoyong Wang, Chi Yan, Ann Richmond, Dana M Brantley-Sieders, Jin Chen.

  Glutamine is the most abundant non-essential amino acid in blood stream; yet it's concentration in tumor interstitium is markedly lower than that in the serum, reflecting the huge demand of various cell types in tumor microenvironment for glutamine. While many studies have investigated glutamine metabolism in tumor epithelium and infiltrating immune cells, the role of glutamine metabolism in tumor blood vessels remains unknown. Here, we report that inducible genetic deletion of glutaminase (GLS) specifically in host endothelium, GLSECKO, impairs tumor growth and metastatic dissemination in vivo. Loss of GLS decreased tumor microvascular density, increased perivascular support cell coverage, improved perfusion, and reduced hypoxia in mammary tumors. Importantly, chemotherapeutic drug delivery and therapeutic efficacy were improved in tumor-bearing GLSECKO hosts or in combination with GLS inhibitor, CB839. Mechanistically, loss of GLS in tumor endothelium resulted in decreased leptin levels, and exogenous recombinant leptin rescued tumor growth defects in GLSECKO mice. Together, these data demonstrate that inhibition of endothelial glutamine metabolism normalizes tumor vessels, reducing tumor growth and metastatic spread, improving perfusion, and reducing hypoxia, and enhancing chemotherapeutic delivery. Thus, targeting glutamine metabolism in host vasculature may improve clinical outcome in patients with solid tumors.

Keywords:  glutaminase; glutamine; host-tumor interactions; leptin; vessel normalization

DOI:  https://doi.org/10.1158/2767-9764.crc-22-0048
Cell Death Dis. 2022 Nov 14. 13(11): 955

Targeting glutamine metabolism in hepatic stellate cells alleviates liver fibrosis.

Xiaochun Yin, Jin Peng, Lihong Gu, Yan Liu, Xihan Li, Jinhui Wu, Bing Xu, Yuzheng Zhuge, Feng Zhang.

Glutamine metabolism plays an essential role in cell growth, and glutamate dehydrogenase (GDH) is a key enzyme. GDH promotes the metabolism of glutamate and glutamine to generate ATP, which is profoundly increased in multiple human cancers. Through in vitro and in vivo experiments, we verified that the small-molecule GDH inhibitor EGCG slowed the progression of fibrosis by inhibiting GDH enzyme activity and glutamine metabolism. SIRT4 is a mitochondrial enzyme with NAD that promotes ADP ribosylation and downregulates GDH activity. The role of SIRT4 in liver fibrosis and the related mechanisms are unknown. In this study, we measured the expression of SIRT4 and found that it was downregulated in liver fibrosis. Modest overexpression of SIRT4 protected the liver from fibrosis by inhibiting the transformation of glutamate to 2-ketoglutaric acid (α-KG) in the tricarboxylic acid cycle (TCA), thereby reducing the proliferative activity of hepatic stellate cells (HSCs). Collectively, our study reveals that SIRT4 controls GDH enzyme activity and expression, targeting glutamine metabolism in HSCs and alleviating liver fibrosis.

DOI: https://doi.org/10.1038/s41419-022-05409-0
Sci Rep. 2022 Nov 16. 12(1): 19657

Multiomics analysis couples mRNA turnover and translational control of glutamine metabolism to the differentiation of the activated CD4+ T cell.

Louise S Matheson, Georg Petkau, Beatriz Sáenz-Narciso, Vanessa D'Angeli, Jessica McHugh, Rebecca Newman, Haydn Munford, James West, Krishnendu Chakraborty, Jennie Roberts, Sebastian Łukasiak, Manuel D Díaz-Muñoz, Sarah E Bell, Sarah Dimeloe, Martin Turner.

The ZFP36 family of RNA-binding proteins acts post-transcriptionally to repress translation and promote RNA decay. Studies of genes and pathways regulated by the ZFP36 family in CD4+ T cells have focussed largely on cytokines, but their impact on metabolic reprogramming and differentiation is unclear. Using CD4+ T cells lacking Zfp36 and Zfp36l1, we combined the quantification of mRNA transcription, stability, abundance and translation with crosslinking immunoprecipitation and metabolic profiling to determine how they regulate T cell metabolism and differentiation. Our results suggest that ZFP36 and ZFP36L1 act directly to limit the expression of genes driving anabolic processes by two distinct routes: by targeting transcription factors and by targeting transcripts encoding rate-limiting enzymes. These enzymes span numerous metabolic pathways including glycolysis, one-carbon metabolism and glutaminolysis. Direct binding and repression of transcripts encoding glutamine transporter SLC38A2 correlated with increased cellular glutamine content in ZFP36/ZFP36L1-deficient T cells. Increased conversion of glutamine to α-ketoglutarate in these cells was consistent with direct binding of ZFP36/ZFP36L1 to Gls (encoding glutaminase) and Glud1 (encoding glutamate dehydrogenase). We propose that ZFP36 and ZFP36L1 as well as glutamine and α-ketoglutarate are limiting factors for the acquisition of the cytotoxic CD4+ T cell fate. Our data implicate ZFP36 and ZFP36L1 in limiting glutamine anaplerosis and differentiation of activated CD4+ T cells, likely mediated by direct binding to transcripts of critical genes that drive these processes.

DOI: https://doi.org/10.1038/s41598-022-24132-6
Chin Med J (Engl). 2022 Nov 17.

Metabolic reprogramming in the immunosuppression of tumor-associated macrophages.

Ying Wang, Dan Wang, Li Yang, Yi Zhang.

ABSTRACT: Tumor-associated macrophages (TAMs) are an essential proportion of tumor-infiltrating immune cells in the tumor microenvironment (TME) and have immunosuppressive functions. The high plasticity and corresponding phenotypic transformation of TAMs facilitate oncogenesis and progression, and suppress antineoplastic responses. Due to the uncontrolled proliferation of tumor cells, metabolism homeostasis is regulated, leading to a series of alterations in the metabolite profiles in the TME, which have a commensurate influence on immune cells. Metabolic reprogramming of the TME has a profound impact on the polarization and function of TAMs, and can alter their metabolic profiles. TAMs undergo a series of metabolic reprogramming processes, involving glucose, lipid, and amino acid metabolism, and other metabolic pathways, which terminally promote the development of the immunosuppressive phenotype. TAMs express a pro-tumor phenotype by increasing glycolysis, fatty acid oxidation, cholesterol efflux, and arginine, tryptophan, glutamate, and glutamine metabolism. Previous studies on the metabolism of TAMs demonstrated that metabolic reprogramming has intimate crosstalk with anti-tumor or pro-tumor phenotypes and is crucial for the function of TAMs themselves. Targeting metabolism-related pathways is emerging as a promising therapeutic modality because of the massive metabolic remodeling that occurs in malignant cells and TAMs. Evidence reveals that the efficacy of immune checkpoint inhibitors is improved when combined with therapeutic strategies targeting metabolism-related pathways. In-depth research on metabolic reprogramming and potential therapeutic targets provides more options for anti-tumor treatment and creates new directions for the development of new immunotherapy methods. In this review, we elucidate the metabolic reprogramming of TAMs and explore how they sustain immunosuppressive phenotypes to provide a perspective for potential metabolic therapies.

DOI: https://doi.org/10.1097/CM9.0000000000002426
J Inherit Metab Dis. 2022 Nov 13.

Cellular and computational models reveal environmental and metabolic interactions in MMUT-type methylmalonic aciduria.

Charlotte Ramon, Florian Traversi, Céline Bürer, D Sean Froese, Jörg Stelling.

  MMUT-type methylmalonic aciduria is a rare inherited metabolic disease caused by the loss of function of the methylmalonyl-CoA mutase (MMUT) enzyme. Patients develop symptoms resembling those of primary mitochondrial disorders, but the underlying causes of mitochondrial dysfunction remain unclear. Here, we examined environmental and genetic interactions in MMUT deficiency using a combination of computational modeling and cellular models to decipher pathways interacting with MMUT. Immortalized fibroblast (hTERT BJ5ta) MMUT-KO (MUTKO) clones displayed a mild mitochondrial impairment in standard glucose-based medium, but they did not to show increased reliance on respiratory metabolism nor reduced growth or viability. Consistently, our modeling predicted MUTKO specific growth phenotypes only for lower extracellular glutamine concentrations. Indeed, two of three MMUT-deficient BJ5ta cell lines showed a reduced viability in glutamine-free medium. Further, growth on 183 different carbon and nitrogen substrates identified increased NADH (nicotinamide adenine dinucleotide) metabolism of BJ5ta and HEK293 MUTKO cells compared to controls on purine- and glutamine-based substrates. With this knowledge, our modeling predicted 13 reactions interacting with MMUT that potentiate an effect on growth, primarily those of secondary oxidation of propionyl-CoA, oxidative phosphorylation and oxygen diffusion. Of these, we validated 3-hydroxyisobutytyl-CoA hydrolase (HIBCH) in the secondary propionyl-CoA oxidation pathway. Altogether, these results suggest compensation for the loss of MMUT function by increasing anaplerosis through glutamine or by diverting flux away from MMUT through the secondary propionyl-CoA oxidation pathway, which may have therapeutic relevance.

Keywords:  CRISPR-Cas9; Rare disease; constraint-based modeling; genetic interaction; metabolism; methylmalonic aciduria

DOI:  https://doi.org/10.1002/jimd.12575
Nat Commun. 2022 Nov 18. 13(1): 7078

Cancer cell survival depends on collagen uptake into tumor-associated stroma.

Kuo-Sheng Hsu, James M Dunleavey, Christopher Szot, Liping Yang, Mary Beth Hilton, Karen Morris, Steven Seaman, Yang Feng, Emily M Lutz, Robert Koogle, Francesco Tomassoni-Ardori, Saurabh Saha, Xiaoyan M Zhang, Enrique Zudaire, Pradip Bajgain, Joshua Rose, Zhongyu Zhu, Dimiter S Dimitrov, Frank Cuttitta, Nancy J Emenaker, Lino Tessarollo, Brad St Croix.

Collagen I, the most abundant protein in humans, is ubiquitous in solid tumors where it provides a rich source of exploitable metabolic fuel for cancer cells. While tumor cells were unable to exploit collagen directly, here we show they can usurp metabolic byproducts of collagen-consuming tumor-associated stroma. Using genetically engineered mouse models, we discovered that solid tumor growth depends upon collagen binding and uptake mediated by the TEM8/ANTXR1 cell surface protein in tumor-associated stroma. Tumor-associated stromal cells processed collagen into glutamine, which was then released and internalized by cancer cells. Under chronic nutrient starvation, a condition driven by the high metabolic demand of tumors, cancer cells exploited glutamine to survive, an effect that could be reversed by blocking collagen uptake with TEM8 neutralizing antibodies. These studies reveal that cancer cells exploit collagen-consuming stromal cells for survival, exposing an important vulnerability across solid tumors with implications for developing improved anticancer therapy.

DOI: https://doi.org/10.1038/s41467-022-34643-5
Free Radic Biol Med. 2022 Nov 14. pii: S0891-5849(22)00986-8. [Epub ahead of print]

Proteomics revealed the crosstalk between copper stress and cuproptosis, and explored the feasibility of curcumin as anticancer copper ionophore.

Ying Yang, Shuyu Liang, Hongen Geng, Mengmeng Xiong, Man Li, Qian Su, Fang Jia, Yimei Zhao, Kai Wang, Jun Jiang, Si Qin, Xiang Li.

  As an essential micronutrient element in organisms, copper controls a host of fundamental cellular functions. Recently, copper-dependent cell growth and proliferation have been defined as "cuproplasia". Conversely, "cuproptosis" represents copper-dependent cell death, in a nonapoptotic manner. So far, a series of copper ionophores have been developed to kill cancer cells. However, the biological response mechanism of copper uptake has not been systematically analyzed. Based on quantitative proteomics, we revealed the crosstalk between copper stress and cuproptosis in cancer cells, and also explored the feasibility of curcumin as anticancer copper ionophore. Copper stress not only couples with cuproptosis, but also leads to reactive oxygen species (ROS) stress, oxidative damage and cell cycle arrest. In cancer cells, a feedback cytoprotection mechanism involving cuproptosis mediators was discovered. During copper treatment, the activation of glutamine transporters and the loss of Fe-S cluster proteins are the facilitators and results of cuproptosis, respectively. Through copper depletion, glutathione (GSH) blocks the cuproptosis process, rescues the activation of glutamine transporters, and prevents the loss of Fe-S cluster proteins, except for protecting cancer cells from apoptosis, protein degradation and oxidative damage. In addition, the copper ionophore curcumin can control the metabolisms of lipids, RNA, NADH and NADPH in colorectal cancer cells, and also up-regulates positive cuproptosis mediators. This work not only established the crosstalk between copper stress and cuproptosis, but also discolored the suppression and acceleration of cuproptosis by GSH and curcumin, respectively. Our results are significant for understanding cuproptosis process and developing novel anticancer reagents based on cuproptosis.

Keywords:  Copper stress; Cuproptosis; Curcumin; Glutathione; Quantitative proteomics

DOI:  https://doi.org/10.1016/j.freeradbiomed.2022.11.023
Semin Cancer Biol. 2022 Oct 28. pii: S1044-579X(22)00209-7. [Epub ahead of print]87 32-47

Tracing the electron flow in redox metabolism: The appropriate distribution of electrons is essential to maintain redox balance in cancer cells.

Minfeng Ying, Xun Hu.

  Cancer cells are characterized by sustained proliferation, which requires a huge demand of fuels to support energy production and biosynthesis. Energy is produced by the oxidation of the fuels during catabolism, and biosynthesis is achieved by the reduction of smaller units or precursors. Therefore, the oxidation-reduction (redox) reactions in cancer cells are more active compared to those in the normal counterparts. The higher activity of redox metabolism also induces a more severe oxidative stress, raising the question of how cancer cells maintain the redox balance. In this review, we overview the redox metabolism of cancer cells in an electron-tracing view. The electrons are derived from the nutrients in the tumor microenvironment and released during catabolism. Most of the electrons are transferred to NAD(P) system and then directed to four destinations: energy production, ROS generation, reductive biosynthesis and antioxidant system. The appropriate distribution of these electrons achieved by the function of redox regulation network is essential to maintain redox homeostasis in cancer cells. Interfering with the electron distribution and disrupting redox balance by targeting the redox regulation network may provide therapeutic implications for cancer treatment.

Keywords:  Antioxidant system; Cancer metabolism; NADPH; ROS; Redox balance

DOI:  https://doi.org/10.1016/j.semcancer.2022.10.005
Front Oncol. 2022 ;12 958155

Relevance of the TRIAP1/p53 axis in colon cancer cell proliferation and adaptation to glutamine deprivation.

Kenza Nedara, Camille Reinhardt, Emilie Lebraud, Giuseppe Arena, Céline Gracia, Valérie Buard, Catherine Pioche-Durieu, Florence Castelli, Benoit Colsch, Paule Bénit, Pierre Rustin, Benoit Albaud, Pierre Gestraud, Sylvain Baulande, Nicolas Servant, Eric Deutsch, Jean-Marc Verbavatz, Catherine Brenner, Fabien Milliat, Nazanine Modjtahedi.

  Human TRIAP1 (TP53-regulated inhibitor of apoptosis 1; also known as p53CSV for p53-inducible cell survival factor) is the homolog of yeast Mdm35, a well-known chaperone that interacts with the Ups/PRELI family proteins and participates in the intramitochondrial transfer of lipids for the synthesis of cardiolipin (CL) and phosphatidylethanolamine. Although recent reports indicate that TRIAP1 is a prosurvival factor abnormally overexpressed in various types of cancer, knowledge about its molecular and metabolic function in human cells is still elusive. It is therefore critical to understand the metabolic and proliferative advantages that TRIAP1 expression provides to cancer cells. Here, in a colorectal cancer cell model, we report that the expression of TRIAP1 supports cancer cell proliferation and tumorigenesis. Depletion of TRIAP1 perturbed the mitochondrial ultrastructure, without a major impact on CL levels and mitochondrial activity. TRIAP1 depletion caused extramitochondrial perturbations resulting in changes in the endoplasmic reticulum-dependent lipid homeostasis and induction of a p53-mediated stress response. Furthermore, we observed that TRIAP1 depletion conferred a robust p53-mediated resistance to the metabolic stress caused by glutamine deprivation. These findings highlight the importance of TRIAP1 in tumorigenesis and indicate that the loss of TRIAP1 has extramitochondrial consequences that could impact on the metabolic plasticity of cancer cells and their response to conditions of nutrient deprivation.

Keywords:  TRIAP1/Mdm35; coiled-coil-helix-coiled-coil-helix domain (CHCHD)-containing proteins; colon cancer; glutamine starvation; lipid homeostasis; mitochondria; p53-mediated stress response

DOI:  https://doi.org/10.3389/fonc.2022.958155
Biomed Pharmacother. 2022 Nov 12. pii: S0753-3322(22)01382-8. [Epub ahead of print]157 113993

Disorders of cancer metabolism: The therapeutic potential of cannabinoids.

Dingya Sun, Xin Li, Shengdan Nie, Jiajia Liu, Shan Wang.

  Abnormal energy metabolism, as one of the important hallmarks of cancer, was induced by multiple carcinogenic factors and tumor-specific microenvironments. It comprises aerobic glycolysis, de novo lipid biosynthesis, and glutamine-dependent anaplerosis. Considering that metabolic reprogramming provides various nutrients for tumor survival and development, it has been considered a potential target for cancer therapy. Cannabinoids have been shown to exhibit a variety of anticancer activities by unclear mechanisms. This paper first reviews the recent progress of related signaling pathways (reactive oxygen species (ROS), AMP-activated protein kinase (AMPK), mitogen-activated protein kinases (MAPK), phosphoinositide 3-kinase (PI3K), hypoxia-inducible factor-1alpha (HIF-1α), and p53) mediating the reprogramming of cancer metabolism (including glucose metabolism, lipid metabolism, and amino acid metabolism). Then we comprehensively explore the latest discoveries and possible mechanisms of the anticancer effects of cannabinoids through the regulation of the above-mentioned related signaling pathways, to provide new targets and insights for cancer prevention and treatment.

Keywords:  Cancer; Cancer metabolism; Cannabinoids; Drug targets; Glycolysis; Metabolic reprogramming

DOI:  https://doi.org/10.1016/j.biopha.2022.113993
Sci Adv. 2022 Nov 18. 8(46): eabq5925

Discovery of DRP-104, a tumor-targeted metabolic inhibitor prodrug.

Rana Rais, Kathryn M Lemberg, Lukáš Tenora, Matthew L Arwood, Arindom Pal, Jesse Alt, Ying Wu, Jenny Lam, Joanna Marie H Aguilar, Liang Zhao, Diane E Peters, Carolyn Tallon, Rajeev Pandey, Ajit G Thomas, Ranjeet P Dash, Tanguy Seiwert, Pavel Majer, Robert D Leone, Jonathan D Powell, Barbara S Slusher.

6-Diazo-5-oxo-l-norleucine (DON) is a glutamine antagonist that suppresses cancer cell metabolism but concurrently enhances the metabolic fitness of tumor CD8+ T cells. DON showed promising efficacy in clinical trials; however, its development was halted by dose-limiting gastrointestinal (GI) toxicities. Given its clinical potential, we designed DON peptide prodrugs and found DRP-104 [isopropyl(S)-2-((S)-2-acetamido-3-(1H-indol-3-yl)-propanamido)-6-diazo-5-oxo-hexanoate] that was preferentially bioactivated to DON in tumor while bioinactivated to an inert metabolite in GI tissues. In drug distribution studies, DRP-104 delivered a prodigious 11-fold greater exposure of DON to tumor versus GI tissues. DRP-104 affected multiple metabolic pathways in tumor, including decreased glutamine flux into the TCA cycle. In efficacy studies, both DRP-104 and DON caused complete tumor regression; however, DRP-104 had a markedly improved tolerability profile. DRP-104's effect was CD8+ T cell dependent and resulted in robust immunologic memory. DRP-104 represents a first-in-class prodrug with differential metabolism in target versus toxicity tissue. DRP-104 is now in clinical trials under the FDA Fast Track designation.

DOI: https://doi.org/10.1126/sciadv.abq5925
Commun Biol. 2022 Nov 14. 5(1): 1248

Anti-tumor effects of P-LPK-CPT, a peptide-camptothecin conjugate, in colorectal cancer.

Lidan Hou, Yichao Hou, Yu Liang, Baiyu Chen, Xintian Zhang, Yu Wang, Kun Zhou, Ting Zhong, Bohan Long, Wenjing Pang, Lei Wang, Xu Han, Linjing Li, Ci Xu, Isabelle Gross, Christian Gaiddon, Wei Fu, Han Yao, Xiangjun Meng.

To explore highly selective targeting molecules of colorectal cancer (CRC) is a challenge. We previously identified a twelve-amino acid peptide (LPKTVSSDMSLN, namely P-LPK) by phage display technique which may specifically binds to CRC cells. Here we show that P-LPK selectively bind to a panel of human CRC cell lines and CRC tissues. In vivo, Gallium-68 (68Ga) labeled P-LPK exhibits selective accumulation at tumor sites. Then, we designed a peptide-conjugated drug comprising P-LPK and camptothecin (CPT) (namely P-LPK-CPT), and found P-LPK-CPT significantly inhibits tumor growth with fewer side effects in vitro and in vivo. Furthermore, through co-immunoprecipitation and molecular docking experiment, the glutamine transporter solute carrier 1 family member 5 (SLC1A5) was identified as the possible target of P-LPK. The binding ability of P-LPK and SLC1A5 is verified by surface plasmon resonance and immunofluorescence. Taken together, P-LPK-CPT is highly effective for CRC and deserves further development as a promising anti-tumor therapeutic for CRC, especially SLC1A5-high expression type.

DOI: https://doi.org/10.1038/s42003-022-04191-1
J Gastrointest Oncol. 2022 Oct;13(5): 2505-2521

Identification and validation in a novel quantification system of the glutamine metabolism patterns for the prediction of prognosis and therapy response in hepatocellular carcinoma.

Shengjie Jin, Jun Cao, Lian-Bao Kong.

   Background: Hepatocellular carcinoma (HCC) has one of the highest mortality rates worldwide. Abnormal glutamine metabolism (GM) has been reported to be involved in HCC progression. The current study sought to examine the predictive value of GM in HCC patient's prognosis and therapy response.
Methods: The RNA-sequencing data and clinical information of HCC samples were obtained from The Cancer Genome Atlas (TCGA) database (N=377) and Gene Expression Omnibus (GEO) database (N=242). By analyzing a data set from TCGA, we showed that the GM landscape of HCC patients was developed based on the non-negative matrix factorization (NMF) algorithm. Univariate Cox regression and least absolute shrinkage and selection operator (LASSO)-penalized Cox regression analyses were used to construct a risk model. The accuracy of the model, which was based on the GM-related genes (GMRGs), was verified by Kaplan-Meier (K-M) and receiver operating characteristic (ROC) curves. We also verified the reliability of the model based on GEO data. Finally, the immune infiltration analysis, pathway enrichment analysis, and treatment response prediction results were compared to each other in the 2 risk groups.
Results: In our study, the HCC samples were divided into 2 GM-related patterns; that is, C1 and C2. The multi-analysis revealed that the GM-related patterns were associated with the pathologic stage, T stages, N stages, histologic grade, and the tumor immune microenvironment (TIME). Next, the prognostic model containing 5 GMRGs (i.e., aldehyde dehydrogenase 5 family member A1, ASNSD1, carbamoyl-phosphate synthetase 1, GMPS, and PPAT) was constructed to calculate the risk score. The high-risk group of HCC patients had significantly worse overall survival (OS) than the low-risk group in both datasets (P<0.001). Multivariate Cox regression uncover the riskScores may serve as an independent prognostic marker for HCC patients [TCGA: hazard ratio (HR) =2.909 (1.940-4.362), P<0.001; GEO: HR =2.911 (1.753-5.848), P=0.043]. Finally, we found that the prognostic model was significantly correlated with the pathologic stage and TIME of the HCC patients in both databases. Moreover, the prognostic model may guide the immunotherapy, chemotherapy, and targeted drugs choice.
Conclusions: In summary, we developed a GM-related 5-gene risk-score model, which may be a useful tool for predicting prognosis and guiding the treatment of HCC patients.

Keywords:  Glutamine metabolism (GM); prognostic signature; tumor immune microenvironment (TIME)

DOI:  https://doi.org/10.21037/jgo-22-895
J Clin Transl Hepatol. 2022 Dec 28. 10(6): 1107-1116

O-GlcNAcylation Coordinates Glutaminolysis by Regulating the Stability and Membrane Trafficking of ASCT2 in Hepatic Stellate Cells.

Feixia Wang, Li Chen, Biyun Zhang, Zhanghao Li, Min Shen, Li Tang, Zili Zhang, Jiangjuan Shao, Feng Zhang, Shizhong Zheng, Shanzhong Tan.

   Background and Aims: Recognition of excessive activation of hepatic stellate cells (HSCs) in liver fibrosis prompted us to investigate the regulatory mechanisms of HSCs. We aimed to examine the role of O-GlcNAcylation modification of alanine, serine, cysteine transporter 2 (ASCT2) in HSCs and liver fibrosis.
Methods: The expression of O-GlcNAcylation modification in fibrotic mice livers and activated HSCs was analyzed by western blotting. Immunoprecipitation was used to assess the interaction of ASCT2 and O-GlcNAc transferase (OGT). In addition, ASCT2 protein stability was assayed after cycloheximide (CHX) treatment. The O-GlcNAcylation site of ASCT2 was predicted and mutated by site-directed mutagenesis. Real-time PCR, immunofluorescence, kit determinations and Seahorse assays were used to clarify the effect of ASCT2 O-GlcNAcylation on HSC glutaminolysis and HSC activation. Western blotting, immunochemistry, and immunohistofluorescence were used to analyze the effect of ASCT2 O-GlcNAcylation in vivo.
Results: We observed significantly increased O-GlcNAcylation modification of ASCT2. ASCT2 was found to interact with OGT to regulate ASCT2 stability. We predicted and confirmed that O-GlcNAcylation of ASCT2 at Thr122 site resulted in HSCs activation. We found Thr122 O-GlcNAcylation of ASCT2 mediated membrane trafficking of glutamine transport and attenuated HSC glutaminolysis. Finally, we validated the expression and function of ASCT2 O-GlcNAcylation after injection of AAV8-ASCT2 shRNA in CCl4-induced liver fibrosis mice in vivo.
Conclusions: Thr122 O-GlcNAcylation regulation of ASCT2 resulted in stability and membrane trafficking-mediated glutaminolysis in HSCs and liver fibrosis. Further studies are required to assess its role as a putative therapeutic target.

Keywords:  ASCT2; Liver fibrosis; O-GlcNacylation; Stability; Trafficking

DOI:  https://doi.org/10.14218/JCTH.2021.00413