A metabolic synthetic lethal strategy with arginine deprivation and chloroquine leads to cell death in ASS1-deficient sarcomas. Bean Gregory R,Kremer Jeff C,Prudner Bethany C,Schenone Aaron D,Yao Juo-Chin,Schultze Matthew B,Chen David Y,Tanas Munir R,Adkins Douglas R,Bomalaski John,Rubin Brian P,Michel Loren S,Van Tine Brian A Cell death & disease Sarcomas comprise a large heterogeneous group of mesenchymal cancers with limited therapeutic options. When treated with standard cytotoxic chemotherapies, many sarcomas fail to respond completely and rapidly become treatment resistant. A major problem in the investigation and treatment of sarcomas is the fact that no single gene mutation or alteration has been identified among the diverse histologic subtypes. We searched for therapeutically druggable targets that are common to a wide range of histologies and hence could provide alternatives to the conventional chemotherapy. Seven hundred samples comprising 45 separate histologies were examined. We found that almost 90% were arginine auxotrophs, as the expression of argininosuccinate synthetase 1 was lost or significantly reduced. Arginine auxotrophy confers sensitivity to arginine deprivation, leading temporarily to starvation and ultimately to cell survival or death under different circumstances. We showed that, in sarcoma, arginine deprivation therapy with pegylated arginine deiminase (ADI-PEG20) maintains a prolonged state of arginine starvation without causing cell death. However, when starvation was simultaneously prolonged by ADI-PEG20 while inhibited by the clinically available drug chloroquine, sarcoma cells died via necroptosis and apoptosis. These results have revealed a novel metabolic vulnerability in sarcomas and provided the basis for a well-tolerated alternative treatment strategy, potentially applicable to up to 90% of the tumors, regardless of histology. 10.1038/cddis.2016.232
    The influence of tumour-derived extracellular vesicles on local and distal metastatic dissemination. Nogués Laura,Benito-Martin Alberto,Hergueta-Redondo Marta,Peinado Héctor Molecular aspects of medicine Extracellular vesicles (EVs) are key mediators of intercellular communication that have been ignored for decades. Tumour cells benefit from the secretion of vesicles as they can influence the behaviour of neighbouring tumour cells within the tumour microenvironment. Several studies have shown that extracellular vesicles play an active role in pre-metastatic niche formation and importantly, they are involved in the metastatic organotropism of different tumour types. Tumour-derived EVs carry and transfer molecules to recipient cells, modifying their behaviour through a process defined as "EV-driven education". EVs favour metastasis to sentinel lymph nodes and distal organs by reinforcing angiogenesis, inflammation and lymphangiogenesis. Hence, in this review we will summarize the main mechanisms by which tumour-derived EVs regulate lymph node and distal organ metastasis. Moreover, since some cancers metastasize through the lymphatic system, we will discuss recent discoveries about the presence and function of tumour EVs in the lymph. Finally, we will address the potential value of tumour EVs as prognostic biomarkers in liquid biopsies, specially blood and lymphatic fluid, and the use of these tools as early detectors of metastases. 10.1016/j.mam.2017.11.012
    Host Control of Tumor Feeding: Autophagy Holds the Key. Venida Anthony,Perera Rushika M Cell metabolism Cancer cells are dependent on functional autophagy both within their cytoplasm and systemically in the host to maintain growth. How systemic autophagy directly contributes to tumor growth remains unclear. In a study published in Nature, Poillet-Perez et al. (2018) show that host autophagy helps to maintain the levels of circulating arginine that feed tumor growth. 10.1016/j.cmet.2019.01.009
    Metabolomics and Metabolic Reprogramming in Kidney Cancer. Weiss Robert H Seminars in nephrology Kidney cancer, or renal cell carcinoma (RCC), is a disease of increasing incidence that commonly is seen in the general practice of nephrology. Despite this state of affairs, this fascinating and highly morbid disease frequently is under-represented, or even absent, from the curriculum of nephrologists in training and generally is underemphasized in national nephrology meetings, both scientific as well as clinical. Although classic concepts in cancer research in general had led to the concept that cancer is a disease resulting from mutations in the control of growth-regulating pathways, reinforced by the discovery of oncogenes, more contemporary research, particularly in kidney cancer, has uncovered changes in metabolic pathways mediated by those same genes that control tumor energetics and biosynthesis. This adaptation of classic biochemical pathways to the tumor's advantage has been labeled metabolic reprogramming. For example, in the case of kidney cancer there exists a near-universal presence of von Hippel-Lindau tumor suppressor (pVHL) inactivation in the most common form, clear cell RCC (ccRCC), leading to activation of hypoxia-relevant and other metabolic pathways. Studies of this and other pathways in clear cell RCC (ccRCC) have been particularly revealing, leading to the concept that ccRCC can itself be considered a metabolic disease. For this reason, the relatively new method of metabolomics has become a useful technique in the study of ccRCC to tease out those pathways that have been reprogrammed by the tumor to its maximum survival advantage. Furthermore, identification of the nodes of such pathways can lead to novel areas for drug intervention in a disease for which such targets are seriously lacking. Further research and dissemination of these concepts, likely using omics techniques, will lead to clinical trials of therapeutics specifically targeted to tumor metabolism, rather than those generally toxic to all proliferating cells. Such novel agents are highly likely to be more effective than existing drugs and to have far fewer adverse effects. This review provides a general overview of the technique of metabolomics and then discusses how it and other omics techniques have been used to further our understanding of the basic biology of kidney cancer as well as to identify new therapeutic approaches. 10.1016/j.semnephrol.2018.01.006
    Biotransformation-based metabolomics profiling method for determining and quantitating cancer-related metabolites. Yue Xiaofei,He Jiuming,Zhang Ruiping,Xu Jing,Zhou Zhi,Zhang Rui,Bi Nan,Wang Zhonghua,Sun Chenglong,Wang Luhua,Chen Yanhua,Abliz Zeper Journal of chromatography. A The discovery and identification of reliable disease biomarkers and relevant disrupted metabolic pathways is still a major challenge in metabolomics. Here, we proposed a biotransformation-based metabolomics profiling method to identify reliable disease biomarkers by simultaneous quantitation and qualification of cancer-related metabolites and their metabolic pathways via liquid chromatography-tandem mass spectrometry (LC-MS/MS). The approach was based on selecting a subset of known cancer-related metabolites from our previous metabolomics work, cancer research literature and biological significance. The metabolic profiling of pathway-related metabolites was developed by predicted multiple reaction monitoring (MRM) of ion pairs based on their chemical structures and biotransformation. Then, a high-throughput quantitative method was established. Overall, this approach enables the sensitive and accurate detection of cancer-related metabolites and the identification of other relevant metabolites, which facilitates better data quality and in-depth investigation of dysregulated metabolic pathways. As a proof of concept, the approach was applied to a small-cell lung cancer (SCLC) study. The results showed that 43 metabolites were significantly changed, and arginine metabolism was apparently disturbed, which proved the proposed approach could be a powerful tool for discovering reliable disease biomarkers and aberrant metabolic pathways. 10.1016/j.chroma.2018.10.034
    [HuArgI (co)-PEG5000]-induced arginine deprivation leads to autophagy dependent cell death in pancreatic cancer cells. Khalil Nathalie,Abi-Habib Ralph J Investigational new drugs In this study, we examined the sensitivity of pancreatic cancer cells to [HuArgI (Co)-PEG5000]-induced arginine deprivation as well as the mechanisms underlying deprivation-induced cell death. [HuArgI (Co)-PEG5000]-induced arginine deprivation was cytotoxic to all cell lines tested with IC values in the pM range at 72 h post-treatment. Three of the five cell lines were rescued by the addition of excess L-citrulline and expressed ASS1, indicating partial arginine auxotrophy. The remaining two cell lines, on the other hand, were not rescued by the addition of L-citrulline and did not express ASS1, indicating complete auxotrophy to arginine. In addition, all cell lines exhibited G0/G1 cell cycle arrest, in the surviving cell fraction, at 72 h following arginine deprivation. Analysis of the type of cell death revealed negative staining for annexin V and a lack of caspase activation in all five cancer cell lines, following treatment, indicating that arginine deprivation leads to caspase-independent, non-apoptotic cell death. Finally, we demonstrated that arginine deprivation leads to a marked activation of autophagy and that inhibition of this autophagy greatly decreases cytotoxicity, indicating that arginine deprivation induces autophagic cell death in pancreatic cancer cells. We have shown that pancreatic cancer cells are auxotrophic for arginine and sensitive to [HuArgI (Co)-PEG5000]-induced arginine deprivation, hence demonstrating that arginine deprivation is a potentially potent and selective treatment for pancreatic cancer. We have also demonstrated that autophagy is activated following arginine-deprivation and that its prolonged activation leads to autophagic cell death. 10.1007/s10637-019-00883-4
    Arginine Methylation: The Coming of Age. Blanc Roméo S,Richard Stéphane Molecular cell Arginine methylation is a common post-translational modification functioning as an epigenetic regulator of transcription and playing key roles in pre-mRNA splicing, DNA damage signaling, mRNA translation, cell signaling, and cell fate decision. Recently, a wealth of studies using transgenic mouse models and selective PRMT inhibitors helped define physiological roles for protein arginine methyltransferases (PRMTs) linking them to diseases such as cancer and metabolic, neurodegenerative, and muscular disorders. This review describes the recent molecular advances that have been uncovered in normal and diseased mammalian cells. 10.1016/j.molcel.2016.11.003
    Acquired Amino Acid Deficiencies: A Focus on Arginine and Glutamine. Morris Claudia R,Hamilton-Reeves Jill,Martindale Robert G,Sarav Menaka,Ochoa Gautier Juan B Nutrition in clinical practice : official publication of the American Society for Parenteral and Enteral Nutrition Nonessential amino acids are synthesized de novo and therefore not diet dependent. In contrast, essential amino acids must be obtained through nutrition since they cannot be synthesized internally. Several nonessential amino acids may become essential under conditions of stress and catabolic states when the capacity of endogenous amino acid synthesis is exceeded. Arginine and glutamine are 2 such conditionally essential amino acids and are the focus of this review. Low arginine bioavailability plays a pivotal role in the pathogenesis of a growing number of varied diseases, including sickle cell disease, thalassemia, malaria, acute asthma, cystic fibrosis, pulmonary hypertension, cardiovascular disease, certain cancers, and trauma, among others. Catabolism of arginine by arginase enzymes is the most common cause of an acquired arginine deficiency syndrome, frequently contributing to endothelial dysfunction and/or T-cell dysfunction, depending on the clinical scenario and disease state. Glutamine, an arginine precursor, is one of the most abundant amino acids in the body and, like arginine, becomes deficient in several conditions of stress, including critical illness, trauma, infection, cancer, and gastrointestinal disorders. At-risk populations are discussed together with therapeutic options that target these specific acquired amino acid deficiencies. 10.1177/0884533617691250
    Critical role for arginase 2 in obesity-associated pancreatic cancer. Zaytouni Tamara,Tsai Pei-Yun,Hitchcock Daniel S,DuBois Cory D,Freinkman Elizaveta,Lin Lin,Morales-Oyarvide Vicente,Lenehan Patrick J,Wolpin Brian M,Mino-Kenudson Mari,Torres Eduardo M,Stylopoulos Nicholas,Clish Clary B,Kalaany Nada Y Nature communications Obesity is an established risk factor for pancreatic ductal adenocarcinoma (PDA). Despite recent identification of metabolic alterations in this lethal malignancy, the metabolic dependencies of obesity-associated PDA remain unknown. Here we show that obesity-driven PDA exhibits accelerated growth and a striking transcriptional enrichment for pathways regulating nitrogen metabolism. We find that the mitochondrial form of arginase (ARG2), which hydrolyzes arginine into ornithine and urea, is induced upon obesity, and silencing or loss of ARG2 markedly suppresses PDA. In vivo infusion of N-glutamine in obese mouse models of PDA demonstrates enhanced nitrogen flux into the urea cycle and infusion of N-arginine shows that Arg2 loss causes significant ammonia accumulation that results from the shunting of arginine catabolism into alternative nitrogen repositories. Furthermore, analysis of PDA patient tumors indicates that ARG2 levels correlate with body mass index (BMI). The specific dependency of PDA on ARG2 rather than the principal hepatic enzyme ARG1 opens a therapeutic window for obesity-associated pancreatic cancer.Obesity is an established risk factor for pancreatic ductal adenocarcinoma (PDA). Here the authors show that obesity induces the expression of the mitochondrial form of arginase ARG2 in PDA and that ARG2 silencing or loss results in ammonia accumulation and suppression of obesity-driven PDA tumor growth. 10.1038/s41467-017-00331-y
    Protein arginine methyltransferase 3-induced metabolic reprogramming is a vulnerable target of pancreatic cancer. Hsu Ming-Chuan,Tsai Ya-Li,Lin Chia-Hsien,Pan Mei-Ren,Shan Yan-Shen,Cheng Tsung-Yen,Cheng Skye Hung-Chun,Chen Li-Tzong,Hung Wen-Chun Journal of hematology & oncology BACKGROUND:The biological function of protein arginine methyltransferase 3 (PRMT3) is not well known because very few physiological substrates of this methyltransferase have been identified to date. METHODS:The clinical significance of PRMT3 in pancreatic cancer was studied by database analysis. The PRMT3 protein level of human pancreatic tumors was detected by immunoblotting and immunohistochemical staining. PRMT3-associated proteins and the methylation sites on the proteins were investigated using mass spectrometry. Seahorse Bioscience analyzed the metabolic reprogramming. Combination index analysis and xenograft animal model were conducted to explore the effects of combination of inhibitors of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and oxidative phosphorylation on tumor growth. RESULTS:We found that the expression of PRMT3 is upregulated in pancreatic cancer, and its expression is associated with poor survival. We identified GAPDH as a PRMT3-binding protein and demonstrated that GAPDH is methylated at R248 by PRMT3 in vivo. The methylation of GAPDH by PRMT3 enhanced its catalytic activity while the mutation of R248 abolished the effect. In cells, PRMT3 overexpression triggered metabolic reprogramming and enhanced glycolysis and mitochondrial respiration simultaneously in a GAPDH-dependent manner. PRMT3-overexpressing cancer cells were addicted to GAPDH-mediated metabolism and sensitive to the inhibition of GAPDH and mitochondrial respiration. The combination of inhibitors of GAPDH and oxidative phosphorylation induced a synergistic inhibition on cellular growth in vitro and in vivo. CONCLUSION:Our results suggest that PRMT3 mediates metabolic reprogramming and cellular proliferation through methylating R248 of GAPDH, and double blockade of GAPDH and mitochondrial respiration could be a novel strategy for the treatment of PRMT3-overexpressing pancreatic cancer. 10.1186/s13045-019-0769-7
    Effect of l-arginine supplementation on C-reactive protein and other inflammatory biomarkers: A systematic review and meta-analysis of randomized controlled trials. Nazarian Behzad,Fazeli Moghadam Ezatollah,Asbaghi Omid,Zeinali Khosroshahi Mohammad,Choghakhori Razieh,Abbasnezhad Amir Complementary therapies in medicine OBJECTIVES:We carried out a systematic review and meta-analysis of randomized controlled trials (RCTs) to assess the effect of L-arginine on inflammatory biomarkers including C-reactive protein (CRP), interleukin-6 (IL-6) and TNFα. METHODS:A systematic search was carried out in PubMed, Embase, Scopus, Cochrane library databases and ISI web of sciences to retrieve the RCTs which examined the effect of L-arginine supplementation on inflammatory biomarkers up to October 2019, with no language and time restriction. Meta-analysis was performed using a random effects model, and I2 index was used to evaluate the heterogeneity. RESULTS:Search yielded 2452 publications. Eleven RCTs were eligible. Results indicated that L-arginine supplementation had no significant effect on inflammatory biomarkers including CRP, IL-6 and TNFα. However, when subgroup analysis was performed, we found that L-arginine supplementation increased CRP levels in subjects with ages >60 years old, participants with baseline circulating CRP levels >3 mg/dl, patients with cancer and when used in enteral formula. CONCLUSION:Results of the present meta-analysis indicated that L-arginine supplementation increased the circulating concentrations of CRP in subjects with ages >60 years old, subjects with higher levels of CRP, patients with cancer and when used in enteral formula. Therefore, L-arginine should be used with caution in these subjects. However, further well designed, large-scale studies are needed. 10.1016/j.ctim.2019.102226
    Arginine Deprivation Inhibits the Warburg Effect and Upregulates Glutamine Anaplerosis and Serine Biosynthesis in ASS1-Deficient Cancers. Kremer Jeff Charles,Prudner Bethany Cheree,Lange Sara Elaine Stubbs,Bean Gregory Richard,Schultze Matthew Bailey,Brashears Caitlyn Brook,Radyk Megan DeAnna,Redlich Nathan,Tzeng Shin-Cheng,Kami Kenjiro,Shelton Laura,Li Aixiao,Morgan Zack,Bomalaski John Stephen,Tsukamoto Takashi,McConathy Jon,Michel Loren Scott,Held Jason Matthew,Van Tine Brian Andrew Cell reports Targeting defects in metabolism is an underutilized strategy for the treatment of cancer. Arginine auxotrophy resulting from the silencing of argininosuccinate synthetase 1 (ASS1) is a common metabolic alteration reported in a broad range of aggressive cancers. To assess the metabolic effects that arise from acute and chronic arginine starvation in ASS1-deficient cell lines, we performed metabolite profiling. We found that pharmacologically induced arginine depletion causes increased serine biosynthesis, glutamine anaplerosis, oxidative phosphorylation, and decreased aerobic glycolysis, effectively inhibiting the Warburg effect. The reduction of glycolysis in cells otherwise dependent on aerobic glycolysis is correlated with reduced PKM2 expression and phosphorylation and upregulation of PHGDH. Concurrent arginine deprivation and glutaminase inhibition was found to be synthetic lethal across a spectrum of ASS1-deficient tumor cell lines and is sufficient to cause in vivo tumor regression in mice. These results identify two synthetic lethal therapeutic strategies exploiting metabolic vulnerabilities of ASS1-negative cancers. 10.1016/j.celrep.2016.12.077
    Arginine starvation kills tumor cells through aspartate exhaustion and mitochondrial dysfunction. Cheng Chun-Ting,Qi Yue,Wang Yi-Chang,Chi Kevin K,Chung Yiyin,Ouyang Ching,Chen Yun-Ru,Oh Myung Eun,Sheng Xiangpeng,Tang Yulong,Liu Yun-Ru,Lin H Helen,Kuo Ching-Ying,Schones Dustin,Vidal Christina M,Chu Jenny C-Y,Wang Hung-Jung,Chen Yu-Han,Miller Kyle M,Chu Peiguo,Yen Yun,Jiang Lei,Kung Hsing-Jien,Ann David K Communications biology Defective arginine synthesis, due to the silencing of (ASS1), is a common metabolic vulnerability in cancer, known as arginine auxotrophy. Understanding how arginine depletion kills arginine-auxotrophic cancer cells will facilitate the development of anti-cancer therapeutic strategies. Here we show that depletion of extracellular arginine in arginine-auxotrophic cancer cells causes mitochondrial distress and transcriptional reprogramming. Mechanistically, arginine starvation induces asparagine synthetase (ASNS), depleting these cancer cells of aspartate, and disrupting their malate-aspartate shuttle. Supplementation of aspartate, depletion of mitochondria, and knockdown of ASNS all protect the arginine-starved cells, establishing the causal effects of aspartate depletion and mitochondrial dysfunction on the arginine starvation-induced cell death. Furthermore, dietary arginine restriction reduced tumor growth in a xenograft model of ASS1-deficient breast cancer. Our data challenge the view that ASNS promotes homeostasis, arguing instead that ASNS-induced aspartate depletion promotes cytotoxicity, which can be exploited for anti-cancer therapies. 10.1038/s42003-018-0178-4
    Mapping Metabolic Events in the Cancer Cell Cycle Reveals Arginine Catabolism in the Committed SGM Phase. Roci Irena,Watrous Jeramie D,Lagerborg Kim A,Lafranchi Lorenzo,Lindqvist Arne,Jain Mohit,Nilsson Roland Cell reports Alterations in cell-cycle regulation and cellular metabolism are associated with cancer transformation, and enzymes active in the committed cell-cycle phase may represent vulnerabilities of cancer cells. Here, we map metabolic events in the G and SGM phases by combining cell sorting with mass spectrometry-based isotope tracing, revealing hundreds of cell-cycle-associated metabolites. In particular, arginine uptake and ornithine synthesis are active during SGM in transformed but not in normal cells, with the mitochondrial arginase 2 (ARG2) enzyme as a potential mechanism. While cancer cells exclusively use ARG2, normal epithelial cells synthesize ornithine via ornithine aminotransferase (OAT). Knockdown of ARG2 markedly reduces cancer cell growth and causes GM arrest, while not inducing compensation via OAT. In human tumors, ARG2 is highly expressed in specific tumor types, including basal-like breast tumors. This study sheds light on the interplay between metabolism and cell cycle and identifies ARG2 as a potential metabolic target. 10.1016/j.celrep.2019.01.059
    Macrophage-Derived IL1β and TNFα Regulate Arginine Metabolism in Neuroblastoma. Fultang Livingstone,Gamble Laura D,Gneo Luciana,Berry Andrea M,Egan Sharon A,De Bie Fenna,Yogev Orli,Eden Georgina L,Booth Sarah,Brownhill Samantha,Vardon Ashley,McConville Carmel M,Cheng Paul N,Norris Murray D,Etchevers Heather C,Murray Jayne,Ziegler David S,Chesler Louis,Schmidt Ronny,Burchill Susan A,Haber Michelle,De Santo Carmela,Mussai Francis Cancer research Neuroblastoma is the most common childhood solid tumor, yet the prognosis for high-risk disease remains poor. We demonstrate here that arginase 2 (ARG2) drives neuroblastoma cell proliferation via regulation of arginine metabolism. Targeting arginine metabolism, either by blocking cationic amino acid transporter 1 (CAT-1)-dependent arginine uptake or therapeutic depletion of arginine by pegylated recombinant arginase BCT-100, significantly delayed tumor development and prolonged murine survival. Tumor cells polarized infiltrating monocytes to an M1-macrophage phenotype, which released IL1β and TNFα in a RAC-alpha serine/threonine-protein kinase (AKT)-dependent manner. IL1β and TNFα established a feedback loop to upregulate ARG2 expression via p38 and extracellular regulated kinases 1/2 (ERK1/2) signaling in neuroblastoma and neural crest-derived cells. Proteomic analysis revealed that enrichment of IL1β and TNFα in stage IV human tumor microenvironments was associated with a worse prognosis. These data thus describe an immune-metabolic regulatory loop between tumor cells and infiltrating myeloid cells regulating ARG2, which can be clinically exploited. SIGNIFICANCE: These findings illustrate that cross-talk between myeloid cells and tumor cells creates a metabolic regulatory loop that promotes neuroblastoma progression. 10.1158/0008-5472.CAN-18-2139
    Amino Acid Uptake Measured by [F]AFETP Increases in Response to Arginine Starvation in ASS1-Deficient Sarcomas. Prudner Bethany Cheree,Sun Fangdi,Kremer Jeffrey Charles,Xu Jinbin,Huang Chaofeng,Sai Kiran Kumar Solingapuram,Morgan Zachary,Leeds Hayden,McConathy Jonathan,Van Tine Brian Andrew Theranostics : In a subset of cancers, arginine auxotrophy occurs due to the loss of expression of argininosuccinate synthetase 1 (ASS1). This loss of ASS1 expression makes cancers sensitive to arginine starvation that is induced by PEGylated arginine deiminase (ADI-PEG20). Although ADI-PEG20 treatment is effective, it does have important limitations. Arginine starvation is only beneficial in patients with cancers that are ASS1-deficient. Also, these tumors may metabolically reprogram to express ASS1, transforming them from an auxotrophic phenotype to a prototrophic phenotype and thus rendering ADI-PEG20 ineffective. Due to these limitations of ADI-PEG20 treatment and the potential for developing resistance, non-invasive tools to monitor sensitivity to arginine starvation are needed. : Within this study, we assess the utility of a novel positron emission tomography (PET) tracer to determine sarcomas reliant on extracellular arginine for survival by measuring changes in amino acid transport in arginine auxotrophic sarcoma cells treated with ADI-PEG20. The uptake of the F-labeled histidine analogue, ()-2-amino-3-[1-(2-[F]fluoroethyl)-1-[1,2,3]triazol-4-yl]propanoic acid (AFETP), was assessed and using human-derived sarcoma cell lines. In addition, we examined the expression and localization of cationic amino acid transporters in response to arginine starvation with ADI-PEG20. : studies revealed that in response to ADI-PEG20 treatment, arginine auxotrophs increase the uptake of L-[H]arginine and [F]AFETP due to an increase in the expression and localization to the plasma membrane of the cationic amino acid transporter CAT-1. Furthermore, PET imaging studies in mice with arginine-dependent osteosarcoma xenografts showed increased [F]AFETP uptake in tumors 4 days after ADI-PEG20 treatment compared to baseline. : CAT-1 transporters localizes to the plasma membrane as a result of arginine starvation with ADI-PEG20 in ASS1-deficient tumor cells and provides a mechanism for using cationic amino acid transport substrates such as [F]AFETP for identifying tumors susceptible to ADI-PEG20 treatment though non-invasive PET imaging techniques. These findings indicate that [F]AFETP-PET may be suitable for the early detection of tumor response to arginine depletion due to ADI-PEG20 treatment. 10.7150/thno.22083
    The Combination of Arginine Deprivation and 5-Fluorouracil Improves Therapeutic Efficacy in Argininosuccinate Synthetase Negative Hepatocellular Carcinoma. Thongkum Angkana,Wu Chunjing,Li Ying-Ying,Wangpaichitr Medhi,Navasumrit Panida,Parnlob Varabhorn,Sricharunrat Thaniya,Bhudhisawasdi Vajarabhongsa,Ruchirawat Mathuros,Savaraj Niramol International journal of molecular sciences Argininosuccinate synthetase (ASS), a key enzyme to synthesize arginine is down regulated in many tumors including hepatocellular carcinoma (HCC). Similar to previous reports, we have found the decrease in ASS expression in poorly differentiated HCC. These ASS(-) tumors are auxotrophic for arginine. Pegylated arginine deiminase (ADI-PEG20), which degrades arginine, has shown activity in these tumors, but the antitumor effect is not robust and hence combination treatment is needed. Herein, we have elucidated the effectiveness of ADI-PEG20 combined with 5-Fluorouracil (5-FU) in ASS(-)HCC by targeting urea cycle and pyrimidine metabolism using four HCC cell lines as model. SNU398 and SNU387 express very low levels of ASS or ASS(-) while Huh-1, and HepG2 express high ASS similar to normal cells. Our results showed that the augmented cytotoxic effect of combination treatment only occurs in SNU398 and SNU387, and not in HepG2 and Huh-1 (ASS(+)) cells, and is partly due to reduced anti-apoptotic proteins X-linked inhibitor of apoptosis protein (XIAP), myeloid leukemia cell differentiation protein (Mcl-1) and B-cell lymphoma-2 (Bcl-2). Importantly, lack of ASS also influences essential enzymes in pyrimidine synthesis (carbamoyl-phosphate synthetase2, aspartate transcarbamylase and dihydrooratase (CAD) and thymidylate synthase (TS)) and malate dehydrogenase-1 (MDH-1) in TCA cycle. ADI-PEG20 treatment decreased these enzymes and made them more vulnerable to 5-FU. Transfection of ASS restored these enzymes and abolished the sensitivity to ADI-PEG20 and combination treatment. Overall, our data suggest that ASS influences multiple enzymes involved in 5-FU sensitivity. Combining ADI-PEG20 and 5-FU may be effective to treat ASS(-)hepatoma and warrants further clinical investigation. 10.3390/ijms18061175
    Targeting the arginine metabolic brake enhances immunotherapy for leukaemia. Mussai Francis,Wheat Rachel,Sarrou Evgenia,Booth Sarah,Stavrou Victoria,Fultang Livingstone,Perry Tracey,Kearns Pamela,Cheng Paul,Keeshan Karen,Craddock Charles,De Santo Carmela International journal of cancer Therapeutic approaches which aim to target Acute Myeloid Leukaemia through enhancement of patients' immune responses have demonstrated limited efficacy to date, despite encouraging preclinical data. Examination of AML patients treated with azacitidine (AZA) and vorinostat (VOR) in a Phase II trial, demonstrated an increase in the expression of Cancer-Testis Antigens (MAGE, RAGE, LAGE, SSX2 and TRAG3) on blasts and that these can be recognised by circulating antigen-specific T cells. Although the T cells have the potential to be activated by these unmasked antigens, the low arginine microenvironment created by AML blast Arginase II activity acts a metabolic brake leading to T cell exhaustion. T cells exhibit impaired proliferation, reduced IFN-γ release and PD-1 up-regulation in response to antigen stimulation under low arginine conditions. Inhibition of arginine metabolism enhanced the proliferation and cytotoxicity of anti-NY-ESO T cells against AZA/VOR treated AML blasts, and can boost anti-CD33 Chimeric Antigen Receptor-T cell cytotoxicity. Therefore, measurement of plasma arginine concentrations in combination with therapeutic targeting of arginase activity in AML blasts could be a key adjunct to immunotherapy. 10.1002/ijc.32028
    Arginine Citrullination at the C-Terminal Domain Controls RNA Polymerase II Transcription. Sharma Priyanka,Lioutas Antonios,Fernandez-Fuentes Narcis,Quilez Javier,Carbonell-Caballero José,Wright Roni H G,Di Vona Chiara,Le Dily François,Schüller Roland,Eick Dirk,Oliva Baldomero,Beato Miguel Molecular cell The post-translational modification of key residues at the C-terminal domain of RNA polymerase II (RNAP2-CTD) coordinates transcription, splicing, and RNA processing by modulating its capacity to act as a landing platform for a variety of protein complexes. Here, we identify a new modification at the CTD, the deimination of arginine and its conversion to citrulline by peptidyl arginine deiminase 2 (PADI2), an enzyme that has been associated with several diseases, including cancer. We show that, among PADI family members, only PADI2 citrullinates R1810 (Cit1810) at repeat 31 of the CTD. Depletion of PADI2 or loss of R1810 results in accumulation of RNAP2 at transcription start sites, reduced gene expression, and inhibition of cell proliferation. Cit1810 is needed for interaction with the P-TEFb (positive transcription elongation factor b) kinase complex and for its recruitment to chromatin. In this way, CTD-Cit1810 favors RNAP2 pause release and efficient transcription in breast cancer cells. 10.1016/j.molcel.2018.10.016
    Recombinant human arginase induces apoptosis through oxidative stress and cell cycle arrest in small cell lung cancer. Xu Shi,Lam Sze-Kwan,Cheng Paul Ning-Man,Ho James Chung-Man Cancer science Small cell lung cancer (SCLC) accounts for approximately 13% of all lung cancer cases. Small cell lung cancer is characterized by frequent relapse, and current treatments lack tumor specificity. Arginine is a non-essential amino acid for human normal cells but critical to some tumor cells that cannot synthesize arginine. Therefore, arginine deprivation has become a potential therapeutic option for selected tumors. BCT-100 is a pegylated arginase that has documented anticancer activity in arginine auxotrophic tumors, such as melanoma, hepatocellular carcinoma, and acute myeloid leukemia. One of the resistance mechanisms to arginase treatment is overexpression of argininosuccinate synthetase (ASS1) and ornithine transcarbamylase (OTC), two important enzymes in the urea cycle. We selected 9 SCLC and 1 non-small cell lung carcinoma cell lines to determine the growth inhibition effects of BCT-100 and established that cell lines with low expression of ASS1 and OTC are relatively sensitive to BCT-100 treatment. Knocking down OTC in a H841 cell line could potentiate its sensitivity to BCT-100 treatment. Arginine concentration was sharply decreased, accompanied by apoptosis through oxidative stress as well as G cell cycle arrest. In addition, BCT-100 showed an anticancer effect on H446 and H510A xenograft models by lowering arginine levels and inducing apoptosis. 10.1111/cas.13782
    Cisplatin-induced synthetic lethality to arginine-starvation therapy by transcriptional suppression of ASS1 is regulated by DEC1, HIF-1α, and c-Myc transcription network and is independent of ASS1 promoter DNA methylation. Long Yan,Tsai Wen-Bin,Chang Jeffrey T,Estecio Marcos,Wangpaichitr Medhi,Savaraj Naramol,Feun Lynn G,Chen Helen H W,Kuo Macus Tien Oncotarget Many human tumors require extracellular arginine (Arg) for growth because the key enzyme for de novo biosynthesis of Arg, argininosuccinate synthetase 1 (ASS1), is silenced. These tumors are sensitive to Arg-starvation therapy using pegylated arginine deiminase (ADI-PEG20) which digests extracellular Arg. Many previous studies reported that ASS1 silencing is due to epigenetic inactivation of ASS1 expression by DNA methylation, and that the demethylation agent 5-aza-deoxycytidine (Aza-dC) can induce ASS1 expression. Moreover, it was reported that cisplatin suppresses ASS1 expression through ASS1 promoter methylation, leading to synthetic lethality to ADI-PEG20 treatment. We report here that cisplatin supppresses ASS1 expression is due to upregulation of HIF-1α and downregulation of c-Myc, which function as negative and positive regulators of ASS1 expression, respectively, by reciprocal bindings to the ASS1 promoter. In contrast, we found that Aza-dC induces ASS1 expression by downregulation of HIF-1α but upregulation of c-Myc. We further demonstrated that the clock protein DEC1 is the master regulator of HIF-1α and c-Myc that regulate ASS1. cDDP upregulates DEC1, whereas Aza-dC suppresses its expression. Using two proteasomal inhibitors bortezomib and carfilzomib which induce HIF-1α accumulation, we further demonstrated that HIF-1α is involved in ASS1 silencing for the maintenance of Arg auxotrophy for targeted Arg-starvation therapy. 10.18632/oncotarget.12308
    Elevated mitochondrial SLC25A29 in cancer modulates metabolic status by increasing mitochondria-derived nitric oxide. Zhang Huiyuan,Wang Qinyi,Gu Junzhong,Yin Le,Liang Shenghui,Wu Lida,Xu Hao,Zhao Chao,Gu Yuchun Oncogene Warburg effect has been recognized as a hallmark of cancer cells for many years, but its modulation mechanism remains a great focus. Our current study found a member of solute carrier family 25 (SLC25A29), the main arginine transporter on mitochondria, significantly elevated in various cancer cells. Knockout of SLC25A29 by CRISPR/Cas9 inhibited proliferation and migration of cancer cells both in vitro and in vivo. SLC25A29-knockout cells also showed an altered metabolic status with enhanced mitochondrial respiration and reduced glycolysis. All of above impacts could be reversed after rescuing SLC25A29 expression in SLC25A29-knockout cells. Arginine is transported into mitochondria partly for nitric oxide (NO) synthesis. Deletion of SLC25A29 resulted in severe decrease of NO production, indicating that the mitochondria is a significant source of NO. SLC25A29-knockout cells dramatically altered the variation of metabolic processes, whereas addition of arginine failed to reverse the effect, highlighting the necessity of transporting arginine into mitochondria by SLC25A29. In conclusion, aberrant elevated SLC25A29 in cancer functioned to transport more arginine into mitochondria, improved mitochondria-derived NO levels, thus modulated metabolic status to facilitate increased cancer progression. 10.1038/s41388-018-0139-x
    Protein arginine methyltransferase 5 mediates enolase-1 cell surface trafficking in human lung adenocarcinoma cells. Zakrzewicz Dariusz,Didiasova Miroslava,Krüger Marcus,Giaimo Benedetto Daniele,Borggrefe Tilman,Mieth Maren,Hocke Andreas C,Zakrzewicz Anna,Schaefer Liliana,Preissner Klaus T,Wygrecka Malgorzata Biochimica et biophysica acta. Molecular basis of disease OBJECTIVES:Enolase-1-dependent cell surface proteolysis plays an important role in cell invasion. Although enolase-1 (Eno-1), a glycolytic enzyme, has been found on the surface of various cells, the mechanism responsible for its exteriorization remains elusive. Here, we investigated the involvement of post-translational modifications (PTMs) of Eno-1 in its lipopolysaccharide (LPS)-triggered trafficking to the cell surface. RESULTS:We found that stimulation of human lung adenocarcinoma cells with LPS triggered the monomethylation of arginine 50 (R50me) within Eno-1. The Eno-1R50me was confirmed by its interaction with the tudor domain (TD) from TD-containing 3 (TDRD3) protein recognizing methylarginines. Substitution of R50 with lysine (R50K) reduced Eno-1 association with epithelial caveolar domains, thereby diminishing its exteriorization. Similar effects were observed when pharmacological inhibitors of arginine methyltransferases were applied. Protein arginine methyltransferase 5 (PRMT5) was identified to be responsible for Eno-1 methylation. Overexpression of PRMT5 and caveolin-1 enhanced levels of membrane-bound extracellular Eno-1 and, conversely, pharmacological inhibition of PRMT5 attenuated Eno-1 cell-surface localization. Importantly, Eno-1R50me was essential for cancer cell motility since the replacement of Eno-1 R50 by lysine or the suppression of PRMT 5 activity diminished Eno-1-triggered cell invasion. CONCLUSIONS:LPS-triggered Eno-1R50me enhances Eno-1 cell surface levels and thus potentiates the invasive properties of cancer cells. Strategies to target Eno-1R50me may offer novel therapeutic approaches to attenuate tumor metastasis in cancer patients. 10.1016/j.bbadis.2018.02.021
    Barriers to cancer nutrition therapy: excess catabolism of muscle and adipose tissues induced by tumour products and chemotherapy. Schiessel Dalton L,Baracos Vickie E The Proceedings of the Nutrition Society Cancer-associated malnutrition is driven by reduced dietary intake and by underlying metabolic changes (such as inflammation, anabolic resistance, proteolysis, lipolysis and futile cycling) induced by the tumour and activated immune cells. Cytotoxic and targeted chemotherapies also elicit proteolysis and lipolysis at the tissue level. In this review, we summarise specific mediators and chemotherapy effects that provoke excess proteolysis in muscle and excess lipolysis in adipose tissue. A nutritionally relevant question is whether and to what degree these catabolic changes can be reversed by nutritional therapy. In skeletal muscle, tumour factors and chemotherapy drugs activate intracellular signals that result in the suppression of protein synthesis and activation of a transcriptional programme leading to autophagy and degradation of myofibrillar proteins. Cancer nutrition therapy is intended to ensure adequate provision of energy fuels and a complete repertoire of biosynthetic building blocks. There is some promising evidence that cancer- and chemotherapy-associated metabolic alterations may also be corrected by certain individual nutrients. The amino acids leucine and arginine provided in the diet at least partially reverse anabolic suppression in muscle, while n-3 PUFA inhibit the transcriptional activation of muscle catabolism. Optimal conditions for exploiting these anabolic and anti-catabolic effects are currently under study, with the overall aim of net improvements in muscle mass, functionality, performance status and treatment tolerance. 10.1017/S0029665118000186
    The story of protein arginine methylation: characterization, regulation, and function. Peng Chao,Wong Catherine Cl Expert review of proteomics INTRODUCTION:Arginine methylation is an important post-translational modification (PTM) in cells, which is catalyzed by a group of protein arginine methyltransferases (PRMTs). It plays significant roles in diverse cellular processes and various diseases. Misregulation and aberrant expression of PRMTs can provide potential biomarkers and therapeutic targets for drug discovery. Areas covered: Herein, we review the arginine methylation literature and summarize the methodologies for the characterization of this modification, as well as describe the recent insights into arginine methyltransferases and their biological functions in diseases. Expert commentary: Benefits from the enzyme-based large-scale screening approach, the novel affinity enrichment strategies, arginine methylated protein family is the focus of attention. Although a number of arginine methyltransferases and related substrates are identified, the catalytic mechanism of different types of PRMTs remains unclear and few related demethylases are characterized. Novel functional studies continuously reveal the importance of this modification in the cell cycle and diseases. A deeper understanding of arginine methylated proteins, modification sites, and their mechanisms of regulation is needed to explore their role in life processes, especially their relationship with diseases, thus accelerating the generation of potent, selective, cell-penetrant drug candidates. 10.1080/14789450.2017.1275573
    Postoperative enteral immunonutrition in head and neck cancer patients: Impact on clinical outcomes. Barajas-Galindo David E,Vidal-Casariego Alfonso,Pintor-de la Maza Begoña,Fernández-Martínez Paula,Ramos-Martínez Tania,García-Arias Sara,Hernández-Moreno Ana,Urioste-Fondo Ana,Cano-Rodríguez Isidoro,Ballesteros-Pomar María D Endocrinologia, diabetes y nutricion BACKGROUND:Head and neck cancer patients have a high rate of complications during the postoperative period that could increase their morbidity rate. Arginine has been shown to improve healing and to modulate inflammation and immune response. The aim of our study was to assess whether use of arginine-enriched enteral formulas could decrease fistulas and length of stay (LoS). METHODS:A retrospective study was conducted in patients who had undergone head and neck cancer surgery and were receiving enteral nutrition through a nasogastric tube in the postoperative period between January 2012 and May 2018. The differences associated to use of immunoformula vs. standard formulas were analysed. Sociodemographic, anthropometric, and nutritional intervention variables, as well as nutritional parameters, were recorded during the early postoperative period. Occurrence of complications (fistulas), length of hospital stay, readmissions, and 90-day mortality were recorded. RESULTS:In a univariate analysis, patients who received nutritional support with immunonutrition had a lower fistula occurrence rate (17.91% vs. 32.84%; p=0.047) and a shorter mean LoS [28.25 (SD 16.11) vs. 35.50 (SD 25.73) days; p=0.030]. After adjusting for age, energy intake, aggressiveness of surgery and tumour stage, fistula occurrence rate and LoS were similar in both groups irrespective of the type of formula. CONCLUSIONS:Use of arginine-enriched enteral nutrition appears to decrease the occurrence of fistulas in the postoperative period in patients with head and neck cancer, with a resultant reduction in length of hospital stay. However, the differences disappeared after adjusting for age, tumour stage, or aggressiveness of the surgery. 10.1016/j.endinu.2019.05.006
    Arginine modification of lycosin-I to improve inhibitory activity against cancer cells. Zhang Peng,Ma Jing,Yan Yujie,Chen Bo,Liu Bobo,Jian Cui,Zhu Baode,Liang Songping,Zeng Youlin,Liu Zhonghua Organic & biomolecular chemistry Lycosin-I is a linear amphipathic α-helical anticancer peptide (ACP) extracted from the spider Lycosa singoriensis, which can activate the mitochondrial death pathway to induce apoptosis in tumor cells and up-regulate p27 to inhibit cell proliferation. However, the applicability of lycosin-I as a novel anticancer drug is limited by its low cellular entry and efficacy in solid tumors. Amino acid substitution presents an effective and modest strategy to improve the anticancer activity and bioavailability of ACPs. Herein, an arginine-modified lycosin-I (named R-lycosin-I) was designed and synthesized by substituting lysine (Lys) with arginine (Arg). This peptide exhibited higher anticancer activity and penetrability against solid tumor cells than lycosin-I. They displayed noticeable differences in their physicochemical properties including the secondary structure, hydrodynamic size, and zeta potential. Fluorescence analyses have confirmed that R-lycosin-I exhibits increased cellular uptake and improved intracellular distribution. Due to its superior physical and chemical properties and high serum stability, R-lycosin-I could penetrate deeply into tumor spheroids and produce strong toxicity in the 3D tumor model. Overall, these findings suggest that arginine modification may provide an effective strategy for improving the anticancer activity of lycosin-I, and R-lycosin-I may be a useful lead for developing anticancer drugs. 10.1039/c7ob02233f
    Myosin phosphatase and RhoA-activated kinase modulate arginine methylation by the regulation of protein arginine methyltransferase 5 in hepatocellular carcinoma cells. Sipos Adrienn,Iván Judit,Bécsi Bálint,Darula Zsuzsanna,Tamás István,Horváth Dániel,Medzihradszky Katalin F,Erdődi Ferenc,Lontay Beáta Scientific reports Myosin phosphatase (MP) holoenzyme is a protein phosphatase-1 (PP1) type Ser/Thr specific enzyme that consists of a PP1 catalytic (PP1c) and a myosin phosphatase target subunit-1 (MYPT1). MYPT1 is an ubiquitously expressed isoform and it targets PP1c to its substrates. We identified the protein arginine methyltransferase 5 (PRMT5) enzyme of the methylosome complex as a MYPT1-binding protein uncovering the nuclear MYPT1-interactome of hepatocellular carcinoma cells. It is shown that PRMT5 is regulated by phosphorylation at Thr80 by RhoA-associated protein kinase and MP. Silencing of MYPT1 increased the level of the PRMT5-specific symmetric dimethylation on arginine residues of histone 2 A/4, a repressing gene expression mark, and it resulted in a global change in the expression of genes affecting cellular processes like growth, proliferation and cell death, also affecting the expression of the retinoblastoma protein and c-Myc. The phosphorylation of the MP inhibitory MYPT1 and the regulatory PRMT5 residues as well as the symmetric dimethylation of H2A/4 were elevated in human hepatocellular carcinoma and in other types of cancers. These changes correlated positively with the grade and state of the tumors. Our results suggest the tumor suppressor role of MP via inhibition of PRMT5 thereby regulating gene expression through histone arginine dimethylation. 10.1038/srep40590
    Arginine Methylation of SREBP1a via PRMT5 Promotes De Novo Lipogenesis and Tumor Growth. Liu Liu,Zhao Xiaoping,Zhao Li,Li Jiajin,Yang Hao,Zhu Zongping,Liu Jianjun,Huang Gang Cancer research Dysregulation of the sterol regulatory element-binding transcription factors sterol regulatory element-binding protein (SREBP) and SREBF activates de novo lipogenesis to high levels in cancer cells, a critical event in driving malignant growth. In this study, we identified an important posttranslational mechanism by which SREBP1a is regulated during metabolic reprogramming in cancer cells. Mass spectrometry revealed protein arginine methyltransferase 5 (PRMT5) as a binding partner of SREBP1a that symmetrically dimethylated it on R321, thereby promoting transcriptional activity. Furthermore, PRMT5-induced methylation prevented phosphorylation of SREBP1a on S430 by GSK3β, leading to its disassociation from Fbw7 (FBXW7) and its evasion from degradation through the ubiquitin-proteasome pathway. Consequently, methylation-stabilized SREBP1a increased de novo lipogenesis and accelerated the growth of cancer cells in vivo and in vitro. Clinically, R321 symmetric dimethylation status was associated with malignant progression of human hepatocellular carcinoma, where it served as an independent risk factor of poor prognosis. By showing how PRMT5-induced methylation of SREBP1a triggers hyperactivation of lipid biosynthesis, a key event in tumorigenesis, our findings suggest a new generalized strategy to selectively attack tumor metabolism. 10.1158/0008-5472.CAN-15-1766
    Arginine-Dual roles as an onconutrient and immunonutrient. Albaugh Vance L,Pinzon-Guzman Carolina,Barbul Adrian Journal of surgical oncology Arginine is an important player in numerous biologic processes and studies have demonstrated its importance for cellular growth that becomes limiting in states of rapid turnover (e.g., malignancy). Thus, arginine deprivation therapy is being examined as an adjuvant cancer therapy, however, arginine is also necessary for immune destruction of malignant cells. Herein we review the data supporting arginine deprivation or supplementation in cancer treatment and the currently registered trials aimed at understanding these divergent strategies. J. Surg. Oncol. 2017;115:273-280. © 2016 Wiley Periodicals, Inc. 10.1002/jso.24490
    Myeloid-derived suppressor cells reveal radioprotective properties through arginase-induced l-arginine depletion. Leonard Wim,Dufait Inès,Schwarze Julia Katharina,Law Kalun,Engels Benedikt,Jiang Heng,Van den Berge Dirk,Gevaert Thierry,Storme Guy,Verovski Valeri,Breckpot Karine,De Ridder Mark Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology BACKGROUND AND PURPOSE:High arginase-1 (Arg) expression by myeloid-derived suppressor cells (MDSC) is known to inhibit antitumor T-cell responses through depletion of l-arginine. We have previously shown that nitric oxide (NO), an immune mediator produced from l-arginine, is a potent radiosensitizer of hypoxic tumor cells. This study therefore examines whether Arg(+) overexpressing MDSC may confer radioresistance through depleting the substrate for NO synthesis. MATERIAL AND METHODS:MDSC and Arg expression were studied in preclinical mouse CT26 and 4T1 tumor models and further validated in rectal cancer patients in comparison with healthy donors. The radioprotective effect of MDSC was analyzed in hypoxic tumor cells with regard to l-arginine depletion. RESULTS:In both mouse tumors and cancer patients, MDSC expansion was associated with Arg activation causing accelerated l-arginine consumption. l-Arginine depletion in turn profoundly suppressed the capacity of classically activated macrophages to synthesize NO resulting in impaired tumor cell radiosensitivity. In advanced cT3-4 rectal cancer, circulating neutrophils revealed Arg overexpression approaching that in MDSC, therefore mounting a protumor compartment wherein Arg(+) neutrophils increased from 17% to over 90%. CONCLUSIONS:Protumor Arg(+) MDSC reveal a unique ability to radioprotect tumor cells through l-arginine depletion, a common mechanism behind both T-cell and macrophage inhibition. 10.1016/j.radonc.2016.01.014
    Arginine refolds, stabilizes, and restores function of mutant pVHL proteins in animal model of the VHL cancer syndrome. Shmueli Merav D,Levy-Kanfo Limor,Haj Esraa,Schoenfeld Alan R,Gazit Ehud,Segal Daniel Oncogene The von Hippel-Lindau (VHL) syndrome is a rare inherited cancer, caused by mutations in the VHL gene, many of which render the VHL protein (pVHL) unstable. pVHL is a tumor-suppressor protein implicated in a variety of cellular processes, most notably in response to changes in oxygen availability, due to its role as part of an E3-ligase complex which targets the hypoxia-inducible factor (HIF) for degradation. Previously we reported, using in silico and in vitro analyses, that common oncogenic VHL mutations render pVHL less stable than the wild-type protein, distort its core domain and as a result reduce the ability of the protein to bind its target HIF-1α. Among various chemical chaperones tested, arginine was the most effective in refolding mutant of pVHL. Here we examined the consequences of administering L- or D-arginine to a Drosophila VHL model and to human renal carcinoma cells, both expressing misfolded versions of human pVHL. Arginine treatment increased pVHL solubility in both models and increased the half-life of the mutant pVHL proteins in the cell culture. In both models, L- as well as D-arginine enhanced the ability of wild-type pVHL and certain misfolded mutant versions of pVHL to bind ODD, the HIF-derived target peptide, reflecting restoration of pVHL function. Moreover, continuous feeding of Drosophila expressing misfolded versions of pVHL either L- or D-arginine rich diet rescued their lethal phenotype. Collectively, these in vivo results suggest that arginine supplementation should be examined as a potential novel treatment for VHL cancer syndrome. 10.1038/s41388-018-0491-x
    Serine-Arginine Protein Kinase 1 (SRPK1) as a Prognostic Factor and Potential Therapeutic Target in Cancer: Current Evidence and Future Perspectives. Nikas Ilias P,Themistocleous Sophie C,Paschou Stavroula A,Tsamis Konstantinos I,Ryu Han Suk Cells Cancer, a heterogeneous disease composed of tumor cells and microenvironment, is driven by deregulated processes such as increased proliferation, invasion, metastasis, angiogenesis, and evasion of apoptosis. Alternative splicing, a mechanism led by splicing factors, is implicated in carcinogenesis by affecting any of the processes above. Accumulating evidence suggests that serine-arginine protein kinase 1 (SRPK1), an enzyme that phosphorylates splicing factors rich in serine/arginine domains, has a prognostic and potential predictive role in various cancers. Its upregulation is correlated with higher tumor staging, grading, and shorter survival. SRPK1 is also highly expressed in the premalignant changes of some cancers, showing a potential role in the early steps of carcinogenesis. Of interest, its downregulation in preclinical models has mostly been tumor-suppressive and affected diverse processes heterogeneously, depending on the oncogenic context. In addition, targeting SRPK1 has enhanced sensitivity to platinum-based chemotherapy in some cancers. Lastly, its aberrant function has been noted not only in cancer cells but also in the endothelial cells of the microenvironment. Although the aforementioned evidence seems promising, more studies are needed to reinforce the use of SRPK1 inhibitors in clinical trials. 10.3390/cells9010019
    Arginine methyltransferase inhibitor 1 inhibits gastric cancer by downregulating eIF4E and targeting PRMT5. Zhang Baolai,Zhang Su,Zhu Lijuan,Chen Xue,Zhao Yunfeng,Chao Li,Zhou Juanping,Wang Xing,Zhang Xinyang,Ma Nengqian Toxicology and applied pharmacology Arginine methylation is carried out by protein arginine methyltransferase (PRMTs) family. Arginine methyltransferase inhibitor 1 (AMI-1) is mainly used to inhibit type I PRMT activity in vitro. However, the effects of AMI-1 on type II PRMT5 activity and gastric cancer (GC) remain unclear. In this study, we provided the first evidence that AMI-1 significantly inhibited GC cell proliferation and migration while induced GC cell apoptosis, and reduced the expression of PRMT5, eukaryotic translation initiation factor 4E (eIF4E), symmetric dimethylation of histone 3 (H3R8me2s) and histone 4 (H4R3me2s). In addition, AMI-1 inhibited tumor growth, downregulated eIF4E, H4R3me2s and H3R8me2s expression in mice xenografts model of GC. Collectively, our results suggest that AMI-1 inhibits GC by downregulating eIF4E and targeting type II PRMT5. 10.1016/j.taap.2017.10.002
    Serine/arginine protein-specific kinase 2 promotes the development and progression of pancreatic cancer by downregulating Numb and p53. Wang Guosen,Sheng Weiwei,Shi Xiaoyang,Li Xin,Zhou Jianping,Dong Ming The FEBS journal Serine/arginine protein-specific kinase 2 (SRPK2) plays a vital role in the progression of a range of different malignancies, including pancreatic cancer. However, the mechanisms are poorly understood. Previous studies have shown that in hepatocellular carcinoma, SRPK2 knockdown leads to the upregulation of the cell fate determining protein Numb, and in pancreatic cancer cells, Numb knockdown prevents ubiquitin-mediated degradation of p53. In this study, we investigated the relationship between SRPK2, Numb and p53 in the development of pancreatic cancer with or without chemical agent treatment in vitro. SRPK2 expression was upregulated in pancreatic cancer tissues and associated with decreased overall survival in pancreatic cancer patients, indicating that expression of this protein can be used as a marker of unfavourable prognosis. Expression of SRPK2 was positively associated with tumour T stage and Union for International Cancer Control (UICC) stage, and negatively associated with Numb expression in serial tissue sections. In pancreatic cancer cells, SRPK2 downregulation or overexpression led to modulation of Numb and wild-type p53 protein expression in response to oxaliplatin treatment. Furthermore, these three endogenous proteins could be coimmunoprecipitated as a triple complex. Numb or p53 knockdown reversed the upregulation of p53 that was induced by silencing SRPK2. SRPK2 overexpression promoted cell invasion and migration, and decreased chemosensitivity of cancer cells to gemcitabine or oxaliplatin treatment. Conversely, SRPK2 silencing decreased cell invasion and migration and increased chemosensitivity; these effects were reversed by silencing p53 in oxaliplatin-treated pancreatic cancer cells. Our data suggest that SRPK2 negatively regulates p53 by downregulating Numb under chemical agent treatment. Thus, SRPK2 promotes the development and progression of pancreatic cancer in a p53-dependent manner. 10.1111/febs.14778
    The arginine metabolome in acute lymphoblastic leukemia can be targeted by the pegylated-recombinant arginase I BCT-100. De Santo Carmela,Booth Sarah,Vardon Ashley,Cousins Antony,Tubb Vanessa,Perry Tracey,Noyvert Boris,Beggs Andrew,Ng Margaret,Halsey Christina,Kearns Pamela,Cheng Paul,Mussai Francis International journal of cancer Arginine is a semi-essential amino acid that plays a key role in cell survival and proliferation in normal and malignant cells. BCT-100, a pegylated (PEG) recombinant human arginase, can deplete arginine and starve malignant cells of the amino acid. Acute lymphoblastic leukemia (ALL) is the most common cancer of childhood, yet for patients with high risk or relapsed disease prognosis remains poor. We show that BCT-100 is cytotoxic to ALL blasts from patients in vitro by necrosis, and is synergistic in combination with dexamethasone. Against ALL xenografts, BCT-100 leads to a reduction in ALL engraftment and a prolongation of survival. ALL blasts express the arginine transporter CAT-1, yet the majority of blasts are arginine auxotrophic due to deficiency in either argininosuccinate synthase (ASS) or ornithine transcarbamylase (OTC). Although endogenous upregulation or retroviral transduced increases in ASS or OTC may promote ALL survival under moderately low arginine conditions, expression of these enzymes cannot prevent BCT-100 cytotoxicity at arginine depleting doses. RNA-sequencing of ALL blasts and supporting stromal cells treated with BCT-100 identifies a number of candidate pathways which are altered in the presence of arginine depletion. Therefore, BCT-100 provides a new clinically relevant therapeutic approach to target arginine metabolism in ALL. 10.1002/ijc.31170
    N -hydroxy-L-arginine as a novel ethnic specific indicator of estrogen-negative breast cancer. Mohan Srinidi,Moua Nancy,Harding Lisa Amino acids As a heterogeneous disease, breast cancer can be divided into distinct subtypes. Among the two major subsets of estrogen receptor-negative (ER) and ER-positive (ER) tumors, the ER is a more aggressive subtype, more difficult to treat, has greater ethnic disparity concerns, worse prognosis, and almost twice the risk of mortality. We provide here a fundamental delineation of N -hydroxy-L-arginine as a sensitive and reliable ethnic specific indicator for ER breast cancer early-prognosis (United States provisional patent application number 62232816). 10.1007/s00726-016-2301-5
    Recent advances in targeting protein arginine methyltransferase enzymes in cancer therapy. Smith Emily,Zhou Wei,Shindiapina Polina,Sif Said,Li Chenglong,Baiocchi Robert A Expert opinion on therapeutic targets INTRODUCTION:Exploration in the field of epigenetics has revealed the diverse roles of the protein arginine methyltransferase (PRMT) family of proteins in multiple disease states. These findings have led to the development of specific inhibitors and discovery of several new classes of drugs with potential to treat both benign and malignant conditions. Areas covered: We provide an overview on the role of PRMT enzymes in healthy and malignant cells, highlighting the role of arginine methylation in specific pathways relevant to cancer pathogenesis. Additionally, we describe structure and catalytic activity of PRMT and discuss the mechanisms of action of novel small molecule inhibitors of specific members of the arginine methyltransferase family. Expert opinion: As the field of PRMT biology advances, it's becoming clear that this class of enzymes is highly relevant to maintaining normal physiologic processes as well and disease pathogenesis. We discuss the potential impact of PRMT inhibitors as a broad class of drugs, including the pleiotropic effects, off target effects the need for more detailed PRMT-centric interactomes, and finally, the potential for targeting this class of enzymes in clinical development of experimental therapeutics for cancer. 10.1080/14728222.2018.1474203
    Protein Kinases Type II (PKG II) Combined with L-Arginine Significantly Ameliorated Xenograft Tumor Development: Is L-Arginine a Potential Alternative in PKG II Activation? Wu Yan,Liu Ying,Cai Zhensheng,Qin Huijuan,Li Hongfan,Su Wenbin,Wang Ying,Qian Hai,Jiang Lu,Wu Min,Pang Ji,Chen Yongchang Medical science monitor : international medical journal of experimental and clinical research BACKGROUND The mammalian cyclic guanosine monophosphate (cGMP)-dependent protein kinases type II (PKG II) plays critical physiological or pathological functions in different tissues. However, the biological effects of PKG II are dependent on cGMP. Published data indicated that L-arginine (L-Arg) promoted NO production, NO can activate soluble guanylate cyclase (sGC), and catalyzes guanosine triphosphate (GTP) into cGMP, which suggested L-Arg could activate PKG II. Therefore, the present work was performed to address: (i) whether L-Arg could be a potential alternative in PKG II activation, and (ii) whether L-Arg also contributes to PKG II against cancer. MATERIAL AND METHODS Nude BALB/c mice were inoculated with human MCF-7, HepG2, and SW480 cell lines via subcutaneous (s.c.) injecting. After 7 days of inoculation, Ad-PKG II was injected into the cancer tissues every 4 days, and the next day 10 μmol/mouse L-Arg was administered. Western blotting and immunohistochemistry were used to assess protein expression. RESULTS Our results demonstrated that L-Arg significantly activated PKG II and effectively ameliorated xenograft tumor development through inhibiting cancer growth, angiogenesis, and metastasis, which was partially dependent on blocking of epidermal growth factor receptor (EGFR) activity, as well as downstream signaling pathways such as Erk1/2. CONCLUSIONS Our results provide an exciting new insight: L-Arg is a potential alternative to PKG II activation. 10.12659/msm.906213
    The Arginine Methyltransferase PRMT6 Regulates DNA Methylation and Contributes to Global DNA Hypomethylation in Cancer. Veland Nicolas,Hardikar Swanand,Zhong Yi,Gayatri Sitaram,Dan Jiameng,Strahl Brian D,Rothbart Scott B,Bedford Mark T,Chen Taiping Cell reports DNA methylation plays crucial roles in chromatin structure and gene expression. Aberrant DNA methylation patterns, including global hypomethylation and regional hypermethylation, are associated with cancer and implicated in oncogenic events. How DNA methylation is regulated in developmental and cellular processes and dysregulated in cancer is poorly understood. Here, we show that PRMT6, a protein arginine methyltransferase responsible for asymmetric dimethylation of histone H3 arginine 2 (H3R2me2a), negatively regulates DNA methylation and that PRMT6 upregulation contributes to global DNA hypomethylation in cancer. Mechanistically, PRMT6 overexpression impairs chromatin association of UHRF1, an accessory factor of DNMT1, resulting in passive DNA demethylation. The effect is likely due to elevated H3R2me2a, which inhibits the interaction between UHRF1 and histone H3. Our work identifies a mechanistic link between protein arginine methylation and DNA methylation, which is disrupted in cancer. 10.1016/j.celrep.2017.11.082
    The regulation, functions and clinical relevance of arginine methylation. Guccione Ernesto,Richard Stéphane Nature reviews. Molecular cell biology Methylation of arginine residues by protein arginine methyltransferases (PRMTs) is involved in the regulation of fundamental cellular processes, including transcription, RNA processing, signal transduction cascades, the DNA damage response and liquid-liquid phase separation. Recent studies have provided considerable advances in the development of experimental tools and the identification of clinically relevant PRMT inhibitors. In this review, we discuss the regulation of PRMTs, their various cellular roles and the clinical relevance of PRMT inhibitors for the therapy of neurodegenerative diseases and cancer. 10.1038/s41580-019-0155-x
    Protein arginine methyltransferase 5 promotes lung cancer metastasis via the epigenetic regulation of miR-99 family/FGFR3 signaling. Jing Pengyu,Zhao Nan,Ye Mingxiang,Zhang Yong,Zhang Zhipei,Sun Jianyong,Wang Zhengxin,Zhang Jian,Gu Zhongping Cancer letters Protein arginine methyltransferase 5 (PRMT5) functions as a tumor initiator to regulate several cancer progressions, such as proliferation and apoptosis, by catalyzing the symmetrical dimethylation (me2s) of arginine residues within targeted molecules. However, the exact role of PRMT5-mediated metastasis in lung cancer is not fully understood. Here, we illustrated its potential effects in lung cancer metastasis in vivo and vitro. PRMT5 was frequently overexpressed in lung tumors, and its expression was positively related to tumor stages, lymphatic metastasis and poor outcome. In this model, PRMT5 repressed the transcription of the miR-99 family by symmetrical dimethylation of histone H4R3, which increased FGFR3 expression and in turn activated Erk1/2 and Akt, leading to cell growth and metastasis in lung cancer. Furthermore, loss of PRMT5 exerted anti-metastasis effects on lung cancer progression by blocking histone-modification of miR-99 family. Overall, this study provides new insights into the PRMT5/miR-99 family/FGFR3 axis in regulating lung cancer progression and identifies PRMT5 as a promising prognostic biomarker and therapeutic target. 10.1016/j.canlet.2018.04.019
    L-Arginine Modulates T Cell Metabolism and Enhances Survival and Anti-tumor Activity. Geiger Roger,Rieckmann Jan C,Wolf Tobias,Basso Camilla,Feng Yuehan,Fuhrer Tobias,Kogadeeva Maria,Picotti Paola,Meissner Felix,Mann Matthias,Zamboni Nicola,Sallusto Federica,Lanzavecchia Antonio Cell Metabolic activity is intimately linked to T cell fate and function. Using high-resolution mass spectrometry, we generated dynamic metabolome and proteome profiles of human primary naive T cells following activation. We discovered critical changes in the arginine metabolism that led to a drop in intracellular L-arginine concentration. Elevating L-arginine levels induced global metabolic changes including a shift from glycolysis to oxidative phosphorylation in activated T cells and promoted the generation of central memory-like cells endowed with higher survival capacity and, in a mouse model, anti-tumor activity. Proteome-wide probing of structural alterations, validated by the analysis of knockout T cell clones, identified three transcriptional regulators (BAZ1B, PSIP1, and TSN) that sensed L-arginine levels and promoted T cell survival. Thus, intracellular L-arginine concentrations directly impact the metabolic fitness and survival capacity of T cells that are crucial for anti-tumor responses. 10.1016/j.cell.2016.09.031
    Protein arginine methylation/demethylation and cancer. Poulard Coralie,Corbo Laura,Le Romancer Muriel Oncotarget Protein arginine methylation is a common post-translational modification involved in numerous cellular processes including transcription, DNA repair, mRNA splicing and signal transduction. Currently, there are nine known members of the protein arginine methyltransferase (PRMT) family, but only one arginine demethylase has been identified, namely the Jumonji domain-containing 6 (JMJD6). Although its demethylase activity was initially challenged, its dual activity as an arginine demethylase and a lysine hydroxylase is now recognized. Interestingly, a growing number of substrates for arginine methylation and demethylation play key roles in tumorigenesis. Though alterations in the sequence of these enzymes have not been identified in cancer, their overexpression is associated with various cancers, suggesting that they could constitute targets for therapeutic strategies. In this review, we present the recent knowledge of the involvement of PRMTs and JMJD6 in tumorigenesis. 10.18632/oncotarget.11376
    Mathematical modeling of tumor-induced immunosuppression by myeloid-derived suppressor cells: Implications for therapeutic targeting strategies. Shariatpanahi Seyed Peyman,Shariatpanahi Seyed Pooya,Madjidzadeh Keivan,Hassan Moustapha,Abedi-Valugerdi Manuchehr Journal of theoretical biology Myeloid-derived suppressor cells (MDSCs) belong to immature myeloid cells that are generated and accumulated during the tumor development. MDSCs strongly suppress the anti-tumor immunity and provide conditions for tumor progression and metastasis. In this study, we present a mathematical model based on ordinary differential equations (ODE) to describe tumor-induced immunosuppression caused by MDSCs. The model consists of four equations and incorporates tumor cells, cytotoxic T cells (CTLs), natural killer (NK) cells and MDSCs. We also provide simulation models that evaluate or predict the effects of anti-MDSC drugs (e.g., l-arginine and 5-Fluorouracil (5-FU)) on the tumor growth and the restoration of anti-tumor immunity. The simulated results obtained using our model were in good agreement with the corresponding experimental findings on the expansion of splenic MDSCs, immunosuppressive effects of these cells at the tumor site and effectiveness of l-arginine and 5-FU on the re-establishment of antitumor immunity. Regarding this latter issue, our predictive simulation results demonstrated that intermittent therapy with low-dose 5-FU alone could eradicate the tumors irrespective of their origins and types. Furthermore, at the time of tumor eradication, the number of CTLs prevailed over that of cancer cells and the number of splenic MDSCs returned to the normal levels. Finally, our predictive simulation results also showed that the addition of l-arginine supplementation to the intermittent 5-FU therapy reduced the time of the tumor eradication and the number of iterations for 5-FU treatment. Thus, the present mathematical model provides important implications for designing new therapeutic strategies that aim to restore antitumor immunity by targeting MDSCs. 10.1016/j.jtbi.2018.01.006
    Elevated expression of protein arginine methyltransferase 5 predicts the poor prognosis of breast cancer. Wu Ying,Wang Zhe,Zhang Jian,Ling Rui Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine Protein arginine methyltransferase 5 is one of the type II protein arginine methyltransferase family members that can symmetrically dimethylate arginine residues on target proteins in both the cytoplasm and the nucleus. Protein arginine methyltransferase 5 was reported to be an oncoprotein that participates in tumor progression through both epigenetic silencing and organelle biogenesis. So far, it has been implicated in various cancers, but its expression pattern in breast cancer has not been elucidated thoroughly. We analyzed the protein arginine methyltransferase 5 expression patterns in several breast cancer samples and tissue arrays to better characterize its contribution to breast cancer. Primary breast tumors showed increased protein arginine methyltransferase 5 expression compared with adjacent normal tissues in both the fresh tissue samples and tissue arrays. Also, there was a tendency that metastatic lymph nodes demonstrated enhanced protein arginine methyltransferase 5 expression compared to primary sites. Moreover, we found a significant correlation between protein arginine methyltransferase 5 and Ki-67, with higher Ki-67 and protein arginine methyltransferase 5 expressions in primary breast tumors compared with normal breast tissues. Moreover, the Cancer Genome Atlas cohort analysis revealed that high protein arginine methyltransferase 5 messenger RNA expression was associated with an unfavorable prognosis in human epidermal growth factor receptor 2 (HER-2) positive and triple negative breast cancer patients. Finally, the roles and mechanisms of protein arginine methyltransferase 5 in the proliferation, cell cycle progression, and apoptosis of MDA-MB-231 cells were assessed using protein arginine methyltransferase 5 and shPRMT5 transfection. In conclusion, we proposed that protein arginine methyltransferase 5 is an independent prognostic biomarker for breast cancer, and targeting protein arginine methyltransferase 5 might be a promising strategy for breast cancer treatment. 10.1177/1010428317695917
    Reduced arginine availability and nitric oxide synthesis in cancer is related to impaired endogenous arginine synthesis. Engelen Mariëlle P K J,Safar Ahmed M,Bartter Thaddeus,Koeman Fari,Deutz Nicolaas E P Clinical science (London, England : 1979) Reduced plasma arginine (ARG) concentrations are found in various types of cancer. ARG and its product nitric oxide (NO) are important mediators in the immune function and the defense against tumour cells. It remains unclear whether the diminished systemic ARG availability in cancer is related to insufficient endogenous ARG synthesis, negatively affecting NO synthesis, and whether a dietary amino acid mixture is able to restore this. In 13 patients with advanced non-small cell lung cancer (NSCLC) and 11 healthy controls, whole body ARG and CIT (citrulline) rates of appearance were measured by stable isotope methodology before and after intake of a mixture of amino acids as present in whey protein. The conversions of CIT to ARG (indicator of de novo ARG synthesis) and ARG to CIT (marker of NO synthesis), and ARG clearance (reflecting ARG disposal capacity) were calculated. Plasma isotopic enrichments and amino acid concentrations were measured by LC-MS/MS. Conversions of CIT to ARG and ARG to CIT (P<0.05), and CIT rate of appearance (P=0.07) were lower in NSCLC. ARG rate of appearance and clearance were comparable suggesting no enhanced systemic ARG production and disposal capacity in NSCLC. After intake of the mixture, ARG rate of appearance and concentration increased (P<0.001), and ARG to CIT conversion was restored in NSCLC. In conclusion, an impaired endogenous ARG synthesis plays a role in the reduced systemic ARG availability and NO synthesis in advanced NSCLC. Nutritional approaches may restore systemic ARG availability and NO synthesis in cancer, but the clinical implication remains unclear. 10.1042/CS20160233
    Arginine Starvation and Docetaxel Induce c-Myc-Driven hENT1 Surface Expression to Overcome Gemcitabine Resistance in ASS1-Negative Tumors. Prudner Bethany C,Rathore Richa,Robinson Anthony M,Godec Abigail,Chang Samuel F,Hawkins William G,Hirbe Angela C,Van Tine Brian A Clinical cancer research : an official journal of the American Association for Cancer Research PURPOSE:The response to acute and long-term arginine starvation results in a conditional adaptive metabolic reprogramming that can be harnessed for therapeutic opportunities in ASS1-negative tumors. Here, we investigate the underlying biology of priming ASS1 tumors with arginine deiminase (ADI-PEG20) before treatment with gemcitabine (GEM) and docetaxel (DTX) in sarcoma, pancreatic cancer, and melanoma cell lines. EXPERIMENTAL DESIGN:ASS1 tumor cell lines were treated to create LTAT (long-term ADI treated) cell lines (ASS1) and used for drug combination studies. Protein expression of ASS1, dCK, RRM2, E2F1, c-MYC, and hENT1 was measured. c-MYC activity was determined, live-cell immunofluorescent studies for hENT1, uptake assays of FITC-cytosine probe, and rescue studies with a c-MYC inhibitor were all determined in the presence or absence of the ADI-PEG20:GEM:DTX. RESULTS:In examining modulations within the pyrimidine pathway, we identified that the addition of DTX to cells treated with ADI-PEG20 resulted in translocation of stabilized c-Myc to the nucleus. This resulted in an increase of hENT1 cell-surface expression and rendered the cells susceptible to GEM. studies demonstrate that the combination of ADI-PEG20:GEM:DTX was optimal for tumor growth inhibition, providing the preclinical mechanism and justification for the ongoing clinical trial of ADI-PEG20, GEM, and DTX in sarcoma. CONCLUSIONS:The priming of tumors with ADI-PEG20 and DTX results in the stabilization of c-MYC potentiating the effect of GEM treatment via an increase in hENT1 expression. This finding is applicable to ASS1-deficient cancers that are currently treated with GEM. 10.1158/1078-0432.CCR-19-0206
    Arginine Deprivation With Pegylated Arginine Deiminase in Patients With Argininosuccinate Synthetase 1-Deficient Malignant Pleural Mesothelioma: A Randomized Clinical Trial. Szlosarek Peter W,Steele Jeremy P,Nolan Luke,Gilligan David,Taylor Paul,Spicer James,Lind Michael,Mitra Sankhasuvra,Shamash Jonathan,Phillips Melissa M,Luong Phuong,Payne Sarah,Hillman Paul,Ellis Stephen,Szyszko Teresa,Dancey Gairin,Butcher Lee,Beck Stephan,Avril Norbert E,Thomson Jim,Johnston Amanda,Tomsa Marianne,Lawrence Cheryl,Schmid Peter,Crook Timothy,Wu Bor-Wen,Bomalaski John S,Lemoine Nicholas,Sheaff Michael T,Rudd Robin M,Fennell Dean,Hackshaw Allan JAMA oncology Importance:Preclinical studies show that arginine deprivation is synthetically lethal in argininosuccinate synthetase 1 (ASS1)-negative cancers, including mesothelioma. The role of the arginine-lowering agent pegylated arginine deiminase (ADI-PEG20) has not been evaluated in a randomized and biomarker-driven study among patients with cancer. Objective:To assess the clinical impact of arginine depletion in patients with ASS1-deficient malignant pleural mesothelioma. Design, Setting, and Participants:A multicenter phase 2 randomized clinical trial, the Arginine Deiminase and Mesothelioma (ADAM) study, was conducted between March 2, 2011, and May 21, 2013, at 8 academic cancer centers. Immunohistochemical screening of 201 patients (2011-2013) identified 68 with advanced ASS1-deficient malignant pleural mesothelioma. Interventions:Randomization 2:1 to arginine deprivation (ADI-PEG20, 36.8 mg/m2, weekly intramuscular) plus best supportive care (BSC) or BSC alone. Main Outcomes and Measures:The primary end point was progression-free survival (PFS) assessed by modified Response Evaluation Criteria in Solid Tumors (RECIST) (target hazard ratio, 0.60). Secondary end points were overall survival (OS), tumor response rate, safety, and quality of life, analyzed by intention to treat. We measured plasma arginine and citrulline levels, anti-ADI-PEG20 antibody titer, ASS1 methylation status, and metabolic response by 18F-fluorodeoxyglucose positron-emission tomography. Results:Median (range) follow-up in 68 adults (median [range] age, 66 [48-83] years; 19% female) was 38 (2.5-39) months. The PFS hazard ratio was 0.56 (95% CI, 0.33-0.96), with a median of 3.2 months in the ADI-PEG20 group vs 2.0 months in the BSC group (P = .03) (absolute risk, 18% vs 0% at 6 months). Best response at 4 months (modified RECIST) was stable disease: 12 of 23 (52%) in the ADI-PEG20 group vs 2 of 9 (22%) in the BSC group (P = .23). The OS curves crossed, so life expectancy was used: 15.7 months in the ADI-PEG20 group vs 12.1 months in the BSC group (difference of 3.6 [95% CI, -1.0 to 8.1] months; P = .13). The incidence of symptomatic adverse events of grade at least 3 was 11 of 44 (25%) in the ADI-PEG20 group vs 4 of 24 (17%) in the BSC group (P = .43), the most common being immune related, nonfebrile neutropenia, gastrointestinal events, and fatigue. Differential ASS1 gene-body methylation correlated with ASS1 immunohistochemistry, and longer arginine deprivation correlated with improved PFS. Conclusions and Relevance:In this trial, arginine deprivation with ADI-PEG20 improved PFS in patients with ASS1-deficient mesothelioma. Targeting arginine is safe and warrants further clinical investigation in arginine-dependent cancers. Trial Registration:clinicaltrials.gov Identifier: NCT01279967. 10.1001/jamaoncol.2016.3049
    l-arginine and docetaxel synergistically enhance anti-tumor immunity by modifying the immune status of tumor-bearing mice. Cao Yu,Wang Qinghui,Du Yunting,Liu Fei,Zhang Yanjun,Feng Yonghui,Jin Feng International immunopharmacology l-arginine (l-Arg) supplementation has been reported to enhance the function of immune cells, including dendritic cells (DCs) and T lymphocytes, in cancer models thereby countering the suppressive effects of myeloid-derived suppressor cells (MDSCs). The balance of the active immune cells is one factor that determines the progression of cancers in vivo. Docetaxel (DTX), an immunomodulatory chemotherapeutic agent, is now widely used in several types of malignancies including breast cancer. We hypothesized that the combination of DTX and l-Arg would elicit a more robust antitumor response than either molecule alone. To test this hypothesis we utilized BALB/c mice inoculated with 4T1 mammary carcinoma cells. DTX and l-Arg synergistically limited tumor growth in vivo and moderately increased the life span of tumor bearing mice. The anti-tumor effects were associated with the proliferation of splenic CD8(+) CTL and CD4(+) Th1 effector cells, as well as increased serum levels of interferon gamma. More importantly, DTX+l-Arg effectively increased anti-tumor immunity within the tumor microenvironment. Furthermore, the combined therapy increased the number of myeloid (mDCs) and plasmacytoid (pDCs) dendritic cells, potent activators of the T cell response, and enhanced expression of the maturation markers CD86 and MHC II (required for antigen presentation). The combination therapy also reduced the proliferation of MDSCs. These data suggest that DTX+l-Arg may be a novel therapeutic strategy for breast cancer patients. 10.1016/j.intimp.2016.03.002
    Identification of arginine and its "Downstream" molecules as potential markers of breast cancer. Hu Lu,Gao Yu,Cao Yunfeng,Zhang Yinxu,Xu Minghao,Wang Yuanyuan,Jing Yu,Guo Shengnan,Jing Fangyu,Hu Xiaodan,Zhu Zhitu IUBMB life Breast cancer (BC) is the most commonly diagnosed cancer in women worldwide. Arginine is a semiessential amino acid in humans and is essential for several biological pathways in malignant and normal cells, such as ornithine and N1, N12-diacetylspermine (DiAcSpm). This study aimed to determine the role of arginine and these downstream molecules in BC. Plasma arginine, ornithine, and arginine-to-ornithine ratio (AOR) were analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Urine samples were measured by the colloid gold aggregation to test determination of urinary diAcSpm. A principal component analysis was performed to evaluate the results observed between breast tumor and control characteristics. Differences in individual metabolite concentrations between BC patients and controls were tested by receiver operating characteristics (ROC) analyses. Student's t tests were used to detect the differences between two groups of normally distributed variables, and Wilcoxon sign rank tests were performed for asymmetrically distributed variables. As we analyzed, BC patients had lower plasma arginine and arginine/ornithine level, and higher plasma ornithine and urinary DiAcSpm concentrations as compared with control patients (P = 0.028, 0.020, 0.002, and 0.011, respectively). And the ROC curve was drawn and the area under the curve of the metabolites was calculated to be 0.659 (P = 0.028), 0.645 (P = 0.045), 0.7233 (P = 0.002), 0.683 (P = 0.011), respectively. In addition, our analysis showed that arginine concentrations and AOR had a positive correlation with ER status, while ornithine had a negative correlation with T stage (P = 0.042, 0.023, respectively).In conclusion, arginine and these downstream molecules were biomarkers for BC. More studies are needed to highlight the theoretical strengths. © 2016 IUBMB Life, 68(10):817-822, 2016. 10.1002/iub.1557
    Inhibition of arginase by CB-1158 blocks myeloid cell-mediated immune suppression in the tumor microenvironment. Steggerda Susanne M,Bennett Mark K,Chen Jason,Emberley Ethan,Huang Tony,Janes Julie R,Li Weiqun,MacKinnon Andrew L,Makkouk Amani,Marguier Gisele,Murray Peter J,Neou Silinda,Pan Alison,Parlati Francesco,Rodriguez Mirna L M,Van de Velde Lee-Ann,Wang Tracy,Works Melissa,Zhang Jing,Zhang Winter,Gross Matthew I Journal for immunotherapy of cancer BACKGROUND:Myeloid cells are an abundant leukocyte in many types of tumors and contribute to immune evasion. Expression of the enzyme arginase 1 (Arg1) is a defining feature of immunosuppressive myeloid cells and leads to depletion of L-arginine, a nutrient required for T cell and natural killer (NK) cell proliferation. Here we use CB-1158, a potent and orally-bioavailable small-molecule inhibitor of arginase, to investigate the role of Arg1 in regulating anti-tumor immunity. METHODS:CB-1158 was tested for the ability to block myeloid cell-mediated inhibition of T cell proliferation in vitro, and for tumor growth inhibition in syngeneic mouse models of cancer as a single agent and in combination with other therapies. Tumors from animals treated with CB-1158 were profiled for changes in immune cell subsets, expression of immune-related genes, and cytokines. Human tumor tissue microarrays were probed for Arg1 expression by immunohistochemistry and immunofluorescence. Cancer patient plasma samples were assessed for Arg1 protein and L-arginine by ELISA and mass spectrometry, respectively. RESULTS:CB-1158 blocked myeloid cell-mediated suppression of T cell proliferation in vitro and reduced tumor growth in multiple mouse models of cancer, as a single agent and in combination with checkpoint blockade, adoptive T cell therapy, adoptive NK cell therapy, and the chemotherapy agent gemcitabine. Profiling of the tumor microenvironment revealed that CB-1158 increased tumor-infiltrating CD8 T cells and NK cells, inflammatory cytokines, and expression of interferon-inducible genes. Patient tumor samples from multiple histologies expressed an abundance of tumor-infiltrating Arg1 myeloid cells. Plasma samples from cancer patients exhibited elevated Arg1 and reduced L-arginine compared to healthy volunteers. CONCLUSIONS:These results demonstrate that Arg1 is a key mediator of immune suppression and that inhibiting Arg1 with CB-1158 shifts the immune landscape toward a pro-inflammatory environment, blunting myeloid cell-mediated immune evasion and reducing tumor growth. Furthermore, our results suggest that arginase blockade by CB-1158 may be an effective therapy in multiple types of cancer and combining CB-1158 with standard-of-care chemotherapy or other immunotherapies may yield improved clinical responses. 10.1186/s40425-017-0308-4
    Metabolic relevance for N-hydroxy L-arginine reduction in estrogen-negative breast cancer cells. Mohan Srinidi,Patel Seema,Greenstein Ian,Ng Cathy,Frazier Kelly,Nguyen Giang,Harding Lisa,Barlow David Amino acids We had shown N-hydroxy-L-arginine (NOHA) as a promising blood-based biomarker for estrogen-receptor-negative (ER) breast cancer (BC) that differentiates ER BC based on grade and molecular phenotype. In this in vitro study, we assessed the metabolic relevance for ER BC-specific NOHA modulation and correlated them with NOHA regulatory responses. This study aids future NOHA clinical utility in ER BC diagnosis and therapy management and would prove useful for potential drug discovery and development process. 10.1007/s00726-018-2603-x
    A TGFβ-PRMT5-MEP50 axis regulates cancer cell invasion through histone H3 and H4 arginine methylation coupled transcriptional activation and repression. Chen H,Lorton B,Gupta V,Shechter D Oncogene Protein arginine methyltransferase 5 (PRMT5) complexed with MEP50/WDR77 catalyzes arginine methylation on histones and other proteins. PRMT5-MEP50 activity is elevated in cancer cells and its expression is highly correlated with poor prognosis in many human tumors. We demonstrate that PRMT5-MEP50 is essential for transcriptional regulation promoting cancer cell invasive phenotypes in lung adenocarcinoma, lung squamous cell carcinoma and breast carcinoma cancer cells. RNA-Seq transcriptome analysis demonstrated that PRMT5 and MEP50 are required to maintain expression of metastasis and Epithelial-to-mesenchymal transition (EMT) markers and to potentiate an epigenetic mechanism of the TGFβ response. We show that PRMT5-MEP50 activity both positively and negatively regulates expression of a wide range of genes. Exogenous TGFβ promotes EMT in a unique pathway of PRMT5-MEP50 catalyzed histone mono- and dimethylation of chromatin at key metastasis suppressor and EMT genes, defining a new mechanism regulating cancer invasivity. PRMT5 methylation of histone H3R2me1 induced transcriptional activation by recruitment of WDR5 and concomitant H3K4 methylation at targeted genes. In parallel, PRMT5 methylation of histone H4R3me2s suppressed transcription at distinct genomic loci. Our decoding of histone methylarginine at key genes supports a critical role for complementary PRMT5-MEP50 transcriptional activation and repression in cancer invasion pathways and in response to TGFβ stimulation and therefore orients future chemotherapeutic opportunities. 10.1038/onc.2016.205
    Molecular basis and current strategies of therapeutic arginine depletion for cancer. Fultang Livingstone,Vardon Ashley,De Santo Carmela,Mussai Francis International journal of cancer Renewed interest in the use of therapeutic enzymes combined with an improved knowledge of cancer cell metabolism, has led to the translation of several arginine depletion strategies into early phase clinical trials. Arginine auxotrophic tumors are reliant on extracellular arginine, due to the downregulation of arginosuccinate synthetase or ornithine transcarbamylase-key enzymes for intracellular arginine recycling. Engineered arginine catabolic enzymes such as recombinant human arginase (rh-Arg1-PEG) and arginine deiminase (ADI-PEG) have demonstrated cytotoxicity against arginine auxotrophic tumors. In this review, we discuss the molecular events triggered by extracellular arginine depletion that contribute to tumor cell death. 10.1002/ijc.30051
    MYC-Driven Small-Cell Lung Cancer is Metabolically Distinct and Vulnerable to Arginine Depletion. Chalishazar Milind D,Wait Sarah J,Huang Fang,Ireland Abbie S,Mukhopadhyay Anandaroop,Lee Younjee,Schuman Sophia S,Guthrie Matthew R,Berrett Kristofer C,Vahrenkamp Jeffery M,Hu Zeping,Kudla Marek,Modzelewska Katarzyna,Wang Guoying,Ingolia Nicholas T,Gertz Jason,Lum David H,Cosulich Sabina C,Bomalaski John S,DeBerardinis Ralph J,Oliver Trudy G Clinical cancer research : an official journal of the American Association for Cancer Research PURPOSE:Small-cell lung cancer (SCLC) has been treated clinically as a homogeneous disease, but recent discoveries suggest that SCLC is heterogeneous. Whether metabolic differences exist among SCLC subtypes is largely unexplored. In this study, we aimed to determine whether metabolic vulnerabilities exist between SCLC subtypes that can be therapeutically exploited. EXPERIMENTAL DESIGN:We performed steady state metabolomics on tumors isolated from distinct genetically engineered mouse models (GEMM) representing the MYC- and MYCL-driven subtypes of SCLC. Using genetic and pharmacologic approaches, we validated our findings in chemo-naïve and -resistant human SCLC cell lines, multiple GEMMs, four human cell line xenografts, and four newly derived PDX models. RESULTS:We discover that SCLC subtypes driven by different MYC family members have distinct metabolic profiles. MYC-driven SCLC preferentially depends on arginine-regulated pathways including polyamine biosynthesis and mTOR pathway activation. Chemo-resistant SCLC cells exhibit increased MYC expression and similar metabolic liabilities as chemo-naïve MYC-driven cells. Arginine depletion with pegylated arginine deiminase (ADI-PEG 20) dramatically suppresses tumor growth and promotes survival of mice specifically with MYC-driven tumors, including in GEMMs, human cell line xenografts, and a patient-derived xenograft from a relapsed patient. Finally, ADI-PEG 20 is significantly more effective than the standard-of-care chemotherapy. CONCLUSIONS:These data identify metabolic heterogeneity within SCLC and suggest arginine deprivation as a subtype-specific therapeutic vulnerability for MYC-driven SCLC. 10.1158/1078-0432.CCR-18-4140
    L-arginine/5-fluorouracil combination treatment approaches cells selectively: Rescuing endothelial cells while killing MDA-MB-468 breast cancer cells. Jahani Mozhgan,Azadbakht Mehri,Rasouli Hassan,Yarani Reza,Rezazadeh Davood,Salari Nader,Mansouri Kamran Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association Reducing the adverse effects of chemotherapy on normal cells such as endothelial cells is a determinant factor of treatment success especially in pregnant women. In this regard, modulatory effect of L-arginine on various cancers is still a controversial topic in cancer therapy. So, this study aimed to compare the effect of L-arginine treatment alone and in combination with 5-fluorouracil (5-FU) on the survival and angiogenesis of primary human umbilical vein endothelial cells (HUVECs) and the breast cancer cell line of MDA-MB-468. Combinations of L-arginine and 5-FU increased cell survival in HUVECs but induced cell death in MDA-MB-468 cells. Nitric oxide assay showed an increase of this molecule in both cell lines. Assessments of metabolic changes as well as molecular docking indicated a decrease in glycolytic activity of cancer cells but not normal cells. Angiogenesis induction in HUVECs was confirmed through VEGF and MMP-2,9 up-regulated gene expressions. However, a down-regulation of the above-mentioned genes expression was observed in MDA-MB-468. Furthermore, an in vivo increased angiogenesis and decreased embryo toxicity was observed in combination treatment. Altogether, these findings clearly suggest that L-arginine inhibits cell death induced by 5-FU in HUVECs through attenuating the adverse effects of 5-FU, while it does not do so in breast cancer cells. 10.1016/j.fct.2018.11.018
    Metabolic pathways of L-arginine and therapeutic consequences in tumors. Szefel Jarosław,Danielak Aleksandra,Kruszewski Wiesław Janusz Advances in medical sciences Difference in the metabolism of normal and cancer cells inspires to search for new, more specific and less toxic therapies than those currently used. The development of tumors is conditioned by genetic changes in cancer-transformed cells, immunological tolerance and immunosuppression. At the initial stages of carcinogenesis, the immune system shows anti-tumor activity, however later, cancer disrupts the function of Th1/Th17/Th2 lymphocytes by regulatory T (Treg) cells, tumor-associated macrophages (TAMs), and myeloid-derived suppressor cells (MDSCs) and finally causes immunosuppression. Recently, much attention has been devoted to the influence of l-arginine metabolism disorders on both carcinogenesis and the immune system. l-Arginine is essential for the maturation of the T cell receptor zeta (TCRζ), and its absence deprives T-cells of the ability to interact with tumor antigens. MDSCs deplete l-arginine due to a high expression of arginase 1 (ARG1) and their number increases 4-10 times depending on the type of the cancer. L-Arginine has been shown to be essential for the survival and progression of arginine auxotrophic tumors. However, the progression of arginine non-auxotrophic tumors is independent of exogenous l-arginine, because these tumors have arginine-succinate synthetase (ASS1) activity and are available to produce l-arginine from citrulline. Clinical studies have confirmed the high efficacy of arginine auxotrophic tumors therapy based on the elimination of l-arginine. However, l-arginine supplementation may improve the results of treatment of patients with arginine non-auxotrophic cancer. This review is an attempt to explain the seemingly contradictory results of oncological therapies based on the deprivation or supplementation of l-arginine. 10.1016/j.advms.2018.08.018
    Arginine-Depleting Enzymes - An Increasingly Recognized Treatment Strategy for Therapy-Refractory Malignancies. Riess Christin,Shokraie Fatemeh,Classen Carl Friedrich,Kreikemeyer Bernd,Fiedler Tomas,Junghanss Christian,Maletzki Claudia Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology Arginine auxotrophy occurs in certain tumor types and is usually caused by the silencing of argininosuccinate synthetase 1 or arginine lyase genes. Such tumors are often associated with an intrinsic chemoresistance and thus a poor prognosis. Arginine auxotrophy however renders these tumors vulnerable to treatment with arginine-degrading enzymes. Among the most frequently applied arginine-degrading agents are bacterial arginine deiminases (ADI). The anti-cancerous effects of ADI derived from different bacteria were extensively studied in numerous preclinical cell culture and xenograft models. Mycoplasma-derived ADI-PEG20 is most commonly used and is currently under clinical investigation as a single agent therapeutic as well as in combination with different antineoplastic compounds. Mechanistically, ADI is capable of reducing metabolic activity in tumor cells, contributing to autophagy, senescence and apoptosis in arginine auxotrophic cells. Although clinical trials are promising, the resistance development upon initial treatment response is an increasing challenge. Furthermore, interference of ADI with the tumor microenvironment is poorly understood. In the present review, we outline recent experimental ADI-based treatment approaches and their translation into the clinic. Furthermore, we summarize new insights into the molecular mechanisms underlying the anti-cancer effects of ADI that might facilitate the refinement of ADI-based combination therapy approaches. 10.1159/000495382
    Epigenetic arginine methylation in breast cancer: emerging therapeutic strategies. Wang Shu-Ching M,Dowhan Dennis H,Muscat George E O Journal of molecular endocrinology Breast cancer is a heterogeneous disease, and the complexity of breast carcinogenesis is associated with epigenetic modification. There are several major classes of epigenetic enzymes that regulate chromatin activity. This review will focus on the nine mammalian protein arginine methyltransferases (PRMTs) and the dysregulation of PRMT expression and function in breast cancer. This class of enzymes catalyse the mono- and (symmetric and asymmetric) di-methylation of arginine residues on histone and non-histone target proteins. PRMT signalling (and R methylation) drives cellular proliferation, cell invasion and metastasis, targeting (i) nuclear hormone receptor signalling, (ii) tumour suppressors, (iii) TGF-β and EMT signalling and (iv) alternative splicing and DNA/chromatin stability, influencing the clinical and survival outcomes in breast cancer. Emerging reports suggest that PRMTs are also implicated in the development of drug/endocrine resistance providing another prospective avenue for the treatment of hormone resistance and associated metastasis. The complexity of PRMT signalling is further underscored by the degree of alternative splicing and the scope of variant isoforms (with distinct properties) within each PRMT family member. The evolution of PRMT inhibitors, and the ongoing clinical trials of PRMT inhibitors against a subgroup of solid cancers, coupled to the track record of lysine methyltransferases inhibitors in phase I/II clinical trials against cancer underscores the potential therapeutic utility of targeting PRMT epigenetic enzymes to improve survival outcomes in aggressive and metastatic breast cancer. 10.1530/JME-18-0224
    Sensitivity of Colorectal Cancer to Arginine Deprivation Therapy is Shaped by Differential Expression of Urea Cycle Enzymes. Alexandrou Constantinos,Al-Aqbi Saif Sattar,Higgins Jennifer A,Boyle William,Karmokar Ankur,Andreadi Catherine,Luo Jin-Li,Moore David A,Viskaduraki Maria,Blades Matthew,Murray Graeme I,Howells Lynne M,Thomas Anne,Brown Karen,Cheng Paul N,Rufini Alessandro Scientific reports Tumors deficient in the urea cycle enzymes argininosuccinate synthase-1 (ASS1) and ornithine transcarbamylase (OTC) are unable to synthesize arginine and can be targeted using arginine-deprivation therapy. Here, we show that colorectal cancers (CRCs) display negligible expression of OTC and, in subset of cases, ASS1 proteins. CRC cells fail to grow in arginine-free medium and dietary arginine deprivation slows growth of cancer cells implanted into immunocompromised mice. Moreover, we report that clinically-formulated arginine-degrading enzymes are effective anticancer drugs in CRC. Pegylated arginine deiminase (ADI-PEG20), which degrades arginine to citrulline and ammonia, affects growth of ASS1-negative cells, whereas recombinant human arginase-1 (rhArg1peg5000), which degrades arginine into urea and ornithine, is effective against a broad spectrum of OTC-negative CRC cell lines. This reflects the inability of CRC cells to recycle citrulline and ornithine into the urea cycle. Finally, we show that arginase antagonizes chemotherapeutic drugs oxaliplatin and 5-fluorouracil (5-FU), whereas ADI-PEG20 synergizes with oxaliplatin in ASS1-negative cell lines and appears to interact with 5-fluorouracil independently of ASS1 status. Overall, we conclude that CRC is amenable to arginine-deprivation therapy, but we warrant caution when combining arginine deprivation with standard chemotherapy. 10.1038/s41598-018-30591-7
    Exploiting Arginine Auxotrophy with Pegylated Arginine Deiminase (ADI-PEG20) to Sensitize Pancreatic Cancer to Radiotherapy via Metabolic Dysregulation. Singh Pankaj K,Deorukhkar Amit A,Venkatesulu Bhanu P,Li Xiaolin,Tailor Ramesh,Bomalaski John S,Krishnan Sunil Molecular cancer therapeutics Distinct metabolic vulnerabilities of cancer cells compared with normal cells can potentially be exploited for therapeutic targeting. Deficiency of argininosuccinate synthetase-1 (ASS1) in pancreatic cancers creates auxotrophy for the semiessential amino acid arginine. We explored the therapeutic potential of depleting exogenous arginine via pegylated arginine deiminase (ADI-PEG20) treatment as an adjunct to radiotherapy. We evaluated the efficacy of treatment of human pancreatic cancer cell lines and xenografts with ADI-PEG20 and radiation via clonogenic assays and tumor growth delay experiments. We also investigated potential mechanisms of action using reverse-phase protein array, Western blotting, and IHC and immunofluorescence staining. ADI-PEG20 potently radiosensitized ASS1-deficient pancreatic cancer cells (MiaPaCa-2, Panc-1, AsPc-1, HPAC, and CaPan-1), but not ASS1-expressing cell lines (Bxpc3, L3.6pl, and SW1990). Reverse phase protein array studies confirmed increased expression of proteins related to endoplasmic reticulum (ER) stress and apoptosis, which were confirmed by Western blot analysis. Inhibition of ER stress signaling with 4-phenylbutyrate abrogated the expression of ER stress proteins and reversed radiosensitization by ADI-PEG20. Independent studies in two xenograft models confirmed significant tumor growth delays, which were associated with enhanced expression of ER stress proteins and apoptosis markers and reduced expression of proliferation and angiogenesis markers. ADI-PEG20 augmented the effects of radiation by triggering the ER stress pathway, leading to apoptosis in pancreatic tumor cells. 10.1158/1535-7163.MCT-18-0708
    Arginine-Nitric Oxide Metabolites and Cardiac Dysfunction in Patients With Breast Cancer. Finkelman Brian S,Putt Mary,Wang Teresa,Wang Le,Narayan Hari,Domchek Susan,DeMichele Angela,Fox Kevin,Matro Jennifer,Shah Payal,Clark Amy,Bradbury Angela,Narayan Vivek,Carver Joseph R,Tang W H Wilson,Ky Bonnie Journal of the American College of Cardiology BACKGROUND:Oxidative/nitrosative stress and endothelial dysfunction are hypothesized to be central to cancer therapeutics-related cardiac dysfunction (CTRCD). However, the relationship between circulating arginine-nitric oxide (NO) metabolites and CTRCD remains unstudied. OBJECTIVES:This study sought to examine the relationship between arginine-NO metabolites and CTRCD in a prospective cohort of 170 breast cancer patients treated with doxorubicin with or without trastuzumab. METHODS:Plasma levels of arginine, citrulline, ornithine, asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), and N-monomethylarginine (MMA) were quantified at baseline, 1 month, and 2 months after doxorubicin initiation. Determinants of baseline biomarker levels were identified using multivariable linear regression, and Cox regression defined the association between baseline levels and 1- or 2-month biomarker changes and CTRCD rate in 139 participants with quantitated echocardiograms at all time points. RESULTS:Age, hypertension, body mass index, and African-American race were independently associated with ≥1 of baseline citrulline, ADMA, SDMA, and MMA levels. Decreases in arginine and citrulline and increases in ADMA were observed at 1 and 2 months (all p < 0.05). Overall, 32 participants experienced CTRCD over a maximum follow-up of 5.4 years. Hazard ratios for ADMA and MMA at 2 months were 3.33 (95% confidence interval [CI]: 1.12 to 9.96) and 2.70 (95% CI: 1.35 to 5.41), respectively, and 0.78 (95% CI: 0.64 to 0.97) for arginine at 1 month. CONCLUSIONS:In breast cancer patients undergoing doxorubicin therapy, early alterations in arginine-NO metabolite levels occurred, and early biomarker changes were associated with a greater CTRCD rate. Our findings highlight the potential mechanistic and translational relevance of this pathway to CTRCD. 10.1016/j.jacc.2017.05.019
    Perspectives on the Therapeutic Benefits of Arginine Supplementation in Cancer Treatment. Beal Fabiani L R,Beal Pedro R,Beal Juliana R,Carvalho-Neves Natan,Franco Octávio L,Silva Osmar N Endocrine, metabolic & immune disorders drug targets BACKGROUND:Arginine is considered a semi-essential amino acid in healthy adults and the elderly. This amino acid seems to improve the immune system, stimulate cell growth and differentiation, and increase endothelial permeability, among other effects. For those reasons, it has been theorized that arginine supplementation may be used as an adjuvant to conventional cancer therapy treatments. OBJECTIVE:This review aims to evaluate the existing knowledge of the scientific community on arginine supplementation in order to improve the efficacy of current cancer treatment. RESULTS:Despite the continued efforts of science to improve treatment strategies, cancer remains one of the greatest causes of death on the planet in adults and elderly people. Chemo and radiotherapy are still the most effective treatments but at the cost of significant side effects. CONCLUSION:Thus, new therapeutic perspectives have been studied in recent years, to be used in addition to traditional treatments or not, seeking to treat or even cure the various types of cancer with fewer side effects. 10.2174/1871530319666190116121451
    Mutations in Cancer Cause Gain of Cysteine, Histidine, and Tryptophan at the Expense of a Net Loss of Arginine on the Proteome Level. Tsuber Viktoriia,Kadamov Yunus,Brautigam Lars,Berglund Ulrika Warpman,Helleday Thomas Biomolecules Accumulation of somatic mutations is critical for the transition of a normal cell to become cancerous. Mutations cause amino acid substitutions that change properties of proteins. However, it has not been studied as to what extent the composition and accordingly chemical properties of the cell proteome is altered as a result of the increased mutation load in cancer. Here, we analyzed data on amino acid substitutions caused by mutations in about 2000 protein coding genes from the Cancer Cell Line Encyclopedia that contains information on nucleotide and amino acid alterations in 782 cancer cell lines, and validated the analysis with information on amino acid substitutions for the same set of proteins in the Catalogue of Somatic Mutations in Cancer (COSMIC; v78) in circa 18,000 tumor samples. We found that nonsynonymous single nucleotide substitutions in the analyzed proteome subset ultimately result in a net gain of cysteine, histidine, and tryptophan at the expense of a net loss of arginine The extraordinary loss of arginine may be attributed to some extent to composition of its codons as well as to the importance of arginine in the functioning of prominent tumor suppressor proteins like p53. 10.3390/biom7030049
    Arginine: Challenges and opportunities of this two-faced molecule in cancer therapy. Jahani Mozhgan,Noroznezhad Fatemeh,Mansouri Kamran Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie Numerous antitumor therapies have been developed based on the differences in cells' metabolisms. Regarding the important role of arginine (Arg) in the regulation of multiple metabolic and signaling pathways, its deprivation has been proposed as a good strategy for tumor regression in tumors with defected Arg metabolic enzymes like argininosuccinate synthase 1 (ASS1). However, modulatory effect of Arg on various cancers is also a controversial issue. Therefore, this review article intends to address some of the challenges faced by Arg deprivation method as well as Arg administration for cancer therapy. 10.1016/j.biopha.2018.02.109
    Assessing N -hydroxy-L-arginine applicability as a novel ethnic specific estrogen-negative breast cancer marker. Mohan Srinidi,Greenstein Ian,Ng Cathy,Frazier Kelly,Nguyen Giang,Harding Lisa,Barlow David Amino acids In our prior study we identified N -hydroxy-L-arginine (NOHA) as a simple, yet sensitive indicator for estrogen negative (ER) breast cancer early-prognosis, but not estrogen positive (ER), and to offer ethnic selectivity for ER detection. However, the ability of NOHA to assess ER breast tumor based on disease progression, and tumor severity needs further delineation. Also, the overall NOHA storage stability needs to be validated. To assess the NOHA predictive capability based on disease progression, ER/ER 3D-spheroids (from breast tumor cell lines of human origin) were cultured for 10 weeks. We found only ER 3D-spheroid cultured for 10 weeks to show a gradual reduction in NOHA (both in culture medium and 3D-spheroid lysates) that correlated with a progressive increase in cellular NOS2 expression and NOS2 activity (measured as total nitrites). We additionally identified the NOHA-NOS2 correlation to be ethnically selective between ER African American versus ER Caucasian groups. Interestingly, such NOHA reduction was observed earlier in ER culture medium (viz., after week 1) than from ER 3D-spheroids lysates (viz., at the end of 3 weeks). When categorized based on 3D-spheroid grade, we found a ≥ 68% NOHA reduction in ER spheroids that were ≤ 3 weeks old, that was categorized as "low-grade" (based on tumor size ≤ 250 µm, and with cellular characteristics identical to healthy cells). A substantial reduction in NOHA of ≥ 87% occurred with ER 3D-spheroids grown for 6 weeks, which were categorized as "intermediate-grade" (with tumor size of ≥ 400 µm, and with less characteristic similarity to control spheroids). These in vitro findings thus suggest a distinct correlation between NOHA reduction and ER tumor grade. Such distinctive correlation between NOHA and ER tumor grade was additionally observed in de-identified clinical samples where a onefold higher reduction in NOHA occurred in grade-2 than with grade-1 de-identified patient plasma (when compared with control), and such correlation offered ethnic selectivity between ER African American and ER Caucasian groups. Of additional interest, when NOHA overall storage stability was assessed by incubating patient plasma and culture medium spiked with 75 pg/ml NOHA at multiple incubation temperatures and time-points, we found NOHA to maintain its stability for up to 6 weeks in culture medium and for 7 days in plasma at 4 °C and below. These results thus provide the first evidence of NOHA as a stable indicator to monitor ER disease progression and tumor severity in ethnically distinctive populations. 10.1007/s00726-017-2523-1
    Arginine and the metabolic regulation of nitric oxide synthesis in cancer. Keshet Rom,Erez Ayelet Disease models & mechanisms Nitric oxide (NO) is a signaling molecule that plays important roles in diverse biological processes and thus its dysregulation is involved in the pathogenesis of various disorders. In cancer, NO has broad and sometimes dichotomous roles; it is involved in cancer initiation and progression, but also restricts cancer proliferation and invasion, and contributes to the anti-tumor immune response. The importance of NO in a range of cellular processes is exemplified by its tight spatial and dosage control at multiple levels, including via its transcriptional, post-translational and metabolic regulation. In this Review, we focus on the regulation of NO via the synthesis and availability of its precursor, arginine, and discuss the implications of this metabolic regulation for cancer biology and therapy. Despite the established contribution of NO to cancer pathogenesis, the implementation of NO-related cancer therapeutics remains limited, likely due to the challenge of targeting and inducing its protective functions in a cell- and dosage-specific manner. A better understanding of how arginine regulates the production of NO in cancer might thus support the development of anti-cancer drugs that target this key metabolic pathway, and other metabolic pathways involved in NO production. 10.1242/dmm.033332
    Cytotoxicity of [HuArgI (co)-PEG5000]-induced arginine deprivation to ovarian Cancer cells is autophagy dependent. Nasreddine Ghenwa,El-Sibai Mirvat,Abi-Habib Ralph J Investigational new drugs In this study, we assess arginine auxotrophy in ovarian cancer cells and attempt to target them using arginine deprivation induced by a pegylated recombinant human Arginase I cobalt [HuArgI (Co)-PEG5000]. Ovarian cancer cells were sensitive to [HuArgI (Co)-PEG5000]-induced arginine deprivation with IC values in the low pM range. Addition of excess L-citrulline rescued only one of three cell lines tested, indicating that the majority of cell lines are completely auxotrophic for arginine. The expression pattern of argininosuccinate synthetase (ASS1) confirmed the degree of auxotrophy of ovarian cancer cell lines with completely auxotrophic cells not expressing ASS1 and partially auxotrophic cells expressing the enzyme. Ovarian cancer cell lines were negative for annexinV staining while showing loss of membrane integrity and absence of caspase activation, indicating caspase-independent, non-apoptotic cell death. [HuArgI (Co)-PEG5000]-induced arginine deprivation led to extensive and prolonged activation of autophagy, which proved to be deleterious to cell survival since its inhibition led to a significant decrease in cytotoxicity. This indicates that the activation of autophagy following arginine-deprivation, rather than being protective, mediates cell cytotoxicity leading to death by autophagy. 10.1007/s10637-019-00756-w
    Arginine deprivation inhibits pancreatic cancer cell migration, invasion and EMT via the down regulation of Snail, Slug, Twist, and MMP1/9. Wang Huan,Li Qing-Fang,Chow H Y,Choi S C,Leung Yun-Chung Journal of physiology and biochemistry Arginine deprivation is currently being evaluated for its efficacy and safety in clinical trials aimed at combating tumors. However, the cellular signaling and molecular changes in response to such deprivation have not been systematically deciphered. Here, we evaluate the effect of arginine deprivation on human pancreatic cancer cells, with respect to their migratory and invasive potentials and their ability to undergo epithelial-mesenchymal transition (EMT). The transcription factors Snail, Slug, and Twist are regulators of EMT, as indicated by the suppression of E-cadherin and other epithelial markers and adhesion molecules. Our data indicated that arginine starvation inhibited the migration and impaired the adhesion and invasion of the pancreatic cancer cells, decreased Snail, Slug, and Twist expression, and increased E-cadherin expression without altering the expression of vimentin. It is well known that matrix metalloproteinases (MMPs) are important for the events that underlie tumor dissemination. Arginine starvation inhibited the expression of MMP-1 and MMP-9. Furthermore, the PI3K/Akt pathway was altered when the pancreatic cancer cells underwent arginine deprivation as exhibited by the decreased Akt phosphorylation. Thus, these data reveal that arginine deprivation has the potential to decrease the metastatic ability of pancreatic cancer cells. 10.1007/s13105-019-00716-1
    Correction of arginine metabolism with sepiapterin-the precursor of nitric oxide synthase cofactor BH-induces immunostimulatory-shift of breast cancer. Zheng Xunzhen,Fernando Veani,Sharma Vandana,Walia Yashna,Letson Joshua,Furuta Saori Biochemical pharmacology Immunotherapy is a first-line treatment for many tumor types. However, most breast tumors are immuno-suppressive and only modestly respond to immunotherapy. We hypothesized that correcting arginine metabolism might improve the immunogenicity of breast tumors. We tested whether supplementing sepiapterin, the precursor of tetrahydrobiopterin (BH)-the nitric oxide synthase (NOS) cofactor-redirects arginine metabolism from the pathway synthesizing polyamines to that of synthesizing nitric oxide (NO) and make breast tumors more immunogenic. We showed that sepiapterin elevated NO but lowered polyamine levels in tumor cells, as well as in tumor-associated macrophages (TAMs). This not only suppressed tumor cell proliferation, but also induced the conversion of TAMs from the immuno-suppressive M2-type to immuno-stimulatory M1-type. Furthermore, sepiapterin abrogated the expression of a checkpoint ligand, PD-L1, in tumors in a STAT3-dependent manner. This is the first study which reveals that supplementing sepiapterin normalizes arginine metabolism, improves the immunogenicity and inhibits the growth of breast tumor cells. 10.1016/j.bcp.2020.113887
    Human Recombinant Arginase I [HuArgI (Co)-PEG5000]-Induced Arginine Depletion Inhibits Colorectal Cancer Cell Migration and Invasion. Al-Koussa Houssam,Al-Haddad Maria,Abi-Habib Ralph,El-Sibai Mirvat International journal of molecular sciences PURPOSE:Colorectal cancer (CRC) is the third most common type of cancer worldwide, and it represents over half of all gastrointestinal cancer deaths. Knowing that cancer cells have a high proliferation rate, they require high amounts of amino acids, including arginine. In addition, several tumor types have been shown to downregulate ASS-1 expression, becoming auxotrophic for arginine. Therefore, Arginine deprivation is one of the promising therapeutic approaches to target cancer cells. This can be achieved through the use of a recombinant human arginase, HuArgI(Co)-PEG5000, an arginine degrading enzyme. METHODS:In this present study, the cytotoxic effect of HuArgI(Co)-PEG5000 on CRC cell lines (HT-29, Caco-2, Sw837) is examined though cytotoxicity assays. Wound healing assays, invasion assays, and adhesion assays were also performed to detect the effect on metastasis. RESULTS:Wound healing and invasion assays revealed a decrease in cell migration and invasion after treatment with arginase. Cells that were treated with arginase also showed a decrease in adhesion, which coincided with a decrease in RhoA activation, demonstrated though the use of a FRET biosensor to detect RhoA activation in a single cell assay, and a decrease in MMP-9 expression. Treating cells with both arginase and L-citrulline, which significantly restores intracellular arginine levels, reversed the effect of HuArgI(Co)-PEG5000 on cell viability, migration, and invasion. CONCLUSION:We can, therefore, conclude that colorectal cancer is partially auxotrophic to arginine and that arginine depletion is a potential selective inhibitory approach for motility and invasion in colon cancer cells. 10.3390/ijms20236018
    Arginine metabolism and deprivation in cancer therapy. Zou Songyun,Wang Xiangmei,Liu Po,Ke Changneng,Xu Shi Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie Certain cancer cells with nutrient auxotrophy and have a much higher nutrient demand compared with normal human cells. Arginine as a versatile amino acid, has multiple biological functions in metabolic and signaling pathways. Depletion of this amino acid by arginine depletor is generally well tolerated and has become a targeted therapy for arginine auxotrophic cancers. However, the modulatory eff ;ect of arginine on cancer cells is very complicated and still controversial. Therefore, this article focuses on arginine metabolism and depletion therapy in cancer treatment to provide systemical review on this issue. 10.1016/j.biopha.2019.109210
    Starvation in cancer cells: circulating arginine is good for cancer but bad for patients. Sharma Nilesh Kumar,Sarode Sachin C,Sarode Gargi S,Patil Shankargouda Expert review of anticancer therapy : Currently, basic understanding of heterogeneity and complexity of tumors is depicted at molecular, cellular, genetic, epigenetic and metabolic adaptations levels. : There are appreciable numbers of views to pinpoint signaling axis that support metabolic adaptations of cancer cells in response to environmental pressures including nutritional factors and drug treatments. Specifically, nutritional deprivation and autophagy in certain types of cancer are linked to the abilities of cancer cells to use arginine in an auxotrophic or prototrophic manner. : Hence, this paper highlights the current scope of arginine- and autophagy-centered metabolic adaptations across tumor types and possible avenues to bring tumors towards cytotoxic or cytostatic death. 10.1080/14737140.2019.1620606
    The importance of plasma arginine level and its downstream metabolites in diagnosing prostate cancer. Selvi Ismail,Basar Halil,Baydilli Numan,Murat Koza,Kaymaz Ozlem International urology and nephrology PURPOSE:There is still no certain threshold value of prostate-specific antigen (PSA) for prostate cancer diagnosis. We aimed to investigate the predictive value of arginine and its metabolites for diagnosing prostate cancer in patients with PSA 4-10 ng/ml and evaluate their usefulness as prognostic tumor markers. METHODS:Seventy-eight patients with a mean age of 64.50 ± 5.49 years were included in our prospective observational study between November 2016 and March 2017. They were divided into two equal groups according to the pathologic results of prostate biopsy (benign vs. malignant). Plasma arginine and ornithine levels were analyzed before biopsy by liquid chromatography-tandem mass spectrometry. ELISA was used for analyzing urinary diacetylspermine. RESULTS:In PSA-adjusted analysis, the malignant group had lower plasma arginine levels (p = 0.021) and arginine to ornithine ratio (AOR) (p = 0.010), but higher plasma ornithine levels (p = 0.012) and urinary diacetylspermine levels (p < 0.001) as compared with the benign group. While arginine (r = - 0.628, p < 0.001) and AOR (r = - 0.714, p < 0.001) were negatively correlated with D'Amico clinical classification (p < 0.001), ornithine (r = 0.659, p < 0.001) and diacetylspermine (r = 0.710, p < 0.001) were found to be positively correlated (p < 0.001). In multivariate analysis, ornithine [OR 3.264, 95% CI (1.045-10.196), p = 0.042] and diacetylspermine [OR 6.982, 95% CI (2.403-20.290), p < 0.001] were found to be more significant in detection of prostate cancer. CONCLUSION:Plasma arginine, ornithine, AOR and urinary diacetylspermine levels may be used as molecular markers to predict prostate biopsy outcomes in patients with PSA 4-10 ng/ml. But according to our results, the use of ornithine and diacethylspermine prior to biopsy seems to be the most cost-effective diagnostic strategy. 10.1007/s11255-019-02261-8
    Alterations in arginine and energy metabolism, structural and signalling lipids in metastatic breast cancer in mice detected in plasma by targeted metabolomics and lipidomics. Kus Kamil,Kij Agnieszka,Zakrzewska Agnieszka,Jasztal Agnieszka,Stojak Marta,Walczak Maria,Chlopicki Stefan Breast cancer research : BCR BACKGROUND:The early detection of metastasis based on biomarkers in plasma may improve cancer prognosis and guide treatment. The aim of this work was to characterize alterations in metabolites of the arginine pathway, energy metabolism, and structural and signalling lipids in plasma in the early and late stages of murine breast cancer metastasis. METHODS:Mice were orthotopically inoculated with 4T1 metastatic breast cancer cells, and plasma was analysed along the pulmonary metastasis progression using LC-MS/MS-based targeted metabolomics and lipidomics. RESULTS:Based on primary tumour growth and pulmonary metastases, 1-2 weeks after 4T1 cancer cell inoculation was defined as an early metastatic stage, and 3-4 weeks after 4T1 cancer cell inoculation was defined as a late metastatic stage. Early metastasis was featured in plasma by a shift of L-arginine metabolism towards arginase (increased ornithine/arginine ratio) and polyamine synthesis (increased putrescine). Late metastasis was reflected in plasma by further progression of changes in the arginine pathway with an additional increase in asymmetric dimethylarginine plasma concentration, as well as by a profound energy metabolism reprogramming towards glycolysis, an accelerated pentose phosphate pathway and a concomitant decrease in tricarboxylic cycle rate ("Warburg effect"). The late but not the early phase of metastasis was also characterized by a different lipid profile pattern in plasma, including a decrease in total phosphatidylcholines, a decrease in diester-bound phospholipid fraction and an increase in lysophospholipids associated with an increase in total sphingomyelins. CONCLUSIONS:The early phase of metastasis in murine 4T1 metastatic breast cancer was associated with plasma metabolome changes characteristic of arginase activation and polyamine synthesis. The late metastasis was reflected in plasma not only by the alterations in arginine pathways but also by a shift towards glycolysis and the pentose pathway, remodelling of structural lipids and activation of lipid signalling, all of which coincided with metastasis progression. 10.1186/s13058-018-1075-y
    Autophagy maintains tumour growth through circulating arginine. Poillet-Perez Laura,Xie Xiaoqi,Zhan Le,Yang Yang,Sharp Daniel W,Hu Zhixian Sherrie,Su Xiaoyang,Maganti Anurag,Jiang Cherry,Lu Wenyun,Zheng Haiyan,Bosenberg Marcus W,Mehnert Janice M,Guo Jessie Yanxiang,Lattime Edmund,Rabinowitz Joshua D,White Eileen Nature Autophagy captures intracellular components and delivers them to lysosomes, where they are degraded and recycled to sustain metabolism and to enable survival during starvation. Acute, whole-body deletion of the essential autophagy gene Atg7 in adult mice causes a systemic metabolic defect that manifests as starvation intolerance and gradual loss of white adipose tissue, liver glycogen and muscle mass. Cancer cells also benefit from autophagy. Deletion of essential autophagy genes impairs the metabolism, proliferation, survival and malignancy of spontaneous tumours in models of autochthonous cancer. Acute, systemic deletion of Atg7 or acute, systemic expression of a dominant-negative ATG4b in mice induces greater regression of KRAS-driven cancers than does tumour-specific autophagy deletion, which suggests that host autophagy promotes tumour growth. Here we show that host-specific deletion of Atg7 impairs the growth of multiple allografted tumours, although not all tumour lines were sensitive to host autophagy status. Loss of autophagy in the host was associated with a reduction in circulating arginine, and the sensitive tumour cell lines were arginine auxotrophs owing to the lack of expression of the enzyme argininosuccinate synthase 1. Serum proteomic analysis identified the arginine-degrading enzyme arginase I (ARG1) in the circulation of Atg7-deficient hosts, and in vivo arginine metabolic tracing demonstrated that serum arginine was degraded to ornithine. ARG1 is predominantly expressed in the liver and can be released from hepatocytes into the circulation. Liver-specific deletion of Atg7 produced circulating ARG1, and reduced both serum arginine and tumour growth. Deletion of Atg5 in the host similarly regulated [corrected] circulating arginine and suppressed tumorigenesis, which demonstrates that this phenotype is specific to autophagy function rather than to deletion of Atg7. Dietary supplementation of Atg7-deficient hosts with arginine partially restored levels of circulating arginine and tumour growth. Thus, defective autophagy in the host leads to the release of ARG1 from the liver and the degradation of circulating arginine, which is essential for tumour growth; this identifies a metabolic vulnerability of cancer. 10.1038/s41586-018-0697-7
    The smell of death and deCYStiny: polyamines play the hero. Combs Joseph A,DeNicola Gina M Nature metabolism 10.1038/s42255-020-0260-3