Cancer metabolism: Addicted to serine.

Cancer cells are biosynthetic factories that gear multiple metabolic pathways toward cell growth and proliferation. Serine is the metabolite consumed third most by cancer cells, after glucose and glutamine, and is used as a building block for proteins and as a carbon donor for nucleotide biosynthesis. Serine can also be synthesized de novo from glucose (Fig. 1, left). Studies in the late 1980s demonstrated that de novo synthesis of serine is increased in cancer cells, suggesting that this pathway might be relevant for their growth. But it was not until the landmark discovery thatphosphoglycerate dehydrogenase (encoded by PHGDH), the first step of de novo serine synthesis, is genomically amplified in breast cancer and melanoma that this pathway came into the limelight. Importantly, silencing PHGDH in PHGDH-dependent cancers significantly affects their growth, making this enzyme an excellent target for cancer therapy. Recent work from Mullarky et al. reported the discovery of a novel noncompetitive inhibitor of PHGDH. However, although this compound was selective against PHGDH-dependent melanoma and breast cancer cell lines, it was unstable in mouse plasma, limiting its use in vivo. In this issue of Nature Chemical Biology, Pacold et al. report the discovery of small-molecule inhibitors of PHGDH that exhibit potent antitumor activity both in vitro an in vivo.This is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/nchembio.208

Fumarate drives EMT in renal cancer

Medical Research Counci

IL-10-Mediated Refueling of Exhausted T Cell Mitochondria Boosts Anti-Tumour Immunity.

Immunotherapy has underscored a revolution in cancer treatment. Yet, many patients fail to respond due to T cell exhaustion. Here, an intervention that restores mitochondrial function reversed the exhausted T cell phenotype to promote cytotoxicity and durable anti-tumour responses in vivo

Post-translational regulation of metabolism in fumarate hydratase deficient cancer cells.

Deregulated signal transduction and energy metabolism are hallmarks of cancer and both play a fundamental role in tumorigenesis. While it is increasingly recognised that signalling and metabolism are highly interconnected, the underpinning mechanisms of their co-regulation are still largely unknown. Here we designed and acquired proteomics, phosphoproteomics, and metabolomics experiments in fumarate hydratase (FH) deficient cells and developed a computational modelling approach to identify putative regulatory phosphorylation-sites of metabolic enzymes. We identified previously reported functionally relevant phosphosites and potentially novel regulatory residues in enzymes of the central carbon metabolism. In particular, we showed that pyruvate dehydrogenase (PDHA1) enzymatic activity is inhibited by increased phosphorylation in FH-deficient cells, restricting carbon entry from glucose to the tricarboxylic acid cycle. Moreover, we confirmed PDHA1 phosphorylation in human FH-deficient tumours. Our work provides a novel approach to investigate how post-translational modifications of enzymes regulate metabolism and could have important implications for understanding the metabolic transformation of FH-deficient cancers with potential clinical applications

Editorial: The Metabolic Challenges of Immune Cells in Health and Disease.

Copyright: © 2015 Frezza and Mauro. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.CM is supported by the British Heart Foundation Fellowship FS/12/38/29640. CF is funded by the UK Medical Research Council

Metabolic determinants of the immune modulatory function of neural stem cells.

BACKGROUND: Neural stem cells (NSCs) display tissue trophic and immune modulatory therapeutic activities after transplantation in central nervous system disorders. The intercellular interplay between stem cells and target immune cells is increased in NSCs exposed to inflammatory cues. Here, we hypothesize that inflammatory cytokine signalling leads to metabolic reprogramming of NSCs regulating some of their immune modulatory effects. METHODS: NSC lines were prepared from the subventricular zone (SVZ) of 7-12-week-old mice. Whole secretome-based screening and analysis of intracellular small metabolites was performed in NSCs exposed to cocktails of either Th1-like (IFN-γ, 500 U/ml; TNF-α, 200 U/ml; IL-1β, 100 U/ml) or Th2-like (IL-4, IL-5 and IL-13; 10 ng/ml) inflammatory cytokines for 16 h in vitro. Isotopologues distribution of arginine and downstream metabolites was assessed by liquid chromatography/mass spectrometry in NSCs incubated with U-(13)C6 L-arginine in the presence or absence of Th1 or Th2 cocktails (Th1 NSCs or Th2 NSCs). The expression of arginase I and II was investigated in vitro in Th1 NSCs and Th2 NSCs and in vivo in the SVZ of mice with experimental autoimmune encephalomyelitis, as prototypical model of Th1 cell-driven brain inflammatory disease. The effects of the inflammatory cytokine signalling were studied in NSC-lymph node cells (LNC) co-cultures by flow cytometry-based analysis of cell proliferation following pan-arginase inhibition with N(ω)-hydroxy-nor-arginine (nor-NOHA). RESULTS: Cytokine-primed NSCs showed significantly higher anti-proliferative effect in co-cultures vs. control NSCs. Metabolomic analysis of intracellular metabolites revealed alteration of arginine metabolism and increased extracellular arginase I activity in cytokine-primed NSCs. Arginase inhibition by nor-NOHA partly rescued the anti-proliferative effects of cytokine-primed NSCs. CONCLUSIONS: Our work underlines the use of metabolic profiling as hypothesis-generating tools that helps unravelling how stem cell-mediated mechanisms of tissue restoration become affected by local inflammatory responses. Among different therapeutic candidates, we identify arginase signalling as novel metabolic determinant of the NSC-to-immune system communication.This work has received support from the National Multiple Sclerosis Society (NMSS, partial grants RG-4001-A1), the Italian Multiple Sclerosis Association (AISM, grant 2010/R/31 and grant 2014/PMS/4), the Italian Ministry of Health (GR08-7), the European Research Council (ERC) under the ERC-2010-StG Grant agreement n° 260511-SEM_SEM and the UK Regenerative Medicine Platform Acellular hub (Partnership award RG69889) and core support grant from the Wellcome Trust and MRC to the Wellcome Trust–Medical Research Council Cambridge Stem Cell Institute. LPJ was supported by a Wellcome Trust Research Training Fellowship (RG79423).This is the final version of the article. It first appeared from BioMed Central via http://dx.doi.org/10.1186/s12974-016-0667-

Hypoxia-induced nitric oxide production and tumour perfusion is inhibited by pegylated arginine deiminase (ADI-PEG20).

The hypoxic tumour microenvironment represents an aggressive, therapy-resistant compartment. As arginine is required for specific hypoxia-induced processes, we hypothesised that arginine-deprivation therapy may be useful in targeting hypoxic cancer cells. We explored the effects of the arginine-degrading agent ADI-PEG20 on hypoxia-inducible factor (HIF) activation, the hypoxia-induced nitric oxide (NO) pathway and proliferation using HCT116 and UMUC3 cells and xenografts. The latter lack argininosuccinate synthetase (ASS1) making them auxotrophic for arginine. In HCT116 cells, ADI-PEG20 inhibited hypoxic-activation of HIF-1α and HIF-2α, leading to decreased inducible-nitric oxide synthase (iNOS), NO-production, and VEGF. Interestingly, combining hypoxia and ADI-PEG20 synergistically inhibited ASS1. ADI-PEG20 inhibited mTORC1 and activated the unfolded protein response providing a mechanism for inhibition of HIF and ASS1. ADI-PEG20 inhibited tumour growth, impaired hypoxia-associated NO-production, and decreased vascular perfusion. Expression of HIF-1α/HIF-2α/iNOS and VEGF were reduced, despite an increased hypoxic tumour fraction. Similar effects were observed in UMUC3 xenografts. In summary, ADI-PEG20 inhibits HIF-activated processes in two tumour models with widely different arginine biology. Thus, ADI-PEG20 may be useful in the clinic to target therapy-resistant hypoxic cells in ASS1-proficient tumours and ASS1-deficient tumours.Thanks to Dr John Bomalaski, (Polaris Pharmaceuticals, Inc) for supplying the ADI-PEG20, to Dr Simon S Hoer for useful discussions and to members of Histopathology/ISH (CRUK Cambridge Institute, UK) for IHC and imaging assistance. This work was supported by the Wellcome Trust and the NIHR Cambridge Biomedical Research Centre Senior Investigator Awards (to P.H.M., supporting N.B.), EU FP7 Metoxia Grant agreement no. 222741 (to P.H.M., supporting G.C.), UCL Cancer Research UK Centre (to M.R.), King’s College London and UCL Comprehensive Cancer Imaging Centre, Cancer Research UK and EPSRC in association with the Medical Research Council (MRC), the DoH (England: to R.B.P.), MRC Cancer Unit Core Funding (to C.F., supporting E.G.).This is the final version of the article. It first appeared from Nature Publishing Group via http://dx.doi.org/10.1038/srep2295

Mitochondrial DNA: the overlooked oncogenome?

Perturbed mitochondrial bioenergetics constitute a core pillar of cancer-associated metabolic dysfunction. While mitochondrial dysfunction in cancer may result from myriad biochemical causes, a historically neglected source is that of the mitochondrial genome. Recent large-scale sequencing efforts and clinical studies have highlighted the prevalence of mutations in mitochondrial DNA (mtDNA) in human tumours and their potential roles in cancer progression. In this review we discuss the biology of the mitochondrial genome, sources of mtDNA mutations, and experimental evidence of a role for mtDNA mutations in cancer. We also propose a 'metabolic licensing' model for mtDNA mutation-derived dysfunction in cancer initiation and progression

Inhibition of glucose-6-phosphate dehydrogenase sensitizes cisplatin-resistant cells to death.

The mechanisms of cisplatin resistance, one of the major limitations of current chemotherapy, has only partially been described. We previously demonstrated that cisplatin-resistant ovarian cancer cells (C13), are characterized by reduced mitochondrial activity and higher glucose-dependency when compared to the cisplatin-sensitive counterpart (2008). In this work we further characterized the role of metabolic transformation in cisplatin resistance. By using transmitochondrial hybrids we show that metabolic reprogramming of cisplatin-resistant cell is not caused by inherent mtDNA mutations. We also found that C13 cells not only present an increased glucose-uptake and consumption, but also exhibit increased expression and enzymatic activity of the Pentose Phosphate pathway (PPP) enzyme Glucose-6-Phosphate Dehydrogenase (G6PDH). Moreover, we show that cisplatin-resistant cells are more sensitive to G6PDH inhibition. Even if the metabolomic fingerprint of ovarian cancer cells remains to be further elucidated, these findings indicate that PPP offers innovative potential targets to overcome cisplatin resistance.This work was financially supported by PRAT (University of Padova), grant no. CPDA124517/12 and MIUR grant no 60A04–0443. DC fellowship was supported by grant no. CPDR134012. AR was supported by the AIRC grant no. IG 15863 and by the University of Padova grant no. CPDA 123598.This is the final version of the article. It first appeared from Impact Journals via http://dx.doi.org/10.18632/oncotarget.494

Immunohistochemistry as a tool for screening rare renal cancers

Recent additions of succinate dehydrogenase (SDH) and (Hereditary Leiomyomatosis and Renal Cell Cancer, HLRCC, associated) fumarate hydratase (FH)-deficient renal cell carcinomas (RCC) to the 2016 WHO Classification of Renal Tumours (1) have highlighted an evolving need for the distinction between renal cancer subtypes. Differences in molecular characterisation, clinical phenotypes, and therapeutic responses (1-3) further corroborates this paradigm shift and strongly points towards the development of subtype-specific management (3). SDH and FH-deficient RCCs are rare tumours strongly associated with hereditary neoplastic syndromes and early-onset(2, 4, 5). FH-deficient RCCs are highly aggressive tumours associated with poor patient prognosis(2, 3, 6), whereas SDH-deficient RCCs are phenotypically more variable, but alsoThis work was supported by the Wellcome Trust (to C Yong), The Urology Foundation (to C Yong), and by the Medical Research Council (to C Frezza) (MRC_MC_UU_12022/6)