title: Hypoxia-induced nitric oxide production and tumour perfusion is inhibited by pegylated arginine deiminase (ADI-PEG20).
abstract: 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.
authors.affiliation: School of Clinical Medicine, Cambridge Institute for Medical Research, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, United Kingdom.
authors.forename: Natalie
authors.initials: N
authors.lastname: Burrows
authors.affiliation: Metabolism and Experimental Therapeutics, Division of Medicine, University College London, 5 University Street, London, WC1E 6JF, United Kingdom.
authors.forename: Gaelle
authors.initials: G
authors.lastname: Cane
authors.affiliation: Tumour Biology Group, UCL Cancer Institute, University College London, London WC1E 6BT, United Kingdom.
authors.forename: Mathew
authors.initials: M
authors.lastname: Robson
authors.affiliation: MRC Cancer Unit, University of Cambridge, Hutchison/MRC Research Centre, Box 197, Cambridge Biomedical Campus, Cambridge, United Kingdom, CB2 0XZ.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Gaude
authors.affiliation: Histopathology/ISH, Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, United Kingdom.
authors.forename: William J
authors.initials: WJ
authors.lastname: Howat
authors.affiliation: Centre for Molecular Oncology, Barts Cancer Institute, Queen Mary University of London, London, EC1M 6BQ, United Kingdom.
authors.forename: Peter W
authors.initials: PW
authors.lastname: Szlosarek
authors.affiliation: Tumour Biology Group, UCL Cancer Institute, University College London, London WC1E 6BT, United Kingdom.
authors.forename: R Barbara
authors.initials: RB
authors.lastname: Pedley
authors.affiliation: MRC Cancer Unit, University of Cambridge, Hutchison/MRC Research Centre, Box 197, Cambridge Biomedical Campus, Cambridge, United Kingdom, CB2 0XZ.
authors.forename: Christian
authors.initials: C
authors.lastname: Frezza
authors.affiliation: Metabolism and Experimental Therapeutics, Division of Medicine, University College London, 5 University Street, London, WC1E 6JF, United Kingdom.
authors.forename: Margaret
authors.initials: M
authors.lastname: Ashcroft
authors.affiliation: School of Clinical Medicine, Cambridge Institute for Medical Research, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, United Kingdom.
authors.forename: Patrick H
authors.initials: PH
authors.lastname: Maxwell
mesh_terms: D000818:Animals; D001120:Arginine / Q000378:metabolism; D001124:Argininosuccinate Synthase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism; D015153:Blotting, Western; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D045325:HCT116 Cells; D006801:Humans; D006867:Hydrolases / Q000494:pharmacology*; D000860:Hypoxia; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D000076222:Mechanistic Target of Rapamycin Complex 1; D016513:Mice, SCID; D046912:Multiprotein Complexes / Q000378:metabolism; D009369:Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D010477:Perfusion; D011092:Polyethylene Glycols / Q000494:pharmacology*; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism; D047368:Tumor Burden / Q000187:drug effects; D056811:Unfolded Protein Response / Q000187:drug effects; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays; D000099162:Endothelial PAS Domain-Containing Protein 1
chemical_list: D001120:Arginine; D001124:Argininosuccinate Synthase; D051792:Basic Helix-Loop-Helix Proteins; D006867:Hydrolases; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D000076222:Mechanistic Target of Rapamycin Complex 1; D046912:Multiprotein Complexes; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D011092:Polyethylene Glycols; D058570:TOR Serine-Threonine Kinases; D042461:Vascular Endothelial Growth Factor A; D000099162:Endothelial PAS Domain-Containing Protein 1; C512527:ADI PEG20