Myeloid cells comprise a major component of the tumor microenvironment (TME) that promotes tumor growth and immune evasion. By employing a small-molecule inhibitor of glutamine metabolism, not only were we able to inhibit tumor growth, but we markedly inhibited the generation and recruitment of myeloid-derived suppressor cells (MDSCs). Targeting tumor glutamine metabolism led to a decrease in CSF3 and hence recruitment of MDSCs as well as immunogenic cell death, leading to an increase in inflammatory tumor-associated macrophages (TAMs). Alternatively, inhibiting glutamine metabolism of the MDSCs themselves led to activation-induced cell death and conversion of MDSCs to inflammatory macrophages. Surprisingly, blocking glutamine metabolism also inhibited IDO expression of both the tumor and myeloid-derived cells, leading to a marked decrease in kynurenine levels. This in turn inhibited the development of metastasis and further enhanced antitumor immunity. Indeed, targeting glutamine metabolism rendered checkpoint blockade-resistant tumors susceptible to immunotherapy. Overall, our studies define an intimate interplay between the unique metabolism of tumors and the metabolism of suppressive immune cells.

Bloomberg~Kimmel Institute for Cancer Immunotherapy Sidney Kimmel Comprehensive Cancer Research Center Department of Oncology and

Department of Medicine Johns Hopkins University School of Medicine Baltimore Maryland USA

Department of Neuroscience Johns Hopkins Drug Discovery Baltimore Maryland USA

Institute of Organic Chemistry and Biochemistry Prague Czech Republic

UPMC Enterprises Pittsburgh Pennsylvania USA

See more in PubMed

DeBerardinis RJ, Chandel NS. Fundamentals of cancer metabolism. Sci Adv. 2016;2(5):e1600200. doi: 10.1126/sciadv.1600200. PubMed DOI PMC

Pavlova NN, Thompson CB. The emerging hallmarks of cancer metabolism. Cell Metab. 2016;23(1):27–47. doi: 10.1016/j.cmet.2015.12.006. PubMed DOI PMC

Altman BJ, Stine ZE, Dang CV. From Krebs to clinic: glutamine metabolism to cancer therapy. Nat Rev Cancer. 2016;16(10):619–634. doi: 10.1038/nrc.2016.71. PubMed DOI PMC

Sica A, Mantovani A. Macrophage plasticity and polarization: in vivo veritas. J Clin Invest. 2012;122(3):787–795. doi: 10.1172/JCI59643. PubMed DOI PMC

Noy R, Pollard JW. Tumor-associated macrophages: from mechanisms to therapy. Immunity. 2014;41(1):49–61. doi: 10.1016/j.immuni.2014.06.010. PubMed DOI PMC

Kondo Y, Arii S, Mori A, Furutani M, Chiba T, Imamura M. Enhancement of angiogenesis, tumor growth, and metastasis by transfection of vascular endothelial growth factor into LoVo human colon cancer cell line. Clin Cancer Res. 2000;6(2):622–630. PubMed

Mantovani A, Marchesi F, Malesci A, Laghi L, Allavena P. Tumour-associated macrophages as treatment targets in oncology. Nat Rev Clin Oncol. 2017;14(7):399–416. doi: 10.1038/nrclinonc.2016.217. PubMed DOI PMC

Munn DH, Mellor AL. Indoleamine 2,3 dioxygenase and metabolic control of immune responses. Trends Immunol. 2013;34(3):137–143. doi: 10.1016/j.it.2012.10.001. PubMed DOI PMC

Lee GK, Park HJ, Macleod M, Chandler P, Munn DH, Mellor AL. Tryptophan deprivation sensitizes activated T cells to apoptosis prior to cell division. Immunology. 2002;107(4):452–460. doi: 10.1046/j.1365-2567.2002.01526.x. PubMed DOI PMC

Mellor AL, Keskin DB, Johnson T, Chandler P, Munn DH. Cells expressing indoleamine 2,3-dioxygenase inhibit T cell responses. J Immunol. 2002;168(8):3771–3776. doi: 10.4049/jimmunol.168.8.3771. PubMed DOI

Rath M, Müller I, Kropf P, Closs EI, Munder M. Metabolism via arginase or nitric oxide synthase: two competing arginine pathways in macrophages. Front Immunol. 2014;5:532. PubMed PMC

Prima V, Kaliberova LN, Kaliberov S, Curiel DT, Kusmartsev S. COX2/mPGES1/PGE2 pathway regulates PD-L1 expression in tumor-associated macrophages and myeloid-derived suppressor cells. Proc Natl Acad Sci U S A. 2017;114(5):1117–1122. doi: 10.1073/pnas.1612920114. PubMed DOI PMC

Tcyganov E, Mastio J, Chen E, Gabrilovich DI. Plasticity of myeloid-derived suppressor cells in cancer. Curr Opin Immunol. 2018;51:76–82. doi: 10.1016/j.coi.2018.03.009. PubMed DOI PMC

Bronte V, et al. Recommendations for myeloid-derived suppressor cell nomenclature and characterization standards. Nat Commun. 2016;7:12150. PubMed PMC

Bronte V, et al. Identification of a CD11b(+)/Gr-1(+)/CD31(+) myeloid progenitor capable of activating or suppressing CD8(+) T cells. Blood. 2000;96(12):3838–3846. PubMed PMC

Li Q, Pan PY, Gu P, Xu D, Chen SH. Role of immature myeloid Gr-1+ cells in the development of antitumor immunity. Cancer Res. 2004;64(3):1130–1139. doi: 10.1158/0008-5472.CAN-03-1715. PubMed DOI

Serafini P, Mgebroff S, Noonan K, Borrello I. Myeloid-derived suppressor cells promote cross-tolerance in B-cell lymphoma by expanding regulatory T cells. Cancer Res. 2008;68(13):5439–5449. doi: 10.1158/0008-5472.CAN-07-6621. PubMed DOI PMC

Schmielau J, Finn OJ. Activated granulocytes and granulocyte-derived hydrogen peroxide are the underlying mechanism of suppression of T-cell function in advanced cancer patients. Cancer Res. 2001;61(12):4756–4760. PubMed

Srivastava MK, Sinha P, Clements VK, Rodriguez P, Ostrand-Rosenberg S. Myeloid-derived suppressor cells inhibit T-cell activation by depleting cystine and cysteine. Cancer Res. 2010;70(1):68–77. doi: 10.1158/0008-5472.CAN-09-2587. PubMed DOI PMC

Almand B, et al. Increased production of immature myeloid cells in cancer patients: a mechanism of immunosuppression in cancer. J Immunol. 2001;166(1):678–689. doi: 10.4049/jimmunol.166.1.678. PubMed DOI

Yang L, Venneti S, Nagrath D. Glutaminolysis: A hallmark of cancer metabolism. Annu Rev Biomed Eng. 2017;19:163–194. doi: 10.1146/annurev-bioeng-071516-044546. PubMed DOI

Rais R, et al. Discovery of 6-diazo-5-oxo-l-norleucine (DON) prodrugs with enhanced CSF delivery in monkeys: a potential treatment for glioblastoma. J Med Chem. 2016;59(18):8621–8633. doi: 10.1021/acs.jmedchem.6b01069. PubMed DOI

Kim K, et al. Eradication of metastatic mouse cancers resistant to immune checkpoint blockade by suppression of myeloid-derived cells. Proc Natl Acad Sci U S A. 2014;111(32):11774–11779. doi: 10.1073/pnas.1410626111. PubMed DOI PMC

Safarzadeh E, Orangi M, Mohammadi H, Babaie F, Baradaran B. Myeloid-derived suppressor cells: Important contributors to tumor progression and metastasis. J Cell Physiol. 2018;233(4):3024–3036. doi: 10.1002/jcp.26075. PubMed DOI

Wang Y, Ding Y, Guo N, Wang S. MDSCs: key criminals of tumor pre-metastatic niche formation. Front Immunol. 2019;10:172. PubMed PMC

Condamine T, Ramachandran I, Youn JI, Gabrilovich DI. Regulation of tumor metastasis by myeloid-derived suppressor cells. Annu Rev Med. 2015;66:97–110. doi: 10.1146/annurev-med-051013-052304. PubMed DOI PMC

Akagi T, Saitoh T, O’Kelly J, Akira S, Gombart AF, Koeffler HP. Impaired response to GM-CSF and G-CSF, and enhanced apoptosis in C/EBPbeta-deficient hematopoietic cells. Blood. 2008;111(6):2999–3004. doi: 10.1182/blood-2007-04-087213. PubMed DOI PMC

Marigo I, et al. Tumor-induced tolerance and immune suppression depend on the C/EBPbeta transcription factor. Immunity. 2010;32(6):790–802. doi: 10.1016/j.immuni.2010.05.010. PubMed DOI

Li W, et al. Aerobic glycolysis controls myeloid-derived suppressor cells and tumor immunity via a specific CEBPB isoform in triple-negative breast cancer. Cell Metab. 2018;28(1):87–103.e6. doi: 10.1016/j.cmet.2018.04.022. PubMed DOI PMC

Perry CJ, et al. Myeloid-targeted immunotherapies act in synergy to induce inflammation and antitumor immunity. J Exp Med. 2018;215(3):877–893. doi: 10.1084/jem.20171435. PubMed DOI PMC

Hoves S, et al. Rapid activation of tumor-associated macrophages boosts preexisting tumor immunity. J Exp Med. 2018;215(3):859–876. doi: 10.1084/jem.20171440. PubMed DOI PMC

Liu PS, et al. α-Ketoglutarate orchestrates macrophage activation through metabolic and epigenetic reprogramming. Nat Immunol. 2017;18(9):985–994. doi: 10.1038/ni.3796. PubMed DOI

Green DR, Ferguson T, Zitvogel L, Kroemer G. Immunogenic and tolerogenic cell death. Nat Rev Immunol. 2009;9(5):353–363. doi: 10.1038/nri2545. PubMed DOI PMC

Krysko DV, Garg AD, Kaczmarek A, Krysko O, Agostinis P, Vandenabeele P. Immunogenic cell death and DAMPs in cancer therapy. Nat Rev Cancer. 2012;12(12):860–875. doi: 10.1038/nrc3380. PubMed DOI

Leone RD, et al. Glutamine blockade induces divergent metabolic programs to overcome tumor immune evasion. Science. 2019;366(6468):1013–1021. doi: 10.1126/science.aav2588. PubMed DOI PMC

Munn DH, Mellor AL. IDO in the tumor microenvironment: inflammation, counter-regulation, and tolerance. Trends Immunol. 2016;37(3):193–207. doi: 10.1016/j.it.2016.01.002. PubMed DOI PMC

Smith C, et al. IDO is a nodal pathogenic driver of lung cancer and metastasis development. Cancer Discov. 2012;2(8):722–735. doi: 10.1158/2159-8290.CD-12-0014. PubMed DOI PMC

D’Amato NC, et al. A TDO2-AhR signaling axis facilitates anoikis resistance and metastasis in triple-negative breast cancer. Cancer Res. 2015;75(21):4651–4664. doi: 10.1158/0008-5472.CAN-15-2011. PubMed DOI PMC

Xue P, Fu J, Zhou Y. The Aryl Hydrocarbon Receptor and Tumor Immunity. Front Immunol. 2018;9:286. PubMed PMC

Tennant DA, Durán RV, Gottlieb E. Targeting metabolic transformation for cancer therapy. Nat Rev Cancer. 2010;10(4):267–277. doi: 10.1038/nrc2817. PubMed DOI

Galluzzi L, Kepp O, Vander Heiden MG, Kroemer G. Metabolic targets for cancer therapy. Nat Rev Drug Discov. 2013;12(11):829–846. doi: 10.1038/nrd4145. PubMed DOI

Xiang Y, et al. Targeted inhibition of tumor-specific glutaminase diminishes cell-autonomous tumorigenesis. J Clin Invest. 2015;125(6):2293–2306. doi: 10.1172/JCI75836. PubMed DOI PMC

Gross MI, et al. Antitumor activity of the glutaminase inhibitor CB-839 in triple-negative breast cancer. Mol Cancer Ther. 2014;13(4):890–901. doi: 10.1158/1535-7163.MCT-13-0870. PubMed DOI

Wang JB, et al. Targeting mitochondrial glutaminase activity inhibits oncogenic transformation. Cancer Cell. 2010;18(3):207–219. doi: 10.1016/j.ccr.2010.08.009. PubMed DOI PMC

Gao P, et al. c-Myc suppression of miR-23a/b enhances mitochondrial glutaminase expression and glutamine metabolism. Nature. 2009;458(7239):762–765. doi: 10.1038/nature07823. PubMed DOI PMC

Romero R, et al. Keap1 loss promotes Kras-driven lung cancer and results in dependence on glutaminolysis. Nat Med. 2017;23(11):1362–1368. doi: 10.1038/nm.4407. PubMed DOI PMC

Davidson SM, et al. Environment impacts the metabolic dependencies of Ras-driven non-small cell lung cancer. Cell Metab. 2016;23(3):517–528. doi: 10.1016/j.cmet.2016.01.007. PubMed DOI PMC

Biancur DE, et al. Compensatory metabolic networks in pancreatic cancers upon perturbation of glutamine metabolism. Nat Commun. 2017;8:15965. PubMed PMC

Ahluwalia GS, Grem JL, Hao Z, Cooney DA. Metabolism and action of amino acid analog anti-cancer agents. Pharmacol Ther. 1990;46(2):243–271. doi: 10.1016/0163-7258(90)90094-I. PubMed DOI

Lemberg KM, Vornov JJ, Rais R, Slusher BS. We’re not “DON” yet: optimal dosing and prodrug delivery of 6-diazo-5-oxo-L-norleucine. Mol Cancer Ther. 2018;17(9):1824–1832. doi: 10.1158/1535-7163.MCT-17-1148. PubMed DOI PMC

Binnewies M, et al. Understanding the tumor immune microenvironment (TIME) for effective therapy. Nat Med. 2018;24(5):541–550. doi: 10.1038/s41591-018-0014-x. PubMed DOI PMC

Sharma P, Hu-Lieskovan S, Wargo JA, Ribas A. Primary, adaptive, and acquired resistance to cancer immunotherapy. Cell. 2017;168(4):707–723. doi: 10.1016/j.cell.2017.01.017. PubMed DOI PMC

Steinberg SM, et al. Myeloid cells that impair immunotherapy are restored in melanomas with acquired resistance to BRAF inhibitors. Cancer Res. 2017;77(7):1599–1610. doi: 10.1158/0008-5472.CAN-16-1755. PubMed DOI PMC

Tan HWS, Sim AYL, Long YC. Glutamine metabolism regulates autophagy-dependent mTORC1 reactivation during amino acid starvation. Nat Commun. 2017;8(1):338. doi: 10.1038/s41467-017-00369-y. PubMed DOI PMC

Durán RV, et al. Glutaminolysis activates Rag-mTORC1 signaling. Mol Cell. 2012;47(3):349–358. doi: 10.1016/j.molcel.2012.05.043. PubMed DOI

Holmgaard RB, Zamarin D, Munn DH, Wolchok JD, Allison JP. Indoleamine 2,3-dioxygenase is a critical resistance mechanism in antitumor T cell immunotherapy targeting CTLA-4. J Exp Med. 2013;210(7):1389–1402. doi: 10.1084/jem.20130066. PubMed DOI PMC

Uyttenhove C, et al. Evidence for a tumoral immune resistance mechanism based on tryptophan degradation by indoleamine 2,3-dioxygenase. Nat Med. 2003;9(10):1269–1274. doi: 10.1038/nm934. PubMed DOI

Huang A, Zhang B, Wang B, Zhang F, Fan KX, Guo YJ. Increased CD14(+)HLA-DR (-/low) myeloid-derived suppressor cells correlate with extrathoracic metastasis and poor response to chemotherapy in non-small cell lung cancer patients. Cancer Immunol Immunother. 2013;62(9):1439–1451. doi: 10.1007/s00262-013-1450-6. PubMed DOI PMC

Yu J, et al. Myeloid-derived suppressor cells suppress antitumor immune responses through IDO expression and correlate with lymph node metastasis in patients with breast cancer. J Immunol. 2013;190(7):3783–3797. doi: 10.4049/jimmunol.1201449. PubMed DOI

Del Paggio JC. Immunotherapy: Cancer immunotherapy and the value of cure. Nat Rev Clin Oncol. 2018;15(5):268–270. doi: 10.1038/nrclinonc.2018.27. PubMed DOI

Larkin J, et al. Combined nivolumab and ipilimumab or monotherapy in untreated melanoma. N Engl J Med. 2015;373(1):23–34. doi: 10.1056/NEJMoa1504030. PubMed DOI PMC

Tumeh PC, et al. PD-1 blockade induces responses by inhibiting adaptive immune resistance. Nature. 2014;515(7528):568–571. doi: 10.1038/nature13954. PubMed DOI PMC

Kawai T, Adachi O, Ogawa T, Takeda K, Akira S. Unresponsiveness of MyD88-deficient mice to endotoxin. Immunity. 1999;11(1):115–122. doi: 10.1016/S1074-7613(00)80086-2. PubMed DOI

Hoebe K, et al. Identification of Lps2 as a key transducer of MyD88-independent TIR signalling. Nature. 2003;424(6950):743–748. doi: 10.1038/nature01889. PubMed DOI

Settembre C, et al. A lysosome-to-nucleus signalling mechanism senses and regulates the lysosome via mTOR and TFEB. EMBO J. 2012;31(5):1095–1108. doi: 10.1038/emboj.2012.32. PubMed DOI PMC

Discovery of tert-Butyl Ester Based 6-Diazo-5-oxo-l-norleucine Prodrugs for Enhanced Metabolic Stability and Tumor Delivery

Effects of metabolic cancer therapy on tumor microenvironment

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

Glutamine Antagonist GA-607 Causes a Dramatic Accumulation of FGAR which can be used to Monitor Target Engagement