Arginase 1 is a key driver of immune suppression in pancreatic cancer
- University of Michigan-Ann Arbor, United States
- Henry Ford Pancreatic Cancer Center, United States
- University of California, Irvine, United States
Abstract
An extensive fibroinflammatory stroma rich in macrophages is a hallmark of pancreatic cancer. In this disease, it is well appreciated that macrophages are immunosuppressive and contribute to the poor response to immunotherapy; however, the mechanisms of immune suppression are complex and not fully understood. Immunosuppressive macrophages are classically defined by expression of the enzyme Arginase 1 (Arg1), which we demonstrated is potently expressed in pancreatic tumor associated macrophages from both human patients and mouse models. While routinely used as a polarization marker, Arg1 also catabolizes arginine, an amino acid required for T cell activation and proliferation. To investigate this metabolic function, we used a genetic and a pharmacologic approach to target Arg1 in pancreatic cancer. Genetic inactivation of Arg1 in macrophages, using a dual recombinase genetically engineered mouse model of pancreatic cancer, delayed formation of invasive disease, while increasing CD8+ T cell infiltration. Additionally, Arg1 deletion induced compensatory mechanisms, including Arg1 overexpression in epithelial cells, namely Tuft cells, and Arg2 overexpression in a subset of macrophages. To overcome these compensatory mechanisms, we used a pharmacological approach to inhibit arginase. Treatment of established tumors with the arginase inhibitor CB-1158 exhibited further increased CD8+ T cell infiltration, beyond that seen with the macrophage-specific knockout, and sensitized the tumors to anti-PD1 immune checkpoint blockade. Our data demonstrate that Arg1 drives immune suppression in pancreatic cancer by depleting Arginine and inhibiting T cell activation.
Data availability
Human sc-RNA-seq data was previously published (N. G. Steele et al., 2020) and both raw and processed data are available at the NIH dbGap database accession number phs002071.v1.p1. Raw and processed sc-RNA-seq data for the WT and KPC were previously published and are available at GEO accession number GSM5011580 and GSE202651. Raw and processed sc-RNA-seq data for the KF and KFCA are available at GEO accession number GSE203016.
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Arginase 1 deletion in myeloid cells decreases immune suppression and tumor formation in pancreatic cancerNCBI Gene Expression Omnibus, GSE203016.
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Multimodal Mapping of the Tumor and Peripheral Blood Immune Landscape in Human Pancreatic CancerNCBI Gene Expression Omnibus, GSE155698.
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Pancreatic cancer is marked by complement-high blood monocytes and tumor-associated macrophagesNCBI Gene Expression Omnibus, GSM5011580.
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Murine models of pancreatic cancer: KPCNCBI Gene Expression Omnibus, GSE202651.
Article and author information
Author details
Daniel Salas-Escabillas
Costas A Lyssiotis
Marina Pasca di Magliano
Funding
National Institutes of Health (T32-GM007315)
- Rosa Elena Menjivar
National Cancer Institute (R01-CA244931)
- Costas A Lyssiotis
National Cancer Institute (R01-CA247516)
- Howard C Crawford
University of Michigan (Postdoctoral Pioneer Program)
- Zeribe C Nwosu
University of Michigan (Training Program in Organogenesis)
- Wenting Du
National Cancer Institute (T32-CA009676)
- Katelyn L Donahue
National Cancer Institute (T32-AI007413)
- Hanna S Hong
National Institute of Diabetes and Digestive and Kidney Diseases (T32-DK094775)
- Hanna S Hong
National Cancer Institute (F31-CA247037)
- Ashley Velez-Delgado
National Institute of General Medical Sciences (T32-GM008353)
- Ashley Velez-Delgado
National Institutes of Health (T32-AI007413)
- Padma Kadiyala
National Cancer Institute (F31-CA257533)
- Rosa Elena Menjivar
National Cancer Institute (T32-CA009676)
- Daniel Salas-Escabillas
American College of Gastroenterology (T32-DK094775)
- Eileen Carpenter
National Cancer Institute (R50-CA232985)
- Yaqing Zhang
National Cancer Institute (F32-CA228328)
- Christopher J Halbrook
National Institutes of Health (R00-CA241357)
- Christopher J Halbrook
National Institutes of Health (T32-HD007505)
- Rosa Elena Menjivar
University of Michigan (Rackham Merit Fellowship)
- Rosa Elena Menjivar
National Institutes of Health (U01-CA224145)
- Marina Pasca di Magliano
National Institutes of Health (R01-CA151588)
- Marina Pasca di Magliano
National Cancer Institute (R01-CA198074)
- Marina Pasca di Magliano
National Cancer Institute (R37-CA237421)
- Costas A Lyssiotis
National Cancer Institute (R01-CA248160)
- Costas A Lyssiotis
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: All the animal studies and procedures were conducted in compliance with the guidelines of the Institutional Animal Care and Use Committee (IACUC) at the University of Michigan, protocol number: PRO00009814.
Human subjects: Human research was performed in accordance with the Declaration of Helsinki and the ethical standards and guidelines approved by the University of Michigan Institutional Review Board. Patients provided written informed consent.
Copyright
© 2023, Menjivar et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Arginase 1 is a key driver of immune suppression in pancreatic cancer
eLife 12:e80721.
https://doi.org/10.7554/eLife.80721
Further reading
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- Biochemistry and Chemical Biology
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Studying the nutrient composition immediately surrounding pancreatic cancer cells provides new insights into their metabolic properties and how they can evade the immune system to promote disease progression.
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Testicular microcalcifications consist of hydroxyapatite and have been associated with an increased risk of testicular germ cell tumors (TGCTs) but are also found in benign cases such as loss-of-function variants in the phosphate transporter SLC34A2. Here, we show that fibroblast growth factor 23 (FGF23), a regulator of phosphate homeostasis, is expressed in testicular germ cell neoplasia in situ (GCNIS), embryonal carcinoma (EC), and human embryonic stem cells. FGF23 is not glycosylated in TGCTs and therefore cleaved into a C-terminal fragment which competitively antagonizes full-length FGF23. Here, Fgf23 knockout mice presented with marked calcifications in the epididymis, spermatogenic arrest, and focally germ cells expressing the osteoblast marker Osteocalcin (gene name: Bglap, protein name). Moreover, the frequent testicular microcalcifications in mice with no functional androgen receptor and lack of circulating gonadotropins are associated with lower Slc34a2 and higher Bglap/Slc34a1 (protein name: NPT2a) expression compared with wild-type mice. In accordance, human testicular specimens with microcalcifications also have lower SLC34A2 and a subpopulation of germ cells express phosphate transporter NPT2a, Osteocalcin, and RUNX2 highlighting aberrant local phosphate handling and expression of bone-specific proteins. Mineral disturbance in vitro using calcium or phosphate treatment induced deposition of calcium phosphate in a spermatogonial cell line and this effect was fully rescued by the mineralization inhibitor pyrophosphate. In conclusion, testicular microcalcifications arise secondary to local alterations in mineral homeostasis, which in combination with impaired Sertoli cell function and reduced levels of mineralization inhibitors due to high alkaline phosphatase activity in GCNIS and TGCTs facilitate osteogenic-like differentiation of testicular cells and deposition of hydroxyapatite.
