Authors:	Zimmer, Niklas Kim, Ella Schupp, Jonathan Sprang, Bettina Leukel, Petra Khafaji, Fatemeh Ringel, Florian Sommer, Clemens Tüttenberg, Jochen Tüttenberg, Andrea
Title:	GARP as an immune regulatory molecule in the tumor microenvironment of glioblastoma multiforme
Online publication date:	8-Nov-2019
Year of first publication:	2019
Language:	english
Abstract:	Glycoprotein A repetition predominant (GARP), a specific surface molecule of activated regulatory T cells, has been demonstrated to significantly contribute to tolerance in humans by induction of peripheral Treg and regulatory M2-macrophages and by inhibition of (tumorantigen specific) T effector cells. Previous work identified GARP on Treg, and also GARP on the surface of several malignant tumors, as well as in a soluble form being shedded from their surface, contributing to tumor immune escape. Preliminary results also showed GARP expression on brain metastases of malignant melanoma. On the basis of these findings, we investigated whether GARP is also expressed on primary brain tumors. We showed GARP expression on glioblastoma (GB) cell lines and primary GB tissue, as well as on low-grade glioma, suggesting an important influence on the tumor micromilieu and the regulation of immune responses also in primary cerebral tumors. This was supported by the finding that GB cells led to a reduced, in part GARP-dependent effector T cell function (reduced proliferation and reduced cytokine secretion) in coculture experiments. Interestingly, GARP was localized not only on the cell surface but also in the cytoplasmatic, as well as nuclear compartments in tumor cells. Our findings reveal that GARP, as an immunoregulatory molecule, is located on, as well as in, tumor cells of GB and low-grade glioma, inhibiting effector T cell function, and thus contributing to the immunosuppressive tumor microenvironment of primary brain tumors. As GARP is expressed on activated Treg, as well as on brain tumors, it may be an interesting target for new immunotherapeutic approaches using antibody-based strategies as this indication.
DDC:	610 Medizin 610 Medical sciences
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 04 Medizin
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-227
URN:	urn:nbn:de:hebis:77-publ-594100
Version:	Published version
Publication type:	Zeitschriftenaufsatz
License:	CC BY
Information on rights of use:	https://creativecommons.org/licenses/by/4.0/
Journal:	International journal of molecular sciences 20 15
Pages or article number:	Art. 3676
Publisher:	Molecular Diversity Preservation International
Publisher place:	Basel
Issue date:	2019
ISSN:	1422-0067 1661-6596
Publisher URL:	http://dx.doi.org/10.3390/ijms20153676
Publisher DOI:	10.3390/ijms20153676
Appears in collections:	JGU-Publikationen