Journal Article

DKFZ-2025-02965

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Novel immunotheranostic FAP-inhibitor target modules for imaging and elimination of FAP-positive cells by UniCAR T-cells.

Boutier, H. ; Kogler, J. ; Loureiro, L. R. ; Neuber, C. ; Berndt, N. ; Arndt, C. ; Stadlbauer, S.DKFZ* ; Stephan, H. ; Feldmann, A.DKFZ* ; Kopka, K.DKFZ* ; Hagemeyer, C. E. ; Bachmann, M.DKFZ*

2025
Taylor & Franics Abingdon

Abstract: The fibroblast activation protein alpha (FAPα) is overexpressed in the tumor microenvironment of most solid cancers and, in some cases, in cancer cells, making it an interesting target for theranostic applications. T-cells modified to express a chimeric antigen receptor (CAR) against FAP have recently been described. We previously established the UniCAR system, in which UniCAR T-cells can be repeatedly switched on and off via dosing with a bifunctional adaptor molecule, known as target module (TM). Here, we describe the first FAPI-based immunotheranostic UniCAR TMs (FAPI TMs), enabling both non-invasive molecular imaging and UniCAR T-cell immunotherapy. The FAPI TMs consist of the UAMC-1110 FAPI moiety, the NODA-GA chelator for copper-64 labeling, and the UniCAR epitope (E5B9). Following computational analyses, three FAPI TMs with polyethylene glycol (PEG) spacers of either four, twelve, or 24 units were synthesized. Although the three novel TMs specifically accumulate in FAP-positive tumors in xenograft mice, only the FAPI TMs with an extended spacer (PEG12 and PEG24) redirect UniCAR T-cells to FAP-positive target cells both in vitro and in an immunodeficient mouse model. In line with the computational studies, the E5B9 epitope is not accessible for binding when the PEG4-based FAPI TM is bound to FAP. Our work demonstrates that the length of the spacer in FAPI TMs is critical for the effective redirection of UniCAR T-cells to FAP-positive cells. Overall, our novel FAPI TMs may represent highly promising immunotheranostic tools for personalized non-invasive diagnostic imaging and immunotherapy of cancer patients.

Keyword(s): Animals (MeSH) ; Humans (MeSH) ; Mice (MeSH) ; T-Lymphocytes: immunology (MeSH) ; T-Lymphocytes: metabolism (MeSH) ; T-Lymphocytes: transplantation (MeSH) ; Serine Endopeptidases: metabolism (MeSH) ; Serine Endopeptidases: immunology (MeSH) ; Membrane Proteins: antagonists & inhibitors (MeSH) ; Membrane Proteins: metabolism (MeSH) ; Membrane Proteins: immunology (MeSH) ; Gelatinases: antagonists & inhibitors (MeSH) ; Gelatinases: metabolism (MeSH) ; Gelatinases: immunology (MeSH) ; Endopeptidases (MeSH) ; Cell Line, Tumor (MeSH) ; Immunotherapy: methods (MeSH) ; Xenograft Model Antitumor Assays (MeSH) ; Female (MeSH) ; Molecular Imaging: methods (MeSH) ; Copper Radioisotopes: chemistry (MeSH) ; Neoplasms: therapy (MeSH) ; Neoplasms: immunology (MeSH) ; Neoplasms: diagnostic imaging (MeSH) ; Immunotherapy, Adoptive: methods (MeSH) ; FAP inhibitor (FAPI) ; Immunotheranostics ; UniCAR T-cells ; copper- 64 (64Cu) ; fibroblast activation protein (FAP) ; positron emission tomography (PET) ; target modules (TMs) ; tumor microenvironment (TME) ; fibroblast activation protein alpha ; Serine Endopeptidases ; Membrane Proteins ; Gelatinases ; Endopeptidases ; Copper Radioisotopes

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Contributing Institute(s):

1. DKTK Koordinierungsstelle Dresden (DD01)

Research Program(s):

1. 899 - ohne Topic (POF4-899) (POF4-899)

Appears in the scientific report 2025

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Database coverage:
; ; Article Processing Charges ; BIOSIS Previews ; Biological Abstracts ; Clarivate Analytics Master Journal List ; DOAJ Seal ; Ebsco Academic Search ; Essential Science Indicators ; Fees ; IF >= 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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