Bradykinin B1 receptor (B1R)
A receptor that healthy tissue barely makes but inflammation and many cancers switch on. Gallium-68 and fluorine-18 peptides built from B1R-blocking drugs give sharp PET images in mice, but no B1R tracer has been given to a patient.
Overview
The bradykinin B1 receptor, encoded by BDKRB1 (HGNC:1029), is a G-protein-coupled receptor that is overexpressed in a variety of cancers while being essentially absent from healthy tissue, which is what first drew imaging groups to it.
Most of the published radiochemistry comes from BC Cancer in Vancouver. In a 2015 Journal of Nuclear Medicine study, three gallium-68-labelled peptides derived from the B1R antagonists B9858 and B9958 bound the receptor with nanomolar affinity (Ki 1.1 to 16.0 nM), cleared through the kidneys, and at one hour showed only kidneys, bladder and B1R-positive tumours on PET; the best, 68Ga-P04158 and 68Ga-Z02090, reached 19.6 and 14.4% injected dose per gram in tumour. The same group then made 68Ga- and 18F-labelled derivatives of the more peptidase-stable antagonist R954, with tumour uptake around 8.5 to 9.3% injected dose per gram at one hour. Those studies used cells engineered to express human B1R. In 2024 a Showa Pharmaceutical University group showed that an indium-111 R954 derivative also tracks B1R expressed naturally in glioblastoma cells, with uptake that followed B1R levels and was blocked by unlabelled R954.
A search of ClinicalTrials.gov on 24 September 2026 found no registered B1R imaging or therapy trial. The gaps are a first-in-human study and evidence of which human tumours carry enough receptor to image or treat.
- Target · the protein and the cell it sits on
- Drug · antibody, small molecule, cell or radioligand
- Effect · signal, damage or kill
In plain words · A receptor that healthy tissue barely makes but inflammation and many cancers switch on. Gallium-68 and fluorine-18 peptides built from B1R-blocking drugs give sharp PET images in mice, but no B1R tracer has been given to a patient.
- 1 · What it is
A receptor that healthy tissue barely makes but inflammation and many cancers switch on. Gallium-68 and fluorine-18 peptides built from B1R-blocking drugs give sharp PET images in mice, but no B1R tracer has been given to a patient.
- 2 · What goes wrong in cancer
An inducible G-protein-coupled receptor for des-Arg kinins.
- 3 · How drugs use it
No product in this corpus aims at Bradykinin B1 receptor (B1R) yet. Drugs bind the molecule precisely: to switch it off, flag the cell for the immune system, or deliver a payload.
External identifiers
Biology
An inducible G-protein-coupled receptor for des-Arg kinins. It is barely expressed in healthy tissue but upregulated by inflammation and in many tumours, and antagonist peptides such as B9858, B9958 and R954 bind it with nanomolar affinity, which is the basis of the radiolabelled derivatives.
- A variety of cancers, with limited or no expression in healthy tissue (BC Cancer radiochemistry series)
- Glioblastoma cell lines: U87MG expresses more than U251MG, and radiotracer uptake follows that difference
- Inflamed tissue, where expression is induced
Latest papers
topQuery for this target: (TITLE:"Bradykinin B1 receptor" OR ABSTRACT:"Bradykinin B1 receptor" OR TITLE:"B1R" OR ABSTRACT:"B1R" OR TITLE:"BDKRB1" OR ABSTRACT:"BDKRB1" OR TITLE:"BKR1" OR ABSTRACT:"BKR1" OR TITLE:"B1BKR" OR ABSTRACT:"B1BKR") AND (radiopharmaceutical OR radioligand OR radionuclide OR theranostic OR "nuclear medicine" OR "molecular imaging" OR radiotracer OR scintigraphy OR cancer OR tumor OR tumour OR oncology OR carcinoma OR lymphoma OR leukemia OR leukaemia OR myeloma OR sarcoma OR melanoma OR glioma). Results are unfiltered search hits about Bradykinin B1 receptor (B1R), not a curated reading list.
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