Dataset Information

First-in-class positron emission tomography tracer for the glucagon receptor.

ABSTRACT: The glucagon receptor (GCGR) is emerging as an important target in anti-diabetic therapy, especially as part of the pharmacology of dual glucagon-like peptide-1/glucagon (GLP-1/GCG) receptor agonists. However, currently, there are no suitable biomarkers that reliably demonstrate GCG receptor target engagement.

Methods

Two potent GCG receptor peptide agonists, S01-GCG and S02-GCG, were labeled with positron emission tomography (PET) radionuclide gallium-68. The GCG receptor binding affinity and specificity of the resulting radiopharmaceuticals [⁶⁸Ga]Ga-DO3A-S01-GCG and [⁶⁸Ga]Ga-DO3A-S02-GCG were evaluated in HEK-293 cells overexpressing the human GCG receptor and on frozen hepatic sections from human, non-human primate, and rat. In in vivo biodistribution, binding specificity and dosimetry were assessed in rat.

Results

[⁶⁸Ga]Ga-DO3A-S01-GCG in particular demonstrated GCG receptor-mediated binding in cells and liver tissue with affinity in the nanomolar range required for imaging. [⁶⁸Ga]Ga-DO3A-S01-GCG binding was not blocked by co-incubation of a GLP-1 agonist. In vivo binding in rat liver was GCG receptor specific with low non-specific binding throughout the body. Moreover, the extrapolated human effective doses, predicted from rat biodistribution data, allow for repeated PET imaging potentially also in combination with GLP-1R radiopharmaceuticals.

Conclusion

[⁶⁸Ga]Ga-DO3A-S01-GCG thus constitutes a first-in-class PET tracer targeting the GCG receptor, with suitable properties for clinical development. This tool has potential to provide direct quantitative evidence of GCG receptor occupancy in humans.

SUBMITTER: Velikyan I

PROVIDER: S-EPMC6377692 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature

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Publications

First-in-class positron emission tomography tracer for the glucagon receptor.

Velikyan Irina I Haack Torsten T Bossart Martin M Evers Andreas A Laitinen Iina I Larsen Philip P Plettenburg Oliver O Johansson Lars L Pierrou Stefan S Wagner Michael M Eriksson Olof O

EJNMMI research 20190215 1

The glucagon receptor (GCGR) is emerging as an important target in anti-diabetic therapy, especially as part of the pharmacology of dual glucagon-like peptide-1/glucagon (GLP-1/GCG) receptor agonists. However, currently, there are no suitable biomarkers that reliably demonstrate GCG receptor target engagement.<h4>Methods</h4>Two potent GCG receptor peptide agonists, S01-GCG and S02-GCG, were labeled with positron emission tomography (PET) radionuclide gallium-68. The GCG receptor binding affinit ...[more]

PMID: 30771019

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Project description:Fluorine-18-fluoro-2-deoxy-D-glucose (FDG) is widely used as positron-emission-tomography (PET) radiotracer for the detection and staging of human cancer. Tumor uptake of FDG varies substantially between different cancer types and between patients with the same tumor type. The molecular basis for this heterogeneity is unknown. Using cancer cell lines and primary human tumors of distinct histologic origins, we here show that increased FDG uptake is universally associated with coordinate upregulation of genes within the glycolysis, pentose-phosphate, and other related metabolic pathways. In primary human breast cancers, this FDG signature shows significant overlap with established breast cancer signatures for the “basal-like” disease subtype and “poor prognosis”. FDG high breast cancer showed significantly more gene copy number alterations genome wide than FDG low cancers. About 50 % of primary breast cancers with high FDG uptake and FDG gene expression signature show DNA copy gain encompassing the c-myc gene locus and express gene sets regulated by the transcription factor MYC. Our data shows that FDG-PET marks a distinct subset of “basal-like” human breast cancer which is characterized by MYC and prognostically unfavorable gene expression signatures, suggesting that FDG-PET imaging may be useful to risk-stratify patients with locally advanced breast cancer. Our general strategy to identify molecular determinants of FDG-retention through a genome-wide approach consisted of FDG uptake measurements in cancer cell lines and primary human tumors, the selection of samples with particularly high versus low FDG-retention, and subsequent pathway-based analysis of RNA expression data collected from these samples. Cell line RNA was extracted from a 10 cm plate seeded simultaneously and at the same density as the wells for FDG-uptake assays. For primary human tumor samples, RNA was extracted from macrodissected frozen tumor tissue. All cell line RNA samples and the astrocytoma RNA aliquots were hybridized to Affymetrix U133 Plus 2.0 arrays. All primary breast cancer RNA samples were hybridized to Affymetrix U133A arrays.

Dataset Information

First-in-class positron emission tomography tracer for the glucagon receptor.

Methods

Results

Conclusion

Publications

First-in-class positron emission tomography tracer for the glucagon receptor.

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