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Development of Preladenant-Based Radiotracers for Imaging A2AR in Tumors
Xueyuan Zeng1, Hongwu Liu1, Guolong Huang1
1State Key Laboratory of Vaccines for Infectious Diseases, Center for Molecular Imaging and Translational Medicine, Xiang An Biomedicine Laboratory, School of Public Health, Xiamen University, Xiamen 361102, China.
Abstract:
Activation of the adenosine 2A receptor (A2AR) can lead to tumor immunosuppression, which results in poor prognosis of immunotherapy. The aim of this study was to design novel 18F-labeled probes ([18F]F-PFP2 and [18F]F-PFP4) to visualize A2AR in the tumor. The uptake of radioprobes in A2AR-negative 4T1 breast tumor was lower than that of A2AR-positive B16F10 melanoma at 1 h p.i. (1.22 ± 0.36% ID/g vs 2.80 ± 0.72% ID/g), 2 h p.i. (1.09 ± 0.20% ID/g vs 2.93 ± 0.76% ID/g) and 3 h p.i. (0.89 ± 0.27% ID/g vs 2.73 ± 0.58% ID/g), respectively. B16F10 lung metastasis models were employed to expand the application scenarios, observing significantly higher uptake of [18F]F-PFP2 in metastatic lesions compared to normal lung tissue (5.55 ± 2.18% ID/g vs 1.89 ± 0.65% ID/g, tumor/lung ratio ∼3). It is given that [18F]F-PFP2 might lay the foundation for establishing an A2AR-targeted imaging evaluation system for tumors, which will provide more precise guidance for personalized treatment.
Insights
Researchers developed new radioactive tracers, [18F]F-PFP2 and [18F]F-PFP4, to visualize adenosine 2A receptors (A2A R) in tumors. These probes show promise for guiding personalized cancer treatment by imaging A2A R expression.
Area of Science:
- Radiochemistry
- Molecular Imaging
- Oncology
Background:
- Activation of adenosine 2A receptors (A2A R) contributes to tumor immunosuppression, negatively impacting immunotherapy outcomes.
- Effective visualization of A2A R is crucial for predicting and improving immunotherapy response.
Purpose of the Study:
- To design and evaluate novel fluorine-18 (18F)-labeled probes for non-invasive imaging of A2A R in tumors.
- To assess the diagnostic potential of these probes in preclinical tumor models.
Main Methods:
- Synthesis and characterization of two novel 18F-labeled probes: [18F]F-PFP2 and [18F]F-PFP4.
- In vivo evaluation of radiotracer uptake in A2A R-positive (B16F10 melanoma) and A2A R-negative (4T1 breast tumor) models.
- Assessment of probe performance in a B16F10 lung metastasis model.
Main Results:
- Both [18F]F-PFP2 and [18F]F-PFP4 demonstrated higher uptake in A2A R-positive B16F10 tumors compared to A2A R-negative 4T1 tumors.
- [18F]F-PFP2 showed significantly higher accumulation in metastatic lung lesions compared to normal lung tissue (tumor/lung ratio ~3).
- The uptake of both probes increased with time in A2A R-positive tumors.
Conclusions:
- The novel 18F-labeled probes, particularly [18F]F-PFP2, can effectively visualize A2A R expression in tumors.
- [18F]F-PFP2 holds potential for developing an A2A R-targeted imaging system for tumors.
- This imaging system could provide crucial guidance for personalized cancer therapy, especially immunotherapy.
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