Purpose: Tumor Necrosis Factor Receptor 1 (TNFR1) and integrin αvβ3 receptor are overexpressed in
breast cancer. We hypothesized that a peptide ligand recognizing both receptors in a single receptor-binding
probe would be advantageous. Here, we developed a novel 18F-labeled fusion peptide probe [18F]-NOTA-Gly3-
E(2PEG4-RGD-WH701) targeting dual receptors (TNFR1 and αvβ3) and evaluated the diagnostic efficacy of
this radioactive probe in both MDA-MB-231 and MCF-7 xenograft models in mice.
Methods: The NOTA-conjugated RGD-WH701 analog was radiolabeled with 18F using NOTA-AlF chelation
method. We used two PEG4 molecules and Glutamic acid (Glu) to covalently link c(RGDyK) with WH701.
Gly3 was also added to further improve the water solubility and pharmacokinetic properties of the probe. The
expression of TNFR1 and Integrin αvβ3 in MCF-7 and MDA-MB-231 cells was detected by western blot analysis
and immunofluorescence staining. The tumor-targeting characteristics of [18F]-NOTA-Gly3-E(2PEG4-RGDWH701)
were assessed in nude mice bearing MDA-MB-231 and MCF-7 xenografts.
Results: HPLC analysis of the product NOTA-G3-E (2P4-RGD-WH701) revealed a purity >95%. The yield
after attenuation correction was approximately 33.5%±2.8% (n=5), and the radiochemical purity was above
95%. The MDA-MB-231 tumor uptake of [18F]-NOTA-Gly3-E(2PEG4-RGD-WH701) was 1.14±0.14%ID/g, as
measured by PET at 40min postinjection (p.i.). In comparison, the tumor uptake of [18F]-NOTA-RGD and [18F]-
NOTA-WH701 in MDA-MB-231 xenografts was 0.96±0.13%ID/g and 0.93±0.28%ID/g, respectively. The
MCF-7 tumor uptake of [18F]-NOTA-Gly3-E(2PEG4-RGD-WH701) was 1.22±0.11%ID/g, as measured by PET
at 40min postinjection (p.i.). In comparison, the tumor uptake of [18F]-NOTA-RGD and [18F]-NOTA-WH701 in
MCF-7 xenografts was 0.99±0.18%ID/g and 0.57±0.08%ID/g, respectively.
Conclusion: [18F]AlF-NOTA-Gly3-E(2PEG4-RGD-WH701) was successfully synthesized and labeled with 18F.
The results from the microPET/CT and biodistribution studies of [18F]AlF-NOTA-Gly3-E(2PEG4-RGDWH701)
showed that the tracer could specifically target TNFR1 and integrin αvβ3 receptors.