title: Synthesis and Evaluation of 64Cu-DOTA-NT-Cy5.5 as a Dual-Modality PET/Fluorescence Probe to Image Neurotensin Receptor-Positive Tumor.
abstract: Overexpression of neurotensin receptors (NTRs) has been suggested to play important roles in the growth and survival of a variety of tumor types. The aim of this study is to develop a dual-modality probe (64Cu -DOTA-NT-Cy5.5) for imaging NTR1 expression in vivo with both positron emission tomography (PET) and fluorescence. In this approach, the thiol group and N terminal amino group of neurotensin analogue (Cys-NT) were chemically modified with Cy5.5 dye and DOTA chelator, respectively. After radiolabeling with 64Cu, the resulting probe (64Cu-DOTA-NT-Cy5.5) was evaluated in NTR1 positive HT-29 tumor model. Small animal PET quantification analysis demonstrated that the tumor uptake was 1.91±0.22 and 1.79±0.16%ID/g at 1 and 4 h postinjection (p.i.), respectively. The tumor-to-muscle ratio was 17.44±3.25 at 4 h p.i. based on biodistribution. Receptor specificity was confirmed by the successful blocking experiment at 4 h p.i. (0.42±0.05%ID/g). In parallel with PET experiment, fluorescence imaging was also performed, which demonstrated prominent tumor uptake in HT-29 model. As a proof of concept, an imaging guided surgery was performed to the fluorescent moiety of this probe and could provide potential surgery guidance for NTR positive patients. In summary, our results clearly indicated that the dual-modality probe, 64Cu-DOTA-NT-Cy5.5, could serve as a promising agent to image NTR positive tumors in vivo.
authors.affiliation: †Biomedical Research Imaging Center and Department of Radiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.|‡PET/CT Center, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510230, China.
authors.forename: Huaifu
authors.initials: H
authors.lastname: Deng
authors.affiliation: †Biomedical Research Imaging Center and Department of Radiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.affiliation: †Biomedical Research Imaging Center and Department of Radiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.
authors.forename: Mengzhe
authors.initials: M
authors.lastname: Wang
authors.affiliation: †Biomedical Research Imaging Center and Department of Radiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.
authors.forename: Zibo
authors.initials: Z
authors.lastname: Li
authors.affiliation: †Biomedical Research Imaging Center and Department of Radiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.
authors.forename: Zhanhong
authors.initials: Z
authors.lastname: Wu
mesh_terms: D000818:Animals; D002232:Carbocyanines / Q000493:pharmacokinetics; D002614:Chelating Agents / Q000493:pharmacokinetics; D003110:Colonic Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology; D003301:Copper Radioisotopes / Q000493:pharmacokinetics*; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000493:pharmacokinetics*; D006573:Heterocyclic Compounds, 1-Ring / Q000493:pharmacokinetics*; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D018028:Receptors, Neurotensin / Q000378:metabolism*; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays
chemical_list: C098793:CY5.5 cyanine dye; D002232:Carbocyanines; D002614:Chelating Agents; D003301:Copper Radioisotopes; D005456:Fluorescent Dyes; D006573:Heterocyclic Compounds, 1-Ring; D019275:Radiopharmaceuticals; D018028:Receptors, Neurotensin; C071349:1,4,7,10-tetraazacyclododecane- 1,4,7,10-tetraacetic acid
keywords: 64Cu; dual-modality; fluorescence imaging; neurotensin; positron emission tomography