title: [(68) Ga]-HP-DO3A-nitroimidazole: a promising agent for PET detection of tumor hypoxia.
abstract: The goal of this study is to evaluate a new (68) Ga-based imaging agent for detecting tumor hypoxia using positron emission tomography (PET). The new hypoxia targeting agent reported here, [(68) Ga]-HP-DO3A-nitroimidazole ([(68) Ga]-HP-DO3A-NI), was constructed by linking a nitroimidazole moiety with the macrocyclic ligand component of ProHance®, HP-DO3A. The hypoxia targeting capability of this agent was evaluated in A549 lung cancer cells in vitro and in SCID mice bearing subcutaneous A549 tumor xenografts. The cellular uptake assays showed that significantly more [(68) Ga]-HP-DO3A-NI accumulates in hypoxic tumor cells at 30, 60 and 120 min than in the same cells exposed to 21% O2 . The agent also accumulated in hypoxic tumors in vivo to give a tumor/muscle ratio (T/M) of 5.0 ± 1.2 (n = 3) as measured by PET at 2 h post-injection (p.i.). This was further confirmed by ex vivo biodistribution data. In addition, [(68) Ga]-HP-DO3A-NI displayed very favorable pharmacokinetic properties, as it was cleared largely through the kidneys with little to no accumulation in liver, heart or lung (%ID/g < 0.5%) at 2 h p.i. The specificity of the agent for hypoxic tissues was further validated in a comparative study with a control compound, [(68) Ga]-HP-DO3A, which lacks the nitroimidazole moiety, and by PET imaging of tumor-bearing mice breathing air versus 100% O2 . Given the commercial availability of cGMP (68) Ge/(68) Ga generators and the ease of (68) Ga labeling, the new agent could potentially be widely applied for imaging tumor hypoxia prior to radiation therapy.
authors.affiliation: Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA.|Deparatment of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Yunkou
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Deparatment of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Guiyang
authors.initials: G
authors.lastname: Hao
authors.affiliation: Deparatment of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Saleh
authors.initials: S
authors.lastname: Ramezani
authors.affiliation: Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Debabrata
authors.initials: D
authors.lastname: Saha
authors.affiliation: Deparatment of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Dawen
authors.initials: D
authors.lastname: Zhao
authors.affiliation: Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA.|Deparatment of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Xiankai
authors.initials: X
authors.lastname: Sun
authors.affiliation: Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA.|Deparatment of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA.|Department of Chemistry, University of Texas at Dallas, Richardson, TX, 75080, USA.
authors.forename: A Dean
authors.initials: AD
authors.lastname: Sherry
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000502:physiology; D015687:Cell Hypoxia / Q000502:physiology*; D045744:Cell Line, Tumor; D003287:Contrast Media / Q000737:chemistry*; D005260:Female; D005710:Gallium Radioisotopes / Q000737:chemistry*; D006573:Heterocyclic Compounds, 1-Ring / Q000737:chemistry*; D006801:Humans; D007553:Isotope Labeling / Q000379:methods; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D051379:Mice; D016513:Mice, SCID; D009368:Neoplasm Transplantation; D009593:Nitroimidazoles / Q000737:chemistry*; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D014183:Transplantation, Heterologous
chemical_list: C544520:10-(2-hydroxypropyl)-1,4,7-tetraazacyclododecane-1,4,7-triacetic acid; D003287:Contrast Media; D005710:Gallium Radioisotopes; D006573:Heterocyclic Compounds, 1-Ring; D009593:Nitroimidazoles; D019275:Radiopharmaceuticals
keywords: 68Ga; PET; nitroimidazole; tumor hypoxia