title: Development and pre-clinical evaluation of new 68Ga-NOTA-folate conjugates for PET imaging of folate receptor-positive tumors.
abstract: In an attempt to develop new folate radiotracers with favorable biochemical properties for detecting folate receptor-positive cancers, we synthesized 68Ga-NOTA- and 68Ga-NOTAM-folate conjugates using a straightforward and a one-step simple reaction. Radiochemical yields were greater than 95% (decay-corrected) with total synthesis time of less than 20 min. Radiochemical purities were always greater than 98% without high-performance liquid chromatography (HPLC) purification. These synthetic approaches hold considerable promise as a rapid and simple method for 68Ga-folate conjugate preparation with high radiochemical yield in a short synthesis time. In vitro tests on the KB cell line showed that significant amounts of the radioconjugates were associated with cell fractions. Biodistribution studies in nude mice bearing human KB xenografts, demonstrated a significant tumor uptake and favorable biodistribution profile for 68Ga-NOTA-folate over the 68Ga-NOTAM-folate conjugate. The uptake in the tumors was blocked by excess injection of folic acid, suggesting a receptor-mediated process. These results demonstrate that the 68Ga-NOTA-folate conjugate may be useful as a molecular probe for detection and staging of folate receptor-positive cancers, such as ovarian cancer and their metastasis, as well as monitoring tumor response to treatment.
authors.affiliation: Cyclotron and Radiopharmaceuticals Department, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia jammaz@kfshrc.edu.sa.
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Aljammaz
authors.affiliation: Cyclotron and Radiopharmaceuticals Department, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Basim
authors.initials: B
authors.lastname: Al-Otaibi
authors.affiliation: Cyclotron and Radiopharmaceuticals Department, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Nourah
authors.initials: N
authors.lastname: Al-Hokbany
authors.affiliation: Cyclotron and Radiopharmaceuticals Department, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Suad
authors.initials: S
authors.lastname: Amer
authors.affiliation: Cyclotron and Radiopharmaceuticals Department, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Subhani
authors.initials: S
authors.lastname: Okarvi
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects*; D005492:Folic Acid / Q000138:chemical synthesis / Q000493:pharmacokinetics; D058972:Folic Acid Transporters / Q000378:metabolism*; D005710:Gallium Radioisotopes / Q000493:pharmacokinetics; D006571:Heterocyclic Compounds / Q000737:chemistry*; D006573:Heterocyclic Compounds, 1-Ring; D006801:Humans; D051379:Mice; D009062:Mouth Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000473:pathology; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays
chemical_list: D058972:Folic Acid Transporters; D005710:Gallium Radioisotopes; D006571:Heterocyclic Compounds; D006573:Heterocyclic Compounds, 1-Ring; D019275:Radiopharmaceuticals; C048993:1,4,7-triazacyclononane-N,N',N''-triacetic acid; D005492:Folic Acid
keywords: 68Ga PET radiopharmaceuticals; 68Ga-NOTA-folate; Folate receptor; ovarian cancer