title: Development of new PTK7-targeting aptamer-fluorescent and -radiolabelled probes for evaluation as molecular imaging agents: Lymphoma and melanoma in vivo proof of concept.
abstract: Aptamers are single-stranded oligonucleotides that recognize molecular targets with high affinity and specificity. Aptamer that selectively bind to the protein tyrosine kinase-7 (PTK7) receptor, overexpressed on many cancers, has been labelled as probes for molecular imaging of cancer. Two new PTK7-targeting aptamer probes were developed by coupling frameworks from the fluorescent dye AlexaFluor647 or the 6-hydrazinonicotinamide (HYNIC) chelator-labelled to99mTc. The derivatizations via a 5'-aminohexyl terminal linker were done at room temperature and under mild buffer conditions. Physicochemical and biological controls for both imaging agents were performed verifying the integrity of the aptamer-conjugates by HPLC. Recognition of melanoma (B16F1) and lymphoma (A20) mouse cell lines by the aptamer was studied using cell binding, flow cytometry and confocal microscopy. Finally, in vivo imaging studies in tumour-bearing mice were performed. The new probes were able to bind to melanoma and lymphoma cell lines in vitro, the in vivo imaging in tumour-bearing mice showed different uptake behaviours showing for the fluorescent conjugate good uptake by B cell lymphoma while the radiolabelled conjugate did not display tumour uptake due to its high extravascular distribution, and both showed rapid clearance properties in tumour-bearing mice.
authors.affiliation: Área de Radiofarmacia-Centro de Investigaciones Nucleares, Facultad de Ciencias, Universidad de la República, 11400 Montevideo, Uruguay.
authors.forename: Victoria
authors.initials: V
authors.lastname: Calzada
authors.affiliation: Departamento de Desarrollo Biotecnológico-Instituto de Higiene, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
authors.forename: María
authors.initials: M
authors.lastname: Moreno
authors.affiliation: Department of Biochemistry, University of Missouri, Columbia, MO, USA; Harry S Truman Veterans' Administration Hospital, Columbia, MO, USA.
authors.forename: Jessica
authors.initials: J
authors.lastname: Newton
authors.affiliation: Laboratorio de Experimentación Animal-Centro de Investigaciones Nucleares, Facultad de Ciencias-Universidad de la República, Montevideo, Uruguay.
authors.forename: Joel
authors.initials: J
authors.lastname: González
authors.affiliation: Laboratorio de Experimentación Animal-Centro de Investigaciones Nucleares, Facultad de Ciencias-Universidad de la República, Montevideo, Uruguay.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Fernández
authors.affiliation: Centro de Medicina Nuclear-Hospital de Clínicas, Universidad de la República, Montevideo, Uruguay.
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Gambini
authors.affiliation: Centro de Evaluación de Biodisponibilidad y Bioequivalencia de Medicamentos, Universidad de la República, Montevideo, Uruguay.
authors.forename: Manuel
authors.initials: M
authors.lastname: Ibarra
authors.affiliation: Departamento de Desarrollo Biotecnológico-Instituto de Higiene, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Chabalgoity
authors.affiliation: Department of Biochemistry, University of Missouri, Columbia, MO, USA; Harry S Truman Veterans' Administration Hospital, Columbia, MO, USA.
authors.forename: Susan
authors.initials: S
authors.lastname: Deutscher
authors.affiliation: Department of Biochemistry, University of Missouri, Columbia, MO, USA; Harry S Truman Veterans' Administration Hospital, Columbia, MO, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Quinn
authors.affiliation: Área de Radiofarmacia-Centro de Investigaciones Nucleares, Facultad de Ciencias, Universidad de la República, 11400 Montevideo, Uruguay.
authors.forename: Pablo
authors.initials: P
authors.lastname: Cabral
authors.affiliation: Área de Radiofarmacia-Centro de Investigaciones Nucleares, Facultad de Ciencias, Universidad de la República, 11400 Montevideo, Uruguay. Electronic address: hcerecetto@cin.edu.uy.
authors.forename: Hugo
authors.initials: H
authors.lastname: Cerecetto
mesh_terms: D052157:Aptamers, Nucleotide / Q000138:chemical synthesis / Q000737:chemistry / Q000493:pharmacokinetics*; D015815:Cell Adhesion Molecules / Q000037:antagonists & inhibitors* / Q000378:metabolism; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry / Q000493:pharmacokinetics*; D006801:Humans; D008223:Lymphoma / Q000175:diagnosis*; D008545:Melanoma / Q000175:diagnosis*; D054802:Molecular Imprinting; D015394:Molecular Structure; D009374:Neoplasms, Experimental / Q000175:diagnosis; D047428:Protein Kinase Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000493:pharmacokinetics*; D020794:Receptor Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D013329:Structure-Activity Relationship; D014018:Tissue Distribution
chemical_list: D052157:Aptamers, Nucleotide; D015815:Cell Adhesion Molecules; D005456:Fluorescent Dyes; D047428:Protein Kinase Inhibitors; C096905:PTK7 protein, human; D020794:Receptor Protein-Tyrosine Kinases
keywords: AlexaFluor647; Aptamer; HYNIC; Molecular imaging; PTK7