New Tris(hydroxypyridinone) Bifunctional Chelators Containing Isothiocyanate Groups Provide a Versatile Platform for Rapid One-Step Labeling and PET Imaging with (68)Ga(3.).
Two new bifunctional tris(hydroxypyridinone) (THP) chelators designed specifically for rapid labeling with (68)Ga have been synthesized, each with pendant isothiocyanate groups and three 1,6-dimethyl-3-hydroxypyridin-4-one groups. Both compounds have been conjugated with the primary amine group of a cyclic integrin targeting peptide, RGD. Each conjugate can be radiolabeled and formulated by treatment with generator-produced (68)Ga(3+) in over 95% radiochemical yield under ambient conditions in less than 5 min, with specific activities of 60-80 MBq nmol(-1). Competitive binding assays and in vivo biodistribution in mice bearing U87MG tumors demonstrate that the new (68)Ga(3+)-labeled THP peptide conjugates retain affinity for the αvβ3 integrin receptor, clear within 1-2 h from circulation, and undergo receptor-mediated tumor uptake in vivo. We conclude that bifunctional THP chelators can be used for simple, efficient labeling of (68)Ga biomolecules under mild conditions suitable for peptides and proteins.
King's College London , Division of Imaging Sciences and Biomedical Engineering, Fourth Floor Lambeth Wing, St Thomas' Hospital, London SE1 7EH, United Kingdom.
Michelle T
MT
Ma
Peter MacCallum Cancer Centre , East Melbourne, Victoria 3002, Australia.|Sir Peter MacCallum Department of Oncology, University of Melbourne , Parkville, Victoria 3010, Australia.
Carleen
C
Cullinane
King's College London , Division of Imaging Sciences and Biomedical Engineering, Fourth Floor Lambeth Wing, St Thomas' Hospital, London SE1 7EH, United Kingdom.
Cinzia
C
Imberti
King's College London , Division of Imaging Sciences and Biomedical Engineering, Fourth Floor Lambeth Wing, St Thomas' Hospital, London SE1 7EH, United Kingdom.
Julia
J
Baguña Torres
King's College London , Division of Imaging Sciences and Biomedical Engineering, Fourth Floor Lambeth Wing, St Thomas' Hospital, London SE1 7EH, United Kingdom.
Samantha Y A
SY
Terry
Peter MacCallum Cancer Centre , East Melbourne, Victoria 3002, Australia.
Peter
P
Roselt
Peter MacCallum Cancer Centre , East Melbourne, Victoria 3002, Australia.|Sir Peter MacCallum Department of Oncology, University of Melbourne , Parkville, Victoria 3010, Australia.
Rodney J
RJ
Hicks
King's College London , Division of Imaging Sciences and Biomedical Engineering, Fourth Floor Lambeth Wing, St Thomas' Hospital, London SE1 7EH, United Kingdom.
Philip J
PJ
Blower
D000818:Animals; D002614:Chelating Agents / Q000737:chemistry* / Q000378:metabolism / Q000493:pharmacokinetics; D005710:Gallium Radioisotopes / Q000737:chemistry* / Q000378:metabolism / Q000493:pharmacokinetics; D039302:Integrin alphaVbeta3 / Q000378:metabolism; D017879:Isothiocyanates / Q000737:chemistry* / Q000378:metabolism / Q000493:pharmacokinetics; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009369:Neoplasms / Q000175:diagnosis / Q000378:metabolism; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism / Q000493:pharmacokinetics; D049268:Positron-Emission Tomography / Q000379:methods; D011728:Pyridones / Q000737:chemistry* / Q000378:metabolism / Q000493:pharmacokinetics; D014018:Tissue Distribution
C580946:1,2-hydroxypyridinone; D002614:Chelating Agents; D005710:Gallium Radioisotopes; D039302:Integrin alphaVbeta3; D017879:Isothiocyanates; D009842:Oligopeptides; D011728:Pyridones; C047981:arginyl-glycyl-aspartic acid