title: Selection of an optimal cysteine-containing peptide-based chelator for labeling of affibody molecules with (188)Re.
abstract: Affibody molecules constitute a class of small (7 kDa) scaffold proteins that can be engineered to have excellent tumor targeting properties. High reabsorption in kidneys complicates development of affibody molecules for radionuclide therapy. In this study, we evaluated the influence of the composition of cysteine-containing C-terminal peptide-based chelators on the biodistribution and renal retention of (188)Re-labeled anti-HER2 affibody molecules. Biodistribution of affibody molecules containing GGXC or GXGC peptide chelators (where X is G, S, E or K) was compared with biodistribution of a parental affibody molecule ZHER2:2395 having a KVDC peptide chelator. All constructs retained low picomolar affinity to HER2-expressing cells after labeling. The biodistribution of all (188)Re-labeled affibody molecules was in general comparable, with the main observed difference found in the uptake and retention of radioactivity in excretory organs. The (188)Re-ZHER2:V2 affibody molecule with a GGGC chelator provided the lowest uptake in all organs and tissues. The renal retention of (188)Re-ZHER2:V2 (3.1 ± 0.5 %ID/g at 4 h after injection) was 55-fold lower than retention of the parental (188)Re-ZHER2:2395 (172 ± 32 %ID/g). We show that engineering of cysteine-containing peptide-based chelators can be used for significant improvement of biodistribution of (188)Re-labeled scaffold proteins, particularly reduction of their uptake in excretory organs.
authors.affiliation: Division of Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Altai
authors.affiliation: Division of Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden.
authors.forename: Hadis
authors.initials: H
authors.lastname: Honarvar
authors.affiliation: KTH Royal Institute of Technology, School of Biotechnology, Division of Protein Technology, Stockholm, Sweden; Division of Biochemistry, Dept. of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Helena
authors.initials: H
authors.lastname: Wållberg
authors.affiliation: Division of Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden.
authors.forename: Joanna
authors.initials: J
authors.lastname: Strand
authors.affiliation: Preclinical PET Platform, Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden.
authors.forename: Zohreh
authors.initials: Z
authors.lastname: Varasteh
authors.affiliation: Preclinical PET Platform, Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Rosestedt
authors.affiliation: Preclinical PET Platform, Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Orlova
authors.affiliation: Affibody AB, Stockholm, Sweden.
authors.forename: Finn
authors.initials: F
authors.lastname: Dunås
authors.affiliation: Medical Physics Uppsala University Hospital, Uppsala, Sweden.
authors.forename: Mattias
authors.initials: M
authors.lastname: Sandström
authors.affiliation: KTH Royal Institute of Technology, School of Biotechnology, Division of Protein Technology, Stockholm, Sweden.
authors.forename: John
authors.initials: J
authors.lastname: Löfblom
authors.affiliation: Division of Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden. Electronic address: vladimir.tolmachev@bms.uu.se.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Tolmachev
authors.affiliation: KTH Royal Institute of Technology, School of Biotechnology, Division of Protein Technology, Stockholm, Sweden.
authors.forename: Stefan
authors.initials: S
authors.lastname: Ståhl
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D045744:Cell Line, Tumor; D002614:Chelating Agents / Q000737:chemistry*; D003545:Cysteine / Q000032:analysis*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D011868:Radioisotopes / Q000737:chemistry*; D011993:Recombinant Fusion Proteins / Q000737:chemistry*; D012211:Rhenium / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid
chemical_list: D002614:Chelating Agents; D010455:Peptides; D011868:Radioisotopes; D011993:Recombinant Fusion Proteins; D012211:Rhenium; D003545:Cysteine
keywords: Affibody; Biodistribution; HER2; Peptide-based chelator; Radionuclide therapy; Rhenium-188