Selection of an optimal cysteine-containing peptide-based chelator for labeling of affibody molecules with (188)Re.

• 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.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Annan medicin och hälsovetenskap -- Övrig annan medicin och hälsovetenskap (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Other Medical and Health Sciences -- Other Medical and Health Sciences not elsewhere specified (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinsk bioteknologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Medical Biotechnology (hsv//eng)

Keyword

Affibody

Affinity discrimination

Cell surface display

FACS

Gram positive

Staphylococcus carnosus

immunoglobulin G

membrane protein

antibody combining site

article

binding affinity

cell interaction

cellular distribution

evaluation

fluorescence activated cell sorting

nonhuman

priority journal

protein domain

protein expression

protein localization

protein targeting

signal transduction

Staphylococcus

Staphylococcus carnosus

surface property

Amino Acid Sequence

Antibody Affinity

Flow Cytometry

Immunoglobulin G

Molecular Sequence Data

Mutation

Peptide Library

Protein Structure

Tertiary

Recombinant Proteins

Sequence Alignment

Staphylococcal Protein A

Staphylococcus

Transformation

Bacterial

Posibacteria

Staphylococcus carnosus

Publication and Content Type

ref (subject category)

art (subject category)