Towards the development of a targeted albumin-binding radioligand: Synthesis, radiolabelling and preliminary in vivo studies
The compound named 4-[10-(4-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)butanamido)decyl]-11-[10-(β,d-glucopyranos-1-yl)-1-oxodecyl]-1,4,8,11-tetraazacyclotetradecane-1,8-diacetic acid is a newly synthesised molecule capable of binding in vivo to albumin to form a bioconjugate. This compound was given the...
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| Published in: | Nuclear medicine and biology Vol. 94-95; pp. 53 - 66 |
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| Main Authors: | , , , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
United States
Elsevier Inc
01-03-2021
Elsevier BV |
| Subjects: | |
| Online Access: | Get full text |
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| Summary: | The compound named 4-[10-(4-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)butanamido)decyl]-11-[10-(β,d-glucopyranos-1-yl)-1-oxodecyl]-1,4,8,11-tetraazacyclotetradecane-1,8-diacetic acid is a newly synthesised molecule capable of binding in vivo to albumin to form a bioconjugate. This compound was given the name, GluCAB(glucose-chelator-albumin-binder)-maleimide-1. Radiolabelled GluCAB-maleimide-1 and subsequent bioconjugate is proposed for prospective oncological applications and works on the theoretical dual-targeting principle of tumour localization through the “enhanced permeability and retention (EPR) effect” and glucose metabolism.
The precursor, GluCAB-amine-2, and subsequent GluCAB-maleimide-1 was synthesised via sequential regioselective, distal N-functionalisation of a cyclam template with a tether containing a synthetically-derived β-glucoside followed by a second linker to incorporate a maleimide moiety for albumin-binding. GluCAB-amine-2 was radiolabelled with [64Cu]CuCl2 in 0.1 M NH4OAc (pH 3.5, 90 °C, 30 min), purified and converted post-labeling in 0.01 M PBS to [64Cu]Cu-GluCAB-maleimide-1. Serum stability and protein binding studies were completed according to described methods. Healthy BALB/c ice (three groups of n = 5) were injected intravenously with [64Cu]Cu-TETA, [64Cu]Cu-GluCAB-amine-2 or [64Cu]Cu-GluCAB-maleimide-1 and imaged using microPET/CT at 1, 2, 4, 8 and 24 h post-injection. Biodistribution of the compounds were determined ex vivo after 24 h using gamma counting.
GluCAB-maleimide-1 was synthesised in five consecutive steps with an overall yield of 11%. [64Cu]Cu-GluCAB-amine-2 (97% labelling efficiency) was converted to [64Cu]Cu-GluCAB-maleimide-1 (93% conversion; 90% radiochemical purity). Biodistribution analysis indicated that the control compounds were rapidly and almost completely excreted as compared to [64Cu]Cu-GluCAB-maleimide-1 that exhibited a prolonged biological half-life (6–8 h). Both, [64Cu]Cu-GluCAB-maleimide-1 and -amine-2 were excreted through the hepatobiliary system but a higher hepatic presence of the albumin-bound compound was noted.
This initial evaluation paves the way for further investigation into the tumour targeting potential of [64Cu]Cu-GluCAB-maleimide-1. An efficient targeted radioligand will allow for further development of a prospective theranostic agent for more personalized patient treatment which potentially improves overall patient prognosis, outcome and health care.
GluCAB is a newly synthesised radioligand designed to bind in vivo to albumin (HSA) for the purpose of development as a potential dual-targeting oncological theranostic agent. Subsequent to its synthesis and 64Cu-radiolabelling, this radioligand has shown a prolonged circulation time in healthy mice but with appropriate systemic clearance within 24 h. This radioligand met the criteria to be further investigated for tumour targeting and uptake. [Display omitted] |
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| Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
| ISSN: | 0969-8051 1872-9614 1872-9614 |
| DOI: | 10.1016/j.nucmedbio.2021.01.001 |