中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
—— | N,N',N'',N'''-tetrakis-(p-tolylsulphonyl)-triethylenetetramine | 55442-07-4 | C34H42N4O8S4 | 762.993 |
N,N′,N′′-三(对甲苯磺酰)二乙撑三胺 | 1,4,7-tritosyl-1,4,7-triazaheptane | 56187-04-3 | C25H31N3O6S3 | 565.736 |
—— | 1,8-bis(p-toluenesulfonyloxy)-3,6-bis(p-toluenesulfonyl)-3,6-diazaoctane | 56234-52-7 | C34H40N2O10S4 | 764.963 |
N,N-双[2-(对甲苯磺酰氧基)乙基]-对甲苯磺酰胺 | N,N-bis(tosyloxyethyl)-p-toluenesulfonamide | 16695-22-0 | C25H29NO8S3 | 567.705 |
The development of 64Cu-based immuno-PET radiotracers requires the use of copper-specific bifunctional chelators (BFCs) that contain functional groups allowing both convenient bioconjugation and stable copper complexes to limit in vivo bioreduction, transmetallation and/or transchelation. The excellent in vivo kinetic inertness of the pentaazamacrocyclic [64Cu]Cu-15-5 complex prompted us to investigate its potential for the 64Cu-labelling of monoclonal antibodies (mAbs), compared with the well-known NODAGA and DOTA chelators. To this end, three NODAGA, DOTA and 15-5-derived BFCs, containing a pendant azadibenzocyclooctyne moiety, were synthesised and a robust methodology was determined to form covalent bonds between them and azide-functionalised trastuzumab, an anti-HER2 mAb, using strain-promoted azide-alkyne cycloaddition. Unlike the DOTA derivative, the NODAGA- and 15-5-mAb conjugates were radiolabelled with 64Cu, obtaining excellent radiochemical yields, under mild conditions. Although all the radioimmunoconjugates showed excellent stability in PBS or mouse serum, [64Cu]Cu-15-5- and [64Cu]Cu-NODAGA-trastuzumab presented higher resistance to transchelation when challenged by EDTA. Finally, the immunoreactive fraction of the radioimmunoconjugates (88–94%) was determined in HER-2 positive BT474 human breast cancer cells, confirming that the bioconjugation and radiolabelling processes implemented had no significant impact on antigen recognition.