DOTAGA-trastuzumab. A new antibody conjugate targeting HER2/Neu antigen for diagnostic purposes.
Fiche publication
Date publication
juin 2012
Auteurs
Membres identifiés du Cancéropôle Est :
Pr BRUNOTTE François, Dr DUCHAMP Olivier
Tous les auteurs :
Moreau M, Raguin O, Vrigneaud JM, Collin B, Bernhard C, Tizon X, Boschetti F, Duchamp O, Brunotte F, Denat F
Lien Pubmed
Résumé
Improved bifunctional chelating agents (BFC) are required for indium-111 radiolabeling of monoclonal antibodies (mAbs) under mild conditions to yield stable, target-specific agents. 2,2',2"-(10-(2,6-Dioxotetrahydro-2H-pyran-3-yl)-1,4,7,10-tetraazacyclododecane-1, 4,7-triyl)triacetic acid (DOTAGA-anhydride) was evaluated for mAb conjugation and labeling with indium-111. The DOTA analogue was synthesized and conjugated to trastuzumab-which targets the HER2/neu receptor-in mild conditions (PBS pH 7.4, 25 degrees C, 30 min) and gave a mean degree of conjugation of 2.6 macrocycle per antibody. Labeling of this immunoconjugate with indium-111 was performed in 75% yield after 1 h at 37 degrees C, and the proportion of (111)In-DOTAGA-trastuzumab reached 97% after purification. The affinity of DOTAGA-trastuzumab was 5.5 +/- 0.6 nM as evaluated by in vitro saturation assays using HCC1954 breast cancer cell line. SPECT/CT imaging and biodistribution studies were performed in mice bearing breast cancer BT-474 xenografts. BT-474 tumors were clearly visualized on SPECT images at 24, 48, and 72 h postinjection. The tumor uptake of [(111)In-DOTAGA]-trastuzumab reached 65%ID/g 72 h postinjection. These results show that the DOTAGA BFC appears to be a valuable tool for biologics conjugation.
Référence
Bioconjug Chem. 2012 Jun 20;23(6):1181-8