Affinity-Guided Conjugation to Antibodies for Use in Positron Emission Tomography.
Mikkel B SkovsgaardTroels Elmer JeppesenMichael R MortensenCarsten H NielsenJacob MadsenAndreas KjaerKurt Vesterager GothelfPublished in: Bioconjugate chemistry (2019)
The radionuclide copper-64 is widely used in combination with biomolecules, such as antibodies, for positron emission tomography (PET). Copper-64 is ideal for the imaging of biomolecules with long circulation times due to its relatively long half-life, and when conjugated to an antibody, specific cells can be targeted in vivo. Here, we have prepared a trastuzumab-chelator conjugate by using affinity-guided conjugation, in which an azide was attached to the antibody prior to a strain promoted azide-alkyne cycloaddition reaction with DBCO-PEG4-NOTA. The conjugate was benchmarked against a standard nonspecific labeled trastuzumab-NOTA conjugate. The conjugates were tested for incorporation of copper-64, stability in buffer and plasma, and tumor targeting in vivo using PET imaging of mice with xenograft tumors expressing HER2. Both conjugates showed good incorporation of copper-64 and a high stability with less than 10% degradation after 36 h. Furthermore, both conjugates showed accumulation at the tumor site with mean uptake of 7.2 ± 2.4%ID/g and 5.2 ± 1.3%ID/g after 40 h for the affinity-guided labeled trastuzumab and the nonspecific labeled trastuzumab, respectively.
Keyphrases
- pet imaging
- positron emission tomography
- cancer therapy
- computed tomography
- drug delivery
- epidermal growth factor receptor
- metastatic breast cancer
- oxide nanoparticles
- pet ct
- induced apoptosis
- high resolution
- capillary electrophoresis
- tyrosine kinase
- cell cycle arrest
- cell death
- photodynamic therapy
- skeletal muscle
- fluorescence imaging