Abstract
Radioimmunoconjugates are promising agents in diagnostics and treatment of different types of cancers. The aim of this study was the formulation of stable freeze dried kits of trastuzumab with three types of bifunctional chelators for further radiolabeling. The integrity of the antibody in formulated conjugates was examined with sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Trastuzumab is a humanized monoclonal antibody used in the therapy of aggressive HER2 positive breast cancer. Conjugation of trastuzumab was made with various chelators: pSCN-Bn-DTPA (1:10; 1:20; 1:50), p-SCN-Bn-DOTA (1:20), and 1B4M-DTPA (1:10; 1:20; 1:50). The purified immunoconjugates were lyophilized by applying two day protocol in order to produce the stable freeze dried kits. Cold labeling with nonradioactive isotopes LuCl3 and YCl3 was performed to examine the possible modifications of secondary structure after radioactive labeling. SDS-PAGE electrophoresis was used to estimate the purity and integrity of the antibody before and after conjugations, lyophilization and labeling under reducing conditions. The obtained results show that there is no degradation of the examined antibody. The trastuzumab-conjugates and cold labeled formulations migrated in two bands (~50 kDa and ~25 kDa), in the same way as IgG1 antibodies and unmodified trastuzumab.
Highlights
The human epidermal growth factor receptor (HER2) is overexpressed on a surface of the cells in aggressive breast cancer
There are various groups that can be attached to the bifunctional chelators (BFCAs) molecules, to achieve an easier conjugation [17]
The results have shown that the conjugation, lyophilization and label-ing were successful, without any damage to the anti-body, with absence of fragmentation, denaturation and aggregation of the trastuzumab
Summary
The human epidermal growth factor receptor (HER2) is overexpressed on a surface of the cells in aggressive breast cancer. HER2 positive breast cancers without anti-HER2 therapy lead to metastasis and very low survival rates of the patients [1]. Trastuzumab is the first approved humanized monoclonal antibody. It's a potent anti-HER2 antibody which originates from murine 4D5 antibody [2]. 1992 [3] cloned hypervariable regions from 4D5 in plasmids which are encoding formation of constant regions from human IgG1 antibody. A vector that is www.medfak.ni.ac.rs/amm encoding formation of chimeric antibody, which is humanized, was successfully generated. Trastuzumab is binding to the IV subdomain of the receptor and manifests the effect through antibodydependent cellular cytotoxicity [4]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
