Cold labeled trastuzumab-p-SCN-Bn-DTPA and trastuzumab-p-SCN-Bn-1B4M-DTPA conjugates– preparation and spectroscopic analysis

Sterjova, Marija and Dzodic, Predrag and Makreski, Petre and Janevik-Ivanovska, Emilija (2018) Cold labeled trastuzumab-p-SCN-Bn-DTPA and trastuzumab-p-SCN-Bn-1B4M-DTPA conjugates– preparation and spectroscopic analysis. In: VII Serbian Congress of Pharmacy with international participation, 10-14 Oct 2018, Belgrade, Serbia.

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Introduction and aim: The importance of immunoconjugates in treatment of various cancers was motivation for us to formulate a stable cold labeled trastuzumab conjugates with two bifunctional chelators (BFCAs) (p-SCN-Bn-1B4M-DTPA (2-(4-isothiocyanatobenzyl)-6-methyl-diethylene-triaminepentaacetic acid and p-SCN-Bn-DTPA (2-(4-izothiocyanatobenzyl)-diethylenetriaminepentaacetic acid)). The labeling with non-radioactive LuCl3 and YCl3 is important to determine the possible physicochemical changes in the structure of immunoconjugates after metal binding. ATR-IR (Attenuated total reflectance-infrared) and Raman spectroscopy as powerful and non-destructive techniques are appropriate for verification of possible secondary structure chances of trastuzumab after conjugation and labeling.
Methodology: Anti-HER2/neu monoclonal antibody trastuzumab was conjugated with p-SCN-Bn-DTPA, p-SCN-Bn-1B4M-DTPA in ratio of 1:10 and 1:50 and lyophilized to solid state. The freeze dried conjugates were labeled with cold LuCl3 and YCl3. The retained secondary structure of the antibody was proven by spectroscopic analysis with ATR-IR and Raman spectroscopy and compared with purified trastuzumab from commercial product Herceptin®.
Results and discussion: The ATR-IR and Raman spectra of four samples have shown the presence of characteristic amide bands and retained native IgG1 structure of the antibody principally composed of β-sheets. Characteristic amide I band at ~1670 cm-1 and amide III band (1230-1300 cm-1) were detected in Raman spectra. IR spectra also contain the amide I (1700-1600 cm-1), amide II (1480-1575 cm-1) and amide III bands (1255-1244 cm-1) specific for secondary structure of the proteins.
Conclusion: No significant changes in antibody structure after cold labeling gives us a hope for further radiolabeling of immunoconjugates with 177LuCl3 and 90YCl3 and development of radioimmunotherapeutics and diagnostic products active against HER2 positive breast tumors.

Item Type: Conference or Workshop Item (Poster)
Subjects: Medical and Health Sciences > Health sciences
Divisions: Faculty of Medical Science
Depositing User: Marija Arev
Date Deposited: 03 Dec 2018 08:59
Last Modified: 03 Dec 2018 08:59

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