Preparation of 68Ga and radiolabelling of anti-HER-2 antibodies

Kód výsledku v IS VaVaI

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Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Preparation of 68Ga and radiolabelling of anti-HER-2 antibodies

Popis výsledku v původním jazyce

This thesis is focused on the development of 68Ge/68Ga radionuclide generator and subsequent use of 68Ga in theranostic pair with 225Ac in radioimmunodiagnostics and therapy.nThe first part is focused on 68Ge/68Ga radionuclide generator for use in nuclear medicine The theoretical part sums up the current state of art of 68Ge/68Ga radionuclide generators and focuses on characteristics of chosen sorption material, cerium dioxide.nThe experimental part is drowned up as a comment of published data. Cerium dioxide was prepared and characterised by available spectrometric methods. Subsequently, its sorption properties were tested regarding 68Ge/68Ga separation. At the end, the experimental 68Ge/68Ga radionuclide generator with nominal activity of 68Ge 119,1 MBq was prepared using CeO2-PAN composite sorbent. The generator was tested for 18 months. It provided 68Ga with yield over 60 % in 1.8 ml for the whole period of testing. Contamination of eluate by 68Ge was decreased after three months of testing under the limit of 0.001 %. The used sorbent CeO2-PAN proved high radiation stability as the contamination of eluate by cerium was held under 5 ppm. The applicability of 68Ga eluate was confirmed by labelling of DOTA chelator and DOTA-TOC peptide. The developed generator is protected by Czech utility model.nIn the second part of the thesis the focus was moved to radioimmunodiagnostics/therapy of oncologic diseases with HER2 overexpression. The principles and the current state of art of research and use of radioimmunoconjugates labelled with mainly 68Ga and 225Ac are described.nThe experimental part is then focused on the development of a radioimmunoconjugate of HER2 targeting monoclonal antibody pertuzumab. Three conjugates of pertuzumab and one conjugate of trastuzumab for comparison were synthesized. The conjugates were firstly radiolabelled with the theranostic pair of radionuclides 68Ga and 225Ac. On the basis of this experiment, two conjugates labelled with 225Ac, 225Ac-DOTA-pertuzumab and 225Ac-DOTA-trastuzumab, were tested in vitro in stability and cell studies. The stability studies confirmed high stability of both conjugates in phosphate buffered saline (PBS) and fetal bovine serum (FBS) for 10 days. Cell studies then confirmed their binding specificity for HER2 and determined dissociation constants of conjugates similar to those found in literature. The central compound of the whole study, 225Ac-DOTA-pertuzumab was studied in ex vivo biodistribution study with normal and tumour xenografted mice lasting 7 days. It proved high uptake in HER2+ tumour, 50 ± 14 %ID/g, and low uptake in HER2- tumour, 5 ± 1,7 %ID/g. The activity of 225Ac-DOTA-pertuzumab measured in blood decreased exponentially and the uptake in liver attributed to the conjugate elimination did not exceed 10 %ID/g. Recorded high uptake in spleen of xenografted mice was attributed to the use of immunodeficient mouse strain SCID. The gained results confirmed the potential of 225Ac-DOTA-pertuzumab and its further testing in in vivo therapeutic studies is then highly desirable.nThanks to the interdisciplinary nature of this thesis its results broaden knowledge of various fields: material research, radionuclide production, nuclear medicine and radiopharmacy.

Název v anglickém jazyce

Preparation of 68Ga and radiolabelling of anti-HER-2 antibodies

Popis výsledku anglicky

This thesis is focused on the development of 68Ge/68Ga radionuclide generator and subsequent use of 68Ga in theranostic pair with 225Ac in radioimmunodiagnostics and therapy.nThe first part is focused on 68Ge/68Ga radionuclide generator for use in nuclear medicine The theoretical part sums up the current state of art of 68Ge/68Ga radionuclide generators and focuses on characteristics of chosen sorption material, cerium dioxide.nThe experimental part is drowned up as a comment of published data. Cerium dioxide was prepared and characterised by available spectrometric methods. Subsequently, its sorption properties were tested regarding 68Ge/68Ga separation. At the end, the experimental 68Ge/68Ga radionuclide generator with nominal activity of 68Ge 119,1 MBq was prepared using CeO2-PAN composite sorbent. The generator was tested for 18 months. It provided 68Ga with yield over 60 % in 1.8 ml for the whole period of testing. Contamination of eluate by 68Ge was decreased after three months of testing under the limit of 0.001 %. The used sorbent CeO2-PAN proved high radiation stability as the contamination of eluate by cerium was held under 5 ppm. The applicability of 68Ga eluate was confirmed by labelling of DOTA chelator and DOTA-TOC peptide. The developed generator is protected by Czech utility model.nIn the second part of the thesis the focus was moved to radioimmunodiagnostics/therapy of oncologic diseases with HER2 overexpression. The principles and the current state of art of research and use of radioimmunoconjugates labelled with mainly 68Ga and 225Ac are described.nThe experimental part is then focused on the development of a radioimmunoconjugate of HER2 targeting monoclonal antibody pertuzumab. Three conjugates of pertuzumab and one conjugate of trastuzumab for comparison were synthesized. The conjugates were firstly radiolabelled with the theranostic pair of radionuclides 68Ga and 225Ac. On the basis of this experiment, two conjugates labelled with 225Ac, 225Ac-DOTA-pertuzumab and 225Ac-DOTA-trastuzumab, were tested in vitro in stability and cell studies. The stability studies confirmed high stability of both conjugates in phosphate buffered saline (PBS) and fetal bovine serum (FBS) for 10 days. Cell studies then confirmed their binding specificity for HER2 and determined dissociation constants of conjugates similar to those found in literature. The central compound of the whole study, 225Ac-DOTA-pertuzumab was studied in ex vivo biodistribution study with normal and tumour xenografted mice lasting 7 days. It proved high uptake in HER2+ tumour, 50 ± 14 %ID/g, and low uptake in HER2- tumour, 5 ± 1,7 %ID/g. The activity of 225Ac-DOTA-pertuzumab measured in blood decreased exponentially and the uptake in liver attributed to the conjugate elimination did not exceed 10 %ID/g. Recorded high uptake in spleen of xenografted mice was attributed to the use of immunodeficient mouse strain SCID. The gained results confirmed the potential of 225Ac-DOTA-pertuzumab and its further testing in in vivo therapeutic studies is then highly desirable.nThanks to the interdisciplinary nature of this thesis its results broaden knowledge of various fields: material research, radionuclide production, nuclear medicine and radiopharmacy.

Druh

O - Ostatní výsledky

CEP obor

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OECD FORD obor

30224 - Radiology, nuclear medicine and medical imaging

Projekt

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Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2024

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů