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Affibody molecules for PET imaging

Strand, Joanna LU (2015) In Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine
Abstract
Optimization of Affibody molecules would allow for high contrast imaging of cancer associated surface receptors using molecular imaging. The primary aim of the thesis was to develop Affibody-based PET imaging agents to provide the highest possible sensitivity of RTK detection in vivo. The thesis evaluates the effect of radiolabelling chemistry on biodistribution and targeting properties of Affibody molecules directed against HER2 and PDGFRβ. The thesis is based on five published papers (I-V).

Paper I. The targeting properties of maleimido derivatives of DOTA and NODAGA for site-specific labelling of a recombinant HER2-binding Affibody molecule radiolabelled with 68Ga were compared in vivo. Favourable in vivo properties were seen... (More)
Optimization of Affibody molecules would allow for high contrast imaging of cancer associated surface receptors using molecular imaging. The primary aim of the thesis was to develop Affibody-based PET imaging agents to provide the highest possible sensitivity of RTK detection in vivo. The thesis evaluates the effect of radiolabelling chemistry on biodistribution and targeting properties of Affibody molecules directed against HER2 and PDGFRβ. The thesis is based on five published papers (I-V).

Paper I. The targeting properties of maleimido derivatives of DOTA and NODAGA for site-specific labelling of a recombinant HER2-binding Affibody molecule radiolabelled with 68Ga were compared in vivo. Favourable in vivo properties were seen for the Affibody molecule with the combination of 68Ga with NODAGA.

Paper II. The aim was to compare the biodistribution of 68Ga- and 111In-labelled HER2-targeting Affibody molecules containing DOTA, NOTA and NODAGA at the N-terminus. This paper also demonstrated favourable in vivo properties for Affibody molecules in combination with 68Ga and NODAGA placed on the N-terminus.

Paper III. The influence of chelator positioning on the synthetic anti-HER2 affibody molecule labelled with 68Ga was investigated. The chelator DOTA was conjugated either at the N-terminus, the middle of helix-3 or at the C-terminus of the Affibody molecules. The N-terminus placement provided the highest tumour uptake and tumour-to-organ ratios.

Paper IV. The aim of this study was to evaluate if the 68Ga labelled PDGFRβ-targeting Affibody would provide an imaging agent suitable for PDGFRβ visualization using PET. The 68Ga labelled conjugate provided high-contrast imaging of PDGFRβ-expressing tumours in vivo using microPET as early as 2h after injection.

Paper V. This paper investigated if the replacement of IHPEM with IPEM as a linker molecule for radioiodination of Affibody molecules would reduce renal retention of radioactivity. Results showed that the use of the more lipophilic linker IPEM reduced the renal radioactivity retention for radioiodinated Affibody molecules.

In conclusion, this thesis clearly demonstrates that the labelling strategy is of great importance with a substantial influence on the targeting properties of Affibody molecules and should be taken under serious considerations when developing new imaging agents. (Less)
Please use this url to cite or link to this publication:
author
supervisor
publishing date
type
Thesis
publication status
published
subject
in
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine
issue
1125
pages
70 pages
publisher
Acta Universitatis Upsaliensis
ISSN
1651-6206
ISBN
978-91-554-9299-1
language
English
LU publication?
no
id
656992e0-e092-4ad0-9472-a31f84ddfcd7
alternative location
https://uu.diva-portal.org/smash/record.jsf?pid=diva2%3A844633&dswid=-7895
date added to LUP
2023-05-18 00:17:53
date last changed
2023-05-23 13:28:17
@phdthesis{656992e0-e092-4ad0-9472-a31f84ddfcd7,
  abstract     = {{Optimization of Affibody molecules would allow for high contrast imaging of cancer associated surface receptors using molecular imaging. The primary aim of the thesis was to develop Affibody-based PET imaging agents to provide the highest possible sensitivity of RTK detection in vivo. The thesis evaluates the effect of radiolabelling chemistry on biodistribution and targeting properties of Affibody molecules directed against HER2 and PDGFRβ. The thesis is based on five published papers (I-V).<br/><br/>Paper I. The targeting properties of maleimido derivatives of DOTA and NODAGA for site-specific labelling of a recombinant HER2-binding Affibody molecule radiolabelled with 68Ga were compared in vivo. Favourable in vivo properties were seen for the Affibody molecule with the combination of 68Ga with NODAGA.<br/><br/>Paper II. The aim was to compare the biodistribution of 68Ga- and 111In-labelled HER2-targeting Affibody molecules containing DOTA, NOTA and NODAGA at the N-terminus. This paper also demonstrated favourable in vivo properties for Affibody molecules in combination with 68Ga and NODAGA placed on the N-terminus.<br/><br/>Paper III.  The influence of chelator positioning on the synthetic anti-HER2 affibody molecule labelled with 68Ga was investigated. The chelator DOTA was conjugated either at the N-terminus, the middle of helix-3 or at the C-terminus of the Affibody molecules. The N-terminus placement provided the highest tumour uptake and tumour-to-organ ratios.<br/><br/>Paper IV. The aim of this study was to evaluate if the 68Ga labelled PDGFRβ-targeting Affibody would provide an imaging agent suitable for PDGFRβ visualization using PET. The 68Ga labelled conjugate provided high-contrast imaging of PDGFRβ-expressing tumours in vivo using microPET as early as 2h after injection.<br/><br/>Paper V. This paper investigated if the replacement of IHPEM with IPEM as a linker molecule for radioiodination of Affibody molecules would reduce renal retention of radioactivity. Results showed that the use of the more lipophilic linker IPEM reduced the renal radioactivity retention for radioiodinated Affibody molecules.<br/><br/>In conclusion, this thesis clearly demonstrates that the labelling strategy is of great importance with a substantial influence on the targeting properties of Affibody molecules and should be taken under serious considerations when developing new imaging agents.}},
  author       = {{Strand, Joanna}},
  isbn         = {{978-91-554-9299-1}},
  issn         = {{1651-6206}},
  language     = {{eng}},
  month        = {{10}},
  number       = {{1125}},
  publisher    = {{Acta Universitatis Upsaliensis}},
  series       = {{Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine}},
  title        = {{Affibody molecules for PET imaging}},
  url          = {{https://uu.diva-portal.org/smash/record.jsf?pid=diva2%3A844633&dswid=-7895}},
  year         = {{2015}},
}