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Molecular imaging of glioblastoma multiforme using anti-insulin-like growth factor-binding protein-7 single-domain antibodies.

Iqbal U, Albaghdadi H, Luo Y, Arbabi M, Desvaux C, Veres T, Stanimirovic D, Abulrob A - Br. J. Cancer (2010)

Bottom Line: In vivo, intravenously injected anti-IGFBP7 sdAb-Cy5.5 bound to GBM vessels creating high imaging signal in the intracranial tumour.Fluorescent microscopy confirmed the presence of anti-IGFBP7 sdAb and anti-IGFBP7 sdAb-PEGylated Fe₃O₄ NPs selectively in GBM vessels.Anti-IGFBP7 sdAbs are novel GBM vessel-targeting moieties suitable for molecular imaging.

View Article: PubMed Central - PubMed

Affiliation: Institute for Biological Sciences, National Research Council of Canada, 1200 Montreal Road, Ottawa, Ontario, Canada K1A 0R6.

ABSTRACT

Background: Insulin-like growth factor-binding protein 7 (IGFBP7) is an abundant, selective and accessible biomarker of glioblastoma multiforme (GBM) tumour vessels. In this study, an anti-IGFBP7 single-domain antibody (sdAb) was developed to target GBM vessels for molecular imaging applications.

Methods: Human GBM was modelled in mice by intracranial implantation of U87MG.EGFRvIII cells. An anti-IGFBP7 sdAb, isolated from an immune llama library by panning, was assessed in vitro for its binding affinity using surface plasmon resonance and by ex vivo immunobinding on mouse and human GBM tissue. Tumour targeting by Cy5.5-labelled anti-IGFBP7 sdAb as well as by anti-IGFBP7 sdAb conjugated to PEGylated Fe₃O₄ nanoparticles (NPs)-Cy5.5 were assessed in U87MG.EGFRvIII tumour-bearing mice in vivo using optical imaging and in brain sections using fluorescent microscopy.

Results: Surface plasmon resonance analyses revealed a medium affinity (K(D)=40-50 nM) binding of the anti-IGFBP7 sdAb to the purified antigen. The anti-IGFBP7 sdAb also selectively bound to both mouse and human GBM vessels, but not normal brain vessels in tissue sections. In vivo, intravenously injected anti-IGFBP7 sdAb-Cy5.5 bound to GBM vessels creating high imaging signal in the intracranial tumour. Similarly, the anti-IGFBP7 sdAb-functionalised PEGylated Fe₃O₄ NP-Cy5.5 demonstrated enhanced tumour signal compared with non-targeted NPs. Fluorescent microscopy confirmed the presence of anti-IGFBP7 sdAb and anti-IGFBP7 sdAb-PEGylated Fe₃O₄ NPs selectively in GBM vessels.

Conclusions: Anti-IGFBP7 sdAbs are novel GBM vessel-targeting moieties suitable for molecular imaging.

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Related in: MedlinePlus

Fluorescent and light microscopic images of mouse orthotopic GBM tumour sections obtained 24 h after intravenous (i.v.) injection of 100 μg anti-IGFBP7 sdAb-Cy5.5. (A) Sections of brain tumour stained with hematoxylin and eosin staining showing brain tumour boundaries from the ipsilatelar healthy brain tissue (left panel, low magnification; right panel, high magnification). Higher magnification fluorescent images of tumour centre (B) and contralateral healthy brain region (C) showing colocalisation of the systemically injected anti-IGFBP7 sdAb-Cy5.5 (red; middle panels) and brain vessels stained with the 40 μg fluorescein tomato lectin (green; right panels) injected i.v. 10 min before killing, and their composite overlay images with nuclei stained with DAPI (blue; left panels). Scale bar: 50 μm. (D) Lower magnification image of the tumour and normal brain illustrating that injected anti-IGFBP7 sdAb-Cy5.5 (red) decorates selectively a majority of tumour vessels 24 h after i.v. injection. Scale bar: 100 μm.
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fig4: Fluorescent and light microscopic images of mouse orthotopic GBM tumour sections obtained 24 h after intravenous (i.v.) injection of 100 μg anti-IGFBP7 sdAb-Cy5.5. (A) Sections of brain tumour stained with hematoxylin and eosin staining showing brain tumour boundaries from the ipsilatelar healthy brain tissue (left panel, low magnification; right panel, high magnification). Higher magnification fluorescent images of tumour centre (B) and contralateral healthy brain region (C) showing colocalisation of the systemically injected anti-IGFBP7 sdAb-Cy5.5 (red; middle panels) and brain vessels stained with the 40 μg fluorescein tomato lectin (green; right panels) injected i.v. 10 min before killing, and their composite overlay images with nuclei stained with DAPI (blue; left panels). Scale bar: 50 μm. (D) Lower magnification image of the tumour and normal brain illustrating that injected anti-IGFBP7 sdAb-Cy5.5 (red) decorates selectively a majority of tumour vessels 24 h after i.v. injection. Scale bar: 100 μm.

Mentions: U87MG brain tumours grew in a spherical shape that was easily distinguishable from the surrounding health brain, when visualised by hematoxylin and eosin staining (Figure 4A). At higher magnification, hematoxylin and eosin staining clearly illustrates the demarcation of the increased cellularity of the tumour vs the normal brain regions (Figure 4A, right panel).


Molecular imaging of glioblastoma multiforme using anti-insulin-like growth factor-binding protein-7 single-domain antibodies.

Iqbal U, Albaghdadi H, Luo Y, Arbabi M, Desvaux C, Veres T, Stanimirovic D, Abulrob A - Br. J. Cancer (2010)

Fluorescent and light microscopic images of mouse orthotopic GBM tumour sections obtained 24 h after intravenous (i.v.) injection of 100 μg anti-IGFBP7 sdAb-Cy5.5. (A) Sections of brain tumour stained with hematoxylin and eosin staining showing brain tumour boundaries from the ipsilatelar healthy brain tissue (left panel, low magnification; right panel, high magnification). Higher magnification fluorescent images of tumour centre (B) and contralateral healthy brain region (C) showing colocalisation of the systemically injected anti-IGFBP7 sdAb-Cy5.5 (red; middle panels) and brain vessels stained with the 40 μg fluorescein tomato lectin (green; right panels) injected i.v. 10 min before killing, and their composite overlay images with nuclei stained with DAPI (blue; left panels). Scale bar: 50 μm. (D) Lower magnification image of the tumour and normal brain illustrating that injected anti-IGFBP7 sdAb-Cy5.5 (red) decorates selectively a majority of tumour vessels 24 h after i.v. injection. Scale bar: 100 μm.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2990581&req=5

fig4: Fluorescent and light microscopic images of mouse orthotopic GBM tumour sections obtained 24 h after intravenous (i.v.) injection of 100 μg anti-IGFBP7 sdAb-Cy5.5. (A) Sections of brain tumour stained with hematoxylin and eosin staining showing brain tumour boundaries from the ipsilatelar healthy brain tissue (left panel, low magnification; right panel, high magnification). Higher magnification fluorescent images of tumour centre (B) and contralateral healthy brain region (C) showing colocalisation of the systemically injected anti-IGFBP7 sdAb-Cy5.5 (red; middle panels) and brain vessels stained with the 40 μg fluorescein tomato lectin (green; right panels) injected i.v. 10 min before killing, and their composite overlay images with nuclei stained with DAPI (blue; left panels). Scale bar: 50 μm. (D) Lower magnification image of the tumour and normal brain illustrating that injected anti-IGFBP7 sdAb-Cy5.5 (red) decorates selectively a majority of tumour vessels 24 h after i.v. injection. Scale bar: 100 μm.
Mentions: U87MG brain tumours grew in a spherical shape that was easily distinguishable from the surrounding health brain, when visualised by hematoxylin and eosin staining (Figure 4A). At higher magnification, hematoxylin and eosin staining clearly illustrates the demarcation of the increased cellularity of the tumour vs the normal brain regions (Figure 4A, right panel).

Bottom Line: In vivo, intravenously injected anti-IGFBP7 sdAb-Cy5.5 bound to GBM vessels creating high imaging signal in the intracranial tumour.Fluorescent microscopy confirmed the presence of anti-IGFBP7 sdAb and anti-IGFBP7 sdAb-PEGylated Fe₃O₄ NPs selectively in GBM vessels.Anti-IGFBP7 sdAbs are novel GBM vessel-targeting moieties suitable for molecular imaging.

View Article: PubMed Central - PubMed

Affiliation: Institute for Biological Sciences, National Research Council of Canada, 1200 Montreal Road, Ottawa, Ontario, Canada K1A 0R6.

ABSTRACT

Background: Insulin-like growth factor-binding protein 7 (IGFBP7) is an abundant, selective and accessible biomarker of glioblastoma multiforme (GBM) tumour vessels. In this study, an anti-IGFBP7 single-domain antibody (sdAb) was developed to target GBM vessels for molecular imaging applications.

Methods: Human GBM was modelled in mice by intracranial implantation of U87MG.EGFRvIII cells. An anti-IGFBP7 sdAb, isolated from an immune llama library by panning, was assessed in vitro for its binding affinity using surface plasmon resonance and by ex vivo immunobinding on mouse and human GBM tissue. Tumour targeting by Cy5.5-labelled anti-IGFBP7 sdAb as well as by anti-IGFBP7 sdAb conjugated to PEGylated Fe₃O₄ nanoparticles (NPs)-Cy5.5 were assessed in U87MG.EGFRvIII tumour-bearing mice in vivo using optical imaging and in brain sections using fluorescent microscopy.

Results: Surface plasmon resonance analyses revealed a medium affinity (K(D)=40-50 nM) binding of the anti-IGFBP7 sdAb to the purified antigen. The anti-IGFBP7 sdAb also selectively bound to both mouse and human GBM vessels, but not normal brain vessels in tissue sections. In vivo, intravenously injected anti-IGFBP7 sdAb-Cy5.5 bound to GBM vessels creating high imaging signal in the intracranial tumour. Similarly, the anti-IGFBP7 sdAb-functionalised PEGylated Fe₃O₄ NP-Cy5.5 demonstrated enhanced tumour signal compared with non-targeted NPs. Fluorescent microscopy confirmed the presence of anti-IGFBP7 sdAb and anti-IGFBP7 sdAb-PEGylated Fe₃O₄ NPs selectively in GBM vessels.

Conclusions: Anti-IGFBP7 sdAbs are novel GBM vessel-targeting moieties suitable for molecular imaging.

Show MeSH
Related in: MedlinePlus