Systemic combinatorial peptide selection yields a non-canonical iron-mimicry mechanism for targeting tumors in a mouse model of human glioblastoma
Fernanda I. Staquicini, … , Renata Pasqualini, Wadih Arap
Fernanda I. Staquicini, … , Renata Pasqualini, Wadih Arap
Published December 22, 2010
Citation Information: J Clin Invest. 2011;121(1):161-173. https://doi.org/10.1172/JCI44798.
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Technical Advance

Systemic combinatorial peptide selection yields a non-canonical iron-mimicry mechanism for targeting tumors in a mouse model of human glioblastoma

Abstract

The management of CNS tumors is limited by the blood-brain barrier (BBB), a vascular interface that restricts the passage of most molecules from the blood into the brain. Here we show that phage particles targeted with certain ligand motifs selected in vivo from a combinatorial peptide library can cross the BBB under normal and pathological conditions. Specifically, we demonstrated that phage clones displaying an iron-mimic peptide were able to target a protein complex of transferrin and transferrin receptor (TfR) through a non-canonical allosteric binding mechanism and that this functional protein complex mediated transport of the corresponding viral particles into the normal mouse brain. We also showed that, in an orthotopic mouse model of human glioblastoma, a combination of TfR overexpression plus extended vascular permeability and ligand retention resulted in remarkable brain tumor targeting of chimeric adeno-associated virus/phage particles displaying the iron-mimic peptide and carrying a gene of interest. As a proof of concept, we delivered the HSV thymidine kinase gene for molecular-genetic imaging and targeted therapy of intracranial xenografted tumors. Finally, we established that these experimental findings might be clinically relevant by determining through human tissue microarrays that many primary astrocytic tumors strongly express TfR. Together, our combinatorial selection system and results may provide a translational avenue for the targeted detection and treatment of brain tumors.

Authors

Fernanda I. Staquicini, Michael G. Ozawa, Catherine A. Moya, Wouter H.P. Driessen, E. Magda Barbu, Hiroyuki Nishimori, Suren Soghomonyan, Leo G. Flores 2nd, Xiaowen Liang, Vincenzo Paolillo, Mian M. Alauddin, James P. Basilion, Frank B. Furnari, Oliver Bogler, Frederick F. Lang, Kenneth D. Aldape, Gregory N. Fuller, Magnus Höök, Juri G. Gelovani, Richard L. Sidman, Webster K. Cavenee, Renata Pasqualini, Wadih Arap

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Figure 5

Targeted therapy and molecular-genetic imaging of intracranial brain tumors in an orthotopic model of human-derived glioblastoma xenograft.

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Targeted therapy and molecular-genetic imaging of intracranial brain tum...
(A) Tumor growth suppression by CRTIGPSVC AAVP–HSV-TK transduction plus treatment with GCV. Cohorts of immunodeficient nude mice (n = 10) with established intracranial tumors received a single systemic administration of targeted CRTIGPSVC AAVP–HSV-TK (5 × 1010 TU) or control AAVP–HSV-TK. Mice received GCV from day 7 after systemic i.v. AAVP administration until the end of the experiment (daily GCV dose i.p. for 5 days). Untreated group received vehicle alone. The boxes represent the upper (25% of data greater than this value) and lower (25% of data less than this value) quartiles. Medians are indicated by horizontal lines; whiskers represent the maximum and minimum values of the data set. *P < 0.05; ***P < 0.001. (B) Temporal dynamics of HSV-TK gene expression as assessed by micro-PET imaging with [18F]-FEAU. *P < 0.05. (C and D) Combined PET/CT images of brain tumor-bearing animals, systemically administered with (C) targeted CRTIGPSVC AAVP–HSV-TK or (D) control insertless AAVP–HSV-TK. Axial, coronal, and sagittal planes are shown. [18F]-FEAU uptake was observed only in animals receiving targeted AAVP. Arrows point to the tumor area. Dashed lines indicate the tumor circumference. R, right; L, left. (E) Detection of apoptotic cells by TUNEL was performed on tumor tissue sections of animals treated with control insertless AAVP or with targeted AAVP. Untreated animals received only vehicle. Nonimmune IgG was used as negative control. Insets of serial tumor sections show the area containing the larger views; the boxes represent the area shown in high magnification in the larger images. (F) CD31 staining was performed on paraffin-embedded brain tumor tissue sections of animals treated with targeted AAVP or control AAVP. Untreated animals received only vehicle. Arrows point to disrupted blood vessels. Tumor tissue stained with IgG control isotype was used as negative control. Scale bar: 200 μm.