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 4

CRTIGPSVC-phage targets human glioblastoma in vivo.

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CRTIGPSVC-phage targets human glioblastoma in vivo. (A–H) Immunohistoche...
(A–H) Immunohistochemistry of CRTIGPSVC-phage after systemic circulation into human-derived glioblastoma xenograft-bearing mice. Staining of phage was observed in (A) tumor blood vessels and (B–E) glioma cells. Arrows indicate positive phage staining in blood vessels. Arrowheads indicate positive phage staining in glioma cells. (F) Insertless phage was used as a negative control. Other areas of the brain such as (G) cerebral cortex and (H) caudate/putamen showed only background staining. (I–N) Immunofluorescence of phage (red) and CD31 (green) revealed accumulation of phage particles in (I–K) tumor blood vessels but not in normal tissue. Dashed lines indicate the tumor circumference. (L–N) Insertless phage, used as a negative control, revealed little or no staining. (O–T) Confocal microscopy showed colocalization of (O) CD31, (P) TfR, and (Q) phage in blood vessels. (R) Merge of images shown in O–Q. Arrowheads point to protein colocalization. (S and T) Phage particles were also found in TfR-expressing cells in the tumor stroma (arrows). Scale bars: 100 μm (A–N); 20 μm (O–T).