Nanoparticles Home in on Tumors by Targeting New Blood Vessels
Virus-based nanoparticles decorated with a newly discovered peptide hold promise for cancer imaging and drug delivery.
The formation of new blood vessels, a process known as angiogenesis, plays a critical role in the growth and spread of cancer. A protein called EGFL7 has been implicated in angiogenesis, is present in a variety of solid tumors and is associated with poor outcomes in several cancers, making it a promising target for imaging or therapeutic strategies.
In a study published in August in the journal Nanoscale, John Lewis of the University of Alberta in Canada and his colleagues used a peptide screening approach to discover a novel EGFL7-binding peptide called E7p72, which specifically targets endothelial cells that form the inner lining of blood vessels.
To evaluate the usefulness of E7p72 for molecular targeting in an animal model, the researchers used bird embryos that had been injected with human tumor cells. They added E7p72 to the exterior surfaces of viral nanoparticles and injected them into the embryos. The nanoparticles accumulated in the tumor-associated endothelium within an hour of injection, allowing for the rapid identification of new tumor-associated blood vessels. Moreover, positron emission tomography (PET) studies confirmed that intravenously injected, radiolabeled E7p72 targeted tumors in mice with cancer.
The viral nanoparticle platform is biocompatible and biodegradable, which potentially makes it safe for use in humans. According to the authors, EGFL7-targeted nanoparticles should provide a robust platform for future noninvasive cancer imaging and drug delivery efforts.