Rapid visualization of human tumor xenografts through optical imaging with a near-infrared fluorescent anti-epidermal growth factor receptor nanobody

Mol Imaging. 2012 Feb;11(1):33-46.

Abstract

Given that overexpression of the epidermal growth factor receptor (EGFR) is found in many types of human epithelial cancers, noninvasive molecular imaging of this receptor is of great interest. A number of studies have employed monoclonal antibodies as probes; however, their characteristic long half-life in the bloodstream has encouraged the development of smaller probes. In this study, an anti-EGFR nanobody-based probe was developed and tested in comparison with cetuximab for application in optical molecular imaging. To this aim, the anti-EGFR nanobody 7D12 and cetuximab were conjugated to the near-infrared fluorophore IRDye800CW. 7D12-IR allowed the visualization of tumors as early as 30 minutes postinjection, whereas with cetuximab-IR, no signal above background was observed at the tumor site. Quantification of the IR-conjugated proteins in the tumors revealed ≈ 17% of injected dose per gram 2 hours after injection of 7D12-IR, which was significantly higher than the tumor uptake obtained 24 hours after injection of cetuximab-IR. This difference is associated with the superior penetration and distribution of 7D12-IR within the tumor. These results demonstrate that this anti-EGFR nanobody conjugated to the NIR fluorophore has excellent properties for rapid preclinical optical imaging, which holds promise for its future use as a complementary diagnostic tool in humans.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • ErbB Receptors / immunology
  • ErbB Receptors / metabolism*
  • Female
  • Humans
  • Immunohistochemistry
  • Mice
  • Mice, Nude
  • NIH 3T3 Cells
  • Neoplasms / immunology
  • Neoplasms / metabolism*
  • Spectroscopy, Near-Infrared / methods*

Substances

  • ErbB Receptors