Colon Cancer Research Today is a free monthly online journal that collates and summarizes the latest research about Colon Cancer, including details on causes, treatment, symptoms.

In vivo near-infrared fluorescence imaging of carcinoembryonic antigen-expressing tumor cells in mice.

Lisy MR, Goermar A, Thomas C, Pauli J, Resch-Genger U, Kaiser WA, Hilger I

Institute for Diagnostic and Interventional Radiology, Friedrich-Schiller-University Jena, FZL Erlanger Allee 101, D-07747 Jena, Germany.

PURPOSE: To prospectively depict carcinoembryonic antigen (CEA)-expressing tumors in mice with a high-affinity probe consisting of a near-infrared (NIR) fluorochrome and the clinically used anti-CEA antibody fragment arcitumomab. MATERIALS AND METHODS: This study was approved by the regional animal committee. By coupling a NIR fluorescent (NIRF) cyanine dye (DY-676) to a specific antibody fragment directed against CEA (arcitumomab) and a nonspecific IgG Fab fragment, a bio-optical high-affinity fluorescent probe (anti-CEA-DY-676) and a low-affinity fluorescent probe (FabIgG-DY-676) were designed. The dye-to-protein ratios were determined, and both probes were tested for NIRF imaging in vitro on CEA-expressing LS-174T human colonic adenocarcinoma cells and CEA-nonexpressing A-375 human melanoma cells by using a bio-optical NIR small-animal imager. In vivo data of xenografted LS-174T and A-375 tumors in mice (n = 10) were recorded and statistically analyzed (Student t test). RESULTS: The dye-to-protein ratios were determined as 3.0-3.5 for both probes. In vitro experiments revealed the specific binding of the anti-CEA-DY-676 probe on CEA-expressing cells as compared with CEA-nonexpressing cells; the FabIgG-DY-676 probe showed a markedly lower binding affinity to cells. In vivo LS-174T tumors xenografted in all mice could be significantly distinguished from A-375 tumors with application of the anti-CEA-DY-676 but not with that of the FabIgG-DY-676 at different times (2-24 hours, P < .005) after intravenous injection of the probes. Semiquantitative analysis revealed maximal fluorescence signals of anti-CEA-DY-676 to CEA-expressing tumors about 8 hours after injection. CONCLUSION: Findings of this study indicate the potential use of the high-affinity probe anti-CEA-DY-676 for specific NIRF imaging in in vivo tumor diagnosis.

Published 19 May 2008 in Radiology, 247(3): 779-87.
Full-text of this article is available online (may require subscription).

© 2004-2008 Colon Cancer Research Today. All Rights Reserved.