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Updated: Jun 11, 2026
Radionuclide-fluorescence Reporter Gene Imaging to Track Tumor Progression in Rodent Tumor Models
Published on: March 13, 2018
Evaluation of two internalizing carcinoembryonic antigen reporter genes for molecular imaging
Bhaswati Barat1, Vania E Kenanova1, Tove Olafsen1
1Crump Institute for Molecular Imaging, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Box 951770, 570 Westwood Plaza, Los Angeles, CA, 90095-1770, USA.
Purpose:
The objective of this article is to develop internalizing positron emission tomography (PET) reporter genes for tracking genetically modified T cells in vivo.
Procedures:
The transmembrane and cytoplasmic domains of the human transferrin receptor (TfR) and CD5 were each fused to the carcinoembryonic (CEA) minigene N-A3 and expressed in Jurkat T cells. Internalization was evaluated by confocal microscopy or by intracellular uptake of ¹²⁵I-labeled anti-CEA scFv-Fc. Reporter gene-transfected Jurkat xenografts in mice were analyzed by immunohistochemistry (IHC) and imaged by PET using ¹²⁴I- or ⁶⁴Cu-scFv-Fc as tracers.
Results:
Surface expression of TR(1-99)-NA3 was lower than that of NA3-CD5. Both reporter genes were internalized following binding of the anti-CEA antibody fragment. IHC of tumors showed strong staining of NA3-CD5, whereas TR(1-99)-NA3 stained weakly. Specific targeting of TR(1-99)-NA3 or NA3-CD5 was shown by PET in xenografted mice.
Conclusions:
The in vivo imaging studies suggest a potential application of the internalizing form of CEA (N-A3) as a PET reporter gene.
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