Optical imaging of transferrin targeted PEI/DNA complexes in living subjects

• Published in: Gene therapy Vol. 10; no. 9; pp. 758 - 764
• Main Authors: Hildebrandt, I J, Iyer, M, Wagner, E, Gambhir, S S
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.05.2003; Nature Publishing Group
• Subjects: Animals; Biological and medical sciences; Bioluminescence; Biomedical and Life Sciences; Biomedicine; Cell Biology; Female; Firefly Luciferin - analysis; Firefly Luciferin - genetics; Fundamental and applied biological sciences. Psychology; Gene Expression; Gene Targeting; Gene Therapy; Human Genetics; Injections, Intravenous; Luminescent Measurements; Mice; Mice, Inbred Strains; Molecular and cellular biology; Nanotechnology; Neoplasms, Experimental - metabolism; Polyethylene glycol; Polyethylene Glycols; Polyethyleneimine; Reporter gene; research-article; Tail - blood supply; Temporal variations; Time Factors; Tissue Distribution; Transfection - methods; Transferrin; Transferrin - genetics; Tumor Cells, Cultured; Tumors; tumor targeting; reporter gene; bioluminescence; optical imaging; firefly luciferase; polyethylenimine; Genetics
• ISSN: 0969-7128; 1476-5462
• DOI: 10.1038/sj.gt.3301939

Noninvasive optical bioluminescence imaging systems are important tools for evaluating gene expression in vivo for study of individual and temporal variation in a living animal. In this report, we demonstrate that expression of the firefly luciferase reporter gene (fl) delivered by transferrin (Tf) targeted polyethylenimine (PEI) complexes with, or without, poly(ethylene glycol) (PEG) modifications can be imaged in living A/J mice bearing N2A tumors using a cooled charged coupled device (CCD) camera. Tf–PEI–PEG, Tf–PEI, and PEI (positive control) complexes were tail-vein injected and mice were imaged at 5, 24, 48, and 72 h after complex injection. After imaging, the organs were analyzed ex vivo for firefly luciferase protein (FL) activity. The Tf and PEG modified formulations show significantly (P<0.05) higher FL activity in vivo and ex vivo at the tumor as compared to other organs, including the lungs (a site of high expression with PEI, the positive control). Furthermore, the in vivo bioluminescent signal correlated well (R 2 =0.83) with ex vivo FL activity. These data support that noninvasive imaging of fl reporter expression can be used to monitor the specificity of Tf–PEI and Tf–PEI–PEG polyplex targeting of N2A tumors in A/J mice.