DNA binding chelates for nonviral gene delivery imaging.

TitleDNA binding chelates for nonviral gene delivery imaging.
Publication TypeJournal Article
Year of Publication2001
AuthorsBogdanov A, Tung CH, Bredow S, Weissleder R
JournalGene Ther
Volume8
Issue7
Pagination515-22
Date Published2001 Apr
ISSN0969-7128
KeywordsAnimals, Chelating Agents, DNA, Female, Gene Transfer Techniques, Genetic Vectors, Melanoma, Experimental, Mice, Mice, Inbred C57BL, Mice, Nude, Radionuclide Imaging, Technetium, Tissue Distribution, Transfection
Abstract

Noninvasive in vivo monitoring of gene delivery would provide a critically important information regarding the spatial distribution, local concentration, kinetics of removal and/or biodegradation of the expression vector. We developed a novel approach to noninvasive gene delivery imaging using heterobifunctional peptide-based chelates (PBC) bearing double-stranded DNA-binding groups and a technetium-binding amino acid motif. One of such chelates: Gly-Cys(Acm)-Gly-Cys(Acm)-Gly-Lys(4)-Lys-(N-epsilon-[4-(psoralen-8-yloxy)]butyrate)-NH(2) has been characterized and labeled with reduced (99m)Tc pertechnetate (oxotechnetate). The psoralen moiety (a DNA binding group of PBC) allowed linking to double-stranded DNA upon short-term irradiation with the near UV range light (>320 nm). Approximately 30-40% of added (99m)Tc-labeled PBC was nonextractable and co-eluted with a model pCMV-GFP vector during the gel-permeation chromatography. Nuclear imaging of "naked" DNA and DNA complexes with lipid-based transfection reagents ("lipoplexes") has been performed after systemic or local administration of (99m)Tc-PBC-labeled DNA in mice. Imaging results were corroborated with the biodistribution using (99m)Tc-PBC and (32)P-labeled DNA and lipoplexes. A markedly different biodistribution of (99m)Tc PBC-labeled DNA and lipoplexes was observed with the latter being rapidly trapped in the liver, spleen and lung. (99m)Tc PBC-DNA was used as an imaging tracer during in vivo transfection of B16 melanoma by local injection of "naked" (99m)Tc PBC-DNA and corresponding lipoplexes. As demonstrated by nuclear imaging, (99m)Tc PBC-DNA lipoplexes showed a slower elimination from the site of injection than (99m)Tc PBC-DNA alone. This result correlated with a higher expression of marker mRNA and green fluorescent protein as determined using RT-PCR and immunohistochemistry, respectively.

DOI10.1038/sj.gt.3301410
Alternate JournalGene Ther
PubMed ID11319618
Grant List1R21 DK55713-01 / DK / NIDDK NIH HHS / United States
5RO1 CA74424-01 / CA / NCI NIH HHS / United States
5RO1 NS35258-03 / NS / NINDS NIH HHS / United States
Related Institute: 
Molecular Imaging Innovations Institute (MI3)

Weill Cornell Medicine
Department of Radiology
525 East 68th Street New York, NY 10065