Dual-expressing adenoviral vectors encoding the sodium iodide symporter for use in noninvasive radiological imaging of therapeutic gene transfer.
BACKGROUND
Noninvasive analysis of therapeutic transgene expression is important for the development of clinical translational gene therapy strategies against cancer. To image p53 and MnSOD gene transfer noninvasively, we used radiologically detectable dual-expressing adenoviral vectors with the human sodium iodide symporter (hNIS) as the reporter gene.


METHODS
Dual-expressing adenoviral vectors were constructed with hNIS cloned into E3 region and therapeutic genes, either MnSOD or p53, recombined into the E1 region. Steady-state mRNA levels of hNIS were evaluated by real-time polymerase chain reaction. hNIS function was determined by iodide uptake assay and MnSOD, and p53 protein levels were assessed by Western blots.


RESULTS
125I- accumulation resulting from hNIS expression in both Ad-p53-hNIS- and Ad-MnSOD-hNIS-infected MDA-MB-435 cells could be visualized clearly on phosphorimaging autoradiograph. Iodide accumulation increased with increasing adenovirus titer, and there was a linear correlation between iodide uptake and dose. p53 and MnSOD protein levels increased as a function of adenovirus titer, and there was a direct positive correlation between p53 and MnSOD expression and hNIS function. P53 and MnSOD overexpression inhibited cell growth in the dual-expressing adenoviral vector-infected cells.


CONCLUSIONS
Radiological detection of hNIS derived from dual-expressing adenoviral vectors is a highly effective method to monitor therapeutic gene transfer and expression in a noninvasive manner.
Niu
Gang
G
Free Radical and Radiation Biology Program, The University of Iowa, Iowa City, IA 52242, USA.
Anderson
Richard D
RD
Madsen
Mark T
MT
Graham
Michael M
MM
Oberley
Larry W
LW
Domann
Frederick E
FE
D000256:Adenoviridae / Q000235:genetics*; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000201:enzymology; D018014:Gene Transfer Techniques; D017930:Genes, Reporter; D005822:Genetic Vectors; D006801:Humans; D007457:Iodine Radioisotopes; D015336:Molecular Probe Techniques; D011877:Radionuclide Imaging; D012974:Sodium Iodide / Q000493:pharmacokinetics; D013482:Superoxide Dismutase / Q000378:metabolism; D027981:Symporters / Q000235:genetics*; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D000099209:Sodium-Iodide Symporters
D007457:Iodine Radioisotopes; D012974:Sodium Iodide; D013482:Superoxide Dismutase; D027981:Symporters; D016159:Tumor Suppressor Protein p53; D000099209:Sodium-Iodide Symporters