Detection and measurement of in vitro gene transfer by gamma camera imaging

Non-invasive gamma camera imaging of gene transfer using an adenoviral vector encoding an epitope-tagged receptor as a reporter

“…This is in agreement with previously published data that demonstrate 495% of A-427 cells express green fluorescent protein (GFP) after infection with an adenovirus encoding GFP at 10 MOI. 33 Thus, these results suggest that the increase in expression of HAhSSTr2 from 1 to 10 MOI is a function of increasing the number of cells infected and possibly the number of receptors per cell, while the increase of HAhSSTr2 from 10 to 100 MOI is a function of increasing the number of receptors per cell since 495% of the cells are infected. This is likely due to multiple infections of the same cell by Ad-HAhSSTr2.…”

“…The imaging of the 96-well plates after incubation at 371C was performed as previously described. 30,33 After imaging, the cells were harvested and counted in a gamma counter and the data are presented as the specific amount of cell-associated radioactivity as a percentage of the total radioactivity added.…”

PET and SPECT Reporter Gene Imaging

“…[120][121][122] These include 99m Tc-P829, a synthetic somatostatin analog approved by FDA, 99m Tc-P2045, another peptide analog of somatostatin analog, and 111 In-Octreotide. Specificity of hSSTr2 RG has been demonstrated in ovarian and non-small cell lung cancer cells.…”

Molecular imaging of gene therapy for cancer

“…The gene encoding the human somatostatin receptor type-2 has been used as a marker gene in combination with the specific marker receptor-binding compound [ 99m Tc]-P2045, which can be detected by gamma-camera and SPECT imaging. 31 The expression of a cell-surface receptor, human carcinoembryonic antigen (CEA), delivered via adenovirus vector into experimental subcutaneous human D54MG gliomas was noninvasively assessed by 131 I-labeled anti-CEA COL-1 monoclonal antibody. 32 This indicates that exogenously introduced cell-surface receptor expression can be imaged by SPECT; however, quantification of receptor expression at high levels might be confounded by saturation of intracellular processing or cell membrane sites.…”