Stability analysis on the radioactive iodine-labelled prostate cancer-specific recombinant oncolytic adenovirus

The aim of the present study was to construct the (125)I-replication-selective oncolytic adenovirus (RSOAds)-human telomerase reverse transcriptase (hTERT)/prostate specific antigen (PSA) nuclide-oncolytic virus marker by labelling the hTERT/PSA double-regulation replicative oncolytic adenovirus with (125)I nuclide, and investigate the influence of viral markers under various reaction conditions on labelling efficiency. N-bromosuccinimide (NBS) was used as the oxidizer for (125)I labelling, and the best conditions for labelling were identified through the reactions between oncolytic adenovirus at various concentrations and NBS. Dosage of (125)I, reaction duration, pH values and reaction volume were respectively evaluated to determine their effects on the labelling efficiency of (125)I-RSOAds-hTERT/PSA nuclide-oncolytic adenovirus markers. Purified nuclide-oncolytic adenovirus markers were isolated by gel-filtration chromatography; paper chromatography was performed to assay the radiochemical purity of (125)I-RSOAds-hTERT/PSA markers at various time points. Radiochemical purity of (125)I-RSOAds-hTERT/PSA was >95%, and could be maintained at 4°C for 7 days. The best reaction conditions were set as follows: 0.5 µl of (125)I (~0.2 m Ci, 7.4 MBq); 25 qg of NBS; 100 µl of 8×10(9) VP/ml (125)I-RSOAds-hTERT/PSA virus solution; 30 min of reaction duration; pH 7.5; 120 µl of PBS. Labelling hTERT/PSA double-regulation replicative oncolytic adenovirus with (125)I was identified to be available, and the radiochemical purity of acquired virus markers could be maintained under specific conditions.