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

The aim of the present study was to construct the ¹²⁵I-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 ¹²⁵I nuclide, and investigate the influence of viral markers under various reaction conditions on labelling efficiency. N-bromosuccinimide (NBS) was used as the oxidizer for ¹²⁵I labelling, and the best conditions for labelling were identified through the reactions between oncolytic adenovirus at various concentrations and NBS. Dosage of ¹²⁵I, reaction duration, pH values and reaction volume were respectively evaluated to determine their effects on the labelling efficiency of ¹²⁵I-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 ¹²⁵I-RSOAds-hTERT/PSA markers at various time points. Radiochemical purity of ¹²⁵I-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 ¹²⁵I (~0.2 m Ci, 7.4 MBq); 25 qg of NBS; 100 µl of 8×10⁹ VP/ml ¹²⁵I-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 ¹²⁵I was identified to be available, and the radiochemical purity of acquired virus markers could be maintained under specific conditions.