Synthesis and biological evaluation of an 123I-labeled bicyclic nucleoside analogue (BCNA) as potential SPECT tracer for VZV-tk reporter gene imaging

An iodine-123 labeled bicyclic nucleoside analogue ([123I]-4) has been synthesized and evaluated as a potential single photon emission tomography (SPECT) reporter probe for the non-invasive imaging of expression of the varicella zoster virus thymidine kinase (VZV-tk) reporter gene. In vitro enzymatic assays revealed that the non-radioactive mono-iodo derivative 4 has good affinity for VZV-TK (IC50: 4.2 μM). Biodistribution of [123I]-4 was examined in normal mice. Evaluation of [123I]-4 in HEK-293T cells showed 1.74-fold higher accumulation in VZV-TK-expressing cells compared to control cells.

Graphical abstractAn 123I-labeled BCNA that has good affinity for VZV-TK (IC50: 4.2 μM) is synthesized and evaluated.Figure optionsDownload full-size imageDownload as PowerPoint slide