Non‐invasive imaging of firefly luciferase reporter gene expression using bioluminescence imaging in human prostate cancer models

Monitoring the expression of therapeutic genes in targeted tissues in disease models is important to assess the effectiveness and safety of systems of gene therapy delivery. In the present study, we employed a CCD (charge-coupled-device) imaging system to monitor how a prostate-specific adenovirus vector (AdPSA-Luc) mediated the long-term, sustained expression of firefly luciferase (Luc) in living human prostate cancer mouse models. The in vivo bioluminescence imaging revealed significantly high levels of luciferase expression up to 1 month, not only in prostate tumours, but also in lungs after intratumoural injection. Systemic tail vein injection of AdPSA-Luc revealed significant luciferase expression in lungs of both human prostate cancer mouse models and naïve mice, but significantly higher in the former, while the control virus, AdCMV-Luc, containing CMV (cytomegalovirus) promoter and luciferase gene, just restricted expression in the livers. Our findings demonstrate the ability of the cooled CCD camera to sensitively and non-invasively track the location, magnitude and persistence of luciferase gene expression in human prostate cancer mouse models. Monitoring of gene therapy studies in small animals may be aided considerably with further extensions of this technique.