ivo Imaging of Tumor Transduced with Bimodal Lentiviral tor Encoding Human Ferritin and Green Fluorescent R tein on a 1.5T Clinical Magnetic Resonance Scanner

Downlo mbination of reporter genes for magnetic resonance imaging (MRI) and optical imaging can provide an nal level of noninvasive and quantitative information about biological processes occurring in deep tise developed a bimodal lentiviral vector to monitor deep tissue events using MRI to detect myc-tagged ferritin heavy chain (myc-hFTH) expression and fluorescence imaging to detect green fluorescent n (GFP) expression. The transgene construct was stably transfected into MCF-7 and F-98 cells. After lantation of the cells expressing myc-hFTH and GFP into mice or rats, serial MRI and fluorescence g were performed with a human wrist coil on a 1.5T MR scanner and optical imaging analyzer for s. No cellular toxicity due to overexpression of myc-hFTH and GFP was observed in MTT and trypan xclusion assays. Iron accumulation was observed in myc-hFTH cells and tumors by Prussian blue g and iron binding assays. The myc-hFTH cells and tumors had significantly lower signal intensities eighted MRI than mock-transfected controls (P ≤ 0.05). This is direct evidence that myc-hFTH expresan be visualized noninvasively with a 1.5T clinical MR scanner. This study shows that MRI and fluoresimaging of transplanted cells at molecular and cellular levels can be performed simultaneously using our bimodal lentiviral vector system. Our techniques can be used to monitor tumor growth, metastasis, and regression during cell and gene-based therapy in deep tissues. Cancer Res; 70(18); 7315–24. ©2010 AACR.