607. In Vitro and In Vivo Monitoring of 5-Fluorosytosine Metabolism with 19F-NMR Spectroscopy after Adenoviral Transduction of Cells with Bifunctional Yeast CDUPRT Fusion Gene

Abstract

Transfer into tumor of genes is an attractive gene therapy strategy for selective elimination of cancer cells. One of the newly invented suicide gene encodes bifunctional yeast CDUPRT fusion protein, which combines the enzymatic activity of cytosine deaminase (CD) and uracil phosphoribosyltransferase (UPRT). This protein efficiently catalyzes the direct conversion of 5-FC (a non-toxic prodrug) into the toxic metabolites 5-fluorouracil (5-FU) and its toxic derivative 5-fluorouridine-5'-monophosphate (FUMP). This study was undertaken to evaluate the applicability of 19F-MRS for monitoring in vitro and in vivo of the conversion of 5-fluorocytosine (5-FC) to fluorouracil after adenovirus mediated transfer of a CDUPRT Fusion Gene. For this purpose a replication incompetent adenoviral vector carrying a cytomegalovirus (CMV)-driven transcription unit of the yeast CDUPRT gene in E1 region was constructed. We employed both 19F-MRS and cell biology techniques to measure the pharmacokinetics and cytotoxicity of 5-FC for infected human glioma D54MG cells.