Schematic of yCD/5FC gene therapy. Transfer of the cDNA for yCD into tumor cells causes them to express the yCD protein. Upon entering such transduced tumor cells, 5FC is converted to the chemotherapeutic agent 5FU. Like 5FC, 5FU is membrane-permeable and may leave the transduced cell to kill neighboring tumor cells. Endogenous enzymes form fluorinated nucleotides (FNuct) from 5FU. FNucts mediate the cytotoxicity of yCD/5FC gene therapy via thymidylate synthase inhibition by FdUMP, disruption of nucleotide pools, and incorporation into RNA.

Temporal analysis of luciferase expression within the 9L tumor following administration of CD/ Luc adenovirus using BLI. The top series of images are shown from a representative rat over time. In these images, a pseudocolor image of the luciferase - generated photon emission is superimposed over the greyscale image of the rat head. Arrows point to the time at which these images were taken during the 5FC treatment period. The plot represents the normalized mean (± s.e.m.) photon counts obtained from the three 5FC- treated animals (diamonds) and three control animals (circles) studied with BLI over time. (Rehemtulla et al, Molecular Imaging . Vol. 1, No. 1, January 2002, pp. 43 - 55)