Strategies of transcriptional regulation in retrovirus production and expression

Abstract

Gene therapy is a promising, yet elusive, method of cancer treatment. Many candidate genes, like p53, are currently being tested in clinical trials using a variety of gene delivery vehicles, such as retroviral vectors. p53 is a well characterized tumor suppressor gene that targets cell cycle arrest and apoptosis via transcriptional control of key mediators, such as p21, bcl-2 and bax. The suitability of p53 for use in gene therapy applications is well documented. Retroviral vectors have been developed as gene transfer agents since they are safe, do not elicit an immune response and are easily modified. Despite the prevalence of retroviral vectors in clinical trials, in vivo viral expression can be diminished by a variety of means. The aim of this project is to develop a pCL-based retroviral vector that has enhanced in vivo expression mediated by p53 transcriptional activation. A p53-responsive element has been inserted into the promoter region of the pCL retrovirus with the hope that viral .expression will be elevated in the presence of p53. In addition, the p53 cDNA has been placed in the virus with the expectation that the p53 protein will serve two functions: 1. Activate viral expression in vivo, and 2. Act as a powerful tumor- suppressing agent. (AU)