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Noninvasive Imaging of Enhanced Prostate-Specific Gene Expression Using a Two-Step Transcriptional Amplification-Based Lentivirus Vector

2004; Elsevier BV; Volume: 10; Issue: 3 Linguagem: Inglês

10.1016/j.ymthe.2004.06.118

1525-0024

Meera Iyer, Felix B. Salazar, Xiaoman Lewis, Liqun Zhang, Michael Carey, Lily Wu, Sanjiv S. Gambhir,

Herpesvirus Infections and Treatments

Noninvasive evaluation of gene transfer to specific cells or tissues will allow for long-term, repetitive monitoring of transgene expression. Tissue-specific promoters that restrict the expression of a transgene to tumor cells play a vital role in cancer gene therapy imaging. In this study, we have developed a third-generation HIV-1-based lentivirus vector carrying a prostate-specific promoter to monitor the long-term, sustained expression of the firefly luciferase (fl) reporter gene in living mice. The fl gene in the transcriptionally targeted vector is driven by an enhanced prostate-specific antigen promoter in a two-step transcriptional amplification (TSTA) system. The efficiency of the lentivirus (LV-TSTA)-mediated gene delivery, cell-type specificity, and persistence of gene expression were evaluated in cell culture and in living mice carrying prostate tumor xenografts. In vivo bioluminescence imaging with a cooled charge-coupled device camera revealed significantly high levels of fl expression in prostate tumors. Injection of LV-TSTA directly into the prostate of male nude mice revealed efficient and long-term fl gene expression in the prostate tissue for up to 3 months. These studies demonstrate the significant potential of TSTA-based lentivirus vectors to confer high levels of tissue-specific gene expression from a weak promoter, while preserving cell-type specificity and the ability to image noninvasively the sustained, long-term expression of reporter genes in living animals.