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- Title
853. Monitoring of Promoter-Controlled Adenoviral Replication with Noninvasive Imaging in Lung Cancer.
- Authors
Davydova, Julia; Nelson, Amy R.; Gavrikova, Tatyana; Le, Long P.; Ono, Hidetaka A.; Curiel, David T.; Yamamoto, Masato
- Abstract
The employment of conditionally replicative adenoviruses (CRAds) provides a novel way to treat lung cancer. To maintain safety and efficacy in clinical application, a noninvasive detection system of viral replication is required. However, there are currently no available methods to dynamically monitor adenovirus replication and spreading ability in clinical settings. Recently we have shown that the EGFP reporter gene placed in the deleted E3 region under the adenoviral major late promoter could be exploited to noninvasively monitor adenovirus replication. In this study, we developed a system which allows monitoring of CRAd replication via the detection of bioluminescence reporter and applied it to derive novel Cox-2 promoter-based CRAds as therapeutic agents for lung cancer. In our reporter vectors most E3 genes except adenoviral death protein (ADP) were deleted or mutated and replaced with the firefly luciferase gene. We combined the Cox-2 promoter-controlled E1 expression cassette with the E3 vector to generate imaging capable Cox-2 CRAds. We designed six different structures to optimize monitoring including configurations with and without ADP and vectors equipped with different fibers accommodating the coxsackie-adenovirus receptor deficiency of cancer cells. The presence or absence of a poly-adenylation signal following the reporter gene has been examined for effect on stability of transgene expression. In vitro, all viruses showed transgene expression augmentation and killing effect over time and in a dose-dependent manner during infection of A549 human lung adenocarcinoma cells. The detected gene expression closely correlated with the viral DNA quantity resulting from viral replication. No expression or cytocidal effect was observed in mouse hepatoma BNL-1NG-A.2 cells in which human adenoviruses do not productively replicate, indicating the dependence of reporter expression on productive replication. All vectors with ADP showed a stronger killing ability without hampering luciferase expression compared to ADP lacking viruses. In vivo optical studies performed in nude mice with A549 subcutaneous xenografts visualized viral replication after both intratumoral and intravenous administration of Cox2-based CRAds. The bioluminescent signal was detected as early as the next day after adenoviral injection, increased with time, persisted over four weeks, and was comparable to that of a matched wild type E1 vector. Surprisingly, in one mouse, bioluminescence signal from a Cox2Crad was detected not only in the A549 subcutaneous nodule but also in spontaneously developed tumor metastases. Of note, in both in vitro and in vivo studies, Cox2-based CRAds demonstrated efficient replication and subsequent oncolysis in Cox2-positive A549 cells but not in Cox-2-negative A431 cells, thus confirming the dependence of their replication on the Cox-2 promoter activity. These data validate the applicability of our promoter-controlled E3 reporter system for noninvasive monitoring of CRAd replication and further development of oncolytic viruses for lung cancer.Molecular Therapy (2006) 13, S328–S328; doi: 10.1016/j.ymthe.2006.08.939
- Subjects
LUNG cancer; VIRAL replication; METASTASIS; ADENOVIRUSES; CANCER invasiveness
- Publication
Molecular Therapy, 2006, Vol 13, pS328
- ISSN
1525-0016
- Publication type
Article
- DOI
10.1016/j.ymthe.2006.08.939