A novel two-step transcriptional activation system for gene therapy directed toward epithelial cells
The two-step transcriptional activation (TSTA) mechanism in gene therapy amplifies cell type–specific promoter activity, allowing for increased levels of gene expression in target tissues. In this system, the specific promoter drives expression of a strong transcriptional activator that binds to DNA...
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Veröffentlicht in: | Molecular cancer therapeutics 2009-12, Vol.8 (12), p.3244-3254 |
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Zusammenfassung: | The two-step transcriptional activation (TSTA) mechanism in gene therapy amplifies cell type–specific promoter activity, allowing
for increased levels of gene expression in target tissues. In this system, the specific promoter drives expression of a strong
transcriptional activator that binds to DNA target sequences located upstream from a second promoter controlling the expression
of the therapeutic gene. The majority of previous studies have exploited a fusion between the DNA binding domain of the yeast
transcriptional activator Gal4 fused to the VP16 activation domain of herpes simplex virus 1 as the transcriptional activator.
In this report, an alternative to this system is described based on a fusion protein containing the DNA binding domain of
the bovine papillomavirus 1 transcriptional activator E2 fused to VP16 that induces target gene expression following binding
to a minimal bovine papillomavirus 4 promoter containing upstream E2 binding sites and only 3 bp of promoter sequence upstream
from the TATA box. VP16-E2 is superior to Gal4-VP16 as the transcriptional activator in a TSTA system driven by either of
the two potentially cancer-specific promoters telomerase RNA and telomerase reverse transcriptase in several cell lines. Results
also suggest that this new system has an advantage in epithelial cells and is therefore ideal for potential targeting of carcinomas.
By incorporating the TRAIL gene as a transgene in the VP16-E2 TSTA system, selective killing of telomerase-positive cells occurs. We propose that our
new system should be considered in future TSTA, particularly when targeting epithelial-derived cells. [Mol Cancer Ther 2009;8(12):3244–54] |
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ISSN: | 1535-7163 1538-8514 |
DOI: | 10.1158/1535-7163.MCT-09-0543 |