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The HDAC inhibitor FK228 enhances adenoviral transgene expression by a transduction-independent mechanism but does not increase adenovirus replication.

Danielsson A, Dzojic H, Rashkova V, Cheng WS, Essand M - PLoS ONE (2011)

Bottom Line: In the present study, we found that the highest increase in transgene expression was achieved when non-toxic concentrations of FK228 were added immediately after transduction, demonstrating that the main effect by which FK228 enhances transgene expression is transduction-independent.In some cases, the effects were dramatic, as demonstrated by an increase in CD40L expression by FK228 from 0.3% to 62% when the murine prostate cancer cell line TRAMP-C2 was transduced with Ad[CD40L].One unexpected finding was that FK228 decreased the transgene expression of an adenoviral vector with the prostate cell-specific PPT promoter in the human prostate adenocarcinoma cell lines LNCaP and PC-346C.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden. angelika.danielsson@igp.uu.se

ABSTRACT
The histone deacetylase inhibitor FK228 has previously been shown to enhance adenoviral transgene expression when cells are pre-incubated with the drug. Upregulation of the coxsackie adenovirus receptor (CAR), leading to increased viral transduction, has been proposed as the main mechanism. In the present study, we found that the highest increase in transgene expression was achieved when non-toxic concentrations of FK228 were added immediately after transduction, demonstrating that the main effect by which FK228 enhances transgene expression is transduction-independent. FK228 had positive effects both on Ad5 and Ad5/f35 vectors with a variety of transgenes and promoters, indicating that FK228 works mainly by increasing transgene expression at the transcriptional level. In some cases, the effects were dramatic, as demonstrated by an increase in CD40L expression by FK228 from 0.3% to 62% when the murine prostate cancer cell line TRAMP-C2 was transduced with Ad[CD40L]. One unexpected finding was that FK228 decreased the transgene expression of an adenoviral vector with the prostate cell-specific PPT promoter in the human prostate adenocarcinoma cell lines LNCaP and PC-346C. This is probably a consequence of alteration of the adenocarcinoma cell lines towards a neuroendocrine differentiation after FK228 treatment. The observations in this study indicate that FK228 enhances adenoviral therapy by a transduction-independent mechanism. Furthermore, since histone deacetylase inhibitors may affect the differentiation of cells, it is important to keep in mind that the activity and specificity of tissue- and tumor-specific promoters may also be affected.

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FK228 concentrations above 3 ng/ml reduce cell viability in prostate cancer cells.TRAMP-C2, LNCaP and PC-346C cells were treated with various concentrations of FK228 (ranging from 0.1 ng/ml to 300 ng/ml) for 24, 48 and 72 h. Cell viability measured by the MTS assay is expressed in relation to the activity in untreated cells. FK228 concentrations higher than 3 ng/ml reduced viability in all cell lines.
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pone-0014700-g001: FK228 concentrations above 3 ng/ml reduce cell viability in prostate cancer cells.TRAMP-C2, LNCaP and PC-346C cells were treated with various concentrations of FK228 (ranging from 0.1 ng/ml to 300 ng/ml) for 24, 48 and 72 h. Cell viability measured by the MTS assay is expressed in relation to the activity in untreated cells. FK228 concentrations higher than 3 ng/ml reduced viability in all cell lines.

Mentions: Cell viability studies were performed to determine FK228 toxicity for the human prostate cancer cell lines LNCaP and PC-346C and the mouse prostate cancer cell line TRAMP-C2. Cells were cultured in medium containing FK228 for 24, 48 and 72 hours before MTS assay analysis. After 72 h of incubation at 3 ng/ml FK228, around 80% of LNCaP and PC-346C cells were viable. TRAMP-C2 appeared to be somewhat less sensitive to FK228 than LNCaP and PC-346C. Reduced cell viability was observed at FK228 concentrations of 3 ng/ml and above for all cell lines and time points (Figure 1).


The HDAC inhibitor FK228 enhances adenoviral transgene expression by a transduction-independent mechanism but does not increase adenovirus replication.

Danielsson A, Dzojic H, Rashkova V, Cheng WS, Essand M - PLoS ONE (2011)

FK228 concentrations above 3 ng/ml reduce cell viability in prostate cancer cells.TRAMP-C2, LNCaP and PC-346C cells were treated with various concentrations of FK228 (ranging from 0.1 ng/ml to 300 ng/ml) for 24, 48 and 72 h. Cell viability measured by the MTS assay is expressed in relation to the activity in untreated cells. FK228 concentrations higher than 3 ng/ml reduced viability in all cell lines.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3040751&req=5

pone-0014700-g001: FK228 concentrations above 3 ng/ml reduce cell viability in prostate cancer cells.TRAMP-C2, LNCaP and PC-346C cells were treated with various concentrations of FK228 (ranging from 0.1 ng/ml to 300 ng/ml) for 24, 48 and 72 h. Cell viability measured by the MTS assay is expressed in relation to the activity in untreated cells. FK228 concentrations higher than 3 ng/ml reduced viability in all cell lines.
Mentions: Cell viability studies were performed to determine FK228 toxicity for the human prostate cancer cell lines LNCaP and PC-346C and the mouse prostate cancer cell line TRAMP-C2. Cells were cultured in medium containing FK228 for 24, 48 and 72 hours before MTS assay analysis. After 72 h of incubation at 3 ng/ml FK228, around 80% of LNCaP and PC-346C cells were viable. TRAMP-C2 appeared to be somewhat less sensitive to FK228 than LNCaP and PC-346C. Reduced cell viability was observed at FK228 concentrations of 3 ng/ml and above for all cell lines and time points (Figure 1).

Bottom Line: In the present study, we found that the highest increase in transgene expression was achieved when non-toxic concentrations of FK228 were added immediately after transduction, demonstrating that the main effect by which FK228 enhances transgene expression is transduction-independent.In some cases, the effects were dramatic, as demonstrated by an increase in CD40L expression by FK228 from 0.3% to 62% when the murine prostate cancer cell line TRAMP-C2 was transduced with Ad[CD40L].One unexpected finding was that FK228 decreased the transgene expression of an adenoviral vector with the prostate cell-specific PPT promoter in the human prostate adenocarcinoma cell lines LNCaP and PC-346C.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden. angelika.danielsson@igp.uu.se

ABSTRACT
The histone deacetylase inhibitor FK228 has previously been shown to enhance adenoviral transgene expression when cells are pre-incubated with the drug. Upregulation of the coxsackie adenovirus receptor (CAR), leading to increased viral transduction, has been proposed as the main mechanism. In the present study, we found that the highest increase in transgene expression was achieved when non-toxic concentrations of FK228 were added immediately after transduction, demonstrating that the main effect by which FK228 enhances transgene expression is transduction-independent. FK228 had positive effects both on Ad5 and Ad5/f35 vectors with a variety of transgenes and promoters, indicating that FK228 works mainly by increasing transgene expression at the transcriptional level. In some cases, the effects were dramatic, as demonstrated by an increase in CD40L expression by FK228 from 0.3% to 62% when the murine prostate cancer cell line TRAMP-C2 was transduced with Ad[CD40L]. One unexpected finding was that FK228 decreased the transgene expression of an adenoviral vector with the prostate cell-specific PPT promoter in the human prostate adenocarcinoma cell lines LNCaP and PC-346C. This is probably a consequence of alteration of the adenocarcinoma cell lines towards a neuroendocrine differentiation after FK228 treatment. The observations in this study indicate that FK228 enhances adenoviral therapy by a transduction-independent mechanism. Furthermore, since histone deacetylase inhibitors may affect the differentiation of cells, it is important to keep in mind that the activity and specificity of tissue- and tumor-specific promoters may also be affected.

Show MeSH
Related in: MedlinePlus