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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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Virus replication is decreased by treatment of HDAC inhibitors.LNCaP and PC-346C were transduced with Ad[i/PPT-E1A, E3] and Ad5 wt and BON cells were transduced with Ad[CgA-E1A] and Ad5 wt. The cells were then incubated in medium with 3 ng/ml FK228 or 5 mM VPA for 72 h. Viral copy numbers were determined by quantitative PCR and related to the values obtained 2 h after transduction. Replication was decreased by FK228 and VPA treatment in most cases. Significance (p<0.0001) is indicated with asterisks.
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pone-0014700-g006: Virus replication is decreased by treatment of HDAC inhibitors.LNCaP and PC-346C were transduced with Ad[i/PPT-E1A, E3] and Ad5 wt and BON cells were transduced with Ad[CgA-E1A] and Ad5 wt. The cells were then incubated in medium with 3 ng/ml FK228 or 5 mM VPA for 72 h. Viral copy numbers were determined by quantitative PCR and related to the values obtained 2 h after transduction. Replication was decreased by FK228 and VPA treatment in most cases. Significance (p<0.0001) is indicated with asterisks.

Mentions: Since reporter gene expression of PPT-based vectors was negatively affected by FK228 and VPA, we also wanted to study if replication of a PPT-controlled oncolytic adenovirus was decreased as well. LNCaP and PC-346C cells were transduced with the conditionally replicating Ad[i/PPT-E1A, E3] and Ad5 wt and BON cells were transduced with Ad[CgA-E1A] and Ad5 wt. The cells were then incubated in medium containing either FK228 or VPA for 72 h. Viral copy numbers were determined by quantitative PCR. Replication of the PPT-driven virus was decreased by FK228 in LNCaP (1.6 times) and PC-346C (1.3 times). VPA treatment reduced replication to a higher extent; 7.7 times in LNCaP and 126 times in PC-346C (Figure 6). In BON cells, a decrease (1.7 times) in replication was observed in Ad[CgA-E1A]-transduced cells treated with VPA (Figure 6). Replication of Ad5 wt was not affected in BON cells but reduced in LNCaP and PC-346C.


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)

Virus replication is decreased by treatment of HDAC inhibitors.LNCaP and PC-346C were transduced with Ad[i/PPT-E1A, E3] and Ad5 wt and BON cells were transduced with Ad[CgA-E1A] and Ad5 wt. The cells were then incubated in medium with 3 ng/ml FK228 or 5 mM VPA for 72 h. Viral copy numbers were determined by quantitative PCR and related to the values obtained 2 h after transduction. Replication was decreased by FK228 and VPA treatment in most cases. Significance (p<0.0001) is indicated with asterisks.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0014700-g006: Virus replication is decreased by treatment of HDAC inhibitors.LNCaP and PC-346C were transduced with Ad[i/PPT-E1A, E3] and Ad5 wt and BON cells were transduced with Ad[CgA-E1A] and Ad5 wt. The cells were then incubated in medium with 3 ng/ml FK228 or 5 mM VPA for 72 h. Viral copy numbers were determined by quantitative PCR and related to the values obtained 2 h after transduction. Replication was decreased by FK228 and VPA treatment in most cases. Significance (p<0.0001) is indicated with asterisks.
Mentions: Since reporter gene expression of PPT-based vectors was negatively affected by FK228 and VPA, we also wanted to study if replication of a PPT-controlled oncolytic adenovirus was decreased as well. LNCaP and PC-346C cells were transduced with the conditionally replicating Ad[i/PPT-E1A, E3] and Ad5 wt and BON cells were transduced with Ad[CgA-E1A] and Ad5 wt. The cells were then incubated in medium containing either FK228 or VPA for 72 h. Viral copy numbers were determined by quantitative PCR. Replication of the PPT-driven virus was decreased by FK228 in LNCaP (1.6 times) and PC-346C (1.3 times). VPA treatment reduced replication to a higher extent; 7.7 times in LNCaP and 126 times in PC-346C (Figure 6). In BON cells, a decrease (1.7 times) in replication was observed in Ad[CgA-E1A]-transduced cells treated with VPA (Figure 6). Replication of Ad5 wt was not affected in BON cells but reduced in LNCaP and PC-346C.

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