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Histone deacetylase 8 is deregulated in urothelial cancer but not a target for efficient treatment.

Lehmann M, Hoffmann MJ, Koch A, Ulrich SM, Schulz WA, Niegisch G - J. Exp. Clin. Cancer Res. (2014)

Bottom Line: Efficient siRNA-mediated knockdown of HDAC8 reduced proliferation up to 45%.Expression of thymidylate synthase was partly reduced; PARP-cleavage was not detected.The influence of the pharmacological inhibition on clonogenic growth and migration show a cell line- and inhibitor-dependent reduction with the strongest effects after treatment with compound 5 and compound 6.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: Previous studies have shown that class-I histone deacetylase (HDAC) 8 mRNA is upregulated in urothelial cancer tissues and urothelial cancer cell lines compared to benign controls. Using urothelial cancer cell lines we evaluated whether specific targeting of HDAC8 might be a therapeutic option in bladder cancer treatment.

Methods: We conducted siRNA-mediated knockdown and specific pharmacological inhibition of HDAC8 with the three different inhibitors compound 2, compound 5, and compound 6 in several urothelial carcinoma cell lines with distinct HDAC8 expression profiles. Levels of HDAC and marker proteins were determined by western blot analysis and mRNA levels were measured by quantitative real-time PCR. Cellular effects of HDAC8 suppression were analyzed by ATP assay, flow cytometry, colony forming assay and migration assay.

Results: Efficient siRNA-mediated knockdown of HDAC8 reduced proliferation up to 45%. The HDAC8 specific inhibitors compound 5 and compound 6 significantly reduced viability of all urothelial cancer cell lines (IC₅₀ 9 - 21 μM). Flow cytometry revealed only a slight increase in the sub-G1 fraction indicating a limited induction of apoptosis. Expression of thymidylate synthase was partly reduced; PARP-cleavage was not detected. The influence of the pharmacological inhibition on clonogenic growth and migration show a cell line- and inhibitor-dependent reduction with the strongest effects after treatment with compound 5 and compound 6.

Conclusions: Deregulation of HDAC8 is frequent in urothelial cancer, but neither specific pharmacological inhibition nor siRNA-mediated knockdown of HDAC8 impaired viability of urothelial cancer cell lines in a therapeutic useful manner. Accordingly, HDAC8 on its own is not a promising drug target in bladder cancer.

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HDAC8 expression in urothelial cancer cell lines. (A) Relative mRNA expression of HDAC8 in eight urothelial cancer cell lines (UCCs) compared to two normal uroepithelial cultures (NUC; mean value set as 1) measured by quantitative RT-PCR. The HDAC8 expression values were adjusted to TBP as a reference gene and are displayed on the y-axis. The dotted line shows the average expression level of the NUC samples. (B) Protein expression of HDAC8 in urothelial cancer cell lines (UCCs) and a normal uroepithelial control (NUC) analyzed by western blotting. As a loading control α-tubulin was stained on each blot.
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Figure 1: HDAC8 expression in urothelial cancer cell lines. (A) Relative mRNA expression of HDAC8 in eight urothelial cancer cell lines (UCCs) compared to two normal uroepithelial cultures (NUC; mean value set as 1) measured by quantitative RT-PCR. The HDAC8 expression values were adjusted to TBP as a reference gene and are displayed on the y-axis. The dotted line shows the average expression level of the NUC samples. (B) Protein expression of HDAC8 in urothelial cancer cell lines (UCCs) and a normal uroepithelial control (NUC) analyzed by western blotting. As a loading control α-tubulin was stained on each blot.

Mentions: To cover this range, we chose a panel of cell lines representing the heterogeneity of the tumor. The mRNA level of HDAC8 was more than twofold upregulated in the UCC UM-UC-3 compared to NUCs. In contrast, UCC RT-112 cells showed a decreased level of HDAC8 mRNA (Figure 1A). The HDAC8 mRNA expression in UCCs was comparable to the measured HDAC8 expression in other tumor entities such as neuroblastoma and mammary carcinoma (data not shown). The HDAC8 protein levels are shown in Figure 1B. The UCC SW-1710 indicated a strong increase of HDAC8 protein compared to NUCs. The cell lines VM-CUB1 and UM-UC-3 showed a moderate increase of HDAC8. In the cell line 639-V, a reduction of HDAC8 protein expression was observed.


Histone deacetylase 8 is deregulated in urothelial cancer but not a target for efficient treatment.

Lehmann M, Hoffmann MJ, Koch A, Ulrich SM, Schulz WA, Niegisch G - J. Exp. Clin. Cancer Res. (2014)

HDAC8 expression in urothelial cancer cell lines. (A) Relative mRNA expression of HDAC8 in eight urothelial cancer cell lines (UCCs) compared to two normal uroepithelial cultures (NUC; mean value set as 1) measured by quantitative RT-PCR. The HDAC8 expression values were adjusted to TBP as a reference gene and are displayed on the y-axis. The dotted line shows the average expression level of the NUC samples. (B) Protein expression of HDAC8 in urothelial cancer cell lines (UCCs) and a normal uroepithelial control (NUC) analyzed by western blotting. As a loading control α-tubulin was stained on each blot.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4230422&req=5

Figure 1: HDAC8 expression in urothelial cancer cell lines. (A) Relative mRNA expression of HDAC8 in eight urothelial cancer cell lines (UCCs) compared to two normal uroepithelial cultures (NUC; mean value set as 1) measured by quantitative RT-PCR. The HDAC8 expression values were adjusted to TBP as a reference gene and are displayed on the y-axis. The dotted line shows the average expression level of the NUC samples. (B) Protein expression of HDAC8 in urothelial cancer cell lines (UCCs) and a normal uroepithelial control (NUC) analyzed by western blotting. As a loading control α-tubulin was stained on each blot.
Mentions: To cover this range, we chose a panel of cell lines representing the heterogeneity of the tumor. The mRNA level of HDAC8 was more than twofold upregulated in the UCC UM-UC-3 compared to NUCs. In contrast, UCC RT-112 cells showed a decreased level of HDAC8 mRNA (Figure 1A). The HDAC8 mRNA expression in UCCs was comparable to the measured HDAC8 expression in other tumor entities such as neuroblastoma and mammary carcinoma (data not shown). The HDAC8 protein levels are shown in Figure 1B. The UCC SW-1710 indicated a strong increase of HDAC8 protein compared to NUCs. The cell lines VM-CUB1 and UM-UC-3 showed a moderate increase of HDAC8. In the cell line 639-V, a reduction of HDAC8 protein expression was observed.

Bottom Line: Efficient siRNA-mediated knockdown of HDAC8 reduced proliferation up to 45%.Expression of thymidylate synthase was partly reduced; PARP-cleavage was not detected.The influence of the pharmacological inhibition on clonogenic growth and migration show a cell line- and inhibitor-dependent reduction with the strongest effects after treatment with compound 5 and compound 6.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: Previous studies have shown that class-I histone deacetylase (HDAC) 8 mRNA is upregulated in urothelial cancer tissues and urothelial cancer cell lines compared to benign controls. Using urothelial cancer cell lines we evaluated whether specific targeting of HDAC8 might be a therapeutic option in bladder cancer treatment.

Methods: We conducted siRNA-mediated knockdown and specific pharmacological inhibition of HDAC8 with the three different inhibitors compound 2, compound 5, and compound 6 in several urothelial carcinoma cell lines with distinct HDAC8 expression profiles. Levels of HDAC and marker proteins were determined by western blot analysis and mRNA levels were measured by quantitative real-time PCR. Cellular effects of HDAC8 suppression were analyzed by ATP assay, flow cytometry, colony forming assay and migration assay.

Results: Efficient siRNA-mediated knockdown of HDAC8 reduced proliferation up to 45%. The HDAC8 specific inhibitors compound 5 and compound 6 significantly reduced viability of all urothelial cancer cell lines (IC₅₀ 9 - 21 μM). Flow cytometry revealed only a slight increase in the sub-G1 fraction indicating a limited induction of apoptosis. Expression of thymidylate synthase was partly reduced; PARP-cleavage was not detected. The influence of the pharmacological inhibition on clonogenic growth and migration show a cell line- and inhibitor-dependent reduction with the strongest effects after treatment with compound 5 and compound 6.

Conclusions: Deregulation of HDAC8 is frequent in urothelial cancer, but neither specific pharmacological inhibition nor siRNA-mediated knockdown of HDAC8 impaired viability of urothelial cancer cell lines in a therapeutic useful manner. Accordingly, HDAC8 on its own is not a promising drug target in bladder cancer.

Show MeSH
Related in: MedlinePlus