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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.

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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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Effect of HDAC8 specific inhibitor treatment on clonogenic growth of urothelial cancer cells. Giemsa-staining of grown colonies from inhibitor treated RT-112, VM-CUB1, SW-1710, 639-V and UM-UC-3 cells is compared to DMSO solvent control (compound 2, compound 5, compound 6; IC50, 72 h).
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Figure 6: Effect of HDAC8 specific inhibitor treatment on clonogenic growth of urothelial cancer cells. Giemsa-staining of grown colonies from inhibitor treated RT-112, VM-CUB1, SW-1710, 639-V and UM-UC-3 cells is compared to DMSO solvent control (compound 2, compound 5, compound 6; IC50, 72 h).

Mentions: The influence of the inhibitors on clonogenic growth after a 72 h treatment at the determined IC50 concentrations is illustrated in Figure 6. Compound 2 inhibited clonogenicity only in VM-CUB1 cells. Treatment with compound 5 resulted in a moderate reduction of colony numbers in RT-112, UM-UC-3 and 639-V cells, whereas in VM-CUB1 cells, clonogenic growth was completely abolished. In contrast, c5 had no effect on SW-1710 cells. Compound 6 was active in all cell lines, being most efficient in VM-CUB1, UM-UC-3 and 639-V cells.


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)

Effect of HDAC8 specific inhibitor treatment on clonogenic growth of urothelial cancer cells. Giemsa-staining of grown colonies from inhibitor treated RT-112, VM-CUB1, SW-1710, 639-V and UM-UC-3 cells is compared to DMSO solvent control (compound 2, compound 5, compound 6; IC50, 72 h).
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Related In: Results  -  Collection

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

Figure 6: Effect of HDAC8 specific inhibitor treatment on clonogenic growth of urothelial cancer cells. Giemsa-staining of grown colonies from inhibitor treated RT-112, VM-CUB1, SW-1710, 639-V and UM-UC-3 cells is compared to DMSO solvent control (compound 2, compound 5, compound 6; IC50, 72 h).
Mentions: The influence of the inhibitors on clonogenic growth after a 72 h treatment at the determined IC50 concentrations is illustrated in Figure 6. Compound 2 inhibited clonogenicity only in VM-CUB1 cells. Treatment with compound 5 resulted in a moderate reduction of colony numbers in RT-112, UM-UC-3 and 639-V cells, whereas in VM-CUB1 cells, clonogenic growth was completely abolished. In contrast, c5 had no effect on SW-1710 cells. Compound 6 was active in all cell lines, being most efficient in VM-CUB1, UM-UC-3 and 639-V cells.

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