Limits...
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.

Show MeSH

Related in: MedlinePlus

Western blot analysis of histone H3 and H4 acetylation in urothelial cancer cell lines after HDAC8 knockdown and HDAC8 inhibitor treatment. Amounts of acetylated and total histone H3 and H4 were analyzed by western blotting. The modifications are determined in the urothelial cancer cell lines RT-112, VM-CUB1, SW-1710, 639-V and UM-UC-3 after (A) siRNA mediated HDAC 8 knockdown (72 h) in comparison to untreated and irrelevant control and (B) pharmacological HDAC8 treatment (compound 2, compound 5, compound 6; IC50, 72 h). DMSO served as a solvent control.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4230422&req=5

Figure 10: Western blot analysis of histone H3 and H4 acetylation in urothelial cancer cell lines after HDAC8 knockdown and HDAC8 inhibitor treatment. Amounts of acetylated and total histone H3 and H4 were analyzed by western blotting. The modifications are determined in the urothelial cancer cell lines RT-112, VM-CUB1, SW-1710, 639-V and UM-UC-3 after (A) siRNA mediated HDAC 8 knockdown (72 h) in comparison to untreated and irrelevant control and (B) pharmacological HDAC8 treatment (compound 2, compound 5, compound 6; IC50, 72 h). DMSO served as a solvent control.

Mentions: Following HDAC8 knockdown or pharmacological inhibition, no effects on the acetylation status of histone H3 were observed (Figure 10). In contrast, acetylation of H4 increased after inhibitor treatment in RT-112 (Figure 10B). In addition, a slight increase of H4 acetylation was observed after c5 and c6 treatment in the cell line 639-V (Figure 10B). No effects on the acetylation status of H4 were seen following HDAC8 knockdown (Figure 10A).


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)

Western blot analysis of histone H3 and H4 acetylation in urothelial cancer cell lines after HDAC8 knockdown and HDAC8 inhibitor treatment. Amounts of acetylated and total histone H3 and H4 were analyzed by western blotting. The modifications are determined in the urothelial cancer cell lines RT-112, VM-CUB1, SW-1710, 639-V and UM-UC-3 after (A) siRNA mediated HDAC 8 knockdown (72 h) in comparison to untreated and irrelevant control and (B) pharmacological HDAC8 treatment (compound 2, compound 5, compound 6; IC50, 72 h). DMSO served as a solvent control.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 10: Western blot analysis of histone H3 and H4 acetylation in urothelial cancer cell lines after HDAC8 knockdown and HDAC8 inhibitor treatment. Amounts of acetylated and total histone H3 and H4 were analyzed by western blotting. The modifications are determined in the urothelial cancer cell lines RT-112, VM-CUB1, SW-1710, 639-V and UM-UC-3 after (A) siRNA mediated HDAC 8 knockdown (72 h) in comparison to untreated and irrelevant control and (B) pharmacological HDAC8 treatment (compound 2, compound 5, compound 6; IC50, 72 h). DMSO served as a solvent control.
Mentions: Following HDAC8 knockdown or pharmacological inhibition, no effects on the acetylation status of histone H3 were observed (Figure 10). In contrast, acetylation of H4 increased after inhibitor treatment in RT-112 (Figure 10B). In addition, a slight increase of H4 acetylation was observed after c5 and c6 treatment in the cell line 639-V (Figure 10B). No effects on the acetylation status of H4 were seen following HDAC8 knockdown (Figure 10A).

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