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Histone deacetylases (HDACs) in XPC gene silencing and bladder cancer.

Xu XS, Wang L, Abrams J, Wang G - J Hematol Oncol (2011)

Bottom Line: Bladder cancer is strongly associated with exposure to environmental carcinogens.The results of our immunohistochemistry (IHC) staining studies further revealed a strong correlation between the over-expression of HDAC4 and increased bladder cancer occurrence (p < 0.001) as well as a marginal significance of increasing incidence of HDAC4 positivity seen with an increase in severity of bladder cancer (p = 0.08).In addition, the results of our caspase 3 activation studies demonstrated that prior treatment with VPA increased the anticancer drug cisplatin-induced activation of caspase 3 in both HTB4 and HTB9 cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Environmental Health Sciences, Wayne State University, 259 Mack Avenue, Detroit, MI 48201, USA.

ABSTRACT
Bladder cancer is one of the most common malignancies and causes hundreds of thousands of deaths worldwide each year. Bladder cancer is strongly associated with exposure to environmental carcinogens. It is believed that DNA damage generated by environmental carcinogens and their metabolites causes development of bladder cancer. Nucleotide excision repair (NER) is the major DNA repair pathway for repairing bulk DNA damage generated by most environmental carcinogens, and XPC is a DNA damage recognition protein required for initiation of the NER process. Recent studies demonstrate reduced levels of XPC protein in tumors for a majority of bladder cancer patients. In this work we investigated the role of histone deacetylases (HDACs) in XPC gene silencing and bladder cancer development. The results of our HDAC inhibition study revealed that the treatment of HTB4 and HTB9 bladder cancer cells with the HDAC inhibitor valproic acid (VPA) caused an increase in transcription of the XPC gene in these cells. The results of our chromatin immunoprecipitation (ChIP) studies indicated that the VPA treatment caused increased binding of both CREB1 and Sp1 transcription factors at the promoter region of the XPC gene for both HTB4 and HTB9 cells. The results of our immunohistochemistry (IHC) staining studies further revealed a strong correlation between the over-expression of HDAC4 and increased bladder cancer occurrence (p < 0.001) as well as a marginal significance of increasing incidence of HDAC4 positivity seen with an increase in severity of bladder cancer (p = 0.08). In addition, the results of our caspase 3 activation studies demonstrated that prior treatment with VPA increased the anticancer drug cisplatin-induced activation of caspase 3 in both HTB4 and HTB9 cells. All of these results suggest that the HDACs negatively regulate transcription of the XPC gene in bladder cancer cells and contribute to the severity of bladder tumors.

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Detection of expression of HDAC4, HDAC1, and HDAC2 in various bladder cancer cells. The cell lysates prepared from the HTB2, HTB3, HTB4, HTB5, HTB9, HT1197, HT1376 bladder cancer cells and GM00637 normal human fibroblast cells (30 μg total protein) were analyzed by western blots to determine the protein levels of HDAC4, HDAC1, HDAC2, and β-actin in each cell lysate. The antibodies against HDAC4 (A-4), HDAC1 (C-19), HDAC2 (H-54) and β-actin (C-2) were purchased from Santa Cruz Biotechnology, Inc. (Santa Cruz, CA) and used in the western blots study.
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Figure 4: Detection of expression of HDAC4, HDAC1, and HDAC2 in various bladder cancer cells. The cell lysates prepared from the HTB2, HTB3, HTB4, HTB5, HTB9, HT1197, HT1376 bladder cancer cells and GM00637 normal human fibroblast cells (30 μg total protein) were analyzed by western blots to determine the protein levels of HDAC4, HDAC1, HDAC2, and β-actin in each cell lysate. The antibodies against HDAC4 (A-4), HDAC1 (C-19), HDAC2 (H-54) and β-actin (C-2) were purchased from Santa Cruz Biotechnology, Inc. (Santa Cruz, CA) and used in the western blots study.

Mentions: The results of our IHC studies revealed strong correlation between over-expression of the HDAC4 and the occurrence of bladder tumors. To validate the IHC result, we further determined expression of several HDACs, including HDAC4, HDAC1, and HDAC2, in the HTB4, HTB9, HTB2, HTB3, HTB5, HT1197 and HT1376 bladder cancer cells (Figure 4). The expression of these HDACs in the GM00637 normal human fibroblast cells was also determined in the western blotting study and used as a control. The results obtained from our western blots study indicated that the protein levels of the HDAC1 and HDAC2 were similar in all the tested cells (Figure 4 middle panels). In contrast, the expression levels of HDAC4 were greatly increased in most of the tested bladder cancer cells except the HTB4 bladder cancer cells in comparison to that of the GM00637 normal human fibroblast cells (Figure 4 top panel). This result confirmed our IHC results and suggested the important role of HDAC4 over-expression in the bladder cancer development.


Histone deacetylases (HDACs) in XPC gene silencing and bladder cancer.

Xu XS, Wang L, Abrams J, Wang G - J Hematol Oncol (2011)

Detection of expression of HDAC4, HDAC1, and HDAC2 in various bladder cancer cells. The cell lysates prepared from the HTB2, HTB3, HTB4, HTB5, HTB9, HT1197, HT1376 bladder cancer cells and GM00637 normal human fibroblast cells (30 μg total protein) were analyzed by western blots to determine the protein levels of HDAC4, HDAC1, HDAC2, and β-actin in each cell lysate. The antibodies against HDAC4 (A-4), HDAC1 (C-19), HDAC2 (H-54) and β-actin (C-2) were purchased from Santa Cruz Biotechnology, Inc. (Santa Cruz, CA) and used in the western blots study.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3108377&req=5

Figure 4: Detection of expression of HDAC4, HDAC1, and HDAC2 in various bladder cancer cells. The cell lysates prepared from the HTB2, HTB3, HTB4, HTB5, HTB9, HT1197, HT1376 bladder cancer cells and GM00637 normal human fibroblast cells (30 μg total protein) were analyzed by western blots to determine the protein levels of HDAC4, HDAC1, HDAC2, and β-actin in each cell lysate. The antibodies against HDAC4 (A-4), HDAC1 (C-19), HDAC2 (H-54) and β-actin (C-2) were purchased from Santa Cruz Biotechnology, Inc. (Santa Cruz, CA) and used in the western blots study.
Mentions: The results of our IHC studies revealed strong correlation between over-expression of the HDAC4 and the occurrence of bladder tumors. To validate the IHC result, we further determined expression of several HDACs, including HDAC4, HDAC1, and HDAC2, in the HTB4, HTB9, HTB2, HTB3, HTB5, HT1197 and HT1376 bladder cancer cells (Figure 4). The expression of these HDACs in the GM00637 normal human fibroblast cells was also determined in the western blotting study and used as a control. The results obtained from our western blots study indicated that the protein levels of the HDAC1 and HDAC2 were similar in all the tested cells (Figure 4 middle panels). In contrast, the expression levels of HDAC4 were greatly increased in most of the tested bladder cancer cells except the HTB4 bladder cancer cells in comparison to that of the GM00637 normal human fibroblast cells (Figure 4 top panel). This result confirmed our IHC results and suggested the important role of HDAC4 over-expression in the bladder cancer development.

Bottom Line: Bladder cancer is strongly associated with exposure to environmental carcinogens.The results of our immunohistochemistry (IHC) staining studies further revealed a strong correlation between the over-expression of HDAC4 and increased bladder cancer occurrence (p < 0.001) as well as a marginal significance of increasing incidence of HDAC4 positivity seen with an increase in severity of bladder cancer (p = 0.08).In addition, the results of our caspase 3 activation studies demonstrated that prior treatment with VPA increased the anticancer drug cisplatin-induced activation of caspase 3 in both HTB4 and HTB9 cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Environmental Health Sciences, Wayne State University, 259 Mack Avenue, Detroit, MI 48201, USA.

ABSTRACT
Bladder cancer is one of the most common malignancies and causes hundreds of thousands of deaths worldwide each year. Bladder cancer is strongly associated with exposure to environmental carcinogens. It is believed that DNA damage generated by environmental carcinogens and their metabolites causes development of bladder cancer. Nucleotide excision repair (NER) is the major DNA repair pathway for repairing bulk DNA damage generated by most environmental carcinogens, and XPC is a DNA damage recognition protein required for initiation of the NER process. Recent studies demonstrate reduced levels of XPC protein in tumors for a majority of bladder cancer patients. In this work we investigated the role of histone deacetylases (HDACs) in XPC gene silencing and bladder cancer development. The results of our HDAC inhibition study revealed that the treatment of HTB4 and HTB9 bladder cancer cells with the HDAC inhibitor valproic acid (VPA) caused an increase in transcription of the XPC gene in these cells. The results of our chromatin immunoprecipitation (ChIP) studies indicated that the VPA treatment caused increased binding of both CREB1 and Sp1 transcription factors at the promoter region of the XPC gene for both HTB4 and HTB9 cells. The results of our immunohistochemistry (IHC) staining studies further revealed a strong correlation between the over-expression of HDAC4 and increased bladder cancer occurrence (p < 0.001) as well as a marginal significance of increasing incidence of HDAC4 positivity seen with an increase in severity of bladder cancer (p = 0.08). In addition, the results of our caspase 3 activation studies demonstrated that prior treatment with VPA increased the anticancer drug cisplatin-induced activation of caspase 3 in both HTB4 and HTB9 cells. All of these results suggest that the HDACs negatively regulate transcription of the XPC gene in bladder cancer cells and contribute to the severity of bladder tumors.

Show MeSH
Related in: MedlinePlus