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Differential expression of 12 histone deacetylase (HDAC) genes in astrocytomas and normal brain tissue: class II and IV are hypoexpressed in glioblastomas.

Lucio-Eterovic AK, Cortez MA, Valera ET, Motta FJ, Queiroz RG, Machado HR, Carlotti CG, Neder L, Scrideli CA, Tone LG - BMC Cancer (2008)

Bottom Line: We found that mRNA levels of class II and IV HDACs were downregulated in glioblastomas compared to low-grade astrocytomas and normal brain tissue (7 in 8 genes, p < 0.05).Additionally, we found that histone H3 (but not histone H4) was more acetylated in glioblastomas than normal brain tissue.Evaluation of histone acetylation levels showed that histone H3 is more acetylated in glioblastomas than normal brain tissue confirming the downregulation of HDAC mRNA in glioblastomas.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pediatrics, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Brazil. abeterov@mdanderson.org

ABSTRACT

Background: Glioblastoma is the most lethal primary malignant brain tumor. Although considerable progress has been made in the treatment of this aggressive tumor, the clinical outcome for patients remains poor. Histone deacetylases (HDACs) are recognized as promising targets for cancer treatment. In the past several years, HDAC inhibitors (HDACis) have been used as radiosensitizers in glioblastoma treatment. However, no study has demonstrated the status of global HDAC expression in gliomas and its possible correlation to the use of HDACis. The purpose of this study was to evaluate and compare mRNA and protein levels of class I, II and IV of HDACs in low grade and high grade astrocytomas and normal brain tissue and to correlate the findings with the malignancy in astrocytomas.

Methods: Forty-three microdissected patient tumor samples were evaluated. The histopathologic diagnoses were 20 low-grade gliomas (13 grade I and 7 grade II) and 23 high-grade gliomas (5 grade III and 18 glioblastomas). Eleven normal cerebral tissue samples were also analyzed (54 total samples analyzed). mRNA expression of class I, II, and IV HDACs was studied by quantitative real-time polymerase chain reaction and normalized to the housekeeping gene beta-glucuronidase. Protein levels were evaluated by western blotting.

Results: We found that mRNA levels of class II and IV HDACs were downregulated in glioblastomas compared to low-grade astrocytomas and normal brain tissue (7 in 8 genes, p < 0.05). The protein levels of class II HDAC9 were also lower in high-grade astrocytomas than in low-grade astrocytomas and normal brain tissue. Additionally, we found that histone H3 (but not histone H4) was more acetylated in glioblastomas than normal brain tissue.

Conclusion: Our study establishes a negative correlation between HDAC gene expression and the glioma grade suggesting that class II and IV HDACs might play an important role in glioma malignancy. Evaluation of histone acetylation levels showed that histone H3 is more acetylated in glioblastomas than normal brain tissue confirming the downregulation of HDAC mRNA in glioblastomas.

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Protein analysis. (A) HDAC9 and (B) acetyl H3 and acetyl H4 in glioblastoma (GBM), astrocytoma grade III (AIII), astrocytoma grades I and II (AI and II), and normal brain. Actin was used as endogenous control.
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Figure 3: Protein analysis. (A) HDAC9 and (B) acetyl H3 and acetyl H4 in glioblastoma (GBM), astrocytoma grade III (AIII), astrocytoma grades I and II (AI and II), and normal brain. Actin was used as endogenous control.

Mentions: In order to validate the data obtained from qRT-PCR, western blot analysis was performed for HDAC9b protein. This protein was chosen because we found the highest levels of mRNA expression for HDAC9b. The results obtained for HDAC9b western blot analysis confirmed the data obtained in quantitative mRNA analysis. The protein levels of HDAC9a were higher in normal brain tissue and low-grade astrocytoma than in the grade III astrocytoma and glioblastoma (Figure 3A).


Differential expression of 12 histone deacetylase (HDAC) genes in astrocytomas and normal brain tissue: class II and IV are hypoexpressed in glioblastomas.

Lucio-Eterovic AK, Cortez MA, Valera ET, Motta FJ, Queiroz RG, Machado HR, Carlotti CG, Neder L, Scrideli CA, Tone LG - BMC Cancer (2008)

Protein analysis. (A) HDAC9 and (B) acetyl H3 and acetyl H4 in glioblastoma (GBM), astrocytoma grade III (AIII), astrocytoma grades I and II (AI and II), and normal brain. Actin was used as endogenous control.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2536671&req=5

Figure 3: Protein analysis. (A) HDAC9 and (B) acetyl H3 and acetyl H4 in glioblastoma (GBM), astrocytoma grade III (AIII), astrocytoma grades I and II (AI and II), and normal brain. Actin was used as endogenous control.
Mentions: In order to validate the data obtained from qRT-PCR, western blot analysis was performed for HDAC9b protein. This protein was chosen because we found the highest levels of mRNA expression for HDAC9b. The results obtained for HDAC9b western blot analysis confirmed the data obtained in quantitative mRNA analysis. The protein levels of HDAC9a were higher in normal brain tissue and low-grade astrocytoma than in the grade III astrocytoma and glioblastoma (Figure 3A).

Bottom Line: We found that mRNA levels of class II and IV HDACs were downregulated in glioblastomas compared to low-grade astrocytomas and normal brain tissue (7 in 8 genes, p < 0.05).Additionally, we found that histone H3 (but not histone H4) was more acetylated in glioblastomas than normal brain tissue.Evaluation of histone acetylation levels showed that histone H3 is more acetylated in glioblastomas than normal brain tissue confirming the downregulation of HDAC mRNA in glioblastomas.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pediatrics, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Brazil. abeterov@mdanderson.org

ABSTRACT

Background: Glioblastoma is the most lethal primary malignant brain tumor. Although considerable progress has been made in the treatment of this aggressive tumor, the clinical outcome for patients remains poor. Histone deacetylases (HDACs) are recognized as promising targets for cancer treatment. In the past several years, HDAC inhibitors (HDACis) have been used as radiosensitizers in glioblastoma treatment. However, no study has demonstrated the status of global HDAC expression in gliomas and its possible correlation to the use of HDACis. The purpose of this study was to evaluate and compare mRNA and protein levels of class I, II and IV of HDACs in low grade and high grade astrocytomas and normal brain tissue and to correlate the findings with the malignancy in astrocytomas.

Methods: Forty-three microdissected patient tumor samples were evaluated. The histopathologic diagnoses were 20 low-grade gliomas (13 grade I and 7 grade II) and 23 high-grade gliomas (5 grade III and 18 glioblastomas). Eleven normal cerebral tissue samples were also analyzed (54 total samples analyzed). mRNA expression of class I, II, and IV HDACs was studied by quantitative real-time polymerase chain reaction and normalized to the housekeeping gene beta-glucuronidase. Protein levels were evaluated by western blotting.

Results: We found that mRNA levels of class II and IV HDACs were downregulated in glioblastomas compared to low-grade astrocytomas and normal brain tissue (7 in 8 genes, p < 0.05). The protein levels of class II HDAC9 were also lower in high-grade astrocytomas than in low-grade astrocytomas and normal brain tissue. Additionally, we found that histone H3 (but not histone H4) was more acetylated in glioblastomas than normal brain tissue.

Conclusion: Our study establishes a negative correlation between HDAC gene expression and the glioma grade suggesting that class II and IV HDACs might play an important role in glioma malignancy. Evaluation of histone acetylation levels showed that histone H3 is more acetylated in glioblastomas than normal brain tissue confirming the downregulation of HDAC mRNA in glioblastomas.

Show MeSH
Related in: MedlinePlus