Elucidation of Chromatin Remodeling Machinery Involved in Regulation of Estrogen Receptor Alpha Expression in Human Breast Cancer Cells
Abstract
Estrogen receptor alpha (ER) is an epigenetically regulated gene. Inhibitors of DNA methyltransferases (DNMT) and histone deacetylases (HDAC) synergistically activate the methylated ER gene promoter in ER negative MDA-MB-23 1 human breast cancer cells. Using chromatin immunoprecipitation (ChIP), we examined the chromatin status and repressor complex associated with silenced ER and changes in the key regulatory factors during reactivation by inhibitors of DNMT (5-aza-2'deoxycytidine or 5-aza-dC) and HDAC (trichostatin A or TSA). The silencing of ER due to CpG hyperrnethylation correlates with binding of specific methyl-binding proteins, DNA methyltransferases and HDAC proteins. Inhibition of HDAC activity by TSA results in the increased accumulation of hyperacetylated core histones. The activation of ER gene expression by 5aza-dC also involves the release of the repressor complex involving various methyl binding proteins, DNMTs, and HDACl. HDAC and DNMT inhibitors also modulated histone methylation at H3-K9 and H3-K4 to fonn a more open chromatin structure. Together our results impart a befter understanding of molecular mechanisms of chromatin remodeling during ER reactivation by DNMT and HDAC inhibitors.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 2005
- Accession Number
- ADA442690
Entities
People
- Dipali Sharma
Organizations
- Emory University