Acetyl was linked to N-terminal of histone by histone acetylase (HAT) catalyzing, then the histone acetyl in N-terminal was hydrolyzed by histone deacetylases(HDACs)[13]. MTA1 was considered one of the nucleosome remodeling and histone deacetylase subunit that

possessed nucleosome remodeling and histone deacetylase activity[14]. MTA1 integrated with HDACs tightly and correlated to histone deacetylase, So it was considered aid actuating factor of HDACs to restrain transcription. Talukger et al[15] Target Selective Inhibitor Library in vitro studied, the molecule mechanism of MTA1 restraining ER alpha expression in breast cancer cells was that MTA1 interacted with MTA1, a cyclin-dependent kinase-activating kinase complex ring finger factor, and regulated estrogen receptor transactivation. Mazumdar et al[16] studied that, MTA1 restrained CAK-induced ER alpha transcription by histone deacetylase PLX4032 mouse in breast cancer cells, the cells deprived reaction to estrogen and possessed malignant phenotype. The protein expression of ER alpha which was inhibitory state recovered again due to silencing MTA1, the mechanism was correlated to deacetylating

of MTA1, so ER alpha resumed to transcription. Sharma et al[17] studied, release of methyl CpG binding proteins and histone deacetylase 1 from the Estrogen receptor alpha promoter could take effect on reactivation in ER alpha-negative human breast cancer cells. The results of our works were in accordance with findings in literature above mentioned. Previous studies and researches indicated that more direct evidence was obtained with estrogen receptor (ER)-positive breast cancer cell lines in which estrogens were found to stimulate the expression of specific genes and the proliferation of these cells. However, ER-positive tumor cells are poorly metastatic when compared with some ER-negative breast cancer cells. In patients,

ER-positive tumors are more differentiated and have lower metastatic potential than ER-negative tumors, suggesting a protective role of the estrogen receptor in Carnitine palmitoyltransferase II tumor progression, and human breast cancer cells are more responsive to antiestrogens[18]. The ability of tumor cells to invade surrouding tissue is one of the most important features of the malignant phenotype[19]. Degradation of the basement menbrane invasion of underlying connective tissue have long been the histologic criteria for diagnosis of carcinoma. Invading tumor cells must secrete proteolytic enzymes to degrade basement membranes. Matrix metallopproteinases(MMPs) are a family proteolytic enzymes that degrade specific basement menbrane components. One member of this family, MMP-9 was up-regulation in invasive cancers, including breast cancer.