ABSTRACT
Objective:To investigate the mechanism of histone deacetylase (HDAC) inhibitor in down-regulating the expression of HER-2 in breast cancer cells and to provide an innovative therapeutic option to overcome the disadvantages of anti-HER-2 therapy. Meth-ods:HER-2-positive breast cell lines were treated with HDAC inhibitors. The changes in the gene and protein levels of HER-2 were de-tected by qPCR and Western blot. MiRNA microarray was used to identify the HDAC inhibitors, whereas qPCR was used to verify the miRNA expression. Results:In vitro cell experiments confirmed that the HDAC inhibitors TSA and SAHA can down-regulate the expres-sion of HER-2 in breast cancer cell lines. TSA can down-regulate the expression of HER-2 gene in BT474 and decrease the concentra-tions of 100 nmol by 10.7%and 200 nmol by 38.9%(P<0.05). TSA had no effect on the primary cells. The expression of HER-2 gene of BT474 was down-regulated by 93.9%(P<0.05) in the 5μmol/L group but not in the 1μmol/L group. SAHA significantly affected the pri-mary cells at a concentration of 1μmol/L and reduced the cells at 87.1%at a concentration of 5μmol/L. Seven miRNAs were identified from the miRNA microarray. MiR-762 was used as a basis to identify the changes in miRNA. The miRNA sputum identified by miRNA microarray and qPCR may be associated with the down-regulation of HER-2 by HDAC inhibitors. Conclusion: HDAC inhibitors may down-regulate the expression of HER-2 in breast cancer cells by changing some miRNAs.