Trichostatin A inhibits proliferation of triple negative breast cancer cells by inducing cell cycle arrest and apoptosis

Triple negative breast cancer (TNBC) is the most aggressive subtype of breast cancer with poor outcome. Because of lacking therapeutic targets, chemotherapy is the main treatment option for patients with TNBC. Overexpression of HDACs correlates with tumorigenesis, highlighting the potential of HDACs as therapeutic targets for TNBC. Here we demonstrate that trichostatin A (TSA, a HDAC inhibitor) selectively inhibits the proliferation of TNBC cell lines HCC1806 and HCC38 rather than a normal breast cell line MCF10A. The inhibition of TNBC by TSA is via its roles in inducing cell cycle arrest and apoptosis. TSA treatment leads to decreased expression of CYCLIN D1, CDK4, CDK6 and BCL-XL, but increased P21 expression. Moreover, combination of TSA with doxorubicin has synergistic effects on inhibiting proliferation of HCC1806 and HCC38 cells. Our studies identified a promising epigenetic-based therapeutic strategy that may be implemented in the therapy of fatal human breast cancer.