Modulation of Estrogen α and Progesterone Receptors in Triple Negative Breast Cancer Cell Lines: The Effects of Vorinostat and Indole-3-Carbinol In Vitro

Background/Aim: Triple negative cancer (TNBC) is a subtype of breast cancer that is highly aggressive, with poor prognosis and responds differently to treatments. This study investigated the role of vorinostat and indole-3-carbinol (I3C) on regulating critical receptors that are not normally expressed in TNBC. Materials and Methods: Using real-time PCR, immunostaining, and western blots, the re-expression of estrogen receptor alpha (ER), progesterone receptor (PR) and human epidermal growth factor receptor-2 (HER2) receptors was examined in four different TNBC cell types. Results: ER alpha was re-expressed in three subtypes using vorinostat and I3C. Re-expression of the PR by vorinostat was also detected. Neither vorinostat nor I3C resulted in re-expression of the HER2 receptor. A significant decrease in growth and sensitivity to tamoxifen was also noted. Conclusion: The results of this study show that vorinostat and I3C modulate the re-expression of critical receptors in certain subtypes of TNBC through several pathways and these effects can be influenced by the molecular profiles of TNBCs.