The effect of hesperetin on estrogen receptor gene expression and its relationship with the downstream pathways of estrogen receptor alpha.

Background: Estrogen receptor (ER) is a transcription factor that affects the expression of some genes involved in the progression and development of breast cancer (BC). Hesperetin (Hst) is a flavonoid that inhibits the proliferation of BC cells. In this study, we investigated the effect of Hst on the cell viability of MCF-7 cells and the gene expression of the ERα, ERβ, IL-6, Ps2, and Cyclin D1. Methods: In this study, cell viability was determined by MTT assay. The cells were seeded in RPMI-1640 medium and then exposed to different concentrations of Hst (0, 25, 50, 100, 200, and 400 µM) for 24 h, and IC50 was calculated. Real-time PCR was used to assess the expression of ERα, ERβ, pS2, Cyclin D1, and IL-6 mRNA. MCF-7 cells were seeded in RPMI-1640 medium and then exposed to different concentrations of Hst (0, 25, 50, 100, and 200 µM) for 24 h. Real-time PCR was carried out using a Step One Real-Time PCR System (ABI, USA) and Amplicon SYBR Green reagents. Results: The MTT assay revealed increased cytotoxicity with higher concentrations of Hst, and the IC₅₀ was calculated at 200 µM. Real-time PCR analysis following treatment with Hst showed a significant increase in ERα gene expression at 25 µM of Hst and a decrease in expression at 50, 100, and 200 µM of Hst (p < 0.0001). ERβ gene expression significantly decreased across all concentrations of Hst (p < 0.0001), while IL-6 gene expression decreased significantly in all concentrations (p < 0.0001). pS2 gene expression increased significantly with all concentrations of Hst (p < 0.0001), while Cyclin D1 gene expression did not significantly decrease upon Hst exposure (p > 0.05). Conclusions: The results of our study demonstrate that Hst has the ability to induce cell death in MCF-7 cells. Furthermore, it was observed that Hst reduces the expression of the ER gene and enhances its activity, which can affect the downstream pathways of the ER. [ABSTRACT FROM AUTHOR]