Investigating the effect of hesperetin on estrogen receptor alpha (ERα) expression, phosphorylation and activity in MCF-7 cells

Purpose: The most common malignancy among women worldwide is breast cancer. The estrogen receptor plays a vital role in this cancer. One of the most well-known mechanisms that affects the activity of this receptor is its phosphorylation by protein kinase pathways. Hesperetin, a flavonoid abundant in citrus species such as lemons, grapefruits, and oranges, is the aglycone form of hesperidin. It has undergone thorough evaluation for its potential anti -cancer properties, particularly in the context of breast cancer. Studies have shown that hesperetin has an effect on intracellular kinase pathways. The aim of this study was to investigate the effect of hesperetin on the expression, phosphorylation and activity of estrogen receptor alpha (ER alpha) in MCF-7 breast cancer cell line. Study design and methods: MCF-7 cells were cultured in RPMI-1640 phenol red -free medium supplemented with charcoal -stripped FBS and treated with hesperetin. The MTT method was used to evaluate cell survival. The levels of the ER alpha protein and its phosphorylated form (Ser118) were determined via western blotting. A luciferase reporter vector was used to evaluate ERE activity. Results: The results of this study indicated that hesperetin reduced the survival of MCF-7 cells in a dosedependent manner. The expression and phosphorylation (at Ser118) of the ER alpha significantly increased and decreased, respectively, in the groups treated with hesperetin. Hesperetin increased the activity of the ER alpha in the absence of E2, although these differences were not statistically significant. Conversely, in the presence of E2, hesperetin caused a significant decrease in receptor activity. Conclusion: Based on the results of this study, it can be concluded that hesperetin has a significant effect on ER alpha expression, phosphorylation and activity.