Modulation of KEAP1/NRF2-Regulated Anticancer Chemopreventive Signalling Pathways by Anacardic Acid in MCF7-ARE Human Breast Cancer Cells

Background

Breast cancer is the most diagnosed cancer worldwide, with an escalating burden over the past decades. Anacardic Acid (AA), a phenolic lipid extracted from cashew nutshell, displays diverse therapeutic properties including anti-tumor effects. However, the molecular mechanisms underlying the anticancer effects of AA have not been fully explored.

Objectives

This study examined the potential anti-cancer effects of AA on MCF7-ARE breast cancer cells in vitro by evaluating cell survival, free radical scavenging ability, cell migration, and NRF2 activation.

Materials and Methods

Western blot analysis was performed to investigate protein expression associated with various signaling pathways, such as cell cycle regulation, PI3K/AKT/mTOR, apoptosis, AP-1, NRF2, and NF-κB. Additionally, immunofluorescence techniques were utilized to examine the cellular localization of NRF-2 and p-NF-κB.

Results

AA markedly reduced cell viability and migration capacity of MCF7-ARE cells. AA dose-dependently induced apoptosis via activation of Caspase-3,-6,-7, reduced Bcl-2, Bcl-xl expressions and elevated expressions of Bax and GSK-3β. AA upregulated the antioxidant response pathway via NRF2 and elevated expression of antioxidant enzymes SOD1, GST, NQO-1 and HO-1. AA downregulated proteins associated with the NF-κB pathway including iNOS, IkB/α and IL-2. AA treatment regulated the cell cycle progression pathway via downregulated BRCA1, HDAC, p-CDK2 expression and elevated p-eNOS and HIF1α expression. Immunofluorescence studies demonstrated that AA treatment triggered the migration of NRF2 from the cytoplasmic region to the nucleus, while concurrently diminishing the signal strength of p-NF-κB.

Conclusion

Taken together, AA may be a promising chemopreventive agent against breast cancer progression.