Quercetin suppresses cell viability in triple-negative breast cancer by targeting ORM2.

Triple-negative breast cancer (TNBC) is known for its aggressive nature, and Quercetin (QUE) has shown potential anti-cancer effects. In this study, we determined the IC50 of QUE for inhibiting cell viability in multiple TNBC, non-TNBC, and normal breast cell lines. We compared the expression of ORM2 in TNBC clinical samples and normal tissues. Additionally, we measured ORM2 expression in TNBC and normal breast cell lines. We determined the IC50 of QUE for inhibiting cell viability after ORM2 knockdown. An orthotopic implantation mice model was used to evaluate the treatment effect of QUE. We also conducted molecular docking and amino acid exchange validation to model the binding of QUE to ORM2. Furthermore, we performed a protein-protein interaction network analysis and GO enrichment analysis of differentially expressed genes associated with ORM2 in TNBC. QUE inhibited the viability of both TNBC and non-TNBC cell lines, but it was specifically associated with worse survival in TNBC patients. We observed higher expression of ORM2 in breast cancer cells compared to normal breast cells. Knockdown of ORM2 reduced the viability of TNBC cells. Treatment with QUE inhibited ORM2 expression and decreased viability in TNBC cells. In the animal model, QUE improved survival and downregulated ORM2 expression in tumors. Enrichment analysis provided insights into the potential functions of ORM2. Conclusion: Our findings indicate that QUE directly inhibits TNBC cell viability through its interaction with ORM2. These results contribute to our understanding of the anti-cancer mechanisms of QUE in TNBC and highlight ORM2 as a potential therapeutic target.