Abstract / Summary
Abstract Objective Triple-negative breast cancer (TNBC) is aggressive and chemoresistant, largely due to constitutive NF-κB activation. Magnolol and honokiol, bioactive lignans from Magnolia officinalis , individually inhibit NF-κB, but their combined ability to enhance epirubicin efficacy in TNBC remains unexplored. This study evaluated synergistic effects of magnolol, honokiol, and epirubicin in MDA-MB-231 cells. Materials and Methods MDA-MB-231 cells were treated with magnolol, honokiol, and epirubicin alone or combined at IC₅₀ doses. Viability was assessed by MTT and combination index (CI) analysis. Proliferation was measured via trypan blue exclusion and colony formation. Migration was evaluated by wound healing. Apoptosis was quantified using Hoechst staining, ELISA-based nucleosome detection, and caspase-3 activity. Gene expression (Bax, p53, Survivin, MMP-9) was analyzed by qRT-PCR, and NF-κB proteins (p65, p-p65, IκBα, p-IκBα) by Western blot. Results All combinations showed synergy (CI < 1). The triple combination yielded the lowest IC₅₀ (2.71 µM) and maximally suppressed migration (27.8%) and colony formation (27.5%). It upregulated Bax (2.67 fold) and p53 (2.3 fold), downregulated Survivin and MMP-9, and inhibited NF-κB by reducing phospho-p65 (34.5%) and phospho-IκBα (33.7%) while increasing total IκBα (2.36-fold). Caspase-3 activity rose 3.38-fold. Conclusion Magnolol and honokiol synergistically enhance epirubicin efficacy in TNBC via dual-level NF-κB blockade, offering a promising dose-reduction strategy to overcome chemoresistance.