• Potentiation of Chemotherapeutic Sensitivity in Breast Cancer Cells by Eugenol: A Study on MCF7 and MCF7-MX Lines
  • Razieh Heidari,1,* Vahideh Assadolhi,2 Somayeh Reiisi,3 Sedigheh Momenzadeh,4
    1. Department of Medical Biotechnology, School of Advanced Technologies, Shahrekord University of Medical Sciences, Shahrekord, Iran.
    3. Department of Genetics, Faculty of Basic Sciences, Shahrekord University, Shahrekord, Iran
    4. Bushehr University of Medical Sciences


  • Introduction: Breast cancer is one of the most common and deadly cancers worldwide, posing major challenges for effective treatment. The MCF7 cell line is a well-established model used to study breast cancer biology and evaluate anticancer drugs. However, the development of multidrug resistance (MDR), particularly in the resistant variant MCF7-MX, significantly limits the effectiveness of chemotherapy. Although the chemotherapeutic agent Mitoxantrone is widely used due to its strong cytotoxic activity, its clinical application is restricted by drug resistance and adverse side effects. To address these challenges, combining conventional chemotherapy with natural compounds like eugenol has gained increasing attention. Eugenol, a phenolic compound found in spices such as clove, cinnamon, and ginger, has demonstrated a wide range of biological activities, including antimicrobial, anti-inflammatory, antioxidant, and anticancer effects. Its anticancer properties include inhibition of cell proliferation, migration, and invasion, as well as induction of apoptosis and cell cycle arrest. This study aimed to investigate the cytotoxic effects of eugenol alone and in combination with mitoxantrone on both sensitive (MCF7) and multidrug-resistant (MCF7-MX) breast cancer cells.
  • Methods: MCF7 and MCF7-MX cells were cultured in RPMI-1640 medium supplemented with 10% fetal bovine serum (FBS) and 1% penicillin-streptomycin. Cells were maintained at 37°C in a humidified incubator with 5% CO₂. For cytotoxicity assays, cells were seeded at a density of 2,000 cells per well in 96-well plates and allowed to attach for 24 hours. Subsequently, cells were treated with a range of concentrations of Mithoxantron (0–700 nM for MCF7; 1–50 µM for MCF7-MX) or Eugenol (0–100 µg/mL) for 72 hours.Cell viability was assessed using the MTT assay. After treatment, 20 µL of MTT reagent was added to each well and incubated for 4 hours to allow formazan crystal formation. The crystals were then dissolved in DMSO, and absorbance was measured at 490 nm using a microplate reader. Data were normalized to untreated controls, and dose-response curves were generated using Excel. The IC₁₀ and IC₅₀ values, indicating the concentrations required to inhibit cell viability by 10% and 50%, respectively, were calculated from fitted trendlines with an R² > 0.9. To investigate the potential synergistic effects, cells were treated with Mithoxantron in combination with the IC₁₀ concentration of Eugenol. After 72 hours, the MTT assay was performed as described to determine the combined effect on cell viability. Changes in the IC₅₀ values of Mithoxantron in the presence of Eugenol were compared.
  • Results: Eugenol demonstrated cytotoxic effects with an IC₁₀ of 1.5 µg/mL in MCF7 cells and 7 µg/mL in MCF7-MX (Figure 1). Figure 1: Eugenol cytotoxicity. The IC10 of Eugenol for MCF7 cells and MCF7-MX cells were 1.5 µg/ml and 7 µg/ml, respectively. Mithoxantron exhibited potent cytotoxicity in MCF7 cells with an IC50 of 150 nM, whereas the multidrug-resistant MCF7-MX cells showed a significantly higher IC50 of 25 µM, indicating reduced sensitivity due to resistance mechanisms (Figure 2). Figure 2: Mithoxantron cytotoxicity. The IC50 of mitoxantrone for MCF7 cells and MCF7-MX cells were 270 nM and 25µM, respectively The finding demonstrated the enhanced sensitivity to Mithoxantron when combined with Eugenol. In the presence of IC₁₀ concentrations of Eugenol, the IC5₀ values of Mithoxantron decreased to 149 nM in MCF7 cells and to 17 µM in MCF7-MX cells. This significant reduction suggests that Eugenol potentiates the cytotoxic effects of Mithoxantron, particularly overcoming resistance in MCF7-MX cells. These results highlight a potential synergistic interaction between the natural compound and chemotherapy agent(Figure 3). . Figure 3: Mithoxantron cytotoxicity when combined with Eugenol. The IC50 of Mithoxantron for MCF7 cells and MCF7-MX cells were 149 nM and 17µM, respectively.
  • Conclusion: This study demonstrates that Eugenol has intrinsic cytotoxic effects on breast cancer cells and can significantly enhance the efficacy of Mithoxantron, especially in multidrug-resistant breast cancer cells. The observed potentiation may allow for reduced doses of chemotherapy, potentially minimizing adverse side effects and improving patient outcomes. Given the challenges of drug resistance in cancer therapy, combining natural compounds like Eugenol with conventional drugs represents a promising strategy. Further investigations are needed to explore the molecular mechanisms behind this synergy and to evaluate the clinical potential of this combination in breast cancer treatment.
  • Keywords: Breast Cancer ,Eugenol, Multidrug resistance