Evaluation of Synergistic Effects of Curcumin and Cisplatin in Inducing Apoptosis in Triple-Negative Breast Cancer Cells

Abstract

Objectives: The triple negative subtype of breast cancer (TNBC) is one of the most aggressive types of breast cancer since it does not have estrogen, progesterone, or HER2 receptors, which leads to the disease having few treatment options and a poor prognosis. This study aims to assess the synergistic effects of Curcumin, a natural polyphenol known for its anti-cancer properties, in combination with cisplatin, a chemotherapy agent, on apoptosis in TNBC cell lines. Methods: Curcumin (2.5 - 20 µM), together with cisplatin (1 - 10 µM), was used to treat TNBC cell lines (MDA-MB-231) both separately and in combination. Cell viability was determined using the MTT assay. Synergism was determined by calculating CI based on the Chou-Talalay method. Apoptosis was assessed by Annexin V/PI staining and by measuring caspase-3/7 activity. Western Blot was done to detect Cleaved PARP, and to evaluate the expression of pro-apoptotic and anti-apoptotic factors like Bax and Bcl-2. Mitochondrial membrane potential (ΔΨm) and ROS generation were also measured to determine some mechanistic pathways. Results: Compared to the control groups, the combination of Curcumin and cisplatin significantly reduced the viability of TNBC cells (p<0.01). The CI values were less than one, confirming the synergistic interaction. Combination treatment had a greater percentage of the early and late apoptotic cells as measured by flow cytometry. The activity levels of Caspase-3/7 were significantly higher. They were associated with increased expression of Bax and cleaved PARP, as well as reduced levels of Bcl-2, suggesting that an intrinsic apoptotic pathway was activated. In addition, there was greater mitochondrial ROS production and a decrease in ΔΨm, implying apoptosis was also triggered in a mitochondrial manner. Conclusion: As a conclusion, Curcumin enhances the cytotoxic and pro-apoptotic effects of cisplatin in triple-negative breast cancer cells by altering mitochondrial functions and oxidative stress pathways. Therefore, this study suggests that Curcumin could be a potential chemosensitizer to increase the effectiveness of cisplatin while decreasing the required dosage and reducing TNBC treatment-related toxic effects.