Synergistic Effects of Lauryl Gallate and Tamoxifen on Human Breast Cancer Cell

Background: Tamoxifen (TAM) is widely used for adjuvant therapy in breast cancer patients. Tamoxifen therapy may lead to serious side effects. Anti-apoptotic substances in combination with chemotherapy drugs can result in additive or synergistic effects. Lauryl gallate (LG), a Gallic acid derivative, has been proven to inhibit tumor growth, without affecting normal cells. This study aimed to investigate the synergistic effect of TAM and LG in breast cancer cell line (MCF-7). Methods: In this experimental study, performed in ShahreKord University of Medical Science, Iran in 2017, the MCF-7 cells were treated by final concentrations of 10 μM TAM alone, and in combination with 200 μM of LG. We also used EX-527, as SIRT-1 inhibitor to examine the role of SIRT1 in cell apoptosis. BCL-2 and SIRT1 gene expression were measured by real-time PCR method, and cell apoptosis was investigated by flow cytometry. Results: Tamoxifen alone and in combination with LG decreased BCL-2 expression 2.64±0.75 and 6.38±1.9 fold, respectively, after 48 h (P<0.05). SIRT1 expression was increased 1.67±0.22 and 2.47±0.34 - fold by TAM alone and in combination with LG, respectively (P<0.05). TAM alone and in combination with LG increased the percentage of apoptotic cells 15.79±2.81 and 60.67±6.23 percent, respectively after 48 h (P<0.001). Conclusion: The combination of LG and TAM is more effective for induction of apoptosis of breast cancer cells, compared to individual use of each. Thus, our data pave the way for new therapeutic options for suppressing breast cancer growth.