Studying the effect of lithium chloride on response of MCF7 cell line to ionizing radiation

Lithium chloride has been used as a drug for bipolar disease. Various studies show that lithium chloride (LiCl) decrease cancer cells proliferation in some tissues such as brain, esophagus and breast. Radiotherapy is a common method for curing cancer by decreasing cell proliferation and inducing cell death. However radiation can induce survival pathways that cause cell resistance to radiation. In a recent study on T47D breast cancer cell line, LiCl increased radiosensitivity. The purpose of this study was to determine the effect of LiCl on radiosensitivity of MCF7 adenocarcinoma breast cancer cell line. MCF7 is a typical cell line for breast cancer researches and has positive expression for estrogen receptor. To determine suitable concentration and treatment time, MTT assay was performed. Our results indicated that 24 hours treatment of MCF7 cell line with a non-lethal concentration of LiCl was suitable and led to little decrease in cell proliferation. We continued our work with control and LiCl-treated cells that were radiated with 4 Gy dose of X-ray with 6 Mv energy and 300 Mn/min dose rate. Growth curves of mentioned groups indicated increase in radiosensitivity and a significant decrease in cell proliferation of LiCl-treated cells with respect to controls. Hence, LiCl can be considered as a radiosensitizer for MCF7 breast cancer cell line.