Tangeretin induces apoptosis and cell cycle arrest in thyroid cancer cells.

Thyroid cancer is a malignant tumor whose incidence is increasing worldwide. While thyroid cancer is treatable and curable, a small number of cases can become metastatic when cancer cells originating in the thyroid gland spread to other parts of the body through the bloodstream or lymphatic system. The most common treatments for thyroid cancer are resection and radioactive iodine therapy. However, these treatments have side effects, such as hypothyroidism and damage to normal non-cancerous cells. Tangeretin is a polymethoxylated flavone found in the peel of citrus plants and has biological activity, including antioxidant, anti-inflammatory, and anti-cancer effects. However, the effects of tangeretin on human thyroid cancer have not been investigated. In this study, the effects of tangeretin on cell proliferation and apoptosis of the thyroid cancer cell line SNU-790 were investigated. To prove the results of this study, A water-soluble tetrazolium salt (WST) assay, cell cycle arrest assay, annexin V/PI, DCF-DA, JC-10, and western blot were used. Treatment with tangeretin decreased SNU-790 cell viability and proliferation ability. Annexin V/PI staining showed that tangeretin increased apoptotic cell death. In the wound healing assay, the tangeretin treatment decreased the wound closure area. In addition, tangeretin treatment increased the level of reactive oxygen species (ROS) in the cytosolic of SNU-790. The JC-10 assay showed that the tangeretin treatment decreased the mitochondrial membrane potential (MMP). Western blot analysis revealed that treatment with tangeretin increased the expression of the tumor protein p53. In conclusion, these results indicated that tangeretin inhibited the progression of thyroid cancer in SNU-790 cells by inhibiting migration ability, inducing mitochondrial dysfunction, and mediating oxidative stress in SNU-790. Hence, this study provides experimental evidence that tangeretin could be a potential candidate for the management of thyroid cancer.