Garcinol inhibits the proliferation of endometrial cancer cells by inducing cell cycle arrest

Endometrial cancer (EC) is the most common gynecological cancer, and one of the most important causes of cancer-related deaths in women worldwide. The long-term survival rate is lower in advanced-stage and recurrent EC, therefore it is important to identify new anticancer drugs. Garcinol, a polyisoprenylated benzophenone, is a promising anticancer drug for various cancer types but its effects on EC remain unclear. To investigate the anticancer effects of garcinol on EC, cell proliferation and cell cycle were assessed by real-time cell proliferation, cell counting, and colony formation assays, flow cytometric analysis, and 5-ethynyl-2′-deoxyuridine (EdU) incorporation assay, in EC Ishikawa (ISH) and HEC-1B cell lines. Western blotting was used to evaluate the expression of cell cycle-related protein cyclins, cyclin-dependent kinase and tumor suppression proteins. Garcinol inhibited ISH and HEC-1B cell proliferation in a dose-dependent manner, and induced ISH and HEC-1B cell cycle arrest at the G1 phase and G2/M phase, respectively, and decreased the S phase and DNA synthesis in these two cell lines. Following garcinol treatment the expression levels of p53 and p21 were increased, while the expression levels of CDK2, CDK4, cyclin D1 and cyclin B1 were gradually decreased in a dose-dependent manner in both ISH and HEC-1B cells. In addition, the expression levels of phosphorylated c-JUN N-terminal kinase (JNK) and p-c-JUN were significantly increased in both types of cells. Collectively, garcinol can induce EC cell cycle arrest and may be a promising candidate for EC chemotherapy.