Investigation of possible effects of apigenin, sorafenib and combined applications on apoptosis and cell cycle in hepatocellular cancer cells

Hepatocellular carcinoma (HCC) is the most common type of liver tumors. There is only one chemodrug for treatment called sorafenib that is an effective multikinase inhibitor. However, most of the patients gain resistance to sorafenib treatment in six months. Thus, there is a limitation for treatment of HCC. Apigenin is a natural flavonoid that has been used for many years as an antioxidant and anti-inflammatory agent. The aim of this study is to investigate the combined therapeutic effects of sorafenib and apigenin upon apoptosis and cell cycle on HepG2 cell line. Cytotoxic effects of sorafenib and apigenin on HepG2 cells were determined by XTT assay. Effects of single and combined treatment on cell migration, invasion and colony formation were analysed by wound healing, transwell matrigel invasion assay and colony formation assay, respectively. TUNEL assay was performed for analyse apoptosis rates. Expression changes of genes related with apoptosis and cell cycle were analysed by quantitative real-time PCR. Combined treatment of sorafenib and apigenin has more decreasing effects on cell viability than single treatment groups. Also, combination group caused significant increase of apoptotic cells. Migration and invasion capability of cells in combined treatment group are decreased. Lastly, quantitative real-time PCR results showed that combination of both drugs arrested cell cycle and increased apoptotic gene expressions more than single treatment groups. This is the first study that investigating the combined treatment of sorafenib and apigenin on HCC in vitro. By combined treatment, apigenin potentiates sorafenib cytotoxicity on HepG2 cells. Effects of combined treatment on migration, invasion, apoptosis and gene expressions showed that may sorafenib and apigenin have synergistic effect.