Chrysin promotes Cisplatin-induced apoptosis via oxidative DNA damage in oral squamous cell carcinoma

Chrysin is an apigenin analog with high therapeutic potential by modulation of apoptotic signaling pathways, improving conventional chemotherapy's effectiveness. In this study, we introduced novel evidence that the Chrysin effect with Cisplatin intensely induced cell death through DNA damage in SCC-25 and CAL-27 of oral squamous cell carcinoma (OSCC). The result of Chrysin and Cisplatin alone or in combination with cell prolif-eration was assessed using the MTT assay. The expression levels of 8-Hydroxy-2 '-deoxyguanosine (8-OXO-dG) were analyzed using an enzyme-linked immunosorbent assay (ELISA). DCFH-DA fluorescence dye was utilized to measure reactive oxygen species (ROS) formation. ELISA cell death and caspase 8 activity assays were used to measure the apoptosis rate in these cells. Chrysin significantly stimulates the cytotoxic activity of Cisplatin. Besides, the co-treatment of Chrysin plus Cisplatin significantly increased the expression levels gamma-H2AX in both cell lines. Besides, this combined treatment considerably improved ROS levels and significantly down-regulated the antioxidant enzyme expression. Moreover, Chrysin treatment led to the enhancement of Cisplatin-induced apoptosis in OSCC cell lines when compared to either Chrysin or Cisplatin treated cells. Chrysin and Cisplatin co-treatment improved cytotoxicity via the increased levels of ROS production, which results in oxidative DNA damage and leads to potent apoptosis induction in tumor cells. Generally, this co-treatment could propose a therapeutic approach that hopefully promotes patients' clinical outcomes of OSCC. These data confirm the chemo-sensitizer effect of Chrysin in OSCC cells.