The Combination of Chrysin and Cisplatin Induces Apoptosis in HepG2 through Down-regulation of cFLIP and Activity of Caspase

Abstract: Aim: The study aims to investigate the combined effects of chrysin and cisplatin on hepatoma(HepG2) cell lines in vivo and in vitro. Objective: Studies have suggested that chrysin can enhance the sensitivity of tumor cells to apoptosis. Drug resistance in tumor cells reduced the effectiveness of chemotherapy drugs such as cisplatin. We investigated whether the combination of chrysin and cisplatin can induce more apoptosis than chrysin alone and cisplatin alone. Methods: HepG2 cells were pretreated with chrysin for 2 h, followed by the addition of cisplatin for another 24 h. The morphologic changes were observed under inverted microscope and the cell viability was measured using the MTT test. The protein and cleavage of caspase-3,8,9, PARP, and cFLIP were determined by Western blotting. Results: The cell viability of the HepG2 cell can be reduced by the combination of chrysin pretreatment for 2 h and cisplatin addition for 24 h; Caspase-3,8,9 and PARP were cleaved after 12 h treatment with chrysin and cisplatin; Pancaspase inhibitor, Z-VAD-fmk, could reverse the apoptosis induced by chrysin and cisplatin in HepG2 cells; cFLIP was down-regulated by the combination of chrysin and cisplatin, and could be reversed by Z-VAD-fmk; the xenografted HepG2 cells formed a tumor in one week; At the end of the experiment, there were significant differences in relative tumor volume (RTV) and relative tumor proliferation rate between the combined group and the control group, the chrysin group and the cisplatin group; Western blotting showed that the levels of PARP, cFLIP, and caspase-3 proteins in isolated tumor tissues also decreased under the combined action of chrysin and cisplatin. Conclusion: The combination of chrysin and cisplatin induces apoptosis of hepatic tumor in vivo and in vitro. It downregulates cFLIP and then activates caspase-8, which triggers caspase-mediated apoptosis of HepG2 cell.