Isoliquiritigenin inhibits cell proliferation and induces apoptosis in human hepatoma cells

Isoliquiritigenin (4,2′,4′-trihydroxychalcone, ISL) is a natural pigment with a simple chalcone structure. In this study, we report the ISL-induced inhibition on the growth of human hepatoma cells (Hep G2) for the first time. The cell growth inhibition achieved by ISL treatment resulted in programmed cell death in a caspase activation-dependent manner, with an IC ₅₀ of 10.51 μg/ mL. Outcomes of ISL treatment included the up-regulation of IκBα expression in the cytoplasm, and the decrease of NF-κB level as well as its activity in the nucleus. In addition, ISL also suppressed the expression of Bcl-X_L and c-IAP1/2 protein, the down-stream target molecule of NF-κB. These results demonstrated that ISL treatment inhibited the NF-κB cell survival-signaling pathway and induced apoptotic cell death in Hep G2 cells.