Figure 1.
Effect of sorafenib and celecoxib, alone and in combination, on cell viability of human hepatocellular carcinoma (HCC) cells. A: Determination of half-maximal (50%) inhibitory concentration (IC50) of sorafenib-mediated cytotoxicity in HCC cells. Cells were cultured in the presence or absence of sorafenib or celecoxib for 48 h in RPMI-1640 containing 10% FBS. Upper panel: Treatment of HepG2 cells with increasing concentrations of sorafenib (0.001-100 μmol/l; left) and celecoxib (0.001-100 μmol/l; right). Lower panel: Treatment of Huh7 cells with sorafenib (left) and celecoxib (right). Data are expressed as the mean±SEM of five replicates. Data shown are representative of two independent experiments. B: Dose-dependence of the synergistic effect of sorafenib and celecoxib on cell proliferation in HCC cells. HepG2 and Huh7 cells were exposed to different concentrations of sorafenib or/and celecoxib for 48 h. Cell viability was assessed by WST-8 analysis. Data points represent the mean±SEM of three replicate wells within the same experiment. Data sets are: Sorafenib-alone, ●; sorafenib plus an IC10 concentration of celecoxib, ▵; sorafenib plus an IC30 concentration of celecoxib, ⋄; sorafenib plus an IC60 concentration of celecoxib, □. In HepG2 cells, the IC10, IC30 and IC60 values were 10, 15 and 24 μmol/L, respectively. In Huh7 cells, the corresponding values were 11, 18, and 32 μmol/L. C; Time-dependence of treatment effect. Cells were treated with 5 μmol/L of sorafenib alone (●), 10 μmol/l celecoxib alone (○), or a combination of these drugs (▵) for 24, 48, and 72 h, and cell viability was assessed at these time points using the WST-8 assay. Data are expressed as the mean of triplicate measurements. Upper and lower panels show the time dependence of cytotoxicity in HepG2 and Huh7 cells, respectively.