Figure 1.

Cell viability of HepG2 and HepG2^R cells incubated with sorafenib (SFB), BEZ235, or a combination of sorafenib and BEZ235, measured with MTT assay. A. HepG2 and HepG2^R cells were treated with various concentrations of drugs for 24 h and IC50 was calculated as described by Chou et al by MTT assay. The IC50 of sorafenib on HepG2 and HepG2^R cells was 6 μM and 16 μM, respectively. B. Left: In comparison with sorafenib, BEZ235 monotherapy and two drugs in combination had a greater effect in reducing the cell viability after 24 h. Also, there was a dose-dependent decrease of cell viability of HepG2 cells treated with sorafenib, BEZ235 or the combination of sorafenib and BEZ235 for 24 h. Right: In comparison with sorafenib (4 μM), BEZ235 (0.25 μM), or combination of sorafenib and BEZ235 decreased cell viability of HepG2 cells for 12 h, 24 h and 48 h. C. The viability of HepG2^R cells treated with sorafenib, BEZ235 or in combination was like that of HepG2 cells. Thus, BEZ235 increases sorafenib inhibition of both HepG2 and HepG2^R cell viability in a dose- and time-dependent fashion. Compared with control and single-drug treatment, the two drugs in combination were significantly (P<0.05). Data shown are the mean ± SD from three independent experiments.