Figure 1.

Effects of panobinostat combined with X-rays or protons on clonogenic survival of human hepatocellular carcinoma (HCC) Huh7 and Hep3B cells. (A) Dose-dependent inhibition of HCC cell proliferation by panobinostat. Huh7 and Hep3B cells were incubated with a range of concentrations of panobinostat for 72 h and their proliferation was determined by using the CCK-8 assay. The data represent the mean ± S.D. (n = 6). GI₅₀, half maximum growth inhibition concentration. (B) Clonogenic survival curves show radiosensitizing activity of panobinostat to X-rays and protons in Huh7 cells. Huh7 cells were pre-treated with 5 nM panobinostat for 3 h, followed by irradiation with the indicated doses of X-rays or protons. Clonogenic assay was performed as described in Materials and Methods. Pre-incubation with panobinostat increased proton RBE. The data are expressed as the mean ± S.D. of three independent experiments performed in triplicate. (C) Pre-treatment with 10 nM panobinostat increased proton RBE in Hep3B cells. The data represent the mean ± S.D. of three independent experiments performed in triplicate.