CASP9 and hepatocellular carcinoma: Cleaved caspase-3, caspase-8, and caspase-9 protein levels (Fig. 5a) were significantly increased in both cell lines after treatment with Res and Sor alone for 48 h (Fig. 5b–d), except cleaved caspase-8 in Huh7 cells treated with Res, cleaved caspase-9 in both HCC cell lines treated with Res, and in HepG2 cells treated with 2.5 μM Sor.