Ouabain and digoxin sufficiently upregulated apoptosis markers, such as the cleavage of poly (ADP-ribose) polymerase, caspase-3, and caspase-9, from a concentration of 0.1 μM in HCC-MCTS [Fig. 5A, Supplementary Fig. 6]. This evidence concerns the gene CASP9 and hepatocellular carcinoma.