CASP3 and hepatocellular carcinoma: In SK-Hep1 cells, MC-LR, NOD or CYN at 10 to 250 nM concentrations did not show a significant effect on cleaved PARP or caspase 3 expression (Figure 1C, right two panels) suggesting that low concentrations of cyanotoxins do not induce cell apoptosis in HCC cells.