Zinc protoporphyrin IX enhances chemotherapeutic response of hepatoma cells to cisplatin

Figure 6 Caspase-3 activity in treated and untreated liver cancer cells. Inhibition of heme oxygenase (HO)-1 activity increased caspase-3 induced by cis-diaminedichloroplatinum (cisplatin; CDDP) in all liver cancer cell lines. Caspase-3 activity was significantly increased in all cells after treatment with cisplatin (10 μg/mL) and re-elevated by addition of zinc protoporphyrin (ZnPP) IX (10 μmol/L). The caspase-3 activity induced by CDDP was markedly reduced in the presence of hemin (10 μmol/L) in all liver cancer cell lines.