Zinc protoporphyrin IX enhances chemotherapeutic response of hepatoma cells to cisplatin

Figure 7 Inhibition of heme oxygenase-1 expression increases susceptibility to chemotherapy in vivo. Each nude mouse was treated with 5 mg/kg zinc protoporphyrin (ZnPP) IX, 10 mg/kg hemin, and/or 5 mg/kg cis-diaminedichloroplatinum (cisplatin; CDDP) for 6 wk and tumor weight was assessed after the last treatment. ZnPP IX treatment significantly reduced tumor growth in CDDP-treated mice, compared with those treated with CDDP alone. CDDP in combination with hemin in mice significantly increased tumor weight compared with CDDP treatment alone.