Figure 8.

Role of iron in the combination of anti-hTfR IgG3-Av and GA in IM-9 cells. IM-9 cells were treated in the presence or absence of 25 μM FAC in the following treatments: (a) Chemosensitization treatments. For cytotoxocity induced by GA alone, cells were incubated for 24 h in medium alone followed by the incubation with 0.1 or 0.3 μM GA for additional 24 h; for the cytotoxicity mediated by anti-hTfR IgG3-Av, cells were incubated with 2.5, or 10 nM of the fusion protein alone for 48 h; for chemosensitization treatment combinations, cells were pre-incubated with 2.5 or 10 nM of anti-hTfR IgG3-Av alone for 24 h followed by the incubation with 0.1 or 0.3 μM GA for additional 24 h in the presence of anti-hTfR IgG3-Av. (b) Simultaneous combination treatments. Cells were simultaneously treated with 0.1 μM GA and 2.5 or 10 nM anti-hTfR IgG3-Av for 48 h as controls. For the combination treatments, cells were treated with 0.1 μM GA and 2.5 or 10 nM anti-hTfR IgG3-Av simultaneously for 48 h. The punctuated line represents the percentage of [³H]-Thymidine incorporation in cells treated with buffer alone. Error bars indicate the standard deviation. Statistically significant growth inhibition compared with buffer plus DMSO treated cells is marked (**P<0.001 or *P<0.05). Each value is the mean of quadruplicate samples and is representative of three independent experiments. GA, gambogic acid; DMSO, dimethylsulfoxide; FAC, ferric ammonium citrate.