Figure 5. Treatment interaction effects of DMTC and gemcitabine in inhibiting EPP85 cell proliferation. (A) Cells were treated with varying concentrations of gemcitabine alone for 72 h, and the percentage of cell proliferation was measured by SRB-based in vitro cell proliferation assay. (B) Cells were treated with varying concentrations of DMTC and gemcitabine in combination at a fixed ratio of 1:10 for 72 h, and the percentage of cell proliferation was measured as in (A). Values, averages of three independent experiments; bars, SD (C) Treatment interaction effects of DMTC and gemcitabine were determined by calculating the CI values for each fraction affected using the CalcuSyn program. CI < 1, synergistic interactions; CI = 1, additive interactions; CI > 1, antagonistic interactions.