Skip to main content
. Author manuscript; available in PMC: 2008 Oct 28.
Published in final edited form as: Mol Pharmacol. 2008 May 28;74(3):724–735. doi: 10.1124/mol.108.047787

Figure 1. Effects of simultaneous gemcitabine and SN-38 exposure on clonogenic survival.

Figure 1

A,Ovcar-5 cells were treated for 24 h with gemcitabine alone, SN-38 alone, or both drugs simultaneously at a fixed molar ratio of 2:1. At the end of the incubation, cells were washed and incubated in drug-free medium until colonies formed. Data from the same experiment are plotted as a function of either SN-38 or gemcitabine concentration. Error bars, ± s.d. from triplicate aliquots. Right panel indicates CI as a function of drug effects. Circles indicate CI calculated from data in left and middle panels under the assumption that effects are mutually exclusive; and line represents second-order regression line calculated from data points. Synergy is indicated by CI < 1, whereas antagonism is indicated by CI > 1. B, BxPC-3 cells were treated for 24 h with the indicated concentrations of gemcitabine alone, SN-38 alone or gemcitabine + SN-38 simultaneously at a 6:1 ratio for 24 h and analyzed as described in panel A. Results in A and B are each representative of 3 independent experiments.