Research Article

Ecdysteroids Sensitize MDR and Non-MDR Cancer Cell Lines to Doxorubicin, Paclitaxel, and Vincristine but Tend to Protect Them from Cisplatin

Figure 3

Fa-CI plots of the nonformulated compound 3 and that enclosed within liposomes (LIP-1, LIP-2, and LIP-3) tested on the cell line. Concentrations correspond to compound 3/doxorubicin ratio of 20.4 M/M in each case. Fa = fraction affected. Dashed horizontal line shows CI = 1, and CI < 1, CI = 1, and CI > 1 represent synergism, additivity, and antagonism, respectively. The error bars show 95% confidence intervals by means of serial deletion analysis. In the table, CI values are presented at 50%, 75%, and 90% of inhibition (ED50, ED75, and ED90, resp.); CIavg = (CI50 + 2CI75 + 3CI90)/6; , , and represent antilog of the x-intercept, slope, and linear correlation coefficient of the median-effect plot, respectively. These parameters indicate the activity (IC50), shape of the dose-effect curve, and conformity of the data, respectively [7]; : significantly stronger synergism with doxorubicin as compared to compound 3 by means of nonoverlapping confidence intervals.