Figure 4.

Figure 4.

Isobolographic analysis of interaction between PAX and EX527 for parallel (a) T47D, (b) BT-549, (c) MDA-MB-468 and non-parallel (d) MCF7, (e) MDA-MB-231 concentration-response effects in BC cells in the MTT assay. The additive interactions between PAX and EX527 are displayed on isobolograms in T47D, BT-549, MDA-MB-468, MCF7 and MDA-MB-231 BC cells. The dotted diagonal line starting from the point (0,0) corresponds to the mixture of PAX and EX527 at the fixed ratio of 1:1. The points: A (on graphs A-C); A’ and A” (on graphs D-E) depicts the theoretically calculated IC_{50 add} values for the isoboles of additivity for parallel and non-parallel concentration-response effects. The points M represents the IC_{50 mix} values for the total concentrations of the experimental mixture of PAX and EX527 that exerted a 50% anti-viability effect (50% isobole) in the MTT assay. The SEM values are illustrated as horizontal and vertical error bars for every IC₅₀ value. The combinations of PAX with EX527 in all analysed BC cell lines were additive in the MTT test because the IC_{50 mix} values for these combinations are placed close to the points A, A’ or A’’. For more detailed information on the isobolographic representation of the data, please refer to²⁹.