Fig. 2

Schematic summary of cell viability results. They demonstrate that pretreatment with 5-azanucleosides can reinforce the effectiveness of most tested topoisomerase inhibitors in all tested CRC cell lines. Crossed hexagons indicate lack of synergy between a DNA demethylating agent and a topoisomerase inhibitor (based on CI values calculated by the Chou-Talalay method). The number of independent experiments (n value) for each combination in each cell line was given. All the data are presented in details in Additional file 1: Table S1. Irin - irinotecan, eto - etoposide, dox - doxorubicin, mit - mitoxantrone