Fig. 2

Cytotoxic potential of BT-cisplatin combination on the isogenic pair of ovarian cancer cell lines IGROV-1 (cisplatin-sensitive) and IGROV-1-CDDP (cisplatin-resistant). After determining viability (via PrestoBlue assay) of cells treated with combinations of BT and cisplatin, combination index (CI) values were calculated and represented as heat maps where a drug combination is synergistic (green color) if CI <0.9; additive (yellow color) if CI is between 0.9 and 1.0; and antagonistic (red color) if CI >1.0. a and c show CI values for IGROV-1 and IGROV-1-CDDP respectively. Percent cytotoxicity induced by BT/cisplatin combination at synergistic ratios for IGROV-1 (b) and IGROV-1-CDDP (d) are shown in bar graphs. Comparisons between cisplatin alone-treated and combination-treated for each cell line were performed by Student’s t-test. Data were expressed as mean ± SD of triplicate experiments. Asterisks (*) indicate p < 0.05