Figure 5.

Relationship between the PI3K inhibitor (GDC-0941): mTORC1/2 inhibitor (KU0063794) concentration ratio and synergy with the MEK inhibitor PD0325901 in the HCT116, DLD1 and HT29 cell lines. Cells were treated with the PI3K inhibitor GDC-0941 alone, the mTORC1/2 inhibitor KU0063794 alone or the indicated ratios of the two inhibitors together, in combination with the MEK inhibitor PD0325901 for 72 h, and an SRB assay was subsequently performed. Median effect analysis (CalcuSyn software) was used to evaluate the interaction between the inhibitor combinations. Points represent the mean of the combination index at 1 × the GI₅₀ concentration for the HCT116 and HT29 cell lines, and 0.5 × the GI₅₀ concentration for the DLD1 cell line, of three independent experiments±standard error. Correlation (r) and significance (P) were calculated using two-tailed Spearman's Rank Correlation analysis.