FIG. 2.

The combined treatment of 17-AAG and celecoxib increases cytotoxicity cooperatively in cancer cells but not in a normal cell line. (A–E) Cells were treated with 17-AAG at IC₅₀ for cancer cells (A549, MOR-P, NCI-H460, or HCT-116) and at 2.5 nM (the highest concentration among IC₅₀ of tested cancer cell lines) for the normal BEAS-2B cell line, and celecoxib at indicated concentrations for 72 h and then surviving fraction (SF) was determined by clonogenic assay. The SFs of combined treatment groups with 17-AAG and celecoxib were normalized by that of 17-AAG alone. (F) Cooperatively cytotoxic effects for 17-AAG and celecoxib combination were analyzed by comparing clonogenic death fractions by combined treatment (C) and sum of death fractions by each drug treatment (A+B). All experiments were performed at least in triplicate and error bars represent±SE. “#” and “†,” indicate statistically significant (p<0.05) cooperative effects by combined treatment of 17-AAG and celecoxib when compared to each 17-AAG and celecoxib alone, respectively. ns, nonspecific effect.