Effects of 17-AAG on HCT-116 cell types. (A) HCT-116 Bax^-/- cells were resistant to 17-AAG—induced apoptosis. The control HCT-116 and Bax-deficient HCT Bax^-/- cells were exposed to 0.5, 1.0, and 2.0 μM 17-AAG for 24 to 48 hours. Following these treatments, treated and untreated cells were stained with annexin V, and the percentages of positively stained cells were quantitated by flow cytometry. Values represent the mean ± standard error of the mean (SEM) of 3 experiments. (B) Treatment with 17-AAG depletes c-Raf-1 and Akt as well as induces Hsp-70, but does not cause PARP cleavage or processing of caspase-3. HCT-116 and HCT-116 Bax^-/- cells were treated with 0.5, 1.0, or 2.0 μM 17-AAG for 24 hours. Cells were harvested, and cell lysates were used to determine the levels of c-Raf-1, Akt, and Hsp-70, as well as processing of PARP and caspase-3 levels by Western blot analysis. As the loading control, β-actin was used.