Figure 8

Cytotoxicity of RKA182 and FBEG100 is independent of chemical decomposition. HL-60 cells were exposed to 100 µmol/L RKA182 (A) or 100 µmol/L FBEG100 (B) for the indicated times. Cytotoxicity was determined by quantification of cellular ATP content (black circles). Data are expressed relative to the ATP content of cells exposed only to vehicle (methanol, 0.5%) at the corresponding timepoints. Following extraction with acetonitrile at the indicated timepoints, the amounts of RKA182 and FBEG100 recovered were quantified by LCMS (white circles), and are expressed relative to the amounts detected at 0 h. An expansion of the 0–3 h timeframe for FBEG100 is shown below the main chart. All data represent mean + SD, n = 3. One-way ANOVA, *P ≥ 0.05, ***P ≥ 0.001 versus vehicle-treated cells (ATP content) or 0 h (LCMS). (C) Cell-free media was supplemented with 100 µmol/L of RKA182 or FBEG100 and extracted with acetonitrile after 24 h. The amount of RKA182 or FBEG100 recovered was quantified by LCMS, and is expressed relative to the amount detected at 0 h. All data represent mean + SD, n = 3. One-way ANOVA, ***P ≥ 0.001 decomposition versus 0 h (LCMS).