Fig 1. Inhibition of the growth of cancer cell lines.

(A) Survival of HT-29 cells exposed to increasing concentrations of 4AZA2891 (dashed line) and 4AZA2996 (solid line) in a clonogenic assay. HT-29 cells were seeded and compounds were added 24 hours later. After 6 days of incubation, cells were fixed with methanol and stained with Trypan blue. Colonies were counted and numbers were normalized to the number of colonies in the non-treated wells. The results are expressed as mean ± SEM of three independent experiments. (B) 4AZA2891 and 4AZA2996 induce cytotoxicity in hematological and solid cancer cell lines while sparing normal cells. Cells were treated with different concentrations of compound, and 72 hours later viability was measured by MTS assay or in the case of PBMC by annexin V/PI flow cytometry. Datapoints are mean ± SD (n = 2–4). (C) IC50 values (nM) as calculated from the linear portions of the log dose response curves depicted in Fig 1B. Numbers represent average values of two to four experiments ± S.D. (D) 4AZA2891 (left) and 4AZA2996 (right) were assessed in the NIH panel of cancer cell lines at 5 concentrations and the GI₅₀ was determined for each cell line from the dose-response curves. The mean GI₅₀ for each compound across all cell lines was calculated and is represented as a vertical line in the graphs. This mean is assigned a value of zero and all the Gi50’s of cell lines are plotted relative to it. The bars representing cell lines that require concentrations higher than the mean for inhibition point to the left; those representing cell lines that are more sensitive to the compound point to the right. The mean GI₅₀ (log₁₀) for 4AZA2891 is -7.45 molar and for 4AZA2996–7.66 molar.