Fig. (6) Pilot screening results from the Prestwick FDA-approved drug library. (A) Pilot screen scatter for the 1,120 compound Prestwick library. Each point represents the percent inhibition value for a single compound. Each 384-well plate is represented by a different color. The threshold for defining actives is set at µ+σ. (B) Histogram of screening data showing a normal distribution. (C) Box plot representing quartiles and outliers. (D) Dose response confirmation for active compound PWK-433663 (propidium iodide) showing a 28 µM IC₅₀ value (average of three independent determinations).