Figure 1.

Different sensitivity spectrum of the NCI drug screen collection in 6- versus 48-hour assays. A, Analysis of apoptotic cell death in NCI-60 cell lines and HUT-78 following romidepsin treatment. Annexin V–positive cells were determined by flow cytometry. Results are baseline mean ± SD from three independent experiments. Each bar represents percentage of increase in cell death compared with untreated control. B, Representative histograms quantitating Annexin staining. C, A graphical representation of z-score of sensitivity of tumor cells to romidepsin following treatment. Drug sensitivity profiles in the NCI-60 cell lines plotted as mean graphs. In these profiles, the mean IC₅₀ value for all cell lines is plotted as the center line. Then the difference in IC₅₀ value for each cell line from the mean is plotted, as Z-scores, with the bars to the left indicating resistance and the bars to the right indicating sensitivity. Left, mean graph showing results following treatment with romidepsin in the conventional NCI-60 48-hour assay. Middle, eliminating cell lines previously shown to express Pgp (SF-295, HCT-15, SW-620, CCRF-CEM, EKVX, HOP-62, NCI-ADR-RES, A498, ACHN, CAKI-1, RXF-393, UO-31) in the 48-hour assay. Right, mean graph showing results of a 6-hour drug exposure after removing the Pgp-expressing cells.