Figure 7.

Increased induction of cell death by T138067 in the presence of a low concentration of SN-38. A. Cell morphologies were photographed under an inverted phase-contrast microscope. Cells were plated in cell cultural plates and grown for 24 h. Cells were sequentially treated with SN-38 for 16 hours at 30 nM and then treated with or without T138067 (30 nM) for 48 hours. B. Experimental conditions were as in A, cell death was analyzed by trypan blue exclusion assay descried in the method section. Data were plotted in a histogram. Each bar is the means ± SD from three independent assays. C. Experimental conditions and photographing were the same as in A with the exception of using ZR-75 breast cancer cells with lower drug concentrations as indicated.