FIG. 2.

AS-48 is a chemically stable analog with low cytotoxicity. (A) AS-48 half-life exceeds 16 h under physiological conditions. Serial dilutions of compound in growth medium were preincubated at 37°C as indicated, followed by transfer to cells, infection with MV, and virus titration as described for Fig. 1A. Values represent averages of two experiments, each performed in duplicate. Standard deviations are shown. (B) AS-48 has low cytotoxicity, comparable to the first-hit compound OX-1. Cells were incubated in the presence of serial dilutions of compound for 24 to 30 h, followed by assessment of cytotoxicity. Values represent averages of four experiments and indicate percent cytotoxicity normalized for control cells treated with solvent (DMSO) only. Standard deviations are shown. For comparison, the first-hit compound OX-1 and a toxic candidate compound (AS-19) are included.