Endothelin receptor B antagonists reduce viable cell number in a dose- and time-dependent manner. (A) A-192621 significantly reduces the number of viable cells in both glioma (LN-229 and SW1088) and melanoma (A375 and WM35) cell lines at 24, 48 and 72 h of treatment. (B) BQ788 significantly reduces the number of viable cells in melanoma at 48 and 72 h of treatment. Values are expressed as the mean of three replicates ± SEM. Symbols for statistical significance as compared with vehicle-treated controls are displayed at the bottom of the figure and are applicable to all panels. Colors correspond to the cell line.