Fig. 4.

Effect of erastin derivatives on ATPase activity of P-gp. The effect of imidazole ketone erastin, piperazine erastin and erastin or the vanadate-sensitive ATPase activity of P-gp was determined as outlined in Materials and Methods. Basal ATPase activity was compared to that in the presence 10 μM concentrations of the compounds; verapamil at 10 μM served as a positive control for stimulation of ATPase activity. Significance was determined by a one-way ANOVA with a test for multiple comparisons. Asterisks denote significant difference from the DMSO control, where p<0.05 (*), or p<0.01 (**). ns; not significant.