Figure 8.

U18666A-mediated suppression of H₂O₂-induced LMP and DEVDase activation. (A) 1c1c7 cultures were incubated with 100, 150 or 200 µM H₂O₂ for different lengths of time prior to being harvested for subsequent analyses of DEVDase activities. (B) 1c1c7 cultures were incubated with different concentrations of U18666A (UA) for ~24 h prior to being washed and refed with medium containing 150 µM H₂O₂. Cultures were harvested at various times after peroxide addition for analyses of DEVDase activities. Data in panels A and B represent means of triplicate analyses performed with the lysate of a single culture. Treatments are noted in the figure. Results similar to those reported in panels A and B were obtained in minimally three additional independent experiments. (C) 1c1c7 cultures were treated with nothing or 1 µM U18666A for ~20 h prior to being washed and refed with medium lacking or containing 150 µM H₂O₂. Cultures were stained with AO 4 or 6 h after medium change and monitored by fluorescence microscopy. Treatments are noted in the figure. Similar results were obtained in a second experiment. White bar represents 20 microns.