Figure 3.

Marizomib (MRZ) induces strong proteasome inhibition and a rapid caspase activation, which is not essential for cell death, but may be variably inhibited by ROS scavenging. (A–C) Chymotrypsin-like activity of cells treated for either 6 or 24 h with 100 nM MRZ, 5 mM NaC, or both. (D–H) Caspase activity over 72 h by fluorescence microscopy in an Incucyte ZOOM for MAF-737A (D), MAF-1298A (E), MAF-1337A (F), BT12 (G), and BT16 (H). Statistics presented are from 2-way ANOVA. (I and J) BT16 cells treated for 24 h with either Dimethyl sulfoxide (DMSO) (I) or 100 nM MRZ (J). Cells are labeled with a nuclear red dye, and caspase activation is shown by green fluorescence. Scale bar is 200 µm. Statistics presented are for Dunnett’s multiple comparisons test.