FIG. 2.
TNF-induced apoptosis occurs independently of MOMP. (A) SV40-transformed MEFs originating from wild-type mice or mice deficient for the indicated genes were treated with 2 μM CHX alone or with the indicated concentrations of TNF for 12 h. Cells were stained with Hoechst 33342 and Sytox Green, and five fields with ∼100 cells were counted to determine the percentage of apoptotic cells. Values represent means ± standard deviations of three independent experiments. (B) Total cell lysates from wt-3 cells infected with a retrovirus encoding Bcl-xL or an empty virus (pBabe) were analyzed for Bcl-xL and GAPDH expression by immunoblot analysis. (C) Cytochrome c release was detected by flow cytometry analysis of cells treated with 4 μM CHX alone or with 1 ng/ml TNF for 7 h. (D) Viability of cells treated with 4 μM CHX alone or with TNF for 17 h was determined by the MTT assay and is presented as a percentage of that of CHX-treated cells. Values represent means ± standard deviations of at least three independent triplicate experiments. (E) Cells were treated with 25 μM etoposide as indicated and stained with Hoechst 33342 and Sytox Green. Five fields with ∼100 cells were counted to determine the percentage of apoptotic cells. Values represent means ± standard deviations of two independent experiments. *, P < 0.05 compared to wild-type cells (A) or wild-type pBabe cells (E).