LF 15-0195 sensitizes Jurkat cells to FADD and caspase-8–dependent apoptosis.

(A) Wild-type, FADD^−/−, and caspase-8^−/−Jurkat T cells were treated with either vehicle (■) or 0.1 μM LF 15-0195 (▪) for 3 days, then treated with CH11 Ab (25 ng/mL) for 6 hours. Apoptosis was studied by Hoechst 33342 staining of the nuclear chromatin. Data are expressed as means ± SD of 3 independent experiments. (B-C) Jurkat T cells were treated with either vehicle or 0.1 μM LF 15-0195 for 3 days, before studying CD95 expression by flow cytometry (panel B: black line, vehicle; dotted line, LF 15-0195), and CD95, FADD, procaspase-8, and c-FLIP_L expression by Western blotting (C). (D) Jurkat T cells were treated with either vehicle or 0.1 μM LF 15-0195 for 3 days before exposure to soluble CD95L (1 μg/mL) for indicated times, then immunoprecipitated with an anti–FLAG M2 Ab (2 μg/mL) followed by Western blot analysis of indicated proteins. (E) The same experiment was performed in RAJI cells. (D-E) The asterisk indicates trimerized CD95, and arrows indicate cleavage fragments.