DEX induces sequential activation of caspase-8, -9, and -3 and cytochrome

c release from mitochondria. Murine thymocytes were pretreated for 30 minutes with the indicated caspase inhibitor and then were untreated or treated with DEX (10⁻⁷ M) for different times (1-6 hours). Cell lysates were analyzed by Western blot for caspase cleavage with anti–caspase-8 (A), anti–caspase-9 (B), or anti–caspase-3 (C) antibodies. Cell lysates from thymocytes untreated or treated with DEX (10⁻⁷ M) for different times (2-6 hours; D) or pretreated with the indicated caspase inhibitor (30 minutes) before DEX treatment (6 hours; E) were assayed for cytochromec release in Western blot using an anti–cytochromec monoclonal antibody.