Figure 6.

IMR-90 (A–C) and CCL-210 (D–F) fibroblasts were treated with or without Fas-Ab (250 ng/ml) in the presence or absence of CHX (500 ng/ml), the Smac/DIABLO mimetic SM164 (100 nM), the Smac/DIABLO mimetic AT406 (1.0 μM), or the Smac/DIABLO mimetics alone for 16 hours. Apoptosis was assessed by Western blotting for cleaved poly-(ADP-ribose) polymerase (PARP) (A and D) and by ELISA detection of histone-associated DNA fragments (C and F). The Western blots were stripped and probed for GAPDH. Relative densitometry was determined by indexing the cleaved PARP/GAPDH ratio for each band to the Fas-Ab treatment (B and E). Densitometry and ELISA data represent at least three independent experiments. *P < 0.01 compared with untreated controls. **P < 0.05 compared with fibroblasts treated with Fas-Ab.