title: Induction of Apoptosis in TNF-Treated L929 Cells in the Presence of Necrostatin-1.
abstract: It has been shown that necroptosis-caspase-independent programmed necrotic cell death-can be induced by treatment with tumor necrosis factor (TNF) in the L929 murine fibrosarcoma cell line, even in the absence of a caspase inhibitor. Although it was reported that necrostatin-1-a specific inhibitor of necroptosis-inhibited TNF-induced necroptosis in L929 cells, it has not been elucidated whether the cells eventually die by apoptosis in the presence of necrostatin-1. In this paper, induction of apoptosis was demonstrated in TNF-treated L929 cells in the presence of necrostatin-1. Co-treatment with cycloheximide expedited apoptosis induction in necrostatin-1/TNF-treated L929 cells: typical apoptotic morphological changes, including membrane blebbing and nuclear fragmentation, induction of caspase-3 activity, proteolytic activation of caspases-3, -8, and -9, and cleavage of poly(ADP-ribose) polymerase (PARP) (a well-known substrate of caspase-3) were observed. Moreover, co-treatment with Z-VAD-fmk (a pan-caspase inhibitor) inhibited apoptosis by completely inhibiting caspases, resulting in a shift from apoptosis to necroptosis. In contrast, co-treatment with Z-Asp-CH2-DCB (a caspase inhibitor preferential to caspase-3) inhibited apoptosis without expediting necroptosis. These results indicate that apoptosis can be induced in TNF-treated L929 cells when the cells are protected from necroptosis, and support the notion that partial activation of caspase-8 in the presence of a caspase inhibitor preferential to caspase-3 suppresses both apoptosis and necroptosis.
authors.affiliation: Department of Internal Medicine, Osaka Dental University, Hirakata 573-1121, Japan. sawai@cc.osaka-dent.ac.jp.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Sawai
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000737:chemistry / Q000378:metabolism; D053181:Caspase 8 / Q000737:chemistry / Q000378:metabolism; D053453:Caspase 9 / Q000737:chemistry / Q000378:metabolism; D061945:Caspase Inhibitors / Q000494:pharmacology; D045744:Cell Line, Tumor; D003513:Cycloheximide / Q000633:toxicity; D007093:Imidazoles / Q000633:toxicity*; D007211:Indoles / Q000633:toxicity*; D051379:Mice; D009336:Necrosis; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D061945:Caspase Inhibitors; D007093:Imidazoles; D007211:Indoles; D014409:Tumor Necrosis Factor-alpha; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; C507699:necrostatin-1; D003513:Cycloheximide; D011065:Poly(ADP-ribose) Polymerases; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9
keywords: L929 cells; TNF; Z-Asp-CH2-DCB; Z-VAD-fmk; apoptosis; caspase-3; caspase-8; necroptosis