Regulation of apoptosis/necrosis execution in cadmium-treated human promonocytic cells under different forms of oxidative stress.
Pulse-treatment of U-937 human promonocytic cells with cadmium chloride followed by recovery caused caspase-9/caspase-3-dependent, caspase-8-independent apoptosis. However, pre-incubation with the glutathione (GSH)-suppressing agent DL-buthionine-(S,R)-sulfoximine (cadmium/BSO), or co-treatment with H2O2 (cadmium/H2O2), switched the mode of death to caspase-independent necrosis. The switch from apoptosis to necrosis did not involve gross alterations in Apaf-1 and pro-caspase-9 expression, nor inhibition of cytochrome c release from mitochondria. However, cadmium/H2O2-induced necrosis involved ATP depletion and was prevented by 3-aminobenzamide, while cadmium/BSO-induced necrosis was ATP independent. Pre-incubation with BSO increased the intracellular cadmium accumulation, while co-treatment with H2O2 did not. Both treatments caused intracellular peroxide over-accumulation and disruption of mitochondrial transmembrane potential (delta psi m). However, while post-treatment with N-acetyl-L-cysteine or butylated hydroxyanisole reduced the cadmium/BSO-mediated necrosis and delta psi m disruption, it did not reduce the effects of cadmium/H2O2. Bcl-2 over-expression, which reduced peroxide accumulation without affecting the intracellular GSH content, attenuated necrosis generation by cadmium/H2O2 but not by cadmium/BSO. By contrast, AIF suppression, which reduced peroxide accumulation and increased the GSH content, attenuated the toxicity of both treatments. These results unravel the existence of two different oxidation-mediated necrotic pathways in cadmium-treated cells, one of them resulting from ATP-dependent apoptosis blockade, and the other involving the concurrence of multiple regulatory factors.
Sancho
P
P
Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
Fernández
C
C
Yuste
V J
VJ
Amrán
D
D
Ramos
A M
AM
de Blas
E
E
Susin
S A
SA
Aller
P
P
D000111:Acetylcysteine / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000032:analysis / Q000378:metabolism; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D001549:Benzamides / Q000494:pharmacology; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D002104:Cadmium / Q000032:analysis / Q000494:pharmacology*; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D004347:Drug Interactions; D005978:Glutathione / Q000032:analysis / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects; D009000:Monocytes / Q000187:drug effects*; D009336:Necrosis / Q000139:chemically induced / Q000473:pathology; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D014162:Transfection; D020298:U937 Cells
D000964:Antimetabolites, Antineoplastic; D001549:Benzamides; D016877:Oxidants; D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D002104:Cadmium; D019328:Buthionine Sulfoximine; C025160:3-aminobenzamide; D000255:Adenosine Triphosphate; D006861:Hydrogen Peroxide; C505407:CASP3 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases; D005978:Glutathione; D000111:Acetylcysteine