title: Modulation of tumor necrosis factor-mediated cell death by fullerenes.
abstract: OBJECTIVE
  The fullerene (C60/C70 mixture-C60/70) nanocrystalline suspension prepared by solvent exchange method using tetrahydrofyran (THF/nC60/70) and polyhydroxylated C60/70 [C60/70(OH)n] were compared for their ability to modulate cytotoxicity of the proinflammatory cytokine tumor necrosis factor (TNF).
  
  
  METHODS
  TNF-induced cytotoxicity was assessed in L929 fibrosarcoma cells by crystal violet assay. The type of cell death (apoptosis/necrosis), production of reactive oxygen species, mitochondrial depolarization and caspase activation were determined by flow cytometry using the appropriate reporter dyes.
  
  
  RESULTS
  THF/nC60/70 augmented, while C60/70(OH)n reduced the cytotoxicity of TNF. The numbers of cells undergoing apoptosis/necrosis, as well as of those displaying the activation of apoptosis-inducing enzymes of caspase family, were respectively increased or reduced by THF/nC60/70 or C60/70(OH)n. The antioxidant N-acetylcysteine and mitochondrial permeability transition inhibitor cyclosporin A each partly blocked the cytotoxic action of TNF, indicating the involvement of oxidative stress and mitochondrial dysfunction in the TNF cytotoxicity. Accordingly, THF/nC60/70 or C60/70(OH)n potentiated or suppressed, respectively, TNF-triggered oxidative stress and mitochondrial depolarization.
  
  
  CONCLUSIONS
  The ability of different fullerene preparations to modulate TNF-induced oxidative stress and subsequent cell death suggests their potential value in the TNF-based cancer therapy or prevention of TNF-dependent tissue damage.
authors.affiliation: Institute for Biological Research, Belgrade, Serbia.
authors.forename: Ljubica
authors.initials: L
authors.lastname: Harhaji
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Isakovic
authors.forename: Ljubica
authors.initials: L
authors.lastname: Vucicevic
authors.forename: Kristina
authors.initials: K
authors.lastname: Janjetovic
authors.forename: Maja
authors.initials: M
authors.lastname: Misirkic
authors.forename: Zoran
authors.initials: Z
authors.lastname: Markovic
authors.forename: Biljana
authors.initials: B
authors.lastname: Todorovic-Markovic
authors.forename: Nadezda
authors.initials: N
authors.lastname: Nikolic
authors.forename: Sanja
authors.initials: S
authors.lastname: Vranjes-Djuric
authors.forename: Zoran
authors.initials: Z
authors.lastname: Nikolic
authors.forename: Vladimir
authors.initials: V
authors.lastname: Trajkovic
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D037741:Fullerenes / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000187:drug effects; D009336:Necrosis; D017382:Reactive Oxygen Species / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D037741:Fullerenes; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; D020169:Caspases