mcf-7 and its multidrug resistant variant mcf-7/adr overcome tnf cytotoxicity through prevention of reactive oxygen species accumulation

Background: signal transduction of numerous cytokines and growth factors are mediated by reactive oxygen species (ros). tumor necrosis factor-α (tnf-α) have stimulated accumulation of ros in various in vitro studies. mcf-7 and its adriamycin resistant variant mcf-7/adr are resistant against tnf-α cytotoxicity. role of ros in the resistance of mcf-7 and mcf-7/adr cells was investigated. methods: ros accumulation and viability in mcf-7 and mcf-7/adr after tnf-α exposure was evaluated using 2',7'-dichlorofluorescein diacetate (dcfh-da) as a fluorescent probe and 3-[4, 5-dimethylthiazol-2-yl]-2, 5 diphenyltetrazolium bromide (mtt) cytotoxicity assay respectively. results: ros level did not change significantly after tnf-α exposure. induction of ros accumulation along with tnf-α treatment sensitized these cells to tnf-α toxicity. conclusion: it can be concluded that lack of ros accumulation following tnf-α exposure is involved at least by part in the resistance of mcf-7 and its drug resistant derivative mcf-7/adr cells to tnf-α cytotoxicity.