MCF7 and its Multidrug Resistant Variant MCF7/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 factorα (TNFα) have stimulated accumulation of ROS in various in vitro studies. MCF7 and its Adriamycin resistant variant MCF7/ADR are resistant against TNFα cytotoxicity. Role of ROS in the resistance of MCF7 and MCF7/ADR cells was investigated. Methods: ROS accumulation and viability in MCF7 and MCF7/ADR after TNFα exposure was evaluated using 2 ,7 dichlorofluorescein diacetate (DCFHDA) as a fluorescent probe and 3[4, 5dimethylthiazol2yl]2, 5 diphenyltetrazolium bromide (MTT) cytotoxicity assay respectively. Results: ROS level did not change significantly after TNFα exposure. Induction of ROS accumulation along with TNFα treatment sensitized these cells to TNFα toxicity. Conclusion: It can be concluded that lack of ROS accumulation following TNFα exposure is involved at least by part in the resistance of MCF7 and its drug resistant derivative MCF7/ADR cells to TNFα cytotoxicity.