Apoptotic mechanisms in T47D and MCF-7 human breast cancer cells.
Bottom Line: MCF-7 cells did not express caspase-3, suggesting that DNA fragmentation occurred in the absence of caspase-3 and that other caspases may be involved.In addition, a time dependent and caspase-independent reduction of the mitochondrial transmembrane potential was observed; which appeared to occur after the release of cytochrome c.Apoptotic events in both cell types differ temporally, involving activation of different caspases and mitochondrial changes.
Affiliation: Institute for Cancer Studies, Division of Genomic Medicine, Medical School, University of Sheffield, Sheffield S10 2RX, UK.Show MeSH
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Mentions: DNA fragmentation is mostly mediated by caspase-3 cleavage of the inhibitory protein DFF45 resulting in release of the endonuclease DFF40 which is then free to cleave DNA (Enari et al, 1998; Wolf et al, 1999). It has been shown that MCF-7 cells lack caspase-3 protein. Caspase-3 expression was also absent in the MCF-7 cells used in this study, however we detected caspase-3 expression in T47D cells (data not shown). Therefore in contrast recent studies where lack of DNA fragmentation in response to TNFα and STS was reported (Janicke et al, 1998b), these results (Figure 3AFigure 3
Affiliation: Institute for Cancer Studies, Division of Genomic Medicine, Medical School, University of Sheffield, Sheffield S10 2RX, UK.