Quercetin and anti-CD95(Fas/Apo1) enhance apoptosis in HPB-ALL cell line

Several malignant cell lines are resistant to CD95(Apol/Fas)-mediated apopt osis, even when the CD95 receptor is highly expressed. Sensitivity to CD95- 1nduced apoptosis can be restored using different molecules. In this study, we showed that quercetin, a naturally occuring flavonoid, in association w ith the agonistic anti-CD95 monoclonal antibody, increases DNA fragmentatio n and caspase-3 activity in HPB-ALL cells. These cells have been selected f or their known resistance to CD95-induced apoptosis, At molecular level, qu ercetin lowers the level of intracellular reactive oxygen species, reduces mitochondrial transmembrane potential, thereby leaving the expression of CD 95 receptor unchanged. (C) 1999 Federation of European Biochemical Societie s.