Abstract
Background: We have shown that compared with silybin, 2,3-dehydrosilybin (DHS) exhibits more potent in vitro anticancer activities alone or in combination with tumor necrosis factor (TNF)-α. Since TNF-α sensitization is related to DNA topoisomerase (topo) inhibition, DHS may be a potent topo inhibitor. Methods: Under significant apoptosis induction by DHS, we measured specific topo I activity in nuclear extracts or purified enzyme. Results: Treatment of more transformed FIB cells with 30 μM DHS for 24 h caused significant decreases in topo I activity in nuclear extracts while silybin did not have any effects. Less transformed EPI cells were more resistant against DHS-induced topo I inhibition. Inhibitory effects of topo I activity by DHS were also found in cell-free assays using purified topo I, whereas silybin again did not have any effects. Conclusion: DHS is a potent topo I inhibitor rendering its ability to sensitize TNF-α for enhanced cytotoxicity.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
