title: Thanatop: a novel 5-nitrofuran that is a highly active, cell-permeable inhibitor of topoisomerase II.
abstract: A series of nitrofuran-based compounds were identified as inhibitors of estrogen signaling in a cell-based, high-throughput screen of a diverse library of small molecules. These highly related compounds were subsequently found to inhibit topoisomerase II in vitro at concentrations similar to that required for the inhibition of estrogen signaling in cells. The most potent nitrofuran discovered is approximately 10-fold more active than etoposide phosphate, a topoisomerase II inhibitor in clinical use. The nitrofurans also inhibit topoisomerase I activity, with approximately 20-fold less activity. Moreover, the nitrofurans, in contrast to etoposide, induce a profound cell cycle arrest in the G(0)-G(1) phase of the cell cycle, do not induce double-stranded DNA breaks, are not substrates for multidrug resistance protein-1 export from the cell, and are amenable to synthetic development. In addition, the nitrofurans synergize with etoposide phosphate in cell killing. Clonogenic assays done on a panel of human tumors maintained ex vivo in nude mice show that the most active compound identified in the screen is selective against tumors compared with normal hematopoietic stem cells. However, this compound had only moderate activity in a mouse xenograft model. This novel class of topoisomerase II inhibitor may provide additional chemotherapeutic strategies for the development of cytotoxic agents with proven clinical utility.
authors.affiliation: European Molecular Biology Laboratory, Heidelberg, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Polycarpou-Schwarz
authors.forename: Kerstin
authors.initials: K
authors.lastname: Müller
authors.forename: Stefanie
authors.initials: S
authors.lastname: Denger
authors.forename: Andrew
authors.initials: A
authors.lastname: Riddell
authors.forename: Joe
authors.initials: J
authors.lastname: Lewis
authors.forename: Frank
authors.initials: F
authors.lastname: Gannon
authors.forename: George
authors.initials: G
authors.lastname: Reid
mesh_terms: D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D002463:Cell Membrane Permeability; D004249:DNA Damage; D004354:Drug Screening Assays, Antitumor; D004791:Enzyme Inhibitors / Q000493:pharmacokinetics / Q000494:pharmacology*; D005047:Etoposide / Q000493:pharmacokinetics / Q000494:pharmacology; D006801:Humans; D009581:Nitrofurans / Q000493:pharmacokinetics / Q000494:pharmacology*; D059005:Topoisomerase II Inhibitors
chemical_list: D004791:Enzyme Inhibitors; D009581:Nitrofurans; D059005:Topoisomerase II Inhibitors; D005047:Etoposide