title: Chloroquinoxaline sulfonamide (NSC 339004) is a topoisomerase IIalpha/beta poison.
abstract: Chloroquinoxaline sulfonamide (chlorosulfaquinoxaline, CQS, NSC 339004) is active against murine and human solid tumors. On the basis of its structural similarity to the topoisomerase IIbeta-specific drug XK469, CQS was tested and found to be both a topoisomerase-IIalpha and a topoisomerase-IIbeta poison. Topoisomerase II poisoning by CQS is essentially undetectable in assays using the common protein denaturant SDS, but easily detectable with strong chaotropic protein denaturants. The finding that detection of topoisomerase poisoning can be so dependent on the protein denaturant used in the assay has implications for drug discovery efforts and for our understanding of topoisomerase poisons.
authors.affiliation: Department of Radiology, College of Medicine, Ohio State University, Columbus 43210, USA.
authors.forename: H
authors.initials: H
authors.lastname: Gao
authors.forename: E F
authors.initials: EF
authors.lastname: Yamasaki
authors.forename: K K
authors.initials: KK
authors.lastname: Chan
authors.forename: L L
authors.initials: LL
authors.lastname: Shen
authors.forename: R M
authors.initials: RM
authors.lastname: Snapka
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002460:Cell Line; D004247:DNA / Q000378:metabolism; D004250:DNA Topoisomerases, Type II; D004268:DNA-Binding Proteins; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D019791:Guanidine / Q000494:pharmacology; D007527:Isoenzymes / Q000037:antagonists & inhibitors*; D007668:Kidney / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D011489:Protein Denaturation; D011810:Quinoxalines / Q000494:pharmacology*; D013424:Sulfanilamides / Q000494:pharmacology*; D059005:Topoisomerase II Inhibitors
chemical_list: D000951:Antigens, Neoplasm; D000970:Antineoplastic Agents; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D011810:Quinoxalines; D013424:Sulfanilamides; D059005:Topoisomerase II Inhibitors; D004247:DNA; D004250:DNA Topoisomerases, Type II; D019791:Guanidine; C048021:5-chloroquinoxaline-2-sulfanilamide