title: Human small cell lung cancer NYH cells resistant to the bisdioxopiperazine ICRF-187 exhibit a functional dominant Tyr165Ser mutation in the Walker A ATP binding site of topoisomerase II alpha.
abstract: Bisdioxopiperazine anti-cancer agents are catalytic inhibitors of topoisomerase II which by unknown means lock the enzyme in a closed clamp form and inhibit its ATPase activity. In order to demarcate a putative pharmacophore, we here describe a novel Tyr165Ser mutation in the enzyme's Walker A ATP binding site leading to specific bisdioxopiperazine resistance when transformed into a temperature-conditional yeast system. The Tyr165Ser mutation differed from a previously described Arg162Gln by being heterozygous and by purified Tyr165Ser enzyme being drug-resistant in a kinetoplast DNA decatenation enzymatic assay. This suggested dominant nature of Tyr165Ser was supported by co-transformation studies in yeast of plasmids carrying wild type and mutant genes. These results enable a model of the bisdioxopiperazine pharmacophore using the proposed asymmetric ATP hydrolysis of the enzyme.
authors.affiliation: Department of Pathology, Laboratory Center, Rigshospitalet 5431, DK-2100 Copenhagen, Denmark.
authors.forename: Irene
authors.initials: I
authors.lastname: Wessel
authors.forename: Lars H
authors.initials: LH
authors.lastname: Jensen
authors.forename: Axelle
authors.initials: A
authors.lastname: Renodon-Corniere
authors.forename: Tina K
authors.initials: TK
authors.lastname: Sorensen
authors.forename: John L
authors.initials: JL
authors.lastname: Nitiss
authors.forename: Peter B
authors.initials: PB
authors.lastname: Jensen
authors.forename: Maxwell
authors.initials: M
authors.lastname: Sehested
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D019943:Amino Acid Substitution; D000951:Antigens, Neoplasm; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001665:Binding Sites / Q000235:genetics; D018288:Carcinoma, Small Cell / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D002455:Cell Division / Q000187:drug effects / Q000235:genetics; D004250:DNA Topoisomerases, Type II / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins; D004305:Dose-Response Relationship, Drug; D025141:Drug Resistance, Fungal / Q000235:genetics; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D005838:Genotype; D006801:Humans; D008175:Lung Neoplasms / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D009154:Mutation; D011485:Protein Binding; D011929:Razoxane / Q000494:pharmacology*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D014170:Transformation, Genetic; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D000951:Antigens, Neoplasm; D000970:Antineoplastic Agents; D004268:DNA-Binding Proteins; D011929:Razoxane; D000255:Adenosine Triphosphate; D004250:DNA Topoisomerases, Type II